Chapter 1:

Prosperity Without Pollution

"I believe that water will one day be employed as a fuel, that hydrogen and oxygen will constitute it, used singly or together, will furnish an inexhaustible source of heat and light..." Jules Verne, Mysterious Island

"In this inconceivably enormous universe, we can never run out of energy or matter. But we can all too easily run out of brains." Sir Arthur C. Clarke, Profiles of the Future, Harper & Row, 1963

The Ultimate Fuel

This book is not about alternative energy. There are no alternatives.

Hydrogen makes up 90% of the atoms in the universe. On Earth it is found mostly in water. Hydrogen is the only fuel that doesn't pollute and is endlessly renewable. Burning hydrogen produces only water vapor.

The environmental effects of pollution and global warming make it clear that we must replace carbon-based fuels with fuel from water. Long after fossil fuels run out, hydrogen will remain. Taken from the world's rivers and oceans, it will keep our wheels turning when imported oil and coal-fired boilers are ancient history.

Using hydrogen doesn't mean abandoning modern life, but the transition from fossil fuels to renewable energy will require public subsidies and forbearance.

Advantages

•    Hydrogen has the highest energy per unit weight — three times gasoline.

•     It dissipates rapidly in air. This reduces explosion hazards.

•     It can be transported safely in pipelines,

•    And is nontoxic.

Disadvantages

•    Hydrogen has the lowest energy per unit of volume - one-third of gasoline.

•    It has a wide range of flammability. It will burn in lower concentrations,

•    And it's harder to store than liquid fuels and other gaseous fuels.

The Hydrogen Economy

Internal combustion engines can be converted to hydrogen in much the same way as with natural gas. With gaseous fuel, the container weighs more, compared to the contents, than a gasoline tank storing the same amount of energy.

The electric motor is a hundred year old technology that today is two to three times more efficient than the internal combustion engine. But it has the same problem as storing gaseous fuel. The batteries are heavy compared to the energy stored. New technology is solving this problem.

•    Hybrids combine electric motors and gasoline engines to increase efficiency.

•    Fuel cells convert hydrogen to electricity.

The power to weight ratio for a vehicle powered by a hybrid or fuel cell is lower than for an internal combustion engine but is superior to electric batteries. Fuel cells are costly and require a long warm up period. Improvements continue.

In 1980 J. 0' M. Bockris in Energy Options described the Hydrogen Economy. Renewable and nuclear energy would produce electricity and hydrogen. In addition to electricity, nuclear energy provides heat for chemical reactions that produce hydrogen. Hydrogen can be used for cars, heat, producing synthetic fuel and waste treatment. 125 Efforts towards a hydrogen economy include:

Japan's WE-NET program, to convert the country to a Hydrogen Economy.

Honda and Toyota are building fuel cell vehicles.

8 internet sites involved in promotion.

8 power production companies cooperating in research.

7 periodicals devoted to the subject.

Shell Hydrogen, a subsidiary of the oil company, actively doing research. 943

Replacing Fossil Fuels

Non Alternative Fuels

So far, the various "alternative fuels" haven't eliminated fossil fuels. In Europe, with decades of research on alternative energy and high gasoline taxes - slowly - some fossil fuel alternatives to gasoline, like natural gas, are catching on.

The U.S. imports 16% of its natural gas. Wider use would reduce both air pollution and oil imports. Some utilities sell natural gas for the equivalent of 70 cents per gallon of gasoline. Engine conversion is simple but expensive — up to $3,000 per car. Few of the 210,000 gas stations in the U.S. offer natural gas. At a cost of about $200,000 to convert a refueling station, such an investment is unlikely.

Theodore Eck, economist at Amoco, says oil companies would sell natural gas if auto companies built cars to use it. Mass production could reduce the conversion cost to about $300. The public won't buy them because the fuel isn't available.

Roy McAlister, of the American Hydrogen Association, claims that if consumers would be willing to pay a higher price, volume production would bring the price down.

The Ultimate Goal - Cheap Electrolysis

Water molecules are composed of two atoms of hydrogen and one of oxygen. When separated, water molecules become two gasses — hydrogen and oxygen.

                                H2O—>H2+O

When burned, hydrogen and oxygen combine to form water.

                                H2+O —> H2O

Most fuels produce carbon dioxide. Hydrogen produces only high temperature steam. It cleans the air by converting pollutants already in the air to carbon dioxide and water vapor. There are two main ways to separate hydrogen from water.

• Electrolysis. Electric current is passed through water to separate the gasses. The main problem is the cost of electricity.
• Steam reforming of natural gas is cheaper than electrolysis but natural gas will run out by 2025. Hot steam causes the carbon in methane (CH4) to combine with the oxygen in water to produce carbon dioxide and hydrogen.

                                2H2O + CH4 —> CO2 + 4H2

Natural gas is among the cheapest of fossil fuels. Replacing it, and all others depends on low cost electricity. Therefore, the main energy policy goal must be to make electrolyzed hydrogen cheaper than natural gas. Natural gas costs about $0.02 per kilowatt hour (kWh). Electrolysis is about 50% efficient. So, the goal should be:

                                Price of electricity = $0.01 per kWh

The cost of generating electricity from utility power in the US is between $0.05 and $0.10 per kWh (in 2003 dollars). The cost of solar and wind technology barely keeps pace with utility power. Solarex, the largest photovoltaic supplier in the U.S., predicts that by 2020 its photocells will operate at $0.10 per kWh (in 2003 dollars).

                John O'M. Bockris of Texas A&M University estimates the environmental cost of gasoline is $1.60 per gallon. (This does not include the billions spent combating terrorists subsidized by imported oil.) Assume the current price of gasoline (in 2002 dollars) is $1.35 per gallon. The total cost $1.35 + $1.60 = $2.95.

                The energy to run a machine is always less than the output. In other words the efficiency is always less than 100%. The efficiency of small scale electrolyzers is about 50%. Therefore, the energy output is half the energy input. It also includes $0.67 for mortgage, maintenance and insurance on the photovoltaic cells that provide electricity from sunlight. 136 The energy of gasoline is 33.652 kWh per gallon. The cost of hydrogen with the same energy as a gallon of gasoline is:

                                Cost of hydrogen = (33.652 kWh / kg X 0.10) + 0.67 = 7.40

                                                                                                                                0.50

Where:

• 33.652 kWh = energy in gallon of gasoline in kWh
• 0.50 = efficiency of electrolyzer
• 0.10 = cost of utility electricity per kWh

In other words the price of hydrogen for the equivalent energy of gasoline is

• $7.40 for electricity at $0.10 per kWh.
• $4.03 for electricity at $0.05 per kWh.
• $1.34 for electricity at $0.01 per kWh. 133

                Cheap electricity is critical to the future of hydrogen. Solar and wind power should be used wherever practical but no source of power yet devised can produce, on a large scale, the $0.01 per kWh electricity needed for a hydrogen economy.

                During World War 2 the US government embarked upon the Manhattan Project to build a nuclear bomb. Chapter 9 describes how a New Manhattan Project, with the participation of all nations, would insure a hydrogen future.

Objectives of This Book

• How hydrogen can be used in place of fossil fuels.
• How to generate hydrogen by electrolysis
• How to convert internal combustion engines to hydrogen.
• How hydrogen is fueling future automotive technology
• How nuclear fusion may make hydrogen cheaper than natural gas.

                Throughout history there has been a trend away from fuels with high carbon content to those rich in hydrogen. The graph shows a trend from wood (with a hydrogen to carbon ratio of 1 to 10%) and heavy oil with 20 atoms per molecule, to methane (with a ratio of 1:4). The higher the hydrogen, the lower the boiling point.

Chapter 2:

Electrolysis

                "We are disinclined as a nation to assign any moral value at all to our habits of consumption." Barbara Kingsolver, Small Wonder

Water Splitting

Breaking Bonds

                Electrolysis is a process for producing hydrogen from water. Each water molecule has two hydrogen atoms and one oxygen atom. When an electric current passes through water, the two gases separate. The oxygen migrates to the positive electrode (the anode). The negative electrode (the cathode) attracts hydrogen. The process yields twice as much hydrogen as oxygen.

                                2H2O —> 2H2+O2.

                The electrical resistance of pure water is 100 ohm/cm (254 ohm/in). It can be reduced in one of several ways.

• Heat at 700 to 1000C (1,290 to 1 800F).
• A salt such as sodium chloride
• An acid such as sulfuric acid, or
• A base such as potassium hydroxide.

Salts corrode electrode metals. Platinum resists phosphoric add. Potassium hydroxide (KOH) with nickel-iron (stainless steel) are compatible. The reaction for an alkaline electrolyte (like KOH) at the cathode is:

                                4 electrons + 4H2O —> 4O2- + 8H+.

                                4O2- + 8H+ —> 4OH- + 4H+.

                                4 electrons +4H+ —> 2H2.

Four water molecules become eight positively charged hydrogen ions (8H+) and four negative oxygen ions (4O2-). Each oxygen ion attaches to one hydrogen ion to form four hydroxyl ions (4OH-). Four hydrogen ions remain to combine with four electrons at the cathode forming four compete hydrogen atoms. The four negative hydroxyl ions are attracted to the positive electrode. The electrolyte allows the ions to be drawn to the anode by increasing the conductivity of the water.

                The reaction for an alkaline electrolyte (like KOH) at the anode is:

                                4OH- —> O2 + 2H2O + 4 electrons

Four hydroxyl ions give up four electrons to form a molecule of oxygen gas (02) and two molecules of water. The four electrons enter the anode and complete the electrical circuit outside the electrolyzer. See Exhibit 2.

                The anode reaction is an oxidation reaction - free electrons are produced. The reaction at the cathode is a reduction reaction- - free electrons are absorbed.   The cathode reaction for an add electrolyte (such as sulfuric add/H2SO4) is:

                                4 electrons + 4H+ —> 2H2

                The anode reaction for an acid is:

                                2H2O —> O2 + 4H+ + 4 electrons

                Alkaline electrolytes are less corrosive than acids. Alkaline electrolyte material "... has the most significant near-term commercial potential for recovery of hydrogen from water on a large industrial scale.." 220pl9l

                The two most common alkaline electrolytes used are sodium hydroxide (NaOH) and potassium hydroxide (KOH). NaOH is less conductive than KOH, but is cheaper. Since KOH combines with CO2 to produce potassium carbonate, periodic replacement is needed in cells open to the atmosphere. However, airtight cells cut down on this loss.

                Distilled water eliminates the formation of chlorides and sulfates from tap water impurities. These chemicals slowly corrode the electrode material. The most common materials are: iron cathodes and stainless steel anodes.

                Salt can be electrolyzed into sodium and chlorine. In the molten state and in a suitably designed electrolyzer solid sodium forms at the cathode and chlorine gas at the anode. A zinc chloride solution under electrolysis yields solid zinc at the cathode and chlorine gas at the anode.

Separators

Electrolyzers consists of five elements:

• Container
• Electrolyte. Water and a chemical added to conduct electrical current.
• The chemical may be a salt, acid, or base.
• Positive electrode (anode)
• Negative electrode (cathode)
• Separator.

                The separator allows the current and ions to pass through but keeps the hydrogen and oxygen from mixing to form an explosive mixture.

• In air, between 4 and 75% hydrogen.
• In pure oxygen, between 4 and 94% hydrogen.

Hydrogen outside these ranges may burn, but not explode.

                Asbestos fiber works well as a separator material because the capillary pressure is greater then the cell pressure. Artificial fiber cloth, rubber cloth, or metallic mesh can also be used. 630 The electrode gap should be minimized.

Measures of Efficiency

                Thermal efficiency compares the energy of combustion of hydrogen and oxygen with the energy needed to separate them. Water electrolysis is typically 30 to 35% thermally efficient. 610

                                Thermal efficiency = Energy in / Energy out.

                The voltage efficiency compares the theoretical voltage needed with the actual voltage needed in the cell.

                Voltage efficiency = 1.24 V / cell voltage = Minimum V needed / Actual V.

This means that the voltage efficiency of a cell varies inversely with the cell voltage needed. For commercial electrolyzers at 1.9V cell efficiency is 65%.

For some advanced cells with expensive platinum electrodes at 1.7V have a voltage efficiency of 73%.

                                Cell voltage = E + iR.

• E= minimum theoretical voltage = 1.24 electron volts.
• iR = electrolyte resistance to current flow (in ohms).

Minimize separator thickness and electrode spacing.

• i =   current passing through the cell.
• R =  area resistance (in ohms). This depends on the conductivity of the electrolyte and the permeability of the membrane to ions.

Energy Requirements

                At 25C (77F) the voltage needed is 1.24V. It is less at higher temperature by 0.82 millivolts (0.82 mV) per degree C. At ten times the pressure, voltage increases by 44.4 mV per degree C.

                Conventional electrolyzers operate at 75 to 80C with current densities of around 2,000 amps per square meter (185.8 amp per sq.ft.). Voltage requirements for electrolyzers are between 1.9 to 2 volts. The required energy input is 4.8 kWh per cubic meter (0.14 kWh per cu.ft.) of hydrogen produced. This includes the total energy for pumps and other equipment.

                Regardless of energy input, the reaction always requires about 2 volts. Exhibit 3 shows no upper limit for current input, but voltage requirements taper off at 2 volts. Increasing current flow increases electrolyzer efficiency. The larger the current flow the lower the voltage becomes in relation to it. However, the current density on the electrodes also increases with increasing current. This increases the resistance in the electrodes. Electrode thickness must, therefore, be minimized at 0.00001 cm (0.000004 in) or less. The smallest amount of energy needed to electrolyze one mole of water is 65.3 Wh at 25 C (77F). When the hydrogen and oxygen are recombined into water during combustion 79.3 Wh of energy is released. 14 Wh more energy is released in burning hydrogen and oxygen than is required to split water. Extra heat is absorbed from the environment during electrolysis. 340p39

Voltage vs. Temperature

                If no heat flowed into the reaction, only 1.481 volts would be needed for electrolysis. As temperature is increased, 1.481 volts at 25C (77F) would just begin to produce waste heat. Over 1.481 volts, more heat is generated. This critical limit of 1.481V is referred to as the thermoneutral voltage. Exhibit 4 shows the relationship between electrolyte temperature and the required voltage. 630 At 25C for voltages of 1.23 to 1.47V, the electrolysis reaction absorbs heat. At over 1.481V at 25C the reaction gives off heat. The horizontal scale shows the desired operating temperature of the cell. In general, for voltages between the thermoneutral (upper limit) voltage and the reversible (lower limit) voltage the electrolysis reaction absorbs heat. The electrolysis cell operates most efficiently in this range. No electrolysis occurs below the reversible voltage.

                With increased temperature both the electrochemical and the electrolyte resistance diminish. This reduces the limit below which hydrogen is not produced. Lower voltages and higher temperatures improve efficiency.

Cost of Electrolysis

                A homemade electrolyzer is about 50% efficient. Watt-hours of electricity are converted into half the energy equivalent of hydrogen. If electricity costs $0.05/kWh then the hydrogen would cost $0.10/kWh. At atmospheric pressure the energy content of hydrogen is 3wh per liter (290 BTU per cu.ft.).

Electrolyzer Design

Components

• Water. Reduce corrosion on steel electrodes by using distilled water.
• Electrolyte. Use baking soda as the electrolyte — six teaspoons per gallon. It requires 4 volts but is a safer to handle than potassium hydroxide. Commercial electrolyzers use 20 to 30% potassium hydroxide in distilled or distilled water.
• Electrode material. Nickel or nickel-containing stainless steel screen. Use the finest mesh possible to provide a large surface area. It should be readily obtainable at building supply stores. An alternative is sintered porous sheet.
• Separator material. Fiberglass shade screen insulator keeps the gasses separate but allows ions to flow between the electrodes.
• Electric source. 4 volts per cell (allowing for 50% voltage efficiency), 3 to 10 amps. Increased current increases gas output.

WARNING: Keep hydrogen and oxygen separate to avoid an explosion.

                Virtually any nonmetallic container may be used so long as the gas is does not to build up and generate a high pressure.   Exhibit 5 shows an engineer at the American Hydrogen Association running an electrolyzer built into a glass jar. The hydrogen-generating electrode is seen in the top photo. Oxygen is generated in the central electrode, not shown. The current source is an auto battery. This is the safest current source to use for home experimenters. As the hydrogen collects in the short Plexiglas container it displaces water into the larger container to the left. The water acts like a sink trap to prevent the hydrogen from backing up into the electrolyzer.

WARNING: Leaking hydrogen is flammable. Vent the oxygen at least 18 meters (60 ft) from the hydrogen. Keep all flames and sparks away from the electrolyzer when it is in operation. Insulate all electrical connections.

                Exhibit 6 is a schematic for a hydrogen-generating system. The gauges monitor the amount and pressure of hydrogen generated. The overflow tank and relief valves prevent excessive pressure build-up. A float-activated safety switch that turns the electrolyzer off could accomplish the same thing.

                Several cells can be connected in series for increased hydrogen production as shown.

WARNING: Never reverse the terminals. This would cause hydrogen to be generated at the oxygen electrode, and oxygen to be generated at the hydrogen electrode. The gases would mix, causing an explosion hazard.

Adding the Electrolyte

                Using an ohm meter to measure the electrical resistance of the electrolyte, add potassium hydroxide until the resistance equals 0.3 ohms, or a 30% solution, whichever comes first. Note that the higher the current of the cell, the less electrolyte needs to be used.

WARNING: When the electrolyzer is first used, hydrogen and oxygen may be mixed. Discard the first hour's production.

Output

                At 100% efficiency, 12 volts and 40 amps, 480 watts (0.6 horsepower) per hour of hydrogen fuel is produced. In practice, efficiency is usually about 50%. This means that output is one-half of what it would be if the unit were 100% efficient.

WARNING: Place the electrolyzer at a safe distance from habitable buildings. Change the electrolyte every 1,000 hours of operation. Ground all circuits. Keep feet dry when touching the electrolyzer.

                The above design may be scaled up for higher output by increasing the height and width of the electrolyte containers, the area of the electrodes, or increasing the number of cells. Larger designs with higher current may employ cooling fins around the cells so that the blower may dissipate heat more readily to avoid damage to the electrolyte materials.

                If 115 volts of alternating utility current is used for electrolysis, a transformer and rectifier are needed to convert the current to 2 volts direct current with boosted amperage.

                Using an independent source of electricity such as a windmill generator or photovoltaic cell, the electrical output can be converted to hydrogen. The following can be used to determine how much hydrogen can be produced from a given electrical output.

• Hydrogen energy content = 3 wh/1 (286 BTU per cu.ft.).

• 1 kWh = 3414 BTU.

If the electrolyzer is 50% efficient, one kilowatt hour of electrical energy will produce about 1700 BTU (0.5 kWh) of hydrogen. This is about 168 1 (5.9 cu.ft) of hydrogen.

Cell Construction

                A typical high pressure electrolyzer is designed to operate at 200C and 98.7 atm (1,450 psi). 340 The electrode gap is 3 mm (0.12 in). Sanded nickel electrodes increase the surface area. The efficiency is 75%. It operates at 1.6 volts and 1 amp per sq.cm. (6.5 A per sq.in.) at 200C (392F) and a 30 to 50 KOH electrolyte.

                Asbestos is corroded in caustic solutions at temperatures above 100C (212F). The diaphragms are made of corrosion resistant metal screens covered with oxide ceramic, small pores. The separator has a high hydraulic resistance to block most of the gas bubbles. The separators also have low electrical resistance: 0.05 to 0.10 ohm per sq.cm. (0.3-0.65 ohm per sq.in.).

Nickel electrodes corrode in heated caustic solutions at a rate of

• about 0.03 mm/year at 0.01 amp per sq.cm. (0.07 amp per sq.in.)
• 0.10 mm/year at 1.0 amp per sq.cm. (7 amp per sq.in.).

The cathode deteriorates at

• 0.01mm/year at 0.01 amp per sq.cm. (0.06 amp per sq.in.)
• 0.0003 mm/year at 1.0 amp per sq.cm. (6 amp per sq.in.).

                Plastic cannot be used in areas exposed to high temperature. Temperatures of 150C (302F) and caustic solutions such as 50 KOH destroy many high temperature plastic materials, such as Nation (R), in days. Instead, all bodies and tubing are made of steel lined with nickel, because it does not absorb hydrogen as many other metals, like steel, do.

                The electrodes are made of coarse screen: 0.6 mm (0.024 in) diameter wire with a 0.52 mm (0.02 in) mesh. A 1 mm (0.04 in) perforated nickel plate is equivalent. The electrode may also be corrugated to increase surface area even further. Each corrugation has a 3 cm (1.2 in) radius.

                Exhibit 7 shows an exploded view of the electrolyzer. Hydrogen is produced slightly above the thermoneutral voltage where it gives off heat

Solid Polymer Electrolyte

                A basic problem is to allow ions to travel between the electrodes while at the same time excluding gas molecules. Liquid electrolytes transfer both the gas bubbles and the ions. Since the distance between electrodes must be small to minimize electrical resistance, the problem of keeping the evolved hydrogen and oxygen gases separate becomes even more acute. Solid porous barriers known as separators are used with liquid electrolytes to keep the evolved gases separate but to allow ion transfer.

                With solid electrolytes the separator is no longer needed. The electrolyte alone performs this function. The electrodes are immersed in water but are separated by the solid electrolyte. See Exhibit 8.

                Solid electrolytes are thinner and accomplish the same task as liquid electrolytes. This reduces internal resistance. Because the solid electrolyte typically has a high melting point, the cell may operate at elevated temperatures, thereby increasing efficiency.

                A General Electric electrolyte is made of perfluorinated sulfonic acid polymer 0.1 mm (0.04 in) thick and capable of operating at temperatures between 120 to 150C (248 to 302F). Current density of 20,000 amp per sq.meter (1/859 A per sq.ft.) allows a 90% thermodynamic efficiency. Capital costs are $200 to 280/kWh. Hydrogen production costs range from $4.10 to 7.00/1,000 kWh if electricity costs $0.06 to 0.23/kWh. 340

                The Teledyne alkaline liquid electrolyzer, requires an investment of $260 to 320/kWh. A high temperature separator withstands a 150C operating temperature. Current density is 4,000 to 6,000 amps per sq.meter (372 to 558 amps per sq.ft.). Production costs are comparable to the GE electrolyzer.

                Exhibit 9 shows a Westinghouse solid polymer cell tube. Water, injected as steam enters one end of the tube and hydrogen gas comes out the other. Oxygen emerges from the outside wall (anode). The cathode forms the inner wall. The solid polymer separates the inner and outer walls. The cell tube is connected in sections and reveals the details of the joints.

Cell Connections

                A pair of electrodes in a container of electrolyte make up one electrode cell. Several cells may be electrically connected in parallel or in series.

                In the parallel (or unipolar) connection (shown in Exhibit 10) each anode is connected separately to the positive terminal of the electric source. Each cathode is similarly connected to the negative terminal. Each cell can be switched off without affecting the neighboring cells. The electrolyte container for each cell is also kept separate from the other cells. This means that each cell can be removed and repaired individually without shutting down the whole unit. The voltage requirement for the entire unit is equal to that of one cell. However/ the current requirements of this array are higher than for a single cell. The total current needed is figured as follows.

                                Current input = current used in each cell X number of cells.

                The series (bipolar) connection electrolyzer is made up of cells each sharing an electrode with the next cell. See Exhibit 11. Each electrode has a positive and a negative side. The positive side is the anode and the negative is the cathode. If one cell breaks down/ the entire electrolyzer shuts off. The voltage needed for the electrolyzer is:

                                Voltage input = voltage used in each cell X number of cells.

The current consumed for the entire series electrolyzer is the same as the current consumption for any one cell. In other words, series connections boost the voltage needed while parallel connections need more current.

Advantages of Parallel Compared to Series Electrolyzers

• Individual cells may be isolated without affecting neighboring cells.
• Higher current density/ results in higher current efficiency approaching 100%. Exhibit 12 Shows the performance for a four cell unit. The voltage requirements taper off at over 2,200 A per sq.meter (204 A per sq.ft.).
• Longer service life is possible (25 years or more) with maintenance-free operation for the first 10 years.

Disadvantages of Parallel Compared to Series Electrolyzers

• Low voltage and high current is needed but requires high capacity transformers and rectifiers. Large conductors (bus bars)/ lower electrical resistance,
• More floor space is needed because each cell is separate and the components are not shared. Liquid electrolyte must be kept in motion in each cell to control heat and remove waste gases. A manifold circulates the electrolyte in each cell separately.

                Exhibit 13 shows a manifold collecting gas to an overhead tank "over water" as in small-scale lab experiments. This prevents reverse gas flow.

Advantages of Series Compared to Parallel Electrolyzers

• High voltage and low current for more efficient AC-DC rectification.
• Less floor space is needed due to thinner cells.
• All cells share a common electrolyte bath, allowing freer circulation of the electrolyte. Gas production also helps circulate the electrolyte.

Disadvantages of Series Compared to Parallel Electrolyzers

• High voltage - low current reduces current efficiencies to 95% or less.
• Each cell must be identical to all the other cells in the electrolyzer to avoid overloads. Capital costs, therefore, are usually higher.

                Solid polymer electrolyte does not require circulation. Exhibit 14 shows solid polymer tubes, described earlier, connected in a single electrolyzer module. The ends of the tubes are capped. High pressure steam enters at one end of the tube. Hydrogen gas still under pressure from the rising steam is forced down a smaller-diameter tube inside each electrolyzer cell. Manifolds deliver steam and remove hydrogen as shown.

                The gas ducts are a high temperature-resistant alloy. The base frame for the cells is aluminum. At high temperatures, aluminum, the manifold, and the cell bodies expand at different rates. Special joining techniques ensure tight connections to prevent gas leaks. 280p29l-295

                Commercial electrolyzers may combine series and parallel connections for the right current-voltage combination. Groups of series connected cells with parallel connections allow each cell to be shut down independently.

Commercial Electrolyzers

                Industrial electrolyzers increase efficiency by operating at high temperature and pressure. The needed voltage decreases about 0.83 millivolts per degree centigrade of temperature rise. Liquid electrolyte cells, see Exhibit 15 and 16, operate at of 20 atm (294 psi) and at 121C. Hydrogen output is 0.04 cu.meter per min. per square meter (0.4 cu.ft./sq.ft.) of electrode area. The Stuart Cell made in Canada by the Electrolyzer Corporation is typical. 630

• Hydrogen output: 818 cu.meter /hour (28,900 cu.ft. per hr). 99.9 pure.
• A.C. 4.7 kWh per cu.meter (0.13 kWh per cu.ft.).
• D.C. 4.52 kWh per cu.meter (0.13 kWh per cu.ft.).
• Current density: 1350 A /m2 (125 A/sq.ft).up to 5000 A/m2 (465A /sq.ft).
• Cell voltage: 2.04 volts.
• Thermodynamic efficiency: 72. State of the art ranges up to 85.
• Electrolyte: 30% potassium hydroxide.
• Water feed rate: 25 liter/hour (6.6 gallon/hour).
• Cooling water feed rate: 1,098 liters/hour (290 gallon/hour).
• Cathode: low carbon steel. Anode: low carbon steel, nickel-plated.
• Separator material: woven asbestos cloth.
• Operating temperature: 70C (158F). Pressure: 1 atm (14.7 psi).
• Teflon gaskets, stainless steel cell frames and end plates.

                For typical installations, hydrogen production costs range from $350 to 680 per kW for large plants and from $680 to $4,250 per kW for small plants. Capital costs are about 30% and operating costs 10% of total costs. 220pl9l-20l

                Most hydrogen plants consume less than 5 megawatts (5 MW). A proposed plant in Canada would have an output of 3,000 kg (6,600 lb)/ equivalent to 3,000 kW. Considered "the largest of its kind," it will provide hydrogen for a liquid hydrogen fuel production facility serving customers in Canada and the northeastern U.S. 22lp297-303 Surplus hydrogen from a nearby chloralkali plant will supplement electricity from Hydro Quebec. The $32 million cost is shared by the Canadian government ($4.1 million), the Quebec provincial government ($3.2 million) and private sources.

                Two rectifiers convert 25,000 volt, 3 phase, 60 cycle A.C. power into 100,000 A at 74.6 volt direct current.

High Pressure Electrolysis

                Some electrolyzers require operating pressures from 5 atm (074 psi) to 30 atm (441 psi) for the DeNora unit. 200 The advantages are:

• Reduced power consumption.
• Compressors used to store hydrogen/ may operate at lower pressure if the electrolyzer supplies some of the input pressure.
• Reduced cell size.
• Reduced voltage losses.

Disadvantages are:

• Increased costs of pressure vessels.
• Gas pressure must be carefully balanced to prevent separator failure.
• Dissolved gases in the electrolyte. Solved with pressurized feed water.

High Temperature Electrolysis

Increased Performance

                As shown in Exhibit 4, high temperature electrolysis requires only slight increases in voltage but provides a substantial increase in efficiency. Energy in the form of heat provides some of the energy needed to split water for higher efficiency 740p309 Reduced demand for electricity at the electrode allows increased current density.

                A high temperature electrolysis (HTE) development program called Hot Elly was begun in 1977 by the German Federal Ministry of Research and Technology. The technology (it is reported) "has reached an advanced status." High temperature operation allows a 30% fall in energy input - from 4.5 to 3.2 kWh per cu.meter (0.13 to 0.09 kWh per cu.ft.). 85% of the steam is converted to hydrogen. For 1,000C experimental results are summarized below for two different energy inputs.

• 1.33 volts/ 5,000 A per sq.meter (465 A per sq.ft.).
• 1.07 volts, 3,000 A per sq.meter (279 A per sq.ft.).

                For commercial uses require a steam conversion of 70% and current density of at least 3,700 A per sq.meter (344 A per sq.ft.) and voltage of no more than 1.33 volts. Exhibit 17 compares the performance of three classes of electrolyzers.

• Conventional commercial electrolyzers using an alkaline electrolyte.
• Experimental low temp. electrolyzers with liquid or solid electrolytes.
• Water vapor electrolysis with a temperature of around 1,000C(1,800F).

                The second group has a clear advantage. The lower the voltage, the higher is the efficiency. High temperature electrolysis (HTE) has an even greater advantage.

Materials

                At high temperatures other materials must be substituted for asbestos in the separator. Two materials, potassium titanite or perfluorinated sulfonic acid polymer, Nafion (R), are used.

                The General Electric solid polymer electrolyzer, mentioned in a previous section, is designed to split 1,000C(1,800F) steam. The solid electrolyte serves a double function as a charge conductor and a gas separator. High temperature materials used were: 280p29l

• Base frame: alumina.
• Gas ducts inside tubes: high temperature-resistant alloy (Iconel 601).
• Electrodes: yttria-stabilized zirconia.

                The main problem in working with such materials at high temperature is in joining materials with different expansion properties.

                Recent developments use polymers as separators. Coating the porous surface with a thing plating of titanium increases permeability of hydrogen 2 to 5 times. 945 p905.

Modes of Operation

                Electrolyzers both consume and produce heat. For any electrolyzer, operating at a specific temperature, there is a voltage (the thermoneutral voltage) at which as much heat is consumed as is produced. Above this voltage, electrolysis produces heat, and below the voltage, it consumes heat. Exhibit 4 shows the voltage-temperature relationship.

                Engineers consider various modes of operation in designing an electrolyzer. 740

                A high temperature electrolyzer operating exothermally (above the thermoneutral voltage) needs no external heat source. Only 200C steam is needed to ensure a gas output temperature 70C (greater than the input. This lowers both investment costs and thermal efficiency (39%).

                In the thermoneutral mode, the temperature of the output gases equals the temperature of the input steam. At a 1.3 volt cell potential, 3.12 kWh per cu.meter (0.09 kWh per cu.ft.) of energy was consumed. This balance of temperatures did not make the best use of the superheating equipment.

                Operating below the thermoneutral voltage (endothermally), the electrolyzer exhibited the highest efficiency. But the reduced voltage (below 1.3 volts) also reduced the allowable current density and the hydrogen output.

At 1.07 volts and 3,000 A per sq.meter (279 A per sq.ft.) the energy input needed is 2.6 Wh per cu.meter (0.07 Wh per cu.ft.) for each volume of hydrogen produced. Increased capital costs were anticipated for coupling the electrolyzer to a high temperature heat source. A heat input of 0.6 kWh provides a thermal efficiency of 44.7% at 19% less electrical power cost.

                Costs increased for operating pressures above 24.7 atm (363 psi). Cell pressures at 3 to 5 atm (44 psi to 73 psi) are more economical even when the output gas was compressed to a 24.7 atm (363 psi) storage pressure.

Costs

                HTE can make use of waste heat from many sources including nuclear power plants. Nuclear fusion is an experimental energy source that is non polluting and virtually limitless. Fusion derives its energy from joining pairs of hydrogen atoms to form helium, releasing large amounts of heat. "The technical integration of fusion and high-temperature electrolysis appears to be feasible and overall hydrogen production efficiencies of 50 to 55% seem possible." 320pl88

                The waste heat from coal-fired plants can be used for HTE, but problems remain. '"Biased, on performance and. cost figures available in 1983, high-temperature electrolysis coupled with thermal electrical energy derived from coal is not yet competitive with processes which make hydrogen from hydrocarbons. If natural gas prices were to double (from $0.012/kWh to $0.027/kWh), catalytic steam reforming and high temperature electrolysis would have comparable hydrogen production costs." 540p44l

                An HTE plant converting 90% of the steam at 38.2% thermal efficiency exceeds the 15% steam conversion and 30.6% efficiency of a comparable coal gasification plant.

                Exhibits 18,19, and 20 show when the cost of hydrogen from HTE is economical compared to the cost of hydrogen from other methods of production. 740p3l4 Exhibit 18 compares HTE with conventional forms of electrolysis. HTE becomes more competitive as electric costs go up. Exhibit 19 compares HTE with hydrogen from the steam reforming of natural gas. The costs of electricity and natural gas are shown on the two axes of the graph. The "break even" line shows at what point the costs of HTE equals steam reforming. At price combinations above the line/ HTE is advantageous. Below the line, natural gas steam reforming is more cost effective. Exhibit 20 shows the cost relationship of coal gasification and HTE at various prices of coal and electricity. In the U.S., the current cost of electricity is too high (above $0.05 per kWh) and the price of coal is too low ($0.007 to $0.008 per kWh) for HTE to be economically competitive.

                The initial costs of conventional plants is about $12 per cu.meter per hr ($0.34 per cu.ft. per hr) of capacity. With HTE this cost could be reduced by:

• Using circular vessels, thus eliminating the need for reinforcing ribs.
• Incorporating vertical stacks of modules into the design. This would reduce capital costs as much as 50%.
• Selling the pure oxygen produced at the current rate of $0.05 per cu.meter ($0.0014 per cu.ft.) to reduce costs by 15%.

                The costs of electrolysis fed by utility power could also be reduced by using heat produced from utility power generation. Hydrogen production cost would be $0.07 to $0.22 per cu.meter ($0.002 to$0.006 per cu.ft.). 540 This is equivalent to $0.04 to $0.06 per kWh for electricity. About 12% of this comes from thermal energy, the rest from electrical energy. This assumes:

• Operating temperatures: 1,000Con average.
• Maximum temperature drop in HTE unit: 200C.
• Cooling water temperature: 15C.
• Hydrogen output temperature: 25C.
• Coal cost: $0.007 / kWh. Natural gas: $0.012/ kWh. Fuel oil: $20 barrel.
• Cost of electricity: $0.050 per kWh.
• Annual capital cost recovery: 20%.
• Thermodynamic efficiency of electrical power generation: 35%.
• Gas to gas average heat transfer coefficient: 60 W per sq.meter per C (3 W per cu.ft. per F).
• Expansion gas-water heat transfer coefficient: 230 W per sq.meter per C (12 W per sq.ft. per F).
• Condensation gas-water heat transfer coefficient: 850 W per sq.meter per C (44 W per sq.ft. per F).

                J.A. Fillo proposes to use waste heat from nuclear reactors, at a cost of: $0.0017 per kWh at 1/300C and $0.002/kWh at 1,150C. Hydrogen from electrolysis may compete with hydrogen from fossil fuels. 320

Photovoltaic-Powered Electrolysis

Hydrogen as an Energy Carrier

                Hydrogen is not a source of energy like petroleum or coal, because it is not available naturally in large quantities. Most of it is derived from the steam heating of hydrocarbons and water or by electrolysis. Because it is rarely found in a pure state on Earth energy is needed to obtain hydrogen from either water or hydrocarbons. Some of the energy is recovered when the gas is burned. Hydrogen is a carrier of the energy used to electrolyze water just as an electrical battery carries the energy stored when it was charged.

                Sunlight can be converted to electricity by photovoltaic (PV) cells. Hydrogen can be used to store this energy. It has much more energy per unit weight than electric batteries do. A solar energy economy is not conceivable without hydrogen being used for storage and energy distribution. 740p3l5

                At the Earth's surface about 1 kWh per sq.meter (317 BTU per sq.ft.) of solar energy is available. If it were harnessed it would supply 10,000 times the current annual world energy needs. 630 Solar energy can be converted to useful energy in various ways.

• PV powered electrolyzers. PV cells convert sunlight to electricity. The electricity is then used by an electrolyzer to produce hydrogen.
• Photoelectrodes. P.V. electrodes immersed in water and an electrolyte produce electricity. However, it is difficult to match the current and voltage output of the electrodes with the demands of the electrolyzer. Separate process work better.

• Photochemical processes. Some chemicals in solution absorb the energy of solar radiation to drive hydrogen-producing reactions.
• Biological sources. Microorganisms in water absorb light to split water to make their own "food" and for respiration. Similar biological processes to synthesize methane, methanol or ethanol are cheaper and more efficient than hydrogen from microorganisms. 100p555-562
• Direct thermal water splitting. At 2,500C water decomposes into hydrogen and oxygen. A lens or reflector is employed to concentrate sunlight to supply heat. The problem is to prevent combustion of the oxygen and hydrogen.
• Thermochemical cycles. Relatively low temperature heat, 1,000C is used to drive reversible chemical reactions.

From Sunlight to Hydrogen

                State-of-the-art PV cells operate at about 10% efficiency. Nevertheless, one square kilometer can produce 26,000 kW. One square mile can produce 67,000 kW. A 120 by 120 km (75 X 75 mile) square array in sunny Arizona could produce 1,000,000 megawatts, equivalent to the projected electrical needs of the U.S. in 2000. 580p6

                A PV cell converts light energy to electricity at a specific voltage and current. The more light received, the greater the energy output. But current and voltage do not increase equally. Exhibit 21 shows that the current doubles, from 10 to 23 milliamps, while the voltage remains around 0.5 volts. The temperature is constant throughout this range. To make the best use of single photocell or any array of cells, the load must operate at an optimal combination of current and voltage known as the maximum power point (M.M.P.). This point is shown on each of the curves.

                Changes in the light intensity or cell temperature will shift the power curve and the M.M.P. Exhibit 22 shows increasing output with lower temperature and more light.

                When PV cells are coupled to an electrolyzer, light energy can be converted, indirectly, to hydrogen production. The current output of the PV cell is expressed in milliamps per square centimeter. Higher current density increases hydrogen production and lowers operating costs.

                The electrolyzer electrode area determines the current requirements while the number of electrolyzer cells (at 2 volts each) determines the voltage needed.

                The amount of light striking the PV cell depends on the time of day, weather conditions and season. The operating temperature of the cells varies when the cells are exposed to the weather. Therefore, the electrolyzer will not always be operating at the maximum power point for the cells.

                Power conditioning equipment constantly adjusts the voltage and current from the cells so that the electrolyzer always operates at the M.M.P. The efficiency of the power conditioning device is typically in excess of 90%. The rate of hydrogen production is higher than without such continual adjustments. However, the equipment needed is complex and costly. Direct coupling of the cells to the electrolyzer (with a fixed voltage-current transformer) is cheaper and simpler but lowers output. The simplest and cheapest power tracking method is a switching interface that changes the parallel and series connections of the cells to adjust the voltage and current from the cells. 370,497

                According to a recent study, in New Mexico, at a latitude of 35° an average annual hydrogen production rate of 4.4 kg per sq.meter (0.9 lb per sq.ft.) of cell area per year is possible. The summer peak rate is calculated to be 0.002 kg per sq.meter (0.0004 lb per sq.ft.) per hour. The average annual efficiency is about 7%. 350 At a latitude of 48°, in central Europe, the hydrogen production rate is half that for New Mexico.

                A PV-powered electrolyzer was constructed and studied at the Florida Solar Energy Center under a NASA grant. 4l0pl53-l60 The experimenters tested hydrogen as a means of storing solar energy. They noted the disadvantages of batteries.

• Low energy to weight ratio.
• The use of scarce materials.
• Energy leaks due to heating and long periods of non use.
• The need for standby charges.

The specifications for the experimental hydrogen plant were as follows.

• Electrolyzer cells:15 cells, each 5.19 cm (2 inches) in diameter and with a

current output of 600 mA per sq.cm. (3/870 mA per sq.in.).

• Peak power output: 1 kW.
• Electrolyzer power input:4 kWh, 500 kWh per month/ in Florida.
• Electrolyzer pressure range: 0 to 1.7 atm (25 psi).
• Electrolyzer type: Series (bipolar, or "filter press").
• Separator: asbestos fabric.
• Electrolyte: 25 by weight KOH.
• Photovoltaic array: 50 Solec Model 3135 modules.
• PV efficiency: 6.1%.

                No power tracking was used. The peak power of the PV cell array was matched to the electrolyzer demand. In 15 days the plant could generate 29.7 kWh of hydrogen equivalent to 3 liters (0.88 gallon) of gasoline. Exhibit 23 summarizes the performance. Another study found that power conditioning equipment increased output only 6%, at 100% efficiency. The researchers concluded that maximum power trackers are probably not desirable in PV- electrolyzer systems. 520p93

Solar Hydrogen Aircraft

                PV cells have always been used in the space program because of their simple maintenance-free operation. The cost of the PV electrolysis is small compared to the total cost of a spacecraft.

                For an application closer to earth, Lockheed has proposed a high altitude aircraft powered by photocells mounted on the skin of the craft. It is designed as a robot reconnaissance plane able to stay aloft for a year or more. The cells power an electric motor that turns a large diameter, low rpm propeller. The same cells also generate hydrogen by way of an on-board electrolyzer. At night, the stored hydrogen is used to feed a fuel cell that supplies an electric motor. The oxygen from the electrolysis is also needed because of the thin atmosphere at 20 km (65,000 ft).

                The Solar High-Altitude Powered Platform is designed to carry a 113 kg (250 lb) payload of communications relays or surveillance cameras. Designed for continuous powered flight, it would cost less than a communications satellite. The wingspan will be 91 m (300 ft). The craft will weigh only 907 kg (2,000 lb). 530p745-746

Costs of Solar Electrolysis

                The Solar Power Corporation in San Diego, California has built a 7 kW solar cell plant. Tracking solar concentrators focus sunlight on 76 sq.meters (818 sq.ft.) of PV cells. The reflector also produces 45.8 kW of heat.

                Relying on current data and future research and development activities, the company anticipates costs of $0.0285 per kWh for a 1,000 Megawatt plant. This is comparable to current costs of electricity from hydropower or natural gas and with $0.0775 per kWh for nuclear power and $0.0993 per kWh for coal-fired plants.

                A study of the solar electric plant at the Florida Energy Center developed a program to estimate the costs of future solar hydrogen plants. The data in Exhibit 24 summarizes the estimated cost of residential hydrogen from a PV array.

                NASA experimented with a 1 kilowatt commercial solar cell array using no power conditioning. They designed the array for peak power. 15 cells are designed for a current density of 600 mA per sq.cm. (3870 A per sq.in.). Each electrode was 5.19 cm (1 in) in diameter. Each cell had an asbestos separator. The energy value of the hydrogen had 50 to 75% of the solar energy input. The overall system efficiency from sunlight to hydrogen was about 4%. For a 500 kWh/month plant located in Florida, the operating costs would be $0.73 per kWh. The average residence in Florida consumes 1,000 kWh per month.

                By 1995, with production of solar cells increased 100 times, the cost of solar electricity from a plant similar to the one studied, is reduced to $0.17 per kW. If present developments in solar cell technology become commercially feasible, further cost reductions can be expected. 920pl-2

                Stanford University is demonstrating a new silicone-based solar cell with a textured surface that is 27.5% efficient. Combined with an electrolyzer with 90% efficiency, the overall efficiency would be = 0.275 X 0.90 = 25.

                J.E. Nitsch, anticipates capital solar power costs to fall to one-half to one-third by 2005, and to one-tenth the current levels by 2015. Capital costs for electrolysis are expected to decline one-third over next 40 years. 620p23-32

                Photovoltaic use has been increasing 18 to 20% per year for the last 20 years from 1 Mw in 1978 to 157.4 Mw in 1998 to 65,000 Mw in 2025. The total electric output in 2025 is expected to be 21,000,000 Mw. Photovoltaics may be 3.6% of that. 547

                Electrolytic hydrogen is expected to become cost competitive with fossil fuels in the 2005 to 2010 time period, assuming the following conditions.

• Interest rates on capital of no more than 6.
• Increasing plant life up to 30 years, due to technical improvements.
• Increasing prices for fossil fuels by 4 to 5 per year.

Titanium Dioxide Photovoltaic System

                The Switzerland Institute of Physical Chemistry devised a solar cell that uses both cheaper materials and fabrication process. The materials are: titanium dioxide, a "charge transfer" dye and an electrolyte. The cell converts 12% of solar energy into electricity. This compares to 10% for silicone panels.

                The key to its success is increased surface area exposed to light. Spheres of Ti02 15 nanometers in diameter cover the surface in a semiconducting layer 10 micrometers thick. The film is transparent for wavelengths below ultraviolet. A dye was added to capture light at these wavelengths and emit electrons into the Ti02 semiconductor.

                The cell is a sandwich of different materials. The bottom layer is conductive glass and is negatively charged during operation. On top of that is the dye infused Ti02. An transparent electrolyte lies on top of the Ti02 and a sheet of positively charged conductive glass forms the topmost layer. The two electrically charged layers connect to the terminals.

Wind Power

                Wind power accounts for 0.10 of the 3620 billion kWh US annual energy production. A wind and photovoltaic farm near Sacramento, CA generates 2 MW year round average. 7 MW peak power in high wind and full sunshine. That's 1 of the Rancho Seco nuclear plant recently shut down.

                A wind turbine slows the wind down, extracting energy. Wind generators at most have an efficiency of about 50%. The faster the blade spins the more power is produced, but if it spins too fast the turbine puts energy back into the wind. The less blade surface area exposed to the wind the faster it can travel without becoming a propeller. That's why long thin blades spin faster and produce more power than multi-blade turbines. The maximum power output of a wind turbine is. 195

                                P = 0.5nD2V3

Where: P = power output in watts

                                n = efficiency of turbine.

                                D = diameter of turbine blades (meters)

                                V = velocity of wind (m / s)

The graph shows output vs wind speed, for a 10 m turbine at 50% efficiency.

                The larger the turbine the more land area is needed for multiple units. Site spacing requires 3 rotor diameters side to side, 10 rotor diameters front to back. About 1.2 W/m2 in land is needed regardless of the turbine size of each unit. A field producing 1000 MW (equivalent to a fossil or nuclear plant) is 833 square km (300 mi2). A conventional plant occupies about 1 sq. km.

                California needs 30,000 MW yearly, equal to the output from a wind farm 25,000 sq km (10,000 sq mi) — twice the size of Connecticut.

                Wind speed varies. Many power plants cut off over a certain speed.

                An average, a US house consumes 30,000 kWh per year. In Oklahoma the wind blows over 10 km/hr 80% of the time. 165 kWh must be stored for two windless days. l080p339-343

Summary

                In summary: the costs of hydrogen or electricity from renewable energy sources are currently uncompetitive with fossil fuels. 285

Chapter 3:

Chemical Hydrogen Production

Chemical Reactions

                One billion cubic meters (35 billion cubic feet) of hydrogen is used in the United States yearly. Produced in various ways, reaction with carbon is the most common. Reactions with heat alone are represented below.

                                C2H6 —> 2C + 3H2

                Heat and high temperature steam reactions are more common. Coal or coke reacts with steam to produce carbon monoxide or carbon dioxide.

                                H2O + C —> CO + N2

                                2H2O + C —> CO2 + 2H2.

Carbon monoxide reacts at 350 C (660 F) using an iron oxide catalyst. A solution of monoethylamine and water absorbs the carbon dioxide.

                                SCO + 3H2O —> 3 CO2 + 3H2

                The most common source of hydrogen involves splitting hydrocarbons such as methane, gasoline, fuel oil, and crude oil into carbon oxides and hydrogen. Steam at 700 to 1,000 C (1,300 to 1,830 F) combines carbon with the oxygen in the water to release the hydrogen. 200 The process for methane (CH4) and propane (C3H9):using a nickel catalyst are:

                                CH4 + 3H2O —> CO + 3 H2

                                C3Hg + 3 H2O —> 3CO + 7.5H2.

                In many parts of the world, coal is more plentiful than natural gas. Using coal, hydrogen can be produced at the energy equivalent of $0.26 per liter ($1.00 per gallon) of gasoline, not including distribution and retail costs.

Iron reacts with steam in a similar process.

                                4 H2O + 3Fe —> Fe3O4 + 4H2

                Ammonia can be split at high temperature, but yields are low.

                                2NH3 —> N2 + 3H2.

                Electrolysis uses electricity to split water, yielding 99.9 pure hydrogen. The price of utility electricity makes electrolysis expensive, but is the most convenient way to produce hydrogen in small amounts.

                                2 H2O —> 2 H2 + O2.

                Metals react with add to produce hydrogen. Acids are compounds that contain hydrogen. Adding the add to the metal yields a metallic compound and hydrogen gas.

                                Metal + Acid —> Metal compound + Hydrogen gas.

The metal displaces the hydrogen in the acid. The reaction of zinc with sulfuric add   produce hydrogen and zinc sulfate. Zinc reacts with hydrochloric acid producing zinc chloride and hydrogen. Iron reacts in a similar way with sulfuric acid.

                                Zn + 2HCI —> ZnCI2 + H2.

                                Fe + H2SO4 —> FeSO4 + H2.

Sulfuric acid or hydrochloric add can be diluted. Pour the acid slowly into the water, not the water into the acid. Dilute acids act more vigorously with zinc than pure add. A little copper sulfate speeds up the reaction.

                Hydrogen is purified by passing through a sodium hydroxide solution. Water vapor is removed by exposure to silica gel or concentrated sulfuric add. Exhibit 26 shows how to prevent the gas from flowing backwards.

                Aluminum (Al), calcium (Ca), iron (Fe), lead (Fb), magnesium (Mg), potassium (K), sodium (Na), and zinc (Zn) /will yield hydrogen in dilute sulfuric/ hydrochloric, and other acids. Potassium, sodium, and calcium react vigorously with water producing enough heat to ignite the hydrogen. Hydroxides are formed. With sodium the reaction is:

                                Sodium + Water —> Hydrogen gas + Sodium Hydroxide.

                                2Na + 2H2O —> 2NaOH + H2

                The elements mentioned above react with only half the water. Sodium hydroxide and potassium hydroxide form a clear solution in water. Calcium hydroxide remains un-dissolved in a milky suspension.

                Sodium hydroxide, water and aluminum also work. 55 square centimeters (sq.cm.) of aluminum produce one liter of hydrogen (61 cu. in.) per minute. A square foot of aluminum yields 16.9 liters (0.6 cu.ft.) of hydrogen per minute. A plate 1 cm thick (0.25 in) lasts 24 hours. Zinc requires 12.5 more surface. Alkali solutions of aluminum react as shown.

                                2AI + 2NaOH + 6 H2O —> 2NaAI(OH)4 + 3 H2

Alkali solutions of silicone are similar.

                                Si + 4NaOH —> Na4Si04 + 2H2.

                                2NaOH + Si + H20 —> Na2SiO3 + 2H2

Reactions with amphoteric metals, such as zinc, are represented below.

                                2NaOH + Zn —> Na2ZnO2 + H2

Calcium hydride (CaH2) 1 kilogram (1 kg) yields 1 cubic meter of hydrogen. 1 Ib. yields about 16 cu.ft. Sodium borohydrate gives more at higher cost.

                                CaH2 + 2H2O —> Ca(OH)2 + 2H2.

                                NaBH4 + 4H2O —> NaB(OH)4 + 4H2.

                Exhibit 25 shows how to control gas production and shut it off when not needed. Hydrogen is in the middle container. As it is drawn off, the pressure drops and the acid in the lower chamber rises and contacts the metal.

Electrochemical Reactions

                Sulfur in the anode during electrolysis reacts with oxygen to form sulfate (S04-2) reducing the required cell voltage by one-third to 0.36 volts. The reaction is:

                                S + 4H20 —> 8H+ + SO4-2 + 6 electrons.

The cathode reaction is:

                                6H+ + 6 electrons —> 3H2.

The overall reaction is:

                                S + 4H20 —> H2SO4 + 3H2.

                Preliminary investigations indicate that sulfur-assisted water electrolysis has the potential of becoming a viable economic process for co-generation of hydrogen and sulfuric acid. 500p639 The high material costs include an expensive platinum mesh electrode. The sulfur forms a layer and reacts with the electrolyte. This process is similar to the Westinghouse Cycle for producing hydrogen and sulfuric acid from sulfur dioxide and water.

                                SO2 + 2H2O "—> H2SO4 + H2.

                                H2SO4 —> H2O + SO2 +  ½ O2.

The overall reaction is:        H2O —> H2 + ½ O2.

                Ideally, the process is 45 thermodynamically efficient and requires less than 0.6 volts. For practical applications high concentrations of sulfuric add are used, thereby increasing the voltage required. This process takes place at higher temperature than the pure sulfur process. In contrast, sulfur- assisted electrolysis needs less than 75C (167F). Hydrogen production is also higher than with the Westinghouse process.

                In comparison with conventional electrolysis, the hydrogen production rate for sulfur-assisted electrolysis is three times higher. The electrical consumption is one-half that required for ordinary electrolysis. Sulfuric acid is produced instead of oxygen, but the acid can be reacted with metals to produce still more hydrogen.

                It is easy to see how it is possible to start with sulfur or sulfur dioxide and produce hydrogen, then add metal (like iron) and get still more hydrogen. Both sulfur dioxide and scrap iron are products of an industrial society that can be recycled into fuel production.

                Either of the following two reactions produces hydrogen and sulfuric acid.

                                S + 4H2O —> H2SO4 + 3H2.

                                SO2 + 2H2O —> H2SO4 + H2.

Sulfuric acid also reacts with iron to produce hydrogen.

                                Fe + H2SO4 —> FeSO4 + H2.

For all three reactions no separator is needed because the reactions produce only one gas. Only liquids or solids form at the oxygen electrode.

Photovoltaic Processes

Solar Electric Hydrogen

                Various research projects demonstrate how the functions of solar cells and electrolyzers can be combined in one device using one or more photoelectrodes or photocatalysts. Light striking the photoelectrode generates an electrical potential (voltage) at the surface of the semiconductor and the electrolyte. This potential then splits water into hydrogen and oxygen. The gases are generated together. Some means of separation is necessary.

                Wavelengths of strong ultraviolet light have enough energy to split water. This process is inefficient because ultraviolet light makes up only 8 of solar radiation.

Photoelectrodes

                Certain chemicals can convert a wider spectrum of light to electrolytic energy. Each of these makes more efficient use of the solar spectrum. Candidate materials include some salts, organic dyes, semiconductors absorbing a wider spectrum of light (these need a band gap over 2.3 electron volts). Some species of algae also do this. 90p2l9-225 Photoelectrode materials generally share one or more of the following problems.

• Photocorrosion causing decomposition under light damages electrode.
• Temperature mismatch: photovoltaic processes are more efficient at low temperature. Electrolytic production occurs at higher temperature.
• Voltage mismatch: the output of the photoelectrode (1.5 volt) does not match the input needed for the electrolysis (2.2 volts). 550p445-46l

These problems have led some researchers to conclude that a separate solar cell array is preferable. 980p225-232 Other researchers continue on, tempted by the elegance of a single process that converts light directly to hydrogen fuel. In the search, oxides of sulfur and phosphorus are specifically excluded from the role of photoelectrodes. 80,647-651

                Mixing ferric oxide and titanium dioxide with silicone produces a photoanode. Ferric oxide and magnesium oxide comprise a photocathode. The two electrodes placed in a neutral electrolyte solution with water and in the presence of light yield electrolytic hydrogen and oxygen.    The entire reaction normally takes place without the need for any input voltage. 8l0pl37- 145 However, what is technically possible is not necessarily economical. "A cheap accessible industrial process for producing titanium dioxide is not now available." 420p773-78l

                Experiments compared cheap zinc and cadmium sulfide precipitated  onto Nafion (R) film, with others precipitated  onto silicone dioxide with more platinum mixed with cadmium sulfide. The conclusion was that:

• Relatively efficient photo assisted hydrogen generation can occur without a noble metal catalyst.
• The type of support for the surface coating of zinc and cadmium sulfide is not a crucial element.
• Close contact of zinc sulfide and cadmium is required. 480p734

In other experiments 1.0 grams (0.002 Ib) of zinc sulfide in suspension in an electrolyte solution produced 16 liters (0.6 cu.ft.) of hydrogen in 35 hours with no observable deactivation of the photocatalyst. 750p5903-59l3 There was no need for platinum to improve the charge transfer.

Electrolysis of Hydrogen Sulfide

                Some hydrogen-containing compounds are easier to split than water. Hydrogen sulfide is an example. It is a derivative of natural gas, coal, and petroleum refining. It requires only one seventh of the amount of energy to electrolyze hydrogen sulfide as it does to electrolyze water. The energy required to split hydrogen sulfide is low enough to use light as a source of energy to split the molecule.

                                H2S + 2 photons of light —> 2H+ + S.

                In one experiment, a specific band of wavelengths stimulates cadmium sulfide to release an electron that splits hydrogen sulfide. Rubidium dioxide (0.1 by weight) was mixed with the cadmium sulfide to form the catalyst. the catalysts were dissolved in a 0.1 mole solution of sodium sulfide illuminated with a 250 W halogen lamp shining through a 15 cm (6 in) water column to remove the infrared portion of the spectrum. This avoids heating of the solution. The 25 ml (1.5 cu.in.) solution produced 2.3 ml per hour of hydrogen. 90% of the hydrogen sulfide was converted to hydrogen. Doubling the rubidium dioxide increased hydrogen output 50%. 150p118 Platinum wasn't needed as an electrocatalyst. Other experimenters, using the same chemical constituents, discovered thermodynamic efficiencies of 2.85. 470p23-26 The experimenters concluded:

                "Apart from its importance for solar energy research, the process might be used in industrial procedures where HzS or sulfides are formed as a waste product whose rapid removal and conversion into a fuel are desired. Also, in intriguing fashion, these systems mimic the function of photosynthetic bacteria that frequently use sulfides as electron donors for the reduction of water to hydrogen." l50pll9

The Texas Instruments Solar Energy System

                Texas Instruments has one of the few reported commercial photoelectrochemical programs. 100 Hydrobromic acid is used as the photoelectrode with an electrolyte of sulfuric add and water. The photoelectrode is coated over microspheres 0.25 to 0.40 mm (0.010 to 0.020 in) in diameter. The microspheres are photoanodes and photocathodes. The photoanodes evolve bromine while hydrogen emerges at the photocathodes. The electrolyte-microsphere suspension is contained between two sheets of glass; one sheet has a conductive backing. Sunlight shines through the transparent side and produces hydrogen with 7% thermodynamic efficiency. They expect to increase this to 8 to 10% by the year 2005.

                In 1992 Texas Instruments Marketing Manager Eric Graf announced plans to produce the Spherical Silicone photovoltaic module in 1993. "Our goal is to help America lead in renewable technology for jobs, balance of trade, and the environment." 442p7 The main customer is Southern California Edison electric company. The panels could be put on the home roofs. One-kilowatt panels could generate one-third of the homes' electricity needs. But an unexpectedly low price of energy has reduced the demand.

Summary

                Photoelectrodes use either semiconductor powder suspensions or photosensitizers that transform electrons to and from water molecules. Compared to solar cell powered electrolysis, photochemical production mixes hydrogen and oxygen, corrodes electrodes, and has low efficiency.

Biological Sources

Plants as a Carbon Source

                Certain bacteria, in the absence of oxygen, will convert organic matter into methane. Among the possibilities are the use of municipal sewage or algae are grown and harvested specifically for this purpose.

                In growing an algae "energy crop" heat is needed to boost the growth rate. The waste heat from the cooling towers of a 100 MW nuclear reactor will support a 4,047 hectare (10,000 acre) algae pond. This pond will yield 4.5 kilograms per square meter (20 tons per acre) of organic matter. Supplying extra carbon dioxide increases the rate by 50%. 22,680 kilograms (25 tons) of algae can reasonably be converted to 10 kWh of methane. 50p33l-338

Biological Production of Hydrogen

                Green plants and algae (microscopic one-celled plants) convert carbon dioxide, water, and sunlight into carbohydrates, water, and oxygen.

                                CO2 + 2H2O —> CH2 + H2O + 3/2 O2.

Hydrogen can be produced by intercepting a plant's production of carbohydrates during photosynthesis.  During photosynthesis the plant absorbs green light (about 500nm wavelength). This is only about 16 of the visible solar spectrum. Hydrogen is formed by water splitting and then used to construct carbohydrates that the plant uses.

                Researchers are trying to find a way to intercept the hydrogen before it is used to form carbohydrates using two approaches. 813

• Using the active ingredient of photosynthesis in water (as a thylakoid membrane of ruptured chloroplasts).
• Preparing a solution of platinum and hexachloroplatinate in water. Light shining on either of these solutions will produce a brief electrical potential. The resulting electrolysis splits water molecules.

                Some microorganisms produce. One species (Rhodobacter sphaeroides 8703) converts 7.9 of the light input energy at 50 W per sq.meter (4.6 W per sq.ft.) to hydrogen gas. At 75 W per sq.meter (7 W per sq.ft.) of light intensity the conversion efficiency drops to 6.2%. 600p147-l49

                In experiments with different growth media, a salt water blue-green algae (Oscillatoria sp. Miami BG7) was found to produce 30% more hydrogen when the cells were grown on a thick jelly and mobility was restricted. 720p83-89 Similar results were found with hydrogen-producing bacteria. 950p623-626

                Synthetic photosynthesis avoids these problems. 890p627 In one process 70% of visible sunlight could be converted to electrical voltage. 250p825-828 In 1992 the University of Miami searched 5,000 strains of cyanobacteria to find hydrogen-producing enzymes for synthesis.

                Exhibit 27 shows the results of experiments with various hydrogen- producing microorganisms. Both algae and bacteria are represented. Algae, as a green plant, produces hydrogen while making carbohydrates. Some bacteria, on the other hand, give off hydrogen as a by-product of digesting carbohydrates.  The algae can be tricked into producing hydrogen by interrupting their photosynthetic activity. To the algae, making hydrogen is a waste of time. Certain bacteria will produce hydrogen in oxygen-poor environments. For this reason, bacteria produce more hydrogen than algae. Under some conditions 25% of intestinal gas of mammals is hydrogen. The rest is methane and carbon dioxide. This process could be duplicated in man-made digesters. The methane could be heated to yield hydrogen and carbon. 441 and 792

                Dark fermentation of biomass on wastes has been little studied. The critical factor is the amount of hydrogen produced per mol of substrate. Theory and experimental evidence indicates than at most 2 to 3 mol of hydrogen can be obtained from substrates such as glucose. 65 p 1185

Summary

                Biological hydrogen is inefficient. Other problems include: exacting biological requirements, and the periodic replacement of the microorganisms and their substrate. See International Journal of Hydrogen Energy, Dec 2002.

Direct Thermal Water-Splitting

Solar Thermal Energy

                At 2730C water decomposes into hydrogen and oxygen. A parabolic reflector or lens can focus the sun's rays enough to reach this temperature. According to Roy McAlister, President of the American Hydrogen Association, 12,000 square miles (31,000 sq. km.) in a sunny climate gathers enough sunlight to supply all the current energy for the U.S. However, the amount of water needed each year would equal the volume of Lake Mead behind Hoover Dam. Seawater could suffice. When burned, one ton of hydrogen makes 9 tons of water. 568 and 235

                50% of sunlight is in the heat-producing infrared spectrum. Direct thermal water splitting would seem to be the simplest method of producing hydrogen from water. However, there are two main problems.

Finding High-Temperature Materials

                One approach is to use a fluid wall. This is a boundary layer of gas injected into the container to keep the high temperature water vapor from the container wall. Research in this area demonstrates that solar direct splitting of water can be accomplished with available materials. 960p9l-100

Hydrogen and Oxygen Separation

• Centrifuging: Since oxygen is heavier than hydrogen, spinning the gas mixture in a centrifuge will separate the oxygen.
• Magnetic separation: Some hydrogen molecules may be deflected in a magnetic field while others are not. This may be a partial solution.
• A molecular membrane: Vanadium or palladium will transmit hydrogen at temperatures above 730C (1,350F). The expense and long term intolerance of high temperatures makes these metals impractical.
• A porous membrane with pores small enough to select the more rapidly moving hydrogen from the slower oxygen. Multiple membranes promote heat recovery and reduce exit pressure. At 2500K and 2 millibars it has 40% thermal efficiency. 487
• Quenching: Cooling the gas before it can recombine. The gases then are carefully separated at lower temperature by other means. 630
• Injection quenching: injecting the hot gas as bubbles into water and collecting them at the top of the water container. 960 As the bubbles rise, the gases can be separated by gravity. Hydrogen, being lighter and more buoyant, rises faster than oxygen.
• Impingement quenching. A jet of a high temperature gas mixture is forced under pressure against a flat plate. 5l0p3-11 The jet strikes the "wall" at a flow rate of from 2 X 105 cu.meter per sec. (7X 104 cu.ft. per sec.) to 6.7 X 105 cu.meter per sec. (2.4 X 103 cu.ft. per sec.). The portion closest to the wall is the coolest. As the stream spreads out, there is a stagnation zone in the center. Fast heat exchange may be efficient enough to prevent back recombination. 5l0p9

Solar Thermal Collectors

                The sun's rays can be focused by a parabolic dish concentrator. The parabolic dish can be easily and cheaply manufactured. Solar radiation is focused on a point above the center of the dish. This is called a "point-focus" solar concentrator. The target is made of a temperature-resistant material. A circulating fluid is heated to turn a turbine and generate electrical power.

                Alternatively, a Stirling engine can be used. The Stirling engine employs heated gas to drive a piston. It is like a steam engine in that it uses a source of heat outside the engine to supply power. John Ericsson developed what he called "sun motors" in the 1880s. Thousands were sold to pump water until they were replaced by electric motors and utility power. Exhibit 29 shows a sun motor that is being tested by Irving Jorgenson of the American Hydrogen Association. The mirrored dish focuses the sun on the black plug at the center of the dish. The finned tube below the plug is the cylinder of the Stirling engine. The heated air expands and drives the piston downward. A valve exhausts the air and returns the piston for a power stroke. The side view of the device shows the parabolic shape that focuses the incoming rays on a single point. Irving Jorgenson, a professional meteorologist, is involved in constructing larger dishes for use on an Arizona Indian reservation. Generally, the larger the diameter of the dish the more power produced.

• A Sterling engine generator with 1/2 meter (20 inch) 310 stainless steel reflector would generate about 4 watts power in full sunlight.
• A3 meter (10 ft.) dish gives 4 to 5 kilowatts.
• A 6.4 meter (21 ft.) dish produces 25 to 30 kilowatts.

In Arizona the generator will get about 1.2 kWh/sq.m (0.1 kWh/sq.ft). in summer and 0.62 kWh/sq.m (0.6 kWh/sq.ft.) in winter. The operating cost is $5.00 (1992$)/kW. The efficiency is between 28 and 30%. According to Paul Klimas of Sandia Labs, this is a "proven, and efficient way of generating solar electricity, designed to let industry lead their own commercialization effort with technical and financial support from Sandia ..." 442p7

                The McDonnell Douglas Corporation has constructed a point-focus concentrator for the Southern California Edison Company in cooperation with the Electric Power Research Institute. The device uses a Stirling engine to generate 25 kW of electricity. In tests the generator converted 28% of the sun's rays to electrical energy. Photovoltaic cells are typically no more than 12% efficient. Exhibit 30 shows the McDonnell Douglas device. The Stirling engine is mounted on the end of the arm that extends from the dish. In the background is the famous "Power Tower" near Barstow, California. It uses the point focus principle on a large scale. The reflector is made up of individual mirrored panels mounted on the ground. Each panel can be moved independently. A computer aligns the entire field to maintain focus all during the day. The focus reaches 1,000C (1,800F) on a clear day to generate 10 Mw of power. Molten salts carry heat to thermal storage tanks. If clouds block the sun for more than 30 minutes, the plant shuts down until the sun reappears. Two new tanks were added in 1992 to allow generation when clouds are overhead. In Southern California's climate, the plant can remain operating 60% of the time. The costs of power are within one to two cents of conventional local utility power with by 2010.

                Solar collectors track the sun as it rises in the sky and from side to side as it travels from east to west across the sky.. A linear-focus system employs a trough that focuses sunlight along a line, the sun need only be tracked up and down, not side to side. Roy McAlister of the American Hydrogen Association has studied focusing solar collectors concludes that the dish-type parabolic collector responds and focuses the sun's rays more efficiently. 569

                Roy McAlister has described a way to store heat energy indefinitely without energy loss. Heat converts methane and carbon dioxide into carbon monoxide and hydrogen. Heat stored in this manner may be transported from sunny areas to distant locations that lack abundant solar energy. 569 With a suitable catalyst, these two gases can be recombined into their original form to give off heat.  The reactions are:

                                Heat + CH4 + CO2 —> 2CO + 2H2.

                                2CO + 2H2 —> Heat + CH4 + CO2.

Thermochemical Cycles

Isothermal Steps

                Avoiding the high temperature needed for direct thermal water splitting requires more complex chemical processes. Thermodynamic cycles operating below 1,000C (1,800F) consist of three steps or more. 300p29l

                Unlike electrolysis, heat energy is used to directly decompose hydrogen-containing compounds. 990p459-462 Some processes utilize both a thermal and an electrical input. They are referred to as hybrid thermochemical cycles or as electrothermochemical processes. 70

                Higher temperature increases the reaction rate to lower costs and reduce the number of steps needed for the process. Bigger thermal steps, mean that fewer steps are needed to arrive at the desired product. 270p67-72 The temperature required at each step must also match the heat input to avoid wasting energy or materials.

Efficiency

                Chemical processes for splitting water that require temperatures over 3000C (5400F) are impractical because they are hard to achieve and production materials cannot withstand them. By breaking the water splitting process down into several steps, lower temperatures may be used, around 800-900C (1500-1650F). Thermochemical cycles operating at these temperatures may be used with high-temperature solar and nuclear fusion power plants. In the future, fusion reactors will produce 1,250C (2,280F) cooling water. This could support a sulfur-iodine thermochemical cycle at 45% efficiency because the thermochemical process can use the exact temperature of the waste heat as it comes from the reactor. 590p178-l83

                The efficiency of a thermochemical process is defined as:

                                79.42/Q.

• 79.42 = combustion energy of 1 gram (0.0022 Ib) of hydrogen (Wh).
• Q = energy required for decomposition at 100% efficiency (Wh) 70

Costs

                The chemicals used in a thermochemical process are used over and over again with little or no loss. The main inputs are water and heat energy. In some processes electricity is used for electrolysis in one or more of the steps.  The chemicals used include various catalysts, organic solvents, complexing agents and molten salts.

                The range of projected costs of thermochemically produced hydrogen compared to gasoline and electricity is given in the following table.

                In comparing alternative processes, economic costs, as well as the efficiency, of various choices must be considered. The costs of high temperature electrolysis with solid polymer electrolytes is comparable to the best thermochemical cycles. 90 Coal gasification, however, remains a cheaper source of hydrogen. Water splitting, either by electrolysis or by thermochemical cycles, is a long term hope. 300

                Exhibit 31 shows the comparative costs of various commercial and experimental processes of generating hydrogen. 540

Demonstration Plants

                In order to determine the practicality of alternative thermochemical cycles it is necessary to study the chemical features of the process.

• Thermodynamic requirements for each of the reaction steps.
• The chemical and energy outputs of each step.
• The effect of other chemical reactions not part of the main reaction.
• The effect of possible losses of chemical reactants, leakages, etc.
• Processes to separate the chemical reactants that are to be recycled from the hydrogen and other chemical outputs.
• Space requirements for the heat transfer machinery.
• High temperature and corrosion resistant materials.
• Availability of raw materials now and in the future.

                A study was conducted of over 1,000 possible thermochemical cycles which use materials that can be recycled. In hydrocarbon reforming processes the input materials are used up.  The only inputs for each of these thermochemical cycles were water, heat, and electricity.

• The Bismuth sulfate cycle, from at Los Alamos Scientific Laboratory.
• The Westinghouse sulfur cycle.
• The iodine-sulfur cycle devised by the General Atomic Company.
• The bromine-sulfur cycle. Mark 13, at Joint Research Center in Italy.

                The bismuth sulfate cycle has estimated efficiency over 50% at 1000C (1800F). The process needs less sulfuric acid than other processes. This reduces the voltage for the electrolysis step (the first step shown below). Corrosion is also reduced. The process requires the use of solid chemicals.

                                2H2O + SO2 —> H2SO4 + H2 Room Temp.

                                H2SO4 + Bi2O3 + SO3 —> Bi2O3 . 2SO3 + H2O   Room Temp.

                                Bi2O3+2SO3 —> Bi2O3SO3 + SO3 800C

                                SO3 —> SO2 +1/2 O2 over 800C

                In the first step, water and sulfur dioxide are electrolyzed to hydrogen and sulfuric add. Next, the sulfuric add is transported to a tank that contains a bismuth oxysulfate compound (Bi203 + S03). This reacts with sulfuric acid to produce a bismuth oxysulfate compound (Bi2O3 + SO3). This compound is dried and heated to about 800C (1500F). It then decomposes to the original bismuth oxysulfate compound along with sulfur trioxide gas. The sulfur trioxide is heated to 800C to break it down to sulfur dioxide and oxygen. The sulfur dioxide is cooled, separated and returned to the electrolyzer.

                The oxygen in this process can be used for iron production and aeration of ponds. If more oxygen is produced than could be used, it could be vented to the atmosphere.

                As with other thermochemical cycles, each step in the above process is a separate chemical reaction that must be modified so that the required amounts of products are available for the next step, with no waste. The Westinghouse cycle takes place at 300 to 375C (570 to 700F).

                                SO2 + 2H2O —> H2SO4 + H2. Room Temp.

                                H2SO4 —> H2O + SO2 + ½ O2. 800C

                As in the bismuth process, the first step involves electrolyzing water to produce sulfuric acid and hydrogen. The last reaction represents a simple splitting of the sulfuric add molecule by heat at 1,200C (2,190F). Decomposition of 84% of the reactants can occur at 1,080C (1,976F).

                The iodine-sulfur cycle thermally splits sulfuric acid and hydrogen iodide. HI can be split at low temperatures and energy input.

                                2H2O +I2 + SO2 —> H2SO4 + 2HI   Room Temp.

                                H2SO4 —> H2O + SO2 +1/2 O2 300C

                                2HI —> H2 + I2  800C

The process gives low yields and presents difficulties in separating the sulfuric acid from the hydrogen iodide.

                Below is another process investigated at Los Alamos. No electrolysis is used in the process.  The main disadvantage is its high temperature requirements.

                                Cd + CO2 + H2O —> CdCO3 + H2   Room Temp.

                                CdCO3 —> CdO + CO2 300C

                                CdO —> Cd + 1/2 O2 over 1500C

                The experimenters found the most promising of the three processes to be the bromine-sulfur cycle. In May 1978 the demonstration of this process was the first complete thermochemical hydrogen production process by water decomposition.

                                2H2O + Br2 + SO2 —> H2SO4 + 2HBr

                                H2SO4 —> H2O + SO2 + 1/2 O2

                                2HBr —-> H2 + 2Br

                Sulfuric add in the first reaction is easily separated in a column still. It is 75 of the total weight of the mixture. The acid is split at 90C to 1,200C (190C to 2/200F) at a low pressure of 3 atm (44 psi). Steel is used as a catalyst. No heat exchangers were required.

                                In the third step, hydrogen bromide is electrolyzed at 0.80 volts. Hydrogen output is 0.1 m3/hr (3.5 ft3/hr). The two gases are easily separated because hydrogen is lighter. No separator is needed. The following summarizes the specifications of a plant 18 months during 1984-85

• Hydrogen output                                                 1,000 cu.meter/hr (35310 cu.ft./ hr).
• Sulfuric acid processed                                       43.7 kg/hr (96 Ib/hr).
• Operating pressure                                                              24.7 atm (2.5 MPa, 363 psi).
• Maximum operating temperature:      950C (1.740F).
• Electrical input:                                                     100kW.
• Efficiency:                                                                             30 to 40%.
• Cost:                                                                                       $1.00/cu.meter/hr. ($0.03/cu.ft./hr).

                The efficiency and cost compares to 28 to 32% for high temperature solid polymer electrolysis. The plant showed no major instabilities, no by-products, or side reactions. It could be started easily. "Industrial pilot plants can already be built with the present knowledge, chemical engineering data and commercial materials  are  available,  no  critical  breakthrough  is  necessary.... Thermochemical production of hydrogen is demonstrated and feasible." 70

The Nitric Acid Process

                Newell C. Cook developed a process for recycling nitric oxide compounds and acid while splitting water to produce hydrogen. Nitric oxide has a low boiling point, low ionization potential, and high thermal stability.

A variety of acids may be used in place of the phosphoric add shown.

                                2NO + 2HPO3 —> 2NO+PO3- + H2

                The phosphoric acid decomposes, releasing hydrogen, and forming nitrosonium phosphate (a salt). When water is added to the salt, the acid and one-half of the nitric oxide is reconstituted. Heat is given off. The N02 is heated, broken down to NO, and recycled,

                                2NO + PO3- + H2O —> 2HPO3 + NO + NO2

                                NO2—> NO +1/2 O2

                Nitric oxide is split into a positive ion (NO+) and a free electron (e-). This reduction process is more efficient than electrolysis.  The energy required is 58.2 Wh at 20C (68F) and 1 atm (14.7 psi). It has low output but is simpler than other chemical cycles, has fewer steps, and uses more readily

available chemicals. 70

Summary

                Regarding the costs of these and other thermochemical processes, the observations of L.P. Bicelli are pessimistic. "Owing to the many problems involved, it is difficult to predict whether one of these hydrogen production processes, which are extremely complex from a technical viewpoint, will ever

reach a commercial stage." 100p558

Chapter 4:

Storing Hydrogen

Perspective

                Fuels may be compared by energy per unit of volume and energy per unit of weight. This is particularly important to consider when comparing a very light gas, like hydrogen, to a relatively dense liquid fuel like gasoline. Hydrogen can be stored in a gaseous, liquid, or solid state. Each has distinct advantages and problems.

                A gas storage container must be made of strong lightweight materials. High tensile strength fibers (aramide, glass or carbon) are wound around an inner container. Because its atoms are unusually small, hydrogen can penetrate many materials, so a suitable container must be able to contain the gas without leaking. Used as a fuel, regulators reduce the gas pressure before combustion in the engine.

                Hydrogen liquefies at -253C (-423F). Storage containers must be highly insulated. Typical containers have double walls with a vacuum between them, even so, 1 to 2% of the liquefied fuel is lost per day in evaporation. As a fuel, hydrogen must get from the tank to the engine. Near absolute zero many metals embrittle to shatter like glass, so a specially designed pump is used to supply the engine with the fuel.

                Gaseous hydrogen may be stored inside certain metals called hydrides. Each atom of hydrogen is surrounded by metal atoms. The metal absorbs the hydrogen gas at high pressure and low temperature. Heat and low pressure are applied to release the hydrogen from the metal. The mass of tiny hydrogen atoms follow the heat flow into and out of the metal, charging and discharging the gas as conditions dictate. Heat exchange tubes carry water to add or remove heat from the hydride.

                Exhibit 41 compares the energy content of some common fuels. Exhibit 42 summarizes some of the information in the previous exhibit. A liter of gaseous hydrogen pressurized to 100 atm (1,450 psi) has an energy content of only 300 Watt-hours compared to 8,890 Watt-hours for the same volume of gasoline. The weight of a container is usually 100 times the weight of the hydrogen gas stored in it.

                A given weight of hydrogen has 2.8 times more energy than same weight of gasoline, but on a volume basis liquid hydrogen has only 27% of the energy of gasoline.

                Natural gas has about the same energy per unit weight as gasoline. But for the same range as a gallon of gasoline, 125 cubic feet, at atmospheric pressure are required. Over a ton of lead add batteries would be equivalent to the range of one gallon of gasoline.

                The above figures indicate the impracticality of using pressurized gaseous fuels for use on long-range vehicles. Some gaseous fuels become liquid under pressure (such as propane). Vehicles powered by propane, with their conspicuous cylindrical tanks, are common in fleet vehicle applications.

                Hydrogen can be stored in what is widely mistaken to be a "solid" form. Certain metals like magnesium, titanium, and iron absorb hydrogen when cooled, and release it when heated. Hydrogen remains a gas but is invisibly confined in the spaces between molecules in the metal. When the metal is filled with hydrogen gas it is called a hydride. Although only 1.5 of the weight of fully charged iron-titanium hydride contains hydrogen, the fuel density of the gas is comparable to liquid hydrogen.

                Liquid hydrogen at -253C (-423F) is denser than hydrogen gas but requires costly and complex storage containers and elaborate refueling procedures. The energy required to liquefy hydrogen gas is approximately equal to one-third of the energy in the liquid.

                Although hydrogen makes up only a few percentage of the weight of hydrides, the total volume and weight of the hydrogen gas stored is larger than for liquid hydrogen. Of the three methods of storing hydrogen (gas, hydride and liquid) pressurized gas comes in a poor third for both hydrogen content and energy per unit of volume. However, a hydride system may take up 50% more space than pressurized gas tanks. 76 liters (4.6 cu.in.) of iron- titanium hydride weighs 680 kg (1/500 Ib).

                Hydride compares favorably to electric batteries used in vehicles. Even the advanced batteries predicted for the future (sodium-sulfur and lithium- sulfur) have less than half the energy density (on a volume or weight basis) of magnesium-nickel hydride.

                Hydride is the safest method of storing hydrogen. If a hydride tank is ruptured, the gas remains in the hydride, posing little fire hazard. Pressurized gas vessels are subject to leaks and accidental punctures. Crash tests found liquid hydrogen to be no more dangerous than gasoline.

                Exhibit 43 summarizes features and problems of various fuels. This illustrates that factors other than energy content, like cost, availability, combustion characteristics and auxiliary equipment, must be considered in comparing fuels and energy storage devices.

Pressurized Gas

Low Pressure Stationary Storage

                Atmospheric pressure is about 14.75 psi. Anything less is called a full or partial vacuum, anything more is "pressurized." Inflating a tire to 30 pounds per square inch includes atmospheric pressure. The equivalent of 44.5 psi must be put in because the atmosphere presses on the outside at 14.5 psi. The difference: 44.5 minus 14.5 is 30 psi.

                The pressure and volume of a gas are inversely proportional. Reducing the volume increases the pressure, and vice versa. Pressure times volume is always constant for a given weight of gas. This is the Ideal Gas Law.

                                P1V1 = P2V2

                For stationary applications hydrogen can be stored at low pressure. Hydrogen can be stored in propane tanks at 60 psi. The fuel can be stored at low pressure in 55 gallon drums inverted over a pool of water. See Exhibit 26.

WARNING: Be sure that no air is in the drum prior to or during the storing of the hydrogen. Water and hydrogen must completely fill the space inside the drum. If air and hydrogen mix there is a danger of explosion.

High Pressure Storage on a Vehicle

                Typically the weight of pressure containers is 100 times the weight of hydrogen contained in them. A 136 kg (300 lb) gas cylinder may store one percent of its weight at 408 atm (6,000 psi) giving a range of 96 km (60 mi). 76 liters (20 gal) of gasoline weighs about 52 kg (115 lb). The energy equivalent of hydrogen weighs 18 kg (40 lb), yet the container is 100 times heavier. l90pl081

                New engines designed for the use of hydrogen could weigh 50% less than their gasoline counterparts. 580pl95

                Despite the problems, gaseous hydrogen is the simplest and cheapest form of hydrogen conversion. Its efficiency and range are sufficient for local round trips under 96 km (60 mi). Hydrogen stored at 100 atm has about three times the energy density, and a thousand times the energy per unit weight than lead acid batteries. See Exhibit 41. This gives pressurized hydrogen a clear advantage over batteries now in use.

                One or two gas cylinders are mounted across the trunk or behind the front seats. Stainless steel fuel lines are used to prevent hydriding and embrittlement of the fuel line by the absorption of hydrogen gas.

                Exhibit 44 shows the layout of a pressurized hydrogen storage system adapted for a vehicle used in a UCLA demonstration postal Jeep. Each tank weighs 135 kg (300 lb) and holds one% of its weight in fuel. An aluminum envelope around the tanks prevents any escaping hydrogen from getting into the trunk or passenger compartment. A small blower ventilates the envelope to the outside through the trunk lid or roof.

                The range of this vehicle is 192 km (120 mi) with a straight six engine.

                Ignition and engine vacuum activate two solenoid valves controlling fuel flow. Fuel is diverted into two sets of pressure regulators. The first set reduces the pressure from 408.3 atm (6,000 psi) to 1.1 atm (16 psi). The second set reduces line pressure still further to a vacuum of 0.03 atm (0.44 psi).

                Inexpensive polyvinyl chloride (PVC) tubing may be used after the second set of regulators. The 100 mesh stainless steel screen breaks up any large droplets of water from the water injector system. Water injection is used to cool the combustion temperature to prevent preignition.

                The Impco CA 300 gas mixer is usually mounted on top of the carburetor. If space is not available it may be attached to one side with an offset adaptor. Its functions being assumed by the gas mixer, the carburetor is now used to inject a water spray. The gasoline tank is converted to a water reservoir. Exhibit 45 shows the engine compartment of a Jeep converted to hydrogen. The hydrogen was stored in gaseous form.

Liquid Hydrogen

Comparisons

                The 1991 Oldsmobile shown in Exhibit 46 was converted to liquid hydrogen as part of the American Hydrogen Association's racing program under the direction of Demetri Wagner. The car won awards horsepower and low exhaust emissions in competitions for alternate energy vehicles. The engine compartment is shown with its electronic ignition and fuel system controls. The trunk holds the liquid hydrogen tank. It has a three gallon capacity and gives a range of about 160 km (100 miles.)

                As can be seen in Exhibit 47, a vehicle run on liquid hydrogen has the greatest range and highest energy density of the hydrides and liquid fuels listed. Compared to gasoline, liquid hydrogen has three times the energy and one-half the weight. The following table is a comparison of performance on gasoline and liquid hydrogen. The range is the same with both fuels. 1000p124

                If the liquid hydrogen vehicle carried its own liquid oxygen the range would be reduced by 75%, as shown in Exhibit 47. Any other fuel would be similarly handicapped if it could not make use of atmospheric oxygen.

                Storage of liquid hydrogen in tanks of 3,400 cu.meter (900,000 gal) have only 0.05 to 0.03 boil-off per day. ensuring a supply lasting five years. 76 liters (20 gal) of liquid hydrogen weigh 54.4 kg (120 lb). 1870 cu.meter (66,000 cu.ft.) of hydrogen weigh 900 kg (2,000 Ib), including the cryogenic tank.

                Exhibit 48 compares the properties of liquid hydrogen and liquid methane (or liquefied natural gas). Methane liquefies at a 38 higher temperature but requires about seven times as much energy to vaporize it (its heat of vaporization). Liquid methane is also about seven times denser than liquid hydrogen. Natural gas is liquefied for shipment on super tankers. It stays liquid for the duration of the voyage and weighs less than gas cylinders.

                The energy required to liquefy hydrogen is equal to about of its energy. For 0.5 kg (1 Ib.) of hydrogen, 5 kWh of electrical energy is required. 200

Liquefaction Plants

                A proposed plant designed to liquefy and store electrolyzed hydrogen is shown in Exhibit 49. Water vapor is removed prior to storage. Some hydrogen is lost due to boil-off. It is recycled and liquefied, as shown. Exhibit 50 shows the capital and operating costs for the same plant. 30p576

                In commercial processes in the U.S., liquefaction costs are 20% of the price of the product. Electricity is from 45 to 70% of liquefaction costs. 900p5-22

                Hydrogen was first liquefied in 1898. The first large scale plant in the U.S. was completed in 1952 at Boulder, Colorado, for the National Bureau of Standards. Its capacity then was 450 kg/day (0.5 ton/day). Today it is 55,000 kg/day (60 ton/day). The cryogenic tanks hold 3,400 cu.m (900,000 gal). 580

                If the process were 100% efficient, it would require only 7.7 kWh/kg for hydrogen liquefaction. It is typically 33% efficient, or about 28 of the energy content, 23.1 kWh/kg of liquid hydrogen. 140

                The current price of liquid hydrogen, as of 1998, is about $1.20 to $2.60 / kWh ($350.00 to 760.00 / million BTU). 580

                One way to improve the 30 to 33% efficiency of conventional refrigeration is to use the gas pressure generated during electrolysis. Oxygen, under pressure, rapidly expands to absorb heat from the hydrogen passing through a heat exchanger. Precooled hydrogen takes less energy to liquefy. 850

Magnetocaloric Effect

                Another experimental method exploits the effect of magnetic fields on certain materials, such as gadolinium alloys. When placed in a magnetic field, the material heats up. It cools when removed. In stages, hydrogen gas is cooled by contact. Different materials are used at each cooling stage.

                Rotating a wheel of the special material in a magnetic field alternately immerses and removes the material from the field. After the heating phase the material is cooled by a heat exchanger.

                A strong magnetic field is needed (60,000 to 100,000 Gauss). Superconducting materials could be used to reduce the current needed.

                John A. Barclay of Los Alamos National Lab expects the efficiency of this process to exceed 60%. This is double the efficiency of conventional refrigeration. Liquefaction costs could also be cut in half.

                The most economical method of liquefying hydrogen may be to combine gas compression with the magnetocaloric process. Four stages of compression and cooling would bring the gas temperature down sufficiently for a single magnetocaloric stage to efficiently cool it to a liquid. Gas compression is the most costly. Magnetocaloric technology would take only one-eighth of the energy value of hydrogen to liquefy the hydrogen.

Cryogenic Tanks

                In the early 1950s, simple vacuum bottle-type devices were used to store liquid hydrogen and other low temperature gases. Later improvements put powder insulation (perlite) in the vacuum space and added a reflective heat shield on the inside of the tank to reduce radiant heat losses. The heat transfer through the wall is cut to one-tenth of the earlier "vacuum bottles."

                The newest tanks use alternate layers of glass fibers and metallized plastic film in the vacuum space. This quilted super insulation, pioneered by the Linde Corporation, reduces heat leakage by another one-tenth. The walls of the Linde tanks are about 5 cm (2 in) thick compared to the 91 cm (3 ft) thick walls of the previous technology. 580p5l

                The largest tanks have a boil-off rate of 0.06/day. A 100 cu.m (3, 500 cu.ft.) tank has a boil-off of 0.2/day at 20C (68F). Demetri Wagner, manager of the American Hydrogen Association's Racing Program, has drag-raced a liquid hydrogen-powered car. See Page 4. The boil off loss for his 75 liter fuel system is 0.5% per day.

                Approximate costs for liquid hydrogen fuel tanks (1995$) are: 900p7

• •     3/800 liters (1,000 gallons)              up to $100,000
• •     380,000 liters (100,000 gallons)         up to $1,000,000
• •     3,800,000 liters (1,000,000 gallons)             up to $10,000,000

                Exhibit 51 shows the relative sizes of various containers storing 3,000 cu.meter (106,000 cu.ft.) of hydrogen gas. 870p325 Exhibit 53 presents summary data from experiments with liquid hydrogen storage tanks.

                The Department of Energy and Brookhaven National Lab. spent $447,000 to improve liquefied natural gas storage for heavy-duty vehicles. Cummins Westport. Engines developed direct injection and advanced fuel management technology. LNG is stored on board at -160C (1256F) along with pressurization and pumping equipment. 17 engines passed road trials covering 1.3 million miles. The technology will be marketed in 2004. 32

Ortho to Para Conversion

                Hydrogen atoms tend to group into pairs to make up hydrogen molecules. In it’s natural state hydrogen gas is a mixture of two kinds of molecules. In orthohydrogen the protons in the atoms of each molecule spin in the same direction. It is slightly magnetic. In parahydrogen the protons spin in opposite directions.

                At 20C (68F) and atmospheric pressure, hydrogen gas is 25 para and 75 ortho. When liquefied, 99% of the orthohydrogen is converted to parahydrogen.

                Ortho to para conversion gives off heat: 196.8 Wh/kg (304.8 BTU/lb). This heat accelerates the evaporation of liquid hydrogen. In Exhibit 52 the evaporation rates of liquid hydrogen for various beginning percentages of parahydrogen are given. 580p6l

                A special catalyst increases the ortho-para conversion in hydrogen before the gas is liquefied. If all the heat that ordinarily goes into the conversion is removed before liquefaction takes place, energy is saved. Experts claim that this procedure is cost effective only if the liquid hydrogen is to be stored for more than 36 hours. 580p55

Using Liquid Hydrogen as a Coolant

                Liquid hydrogen is evaporated back to the gaseous state just before it is burned as a fuel. The cooling properties of the liquid can be exploited to recover part of the production costs. Various possibilities for this thermal energy include food warehousing, liquid air production, and turbine blade cooling in jet engines.

                Energy can also be recovered from liquefied natural gas. The energy is four times greater, on a weight basis, than that recovered from liquid hydrogen. This is due to the lower molecular weight of hydrogen. 900p5-22

Liquid Hydrogen as an Aviation Fuel

                Aircraft fueled with liquid hydrogen use 19 less energy than with fossil fuel. For supersonic aircraft, the advantage is 38. 610 Since hydrogen fuel is lighter, this reduces the weight of fully loaded aircraft and allows shorter wingspans. By 2040 all long range flights may use hydrogen. 100

                The properties of liquid hydrogen can be used in jet aircraft to cool engine parts and the skin of the craft flying at supersonic speeds. The cooling capacity is 20 times higher than that for jet fuel. Nasa and Lockheed deem hydrogen the only fuel capable of powering hypersonic planes. 580p826

                Planes that fly 6,400 km/hr (4,000 mi/hr) may be in commercial operation by 2030. See Exhibit 54. Only hydrogen burns fast enough to propel an air-breathing craft from London to Sydney in 67 minutes. This is possible with planes that fly part of their journey in orbital space at speeds usually associated with spacecraft. This hybrid airplane/spacecraft is called a transatmospheric vehicle. It takes off from conventional runways to travel beyond the atmosphere at 24, 000 km/hr (15,000 mi/hr). Once in space, low air resistance makes high speeds possible. After a brief flight the craft will plunge back into the atmosphere and land on a runway.

                One such craft, under development, is the British Horizontal Takeoff and Landing Launcher (HOTOL). The plane is air-breathing at low altitudes and acts like a rocket with its own liquid oxygen supply in space. Using the atmospheric oxygen reduces the amount of liquid oxygen stored on board.

                NASA's Hypersonic Transport (HST) may serve several of purposes: a transport, orbital bomber, or reconnaissance craft. Boeing, General Dynamics, and Rockwell are the major contractors. The ability of the HST to take off and land reduces operating costs one fifth compared with the space shuttle for low orbits and one-half for geosynchronous orbits at 35,200 km (22,000 mi).

                Aerojet General is developing an air turbo-ramjet. It works like a conventional turbojet, using hydrogen fuel up to a speed of 4,800 to 6,400 km/hr (3,000 to 4,000 mi/hr). This is the upper limit for turbojets on any fuel. Above this speed, the supersonic ram jet is used. In orbital space, liquid oxygen is used. The U.S. Defense Department spent $90 million on it in 1986 and plan to spend $90 billion over 15 years. 880p745-746

                For more conventional aircraft, both liquid methane, and liquid hydrogen, have been proposed. Exhibit 55 compares the relative placement and size of the fuel tanks on three converted Boeing 747s with the same range. 30p584 This subsonic plane flys at about 1,041 km/hr (650 mi/hr).

                The petroleum-based fuel widely used for aircraft, jet A, is generally stored in unused spaces in the wings.

                Liquefied gases must be stored in containers with a low surface to volume ratio. Cryogenic fuel tanks are shown in the fuselage, one behind the wings and one in front, for balance.

                The diagram shows that Liquid hydrogen occupies the greatest volume, but is the lightest. Exhibit 56 shows that a liquid hydrogen craft when fully loaded weighs less than a similar craft with liquid methane. For shorter distances of 3,250 km (2,020 mi) liquid hydrogen imposes a 20% weight penalty - the tanks are emptied more frequently. See Exhibit 57. The shorter range tanks have less volume, but the weight of the tank is proportionately more than for a larger volume tank on the longer distance craft in Exhibit 56. Liquid hydrogen has the greatest advantage at longer distances and higher speeds.

                Specifications for a proposed facility for one aircraft are below. 900p5-22

• Flight schedule                                                                                                     one per day. 4/800 km (3,000 miles).
• Fuel on board                                                                                                                       25,000 kilograms (55/000 Ib.)
• Fueling times                                                                                                                        38 minutes.
• Supply needed (including boil-off and transfer losses):               3,000 kg/day (6,600 Ib/day).
• Plant output:                                                                                                                         36,000 kg/day (80,000 Ib/day).
• Electric power needed                                                                                         40 MW.
• Excess fuel storage needed                                                                                14,000 cubic meters (494,000 ft3).
• Minimum stored                                                                                                   10 days supply.
• Means of transfer                                                                                                                pipeline transfer with gas recovery.
• Boil-off rate                                                                                                                           1,000 kilograms/hour (2,200 Ib/hr).
• Liquefaction rate                                                                                                  1,000 kilograms/hour (2,200 Ib/hr)

Cryogenic Auto Fuel

                Liquid hydrogen offers some of the same advantages and disadvantages for automobile fuel as it does in aviation.

                Researchers converted a 1973 Chevrolet V8, 5.7 liter (350 cu.in.) to liquid hydrogen. Ifs range was 483 km (300 mi). Fuel use was equivalent to 11 km/liter (25 mi/gal) of gasoline. A 1975 Datsun B210 with 1.4 liter (84 cu.in.) displacement ran for 2,784 km (1,730 mi) on 231 liters (61 gallons) of liquid hydrogen. Two tanks, each 20.3 cm (8 in) in diameter and 109.2 cm (43 in) long, stored 32 kg (70 lb) of liquid hydrogen. 586 kwh (2,000,000 BTU) of energy was stored. The gasoline fuel use equivalent was 12 km/liter (28 mi per gal). The total cost of the stored hydrogen was $263.

                A postal Jeep was converted to liquid hydrogen. The tank refilled in 15 minutes. It used 1.3 cm (0.5 in) bayonet fittings to refuel. The manual fill vent was opened, then the fill valves opened to transfer the fuel. The fuel lines were vacuum insulated.

                The engine produced only 0.04 grams per mile of nitrous oxide compared with the 1977 federal standard of 0.49 grams per mile.

                The six cylinder Jeep postal truck used a Minnesota Valley Engineering ULH-50G spherical tank. Two concentric shells separated by a vacuum space kept the liquid hydrogen at -253C (-423F) and prevented water condensation. The diameter of the outer sphere was 86.4 cm (34 in), and the inner sphere was 71.1 cm (28 in). The material was spun aluminum with 1.2 manganese giving a total weight of 42.6 kg (94 Ib) empty and 56.3 kg (124 Ib) when full The 189 liters (50 gal) of fuel boiled off at 3.3 per day.

                A heater in the tank, see Exhibits 58 and 59, maintains gas pressure for fuel flow when the engine is running. It uses 25 to 30% of the heating value of the fuel to vaporize the gas. Its composition was 22 gauge nichrome wire in a conical-shaped spiral wrapped around four phenolic supports epoxied to the bottom of the fuel withdrawal tube.

                Raising the temperature of liquid hydrogen from -253 to 27C (-423 to 81F) requires 1,100 Wh per kg (1703.66 BTU per lb). Compare this to the heat of vaporization of water which is 631Wh per kg (977.28 BTU per lb).

                An automatic feedback shuts off the heater when the tank is empty to avoid heat damage to the tank. When the temperature goes over 21C (70F) a Motorola 320M7348 diode, wired in parallel with the heater, short circuits, a fuse blows and the heater goes off.

                A 0.15 cm (0.06 in) thick stainless steel splash shield separates the passenger compartment from the liquid hydrogen tank. The tank is vented through the rear roof.

                In crash tests, the mail truck did not burn, nor spill any fuel. The researchers report that liquid hydrogen fuel is as safe as gasoline. 380

                Billings Energy Corp. converted a 1979 Buick Century to liquid hydrogen for use at the Los Alamos National Laboratory in New Mexico. See Exhibit 60. Notice the large liquid hydrogen storage tank in the background.

                Fuel consumption is 2.4 km per 1 (5.6 mi per gal). Energy consumption is 2,557 kWh/km (5.4 million BTU/mi). Acceleration to 80 km/hr (50 mi/hr) took 13 seconds. Range was 354 km (220 mi). The tank is 66 cm (26 in) high and 86 cm (34 in) in diameter and holds 151 liters (40 gal) of liquid hydrogen. Liquid hydrogen costs the experimenters $0.97/1 ($3.66/gal). The tank has an insulated space between double shells.

                When refueling, a hydrogen detector is used to check for leaks. Then, the refueling hose is connected and air is removed from the fuel lines. The tank is filled, and fuel line purged of hydrogen, and hose is disconnected. If the empty tank is at atmospheric temperature, chilling is necessary before fueling. Refill time may take 15 to 30 minutes.

                In a later development, a single cylinder reciprocating pump delivered fuel from a 150 liter (39.6 gal) tank . The pump is located inside the tank. With the piston held stationary, the barrel moves up for the delivery stroke and down for the suction stroke. In this arrangement, the piston rod is under tension, not compression. This permits a thinner piston rod with less mass and with less heat inflow. Clearance between the plunger and barrel is minimized to around 1.5 micrometers (0.00006 in). See Exhibit 62.

                A heat exchanger evaporates the liquid hydrogen in the fuel line. A small tank between the pump and the engine stores the gaseous hydrogen. As can be seen in Exhibit 63, a computer regulates the electric motor driving the pump to maintain a constant pressure in the gaseous hydrogen tank.

                A fuel vaporizer heats the liquid hydrogen fast enough to meet engine demand. If only boil-off gas is used, a speed of only 0.04 meter per sec. (0.1 ft per sec) is possible. Fuel consumption of 5.5 km/liter (13 mi/gal) on gasoline is thermodynamically equivalent to 3.2 km/liter (7.5 mi/gal) on liquid hydrogen. 650 W of energy for evaporation are needed to sustain a speed of 44.7 meters per sec. (147 ft per sec.).

                Fuel is injected into the liquid hydrogen tank at the rate of 56.8 liters/min. (15 gal/min) through a 1.3 cm (0.5 in) inside diameter fill line and a 5.1 cm (2 in) inside diameter vent line. Refills take 3 min. without "excessive fill losses." 319 The tanks are cleaned annually to remove dirt and discover leaks. There is a boil off of 1 per day without loss of hydrogen from venting the safety valve. Y. Rotenberg found that the boil-off rate of a liquid hydrogen tank being vibrated when driving is 12 times greater. 790p729-735

                The vehicle using the above system, a small diesel truck, has a range of 230 km (143 mi) on one tank of liquid hydrogen. There was no change in power compared to its former diesel operation. See Exhibit 64. 780p427

                Shoichi Furuhama, experienced in hydrogen-fueled vehicles, entered a converted diesel truck in the Vehicle Design Competition as part of the Vancouver, Canada, Expo 86. The project was sponsored by the Musashi Institute of Technology of Japan over 16 years. It won second place in the 150 km (94 mi) 3 hour race. Only 30% of the vehicles that started finished. Vehicle specifications were judged to be the optimum combination for best performance, low noise, low vibration and nitrous oxide emissions. 780p429

• Manufacturer: Hino Motor Co.
• Weight: 2,550 kg (5,622 Ib).
• Engine: diesel, 4 cylinder.
• Compression ratio: 17:9.
• Fuel mixing: injection, turbo.

                The fuel is ignited by a hot ceramic surface at 950C (1,740F). The temperature of the fuel is electronically controlled for ignition at all operating temperatures.

                The German DFVLR (Institute for Energy Conversion) in Stuttgart experimented with a liquid hydrogen tank. Like the Musashi truck, they minimized boil-off during operation by removing both liquid and vapor from the tank in response to engine demand. The cylindrical aluminum tank is 40 kg (88 Ib) in weight and holds 120 liters (32 gal). The maximum design pressure is 7.9 atm (116 psi) but usually operates at about 40 to 45% of this. A boil-off of 5.2 liters (1.4 gal) per day implies a heat leak of 2 W for this storage system. See Exhibit 65.

                At the Ninth World Hydrogen Energy Conference in 1992 at Paris, BMW presented a hybrid gasoline-liquid hydrogen vehicle. With their new tank design practically no hydrogen is lost during filling. The tank can be filled in 15 minutes.

                With 50 million fans in the U.S., racing is good publicity for hydrogen. The Tennessee State University race car is shown on the title page. Demetri Wagner, manager of the American Hydrogen Association's Racing Program, has drag raced an Oldsmobile at 439 km per hr (273 mph) on 2.3 liters of liquid hydrogen at 7500 rpm. See Exhibit 46. The car is a "Quad-4", with a 2.3 liter engine with a forged steel crankshaft and pistons, double overhead cam and 4 valves per cylinder. It raced in the "Unlimited Fuel" class. The 75 liter tank (20 gal.) is refueled from a 500 liter (132 gal.) tank at the pit stop. Before refueling liquid hydrogen circulates to cool the tank. A break off valve instantly seals when the fill nozzle is removed.

                Exhibit 66 shows major liquid hydrogen vehicle experiments. 7l0p72l 91

Recovering Refrigeration Energy

                It is possible to use the cryogenic properties of liquid hydrogen to boost the efficiency of the vehicle. The boil-off can be used to cool the engine when the ignition is off or to supply hydrogen to a fuel cell to charge batteries.

                Air is a mixture of gases. It is approximately 70% nitrogen and 20% oxygen. Each of the atmospheric gasses liquefies at different temperatures. Nitrogen liquefies at a higher temperature than oxygen. The boiling point of liquid hydrogen is below most atmospheric gases. For example, air coming into contact with un-insulated liquid hydrogen fuel lines will liquefy nitrogen before the oxygen. Oxygen can thus be separated out from the air and used in pure form in engine combustion. Suitable devices that accomplish this have yet to be designed and tested in vehicles.

                In stationary applications, evaporating liquid hydrogen can drive a Stirling engine which can turn a generator. Invented over 100 years ago, the engine runs on temperature differences, not combustion. 580 The engine has high efficiency and is relatively quiet and vibration free. Having a low power to weight ratio, it is too heavy to use on board a vehicle as the primary power source.

                The Lewis Research Center in Cleveland, Ohio developed a new alloy. It is low in chromium and cobalt, low cost, resists oxidation and corrosion, does not become excessively brittle at cryogenic temperatures or promote hydrogen permeation, and is capable of being welded and fabricated.

Railroads

                In a 1976 the U.S. Department of Transportation study found liquid hydrogen to be preferable to hydride storage in railroad locomotives. It would have high pressure injection at 238 atm (3,500 psi). Iron-titanium hydride would increase the weight of locomotives 12 times and cost by 10 times but would have a longer life and less pollution. Diesel locomotives have from 8 to 20 cylinders, are naturally aspirated and turbocharged, with 750 to 2240 kW (1/000 to 3,000 hp) power output. The train tows, a fuel car behind the engine. The 106,000 liter (28,000 gal) car would weigh 35,800 kg (79/000 Ib).

                Liquid hydrogen would increase power output by 15% to 20% while decreasing thermal efficiency 1% to 2%. Exhaust heat recovery would improve efficiency 5%. Turbo charging would boost power by another 32% to 44%. Longer life and lower hydrocarbon emissions can also be expected. Diesel fuel is cheaper but future increases in imported fuel prices can make hydrogen competitive. "With regard to technological and operating feasibility, the DOE study concluded that locomotive diesels can be converted successfully to hydrogen." 20lp60

Hydride Energy Storage

Using Heat to Store Hydrogen

                A hydride is any compound containing hydrogen. Groups of hydrides are shown below according to where they are found in the Periodic Table of Elements. In the ionic hydrides hydrogen carries a more negative charge while with the volatile hydrides the charge is positive.

Ionic                                       Metallic or                                                             Polymeric                               Volatile

                                                Interstitial                                                              Solid

LI                                                                                                                            Be                                           B C N O F

Na                                                                                                                           Mg          Al                            Si P S Cl

K             Ca                           Sc Ti V Cr Mn Fe Co Ni       Cu           Zn                           Ga Ge As Se Br

Rb           Sr                            Y Zr Nb MoTc Ru Rh Pd    Ag Cd                    In Sn Sb Te I

Cs           Ba                           La Hf Ta W Ra Os Ir Pt                       Au Hg                    TI Pb Bi Po At

Fr            Ra                           Ac Pa U Pu

The Metallic (or interstitial) hydrides carry hydrogen between the atoms of metal. The hydrogen proportion does not have to be a whole number. Example: vanadium and thorium hydrides are written: VH0.6 and ThH3.1. This group is used most frequently to store hydrogen. The metals that most strongly absorb hydrogen are: ruthenium/ rhodium/ palladium/ osmium/ iridium and platinum. These are not necessarily the best for use as fuel storage. Other considerations such as temperature at which hydrogen is absorbed or emitted also come into play.

                P. Solvani describes a hydride energy storage system as "...the only system where energy and environment are not adversaries." 830pl69 Hydrides use special metals that absorb hydrogen when cooled and release the gas when heated. The hydrogen atoms dissolve into the metal and "hide" until released by heat.

                The hydrogen content of a volume of fully charged hydride exceeds an equal volume of liquid hydrogen. However/ the energy content for an equal weight of hydride is less than for an equal weight for liquid hydrogen. Liquid hydrogen contains from 10 to 100 times as much hydrogen as hydride/ on a weight basis. 770p22 Nevertheless, the energy required to refrigerate and the problems of storing liquid hydrogen make hydride preferable in some cases.

                When being charged with hydrogen, the hydride material is cooled. Absorption proceeds up to a certain equilibrium pressure called the dissociation pressure. The exact value of the dissociation pressure depends upon the hydride material used and the temperature. When this pressure is reached, the pressure of hydrogen being forced into the hydride must be increased in order to get the hydride to absorb more hydrogen.

                Exhibit 67 shows the amount of hydrogen that can be absorbed at different pressures. Several curves are shown. 460 Each curve shows hydrogen absorption taking place at a constant temperature. The top curve shows results for the highest temperature. The bottom curve assumes the lowest constant temperature. The higher the temperature, the higher the pressure needed for the hydride to accept the hydrogen.

                For each curve, increasing pressure is needed to get the hydride to absorb more hydrogen. The broad flat plateau area of each curve means that at a certain pressure (the dissociation pressure) hydrogen can be absorbed without increased pressure. When the hydride becomes saturated, more pressure must again be applied to absorb more hydrogen.

                When discharged, heat is applied to the hydride and hydrogen is driven out of the metal. Unless the hydrogen gas in the hydride container is removed, pressure will build up and the discharge will stop. The gas must be continually removed to relieve pressure so that the process can continue.

                Sievert's Law gives the approximate concentration of hydrogen in hydride.

                                H2 concentration = RP172

• k = equilibrium constant of the hydride material.
• P = equilibrium pressure (as shown on the curve).

                By using heat efficiently, a storage system makes the best use of the hydrogen gas stored and the hydride metal used to store it. During discharge, the amount of heat added to the hydride should be able to fully discharge the hydride without increasing the hydride temperature and losing heat to the environment. During charging, the amount of heat energy withdrawn from the hydride material should be approximately the same as the amount of heat energy added during discharge. Designing the system so that the heat energy is used efficiently means bringing the amount of heat added during discharge as close as possible to the amount of heat withdrawn during charging. Making the heat input approximately equal to the heat output minimizes energy losses. The ability of the hydride to absorb heat determines the amount of energy needed to saturate all the hydride with hydrogen without wasting either the gas or the hydride.

                The thermal capacity of the hydride material determines the best amount to use without either wasting this expensive material or under powering the vehicle. The thermal capacities of selected materials are given in Exhibit 68.

Heat Exchange Fluid

                The temperature of water from the local water company can cool iron- titanium hydride during charging. The heat absorbed by the water can be stored in the thermal materials mentioned above. If this water is kept out of contact with the hydride it may also be used in a domestic hot water system.

                If an aluminum container of iron-titanium hydride is used. Then the amount of water needed for heating and cooling a given mass of hydride is calculated as follows. 201

                                MH20 / MmH = ( MH / MmH X hsg / dT) - CmH - ( Mal / MmH) X (Cal / CH20)

• MH20 = mass of cooling water.
• MmH = mass of hydride.
• MH = maximum weight of hydrogen that can be stored
• MH/MmH =0.016
• CmH = heat capacity of metal hydride = 0.026 Wh/kgoc (0.04 BTU/lb°F).
• Mai = mass of aluminum container = 27 weight of hydride (typically).
• Cal = heat capacity of aluminum container =0.139 Wh/kg (0.215 BTU/lb).
• CH20 = heat capacity of water coolant = 0.646 Wh/kg (1.0 BTU/lb).
• hsg/dT = 6,500oC/ temperature change.

Usually, iron-titanium dT = 88.0 - 4.4C = 83.6C (183F). Solving for the typical values given above we get 48.3. Therefore, in this case, the cooling and heating water makes up about 50% of the weight of the iron-titanium in an aluminum container.

                "Hydride formation takes place faster near the cooled boundary walls and slower around the core region of the bed. It is found that the fluid flow effects the temperature distribution in the system, however, it does not significantly impair the amount of hydrogen absorbed." 25 p. 1049

Types of Hydride

                A wide variety of metals can be used to absorb hydrogen according to the general reaction:

                                M + xH2 —> MH2x + heat

The metal (M) releases (desorbs) hydrogen in a similar manner. 940p990-l29

                                MH2x + heat —> M + xH2.

                The curves in Exhibit 67 apply to most hydride materials. Any particular hydride curve will have its own unique characteristics, but the general shape, including the plateau, is the same for all.

                Exhibit 69 shows absorption-desorption curves for specific hydrides. l90p2l4 The plateaus for some hydrides are steeper than for others. The steeper the plateau, the less stable the hydride is. All the curves are held constant for 25C (77F). Hydrogen is released from iron-titanium (FeTi) at pressures above 1 atm (14.7 psi) and temperatures above -20C (-4F) when fully charged. A different curve is shown for FeTi at each of four different temperatures. The temperature of auto exhaust is sufficient to guarantee a supply of hydrogen fuel from a FeTi hydride-powered car. Most of the hydrides also contain nickel. For comparison. Exhibit 69 shows curves for a different hydride, lanthanum-nickel.

                At atmospheric pressure, magnesium hydride holds more hydrogen per unit weight than FeTi but must be heated to higher temperatures, 204C (400F), as opposed to 20C (68F), to release its stored hydrogen. In both LaNi and FeTi hydrides the equivalent of 10% of the energy of the stored hydrogen is needed to absorb and release hydrogen from the metals. 8.3 Wh/mole of hydrogen is stored.

                FeTi weighs two times as much as magnesium hydride and holds only one-fourth as much hydrogen on a weight basis.

                Each hydride has a different combination of properties as shown in Exhibit 70. However, for automotive applications only certain properties are needed. 870p325

• Rapid absorption and desorption of hydrogen.
• Reversibility of the hydriding/dehydriding reaction.
• Sensitivity to changes in pressure and temperature.
• Rejection of aU gases except hydrogen.
• Holding a high percentage by weight of hydrogen fuel.
• Durability: hydride must hold up under 300,000 or more cycles.

                In some hydride alloys expensive metals may be replaced with cheaper ones to give similar performance. Lanthanum is sometimes replaced with mischmetal:a mixture of rare earth metals as found in nature. It is possible to substitute aluminum for nickel in MnNi hydride. This reduces the hydrogen capacity but increases thermal stability. 460

Exhibit 71 shows the "bottom line" comparison between FeTi/ magnesium nickel (MgNi), and pure magnesium (Mg) hydrides.  For the same volume of hydrogen stored/ a vehicle using Mg can go twice as far as either MgNi or FeTi. FeTi has twice the weight of either MgNi or Mg. When the weight of the hydride material is held constant/ magnesium holds four times/ and MgNi holds twice, the amount of hydrogen as FeTi. For a constant distance traveled, a vehicle using FeTi has a substantial weight penalty.

                Magnesium has the highest storage capacity: 6 to 7 by weight. One- fifth cu.meter (7.1 cu.ft.) of magnesium is equivalent to 216 liters (57 gal) of gasoline.  221 kg (488 lb) of magnesium hydride store 16.8 kg (37.0 lb) of hydrogen or the energy equivalent of 45 kg (100 lb) of gasoline.

                Magnesium hydride loosely packed in a container has empty spaces between grains of hydride. These void spaces typically take up 40% of the total volume. The void space is not wasted, however. This space allows for gas to enter and leave the hydride. The above amount of magnesium hydride takes up 253 liters (8.9 cu.ft.). This is equivalent to 237 liters (8.37 cu.ft.) of liquid hydrogen. 580p207

                Magnesium is the cheapest hydride at less than $5.00/kg ($2.27/lb). Disadvantages include a high working temperature, over 280C (536F) at 1 atm (14.7 psi) and a large amount of energy is needed for dissociation: 10,331 Wh/kg (16,000 BTU/lb) of hydrogen. Engine heat is not enough to flush out enough hydrogen. The energy to dissociate magnesium hydride is 15% more than the energy stored. 201

                Magnesium and magnesium nickel hydrides have a tendency to fracture with repeated charge/discharge cycles. The pea-sized hydride particles are reduced to a fine powder that packs down and impedes gas flow. This reduces the storage capacity.

                Contaminants are also a problem with magnesium hydride. The dehydrided metal, when contaminated with oxygen, forms oxides such as magnesium oxide and magnesium hydroxide that form a film around the metal particles and reduce absorption. 830

                With half the weight of FeTi, Magnesium nickel hydride has the same advantages as pure magnesium; 870p325 high hydrogen content (over 7 by weight) and low storage costs $5.00/kg ($2.27/lb) and low density. 650pl82l

                Working temperatures are similar to pure magnesium, but magnesium nickel requires less energy for storing and releasing hydrogen- 8/846 Wh/kg (13,700 BTU/lb).

                FeTi has the lowest hydrogen capacity: (1 to 1.9 by weight). 134 kg (295 lb) of FeTi is equivalent to 75.7 liters (20 gal) of gasoline. Hydrogen burns more completely than gasoline, it could increase engine efficiency over the 30% of fossil fuels. Only 103 kg (227 lb) of hydride would be needed.

                The density of FeTi exceeds that of the other two hydrides. Energy densities are high compared to electric batteries: 143 Wh/kg (221 BTU/lb). 580

                The main advantage of FeTi is in its low heat of dissociation 25C (77F) at 5 atm (73.5 psi). The energy involved in storing hydrogen is 4/681 W/kg (7,250 BTU/lb) at 1 to 10 atm. (14.7 to 147 psi). 201

                FeTi also does not decompose as readily with repeated hydriding cycles as do the other two hydrides.

                For the above reasons, FeTi is the most commonly used hydride in automotive applications. The metal is ground into pea-sized particles. Exhibit 72. The coal-like texture of the particles is shown in Exhibit 73.

                Hydride metals can be mixed together to exploit the combined advantages of each. TiMgNi stores 11% of its weight in hydrogen. 549p9l5

Hydride Packing

                Hydriding and dehydriding expands and contracts the hydride material. This tends to split the granules into finer and finer particles. The problem is greater with magnesium, magnesium nickel, and lanthanum nickel hydrides. After thousands of cycles, the particles become like flour. A filter can keep the powder out of the fuel flow system. As the particles and void spaces get smaller, the hydride packs down in the container. Less of the hydride's surface area is exposed to the incoming hydrogen during charging.

Storage capacity is diminished. The expansion and contraction of the material stress the container, even bursting it. Solutions to packing include:

• Increasing the absorption and desorption times to allow the particles to adjust more gradually to the thermally induced stresses.
• Hydride ground into powder and squeezed into pellets. An inert metal bind the hydride and reduces the rate of thermal change in the hydride.
• Suspending hydride powder in a liquid and bubbling hydrogen through it. This increases contact with the hydride and eliminates packing stresses on the vessel. However, the added mass of the liquid reduces the system's overall energy content per unit weight. Experimenters used 2,2,4 trimethylpentone (isooctane) as the liquid and lanthanum nickel aluminum as the hydride. 650pl82l

• Using FeTi essentially eliminates these problems.

Contamination

                Hydrides are also susceptible to contamination by reactive chemicals such as carbon dioxide and oxygen. 300 parts per million (300 ppm) of carbon dioxide reduce the capacity of hydride 50 over five cycles. Oxygen, similarly, impairs the storage efficiency of hydride materials. Hydrogen must avoid contact with the air to operate most efficiently. The air in the tank and fuel lines should be vented prior to charging to prevent contamination of the hydride and to avoid explosions. Nitrogen could be used to purge the tank of gaseous contaminants.

                In magnesium-based hydrides 10% nitrogen contamination reduced hydride to 50 cycles before becoming unusable and the hydrogen storage capacity 20%. With oxygen the maximum number of cycles was 50 with a 45% hydrogen storage loss. With Carbon dioxide: 10 cycles and a 100% loss. l55p909

Heat Exchange Systems with Magnesium Hydride

                For 100 g (0.2 lb) of hydride, or less, no heat exchanger may be needed. This is particularly true if the tank is aluminum or any other metal with an equal or better rate of heat transfer. Magnesium hydride fuel systems adapted for use in an automobile need heat to start discharging. Heat from the engine exhaust or coolant is used for this purpose. Lanthanum nickel starter hydride can be used to start the engine and get it warmed up to the point where it has enough heat to release hydrogen from the magnesium hydride. Lanthanum nickel requires over 30C (86F) to discharge.  Magnesium hydride requires more heat than lanthanum nickel to discharge hydrogen. The system also has a booster heater powered by hydrogen from the lanthanum nickel tank. This dual hydride system is used where the hydride tank is very large in relation to the size of the motor.

                An auxiliary heater is needed to start discharging lanthanum nickel. A separate high pressure small gaseous hydrogen tank may supply the heat.

                A thermostatically controlled blower could circulate part of the hydrogen through an exhaust or engine coolant heat exchanger. The heated hydrogen is used to force more hydrogen from the tank. The engine must be warmed up for this to work.

Heat Exchange Systems with Iron-Titanium Hydride

                FeTi with low dissociation temperature compared to magnesium or magnesium nickel, still needs more heat than what it can get from the engine. The extra heat may come from the engine exhaust or the coolant.

                Engine exhaust passes through metal tubes running through the hydride tank. An intermediate heat exchanger may also be used. The one shown in Exhibit 74, absorbs heat from the exhaust and passes it on to a circulating fluid that runs through tubes in the hydride tank. Or it can circulate in a jacket around the hydride tank. The fluid can be a water and antifreeze mixture. Water transfers heat to the hydride more efficiently than exhaust.

                The exhibit shows an exhaust system with a valve that can divert some or all of the exhaust to the heat exchanger. The unused exhaust bypasses the heat exchanger and is vented outside. All the exhaust heat is needed to start. When a sufficient rate of dehydriding is reached, half of the exhaust is diverted to avoid boiling the circulating fluid. During brief periods when the hydride overheats, all the exhaust passes by the heat exchanger. There are, however, two main drawbacks to this system.

• Reduced dependability of parts immersed in the exhaust stream.
• The heat exchanger impedes the flow of the exhaust, thereby creating back pressures reducing engine power.

                Usually only 13 of the engine coolant heat is needed to discharge the FeTi hydride. 35% of the heating value of the engine fuel ends up in the engine coolant. 201 Exhibit 75 shows an engine block serving as the heat exchanger between exhaust and liquid coolant. The coolant can be diverted from the radiator to the hydride tank. The hydride tank serves as a second radiator. The amount of coolant to the hydride can be varied. Another approach allows both the exhaust and engine coolant to heat the hydride.

1975 Pontiac

                Billings Energy Corporation converted a 1975 Pontiac to use 198 kg (437 lb) of hydride in a tank weighing 136 kg (300 lb) and measuring: 25.4 cm (10 in) in diameter by 119.4 cm (47 in) long. Range: 241 km (150 mi) consuming 2.4 kg (5.29 lb) of hydrogen.

                The hydride vessel is charged 40% in one minute at 17C (63F). 80% in 15 minutes and 100% in 60 minutes. A water-jacketed aluminum tank holds the FeTi hydride. An Impco model PEV-2 regulator connected to an Impco model CA50 gas mixer controls the pressure. The hydrogen supply to the engine is turned on and off by a solenoid valve.

                The experimenters decreased the sparkplug gap and eliminated the centrifugal spark advance. The standard compression ratio for the air-cooled Kohler engine was unchanged.

                Water injection cools combustion to lower nitrous oxide emissions. It uses two spray nozzles mounted above the intake valves. The induction pump and solenoid valve are controlled manually. The engine is air-cooled.

                After conversion, there was slightly less power and performance. The engine cold-started even when the hydride was nearly discharged.

1977 Cadillac Seville

                This vehicle was part of the Billings Hydrogen Homestead. A big car usually uses much fuel. The weight of the hydride tank adds greater penalties. The car was modified to use two fuels: hydrogen and gasoline.

Hydrogen is used for short commuter trips — where the car is used most. Gasoline is used for longer trips on the highway. It is possible to switch from one fuel to another while the car is in motion. A home-based electrolyzer charges the hydride overnight. The fuel system is shown in Exhibit 77.

                This car was driven in President Carter's inaugural parade in January 1977. It was also displayed at various energy fairs and symposia nationwide.

                Engine displacement is 5.7 liters (348 cu.in.). The standard electronic ignition and fuel-injection systems are compatible with hydrogen. Propane regulators and mixer adapt to hydrogen fuel. Gasoline uses the existing carburetion system. Engine coolant is pumped through the hydride tank to release hydrogen at low pressure. The main fuel is hydrogen. Pollution control equipment is discarded and an increase in fuel economy realized. 760

Dodge Omni

                Billings also converted a Dodge Omni to dual hydrogen and gasoline fuel. The engine has 4 cylinders, in line, with an overhead cam, and compression ratio of 8.2:1. The 1.7 liter (104 cu.in.) block is cast iron, with an aluminum head, intake manifold and water pump, and forged steel crankshaft. Aluminum provides better heat transfer and less weight.

                A microprocessor with three integrated circuits controls the ignition system and timing. A Hall-effect speed and angular relationship pickup electric ignition coil replace the standard induction coil for optimum performance with both hydrogen and gasoline.

                Radiator coolant is circulated to the hydride tank to release hydrogen. If the hydride overheats, a thermostatically controlled fan turns on. This on board fan is used with an electric pump when the hydride is being recharged.

Outside electricity is needed to run the fan and pump when charging.

                The position of the hydride tank and other components of the system are seen in the cross-section of the vehicle in Exhibit 79.

                The hydride tank is the same size of a tire and fits inside the spare tire pocket in the trunk. The hydride has an internal heat exchanger. It has better heat transfer and is more compact than earlier models having water jackets. The exchanger is made of copper tubing coiled inside the tank. See Exhibit 80. The tank adds 180 kg (400 lb) to the rear of the vehicle but holds only 2.5 kg (5.5 lb) of hydrogen. The range on hydrogen alone is 169 km (105 mi). Rear air lift bags compensate for the increased weight.

                A Billings BE-5A electrolyzer produces 2.3 kg (5 lb) of hydrogen per day. 35 kWh at 220 V.A.C. evolve 0.5 kg (1 Ib) of hydrogen. The device is 65% efficiency, making 10,874 to 26,054 liters (384 to 920 cu.ft.) of hydrogen per day.

                The fuel economy with gasoline is 13 km/liter (30 mi/gal) and 19 km/liter(45 mi/gal) with hydrogen. Top speed is 129 km/hr (80 mi/hr).

Hydride on the Racetrack

                In May 1984 Kenji Watanabe demonstrated a hydride powered 1973 Mazda RX-4 on the Fuji race course in Gotemba, Japan. He averaged 130 km/hr (80 mi/hr). The top speed was 210 km/hr (130 mi/hr) over a range of 200 km (124 mi).

                The exhaust temperature of the 1.2 liter (73 cu.in.) rotary engine was half that for a comparable engine running on gasoline. At 128 km/hr (80 mi/hr) the temperature was 565C (1050F). At 59 km per hr (37 mph) it was 460C (860F). This could double the engine life. Large diameter exhaust pipes, 3.81 cm (1.5 in) increase the cooling effect. Nitrous oxides were measured at 15 ppm at 6,500 rpm. The Japanese standard is 240 ppm. There were no detectable levels of carbon monoxide or hydrocarbons.

                Mitsui and Co. designed and built the $20,000 stainless steel hydride tank. Japan Metals and Chemical Co. supplied the FeTi hydride. In production, using aluminum, the tank cost could be reduced to $8,000.

                480 kg (1/060 Ib) of hydride holds 70 cu.meter (2,472 cu.ft.) of hydrogen. The energy content of one cu.meter (35 cu.ft.) of hydrogen is equivalent to 0.5 liters (1/8 gal) of gasoline. It takes from 10 to 15 minutes to fill the tank. Water injection is used to increase engine power. Inside the cylinder, at 374C (705F) water expands 1,700 times, applying a force of 225 kg per sq.cm. (3,200 lb per sq.in). Fuel combustion contributes 175 kg per sq.cm (2,500 lb per sq.in.) to give a force of 400 kg per sq.cm. (5,700 lb per sq.in.).

                According to a passenger, "on balance, the ride was very smooth. Pickup was very good." 970p52

                Watanabe has experimented with hydrogen power for 25 years without government help. He has been the president and owner of Hydrogen Energy Laboratory Project (H.E.L.P.) since 1982. He estimates that future conversion costs for similar cars, mass produced, will be about $1,000.

Hydrogen Tractors

                As part of the Billings Hydrogen Homestead, a Jacobsen lawn and garden tractor was converted to hydrogen. With a convenient source of hydrogen, this project can prove that hydrogen is practical for work vehicles.

                Exhibit 81 shows the specifications. A diagram of the hydrogen system is given in Exhibit 83. A 29.8 kW (40 hp) gasoline-powered Massey Ferguson Model 65 tractor, converted to hydride, was tested at Rockhaven Farm, near Clarksburg, Ontario, Canada. A propane carburetor and gas mixer (Impco CA50) was modified for hydrogen fuel for the 2.9 liter (177 cu.in.) engine.

                Dynamometer tests showed a 30% power loss compared to gasoline. Exhaust gas recirculation and a Holly water injector minimized it.

                The extra weight of the hydride tank is not seen as a liability because farm tractors often use ballast to improve traction and prevent upsets, Tractors are generally used close to home. This simplifies the problem of finding a recharging station.  A 20 kW electrolyzer with a potassium hydroxide electrolyte supplies hydrogen at 6.8 atm (100 psi).

                The hydride is a mischmetal alloy (MNi4.5A10.5) with hydriding characteristics similar to FeTi. See Exhibit 67. Ergenics Corp. of New Jersey supplied the Hystor 208 hydride. The minimum absorption pressure is less than the electrolyzer pressure. This makes for easy starting in cold weather. The hydride is relatively resistant to impurities such as water, carbon monoxide and oxygen. If contaminated, reactivation of the hydride is easy using a vacuum pump for 24 hours to draw the impurities out.

                A bundle of tubes stores hydride with an input and output manifold on opposite ends of the tank. See Exhibit 82. The 11 stainless steel tubes are each 6.35 cm (2.5 in) in diameter and 83.8 cm (33 in) long. The total hydride capacity is 80 kg (176 Ib), enough for four hours of operation. The overall gross weight is 154 kg (340 Ib). The tank stores up to 1 kg (2.2 Ib) of hydrogen to supply 14.2 kW per hr (19 hp per hr) of hydrogen.

                The tractor could use gasoline from the standard fuel system. With a switch, the driver can select either fuel. The ignition timing has to be manually adjusted for peak performance on either fuel.

                Located on top of the engine, the hydride container is heated by engine exhaust running through a single pass heat exchanger. A thermocouple in the manifold measures the hydride temperature. During charging, the temperature increases less than 50C (122F). See Exhibit 84. An initial discharge at 15C (59F) supplies enough hydrogen for ignition. It reaches 25C (77F) while driving, with a hydrogen pressure of 4.1 atm (60 psi). Measurement of the bed conditions during charging and for a typical running cycle indicate the system can meet farm tractor requirements." 260p39

                Hydride fragmentation during repeated cycles makes particles 1 micrometer (0.00003 in) in size. The filter is installed outside the bed. Particles of 3 gram per cu.meter (1.9 X 104 lb per cu.ft.) were reported.

                The researchers conclude; Regular operation of a tractor by non-technical personnel makes the choice of an easily regenerated hydride alloy a necessity. As well, simplicity of operation and operator safety are paramount requirements and these requirements can be met. 260p42

The Riverside Bus

                The city of Riverside, California, with funding from the Department of Energy and $125,000 from the California Transportation Department converted one of it's six minibuses to hydrogen. Billings Energy Corporation provided the design and engineering. The firm owns the bus and leases it to the city for testing on a two year renewable lease option. The bus is the first hydrogen vehicle operated in regular service by a transit authority.

                The vehicle is a 21 passenger 7.3 m (24 ft) Argosy. See Exhibit 86. Some seats were removed to accommodate the water induction reservoir, thereby limiting the bus to 19 passengers as seen in Exhibit 87.

                Hydrogen is the principal fuel for the vehicle, but propane is used as a backup source of power if needed. Enough hydrogen is stored in the aluminum hydride tanks for a range of 129 to 145 km (80 to 90 mi). The hydride is Fe4.4Ti5.1 Mn5 developed by Brookhaven National Lab.

                Ten hydride-containing tubes are linked together by a manifold and mounted under the floor. Data for each tube are as follows.

• Diameter                                20.3 cm (8 in)
• Wall thickness                      0.92 cm (0.36 in).
• Length                                   122.2 cm (48.1 in).
• Volume                                   29.45 liter (1797 cu.in.)
• Weight                                   22.6 kg (49.8 lb).
• Service pressure   137.2 atm (2,016 psi).

Each tube is surrounded by a large diameter tube that contains a circulating water jacket used to control the temperature of the tubes for charging and discharging. End plates support the concentric tube arrangement. Manifolds that collect the gas are separate from those that circulate the coolant. Coolant flows from one tube to another in series, as shown in Exhibit 88. The hydrogen manifolds are in parallel. The driver can turn off the flow of hydrogen from one tank without affecting the others.

                A 83.3 liter (22 gal) propane tank boosts the range another 241 km (150 mi). The change from one fuel to another is controlled by a switch on the dashboard. Recharge for the iron-titanium hydride tanks takes on hour. The twice daily refueling stops are scheduled for the driver's lunch breaks or at night. The bus cannot travel beyond the availability of hydrogen fuel.

                Hydrogen is advantageous for fleet vehicle use because:

• It helps reduce pollution in urban areas.
• Route travel simplifies fuel distribution problems.
• The%age of the weight of larger vehicles devoted to hydride is less than for smaller vehicles.

95% of auto trips occur within 48 km (30 mi), 60 of all vehicle miles. 201 It takes 3 hours to recharge the hydride completely, but a short recharge can supply much of the capacity the hydride is designed to take.

• 40% recharge takes place in the first 5 minutes.
• 55% recharge takes place in the first 10 minutes.
• 78% recharge takes place in the first 30 minutes.
• 86% recharge takes place in the first 60 minutes.

When charging, the heat exchange circuit is tapped at two points. Cooling water circulates through the hydride tanks from the outside. A thermostatically-controlled water pump varies the flow rate in response to the temperature. 907kg (2,000 Ib) of FeTi stores up to 58.6 kWh (200/000 BTU).

                The nearby Linde Division of Union Carbide in Fontana, California makes delivery of hydrogen from steam reformed natural gas economical.

                Engine coolant provides the heat necessary to release stored hydrogen from the hydride. The coolant is circulated by a water pump turned by the engine as shown in Exhibit 88. (An extra 120 V.A.C. pump is installed and runs on converted 12 V.D.C. current from the battery.)

                A schematic diagram of the Riverside bus is shown in the exhibit. Six flow circuits make up the fuel system.

• Hydrogen delivery.
• Heat exchanging.
• Water induction.
• Pneumatic air for controls.
• Fuel and air mixing.
• Propane fuel delivery.

Air pressure from a pneumatic tank activates the main hydrogen ball valves only when all of the following conditions are met.

• The ignition key is ON, and
• The hydrogen flow switch is ON, and
• Manifold vacuum is sensed.

                The 7.4 liter (452 cu.in.) Chevrolet engine has a four barrel Mudd CA 425 carburetor and two model EV regulators. Made for propane fuel, the components had to be modified for the less dense hydrogen gas. Impco regulators are mounted in the left front wheel well. The regulators provide the final pressure adjustment before the hydrogen goes to the gas mixer. Two regulators are connected in parallel to "check" each other for greater accuracy. The pressure regulators reduce the pressure of the hydrogen gas delivered to the engine from 51.0 atm (750 psi) to 13.6 atm (200 psi). Gas flow bypasses the regulators when the hydride tank pressure is less than 13.6 atm.

                A fine mist of water is injected into the intake manifold to control nitrous oxide emissions. The pneumatic air tank supplies pressure to a small water reservoir. The spray nozzles are located in the intake manifold. A solenoid valve activates the spray in response to manifold vacuum. Nitrous oxides were 1.27 gram per kWh (0.9 gram per horsepower hour). The 1977 California standard was 9.4 gram per kWh (7.0 gram per hp.hr).

                The air filter is mounted in front of the radiator. It can be seen clearly through the grille of the bus in Exhibit 86. It takes cooler air from the outside. Reduced air intake temperature improves combustion efficiency.

                When propane is used, it is fed through an Impco VFF fuel filter and lock-off and a single model EV combination vaporizer and regulator. The filter-fuel lock-off and the regulator for the propane system are positioned in the right front wheel well. The propane tank is nestled under the floor behind it. Manifold vacuum activates a separate propane pressure regulator. The driver can switch between hydrogen and propane while driving. This fuel is best used for light loads only unless the ignition timing is changed to accommodate the different combustion characteristics of propane.

Specifications and performance data for the bus are given below: 201

• Number of Passengers                                                        19
• Manufacturer                                                                                        Winnebago
• Weight without hydride                                                     3/690 kg (8,135 lb)
• Weight of FeTi hydride                                                      1,002 kg (2,209 lb)
• Weight of stored hydrogen                                                               12.6 kg (28 lb)
• Weight of FeTi tanks                                                          400 kg (882 lb)
• Weight of structural reinforcement                   54 kg (119 lb)
• Weight of payload                                                                               1,612 kg (3,554 lb)
• H2 available at 80 km/hr(50 mi/hr)                     7.7 kg (17 lb)
• Fuel economy at 80 km/hr (50 mi/hr)                 16 km/kg (4.5 mi./lb)
• Range at 80 km/hr                                                                                121 km (75 miles).

The experiment in Riverside met with numerous technical failures and was discontinued in 1979 due to lack of funding.

                Stuart Energy Systems has established eight hydrogen refueling stations in North America. Four of them are in California. One of them is 70 miles southwest of Sacramento and is strategically located for access to the San Francisco Bay Area. A hydrogen refueling station in Richmond, CA fuels the municipal bus and vehicle fleet. It includes fuel cell cars from Daimler Chrysler, Ford, Hyundai and Toyota. Storage capacity is 47kg. "Intelligent" fueling needs only a swipe of the "smart" card activates the dispenser - just attach the nozzle and fill up. Automatic pressure control and shutoff does the rest. Other partners in the project include the California Fuel Cell Partnership and the Richmond, CA Transit. 32

                Industry is also finding hydrogen useful for powering forklifts, underground mining vehicles, tractors, and other kinds of transportation without danger of contaminating indoor air space.

Mercedes-Benz Van

                Daimler Benz, of Germany, has developed a van that uses two hydrides. The vehicle is designed to exploit the advantages of both FeTi and magnesium nickel hydride. TiFe makes up two-thirds of the weight of the total amount of hydride. Magnesium nickel (Mg2Ni) comprises the remaining third.

                TiFe holds only 1.6 to 1.95 of its weight in hydrogen but dissociates at a relatively low temperature. Mg2Ni has the opposite feature: dissociating at 200 to 400C (390 to 750F) and requiring twice the energy for dissociation as TiFe. The hydrogen stored in the Mg2Ni can be recovered only when the engine coolant is hot enough.

                The engine uses water injection to control backfiring and preignition.

                Hydrogen is withdrawn from the hydride in discrete cycles, unlike most hydride-powered vehicles. First, the hydride is heated enough to increase pressure in the tank. Then, the heat is cut off as the hydrogen build- up is drawn off, the temperature of the hydride drops and the cycle repeats. The temperature is allowed to vary between -20 and 20C (-4 and 68F). The pressure varies between 0.99 atm (14.5 psi) and 1.97 atm (29 psi).

                Vehicle specifications are as follows:

• Number of cylinders                                            4
• Displacement                                                        2.3 liters (140 cu.in.)
• Power output                                                        44 kW (59 hp) at 4,800 rpm.
• Compression ratio                                                9:1.
• Exhaust gas recirculation                    25.
• Hydride                                                                  67 FeTi, 33 Mg2Ni.
• Range on highway                                               152 to 200 km (94 to 124 mi).
• Range in city traffic                                             120 km (75 mi).
• Heat exchange fluid                                             standard engine coolant.
• Recharge by cooling water                 75 recharge in 10 minutes.

                The Mercedes van uses hydride air conditioning. 700p48l-499 Heat from the inside is used to heat the hydride and cool the passengers.

                Exhibit 89 and 90 reveal the mechanical details of the van. Exhibits 91 and 92 show a cross section of the hydride vessel and it's performance. 201

                A Mercedes-Benz passenger car was converted to run on both gasoline and hydrogen. Exhibit 93 shows an inside view of the major components of the car. This scheme allows flexible use of available fuel. Gasoline is to be used for long distance journeys, while hydrogen provides the power for shorter trips. Exhibit 94 presents the test data for the car running on hydrogen at various distances.

Formate Salts as Storage Media

The challenge of finding a media for storing hydrogen is in meeting three criteria.

• Low temperature and pressure reaction.
• Reversibility.
• High storage capacity.

                Each hydride meets some of the criteria better than others. An experimental process that uses formate salts to store and release hydrogen seems to meet all three.

                A formate salt (sodium formate in this case) is mixed with water to yield sodium bicarbonate and hydrogen. This takes place at 20C (68F) and 1 atm (14.7 psi). The process uses a charcoal catalyst coated with palladium. The reaction works in reverse by adding hydrogen to the bicarbonate to reconstitute the formate.

                In practical applications, the hydrogen gas being stored may be include carbon monoxide without affecting the absorption of the hydrogen. Synthesis gas, a combination of CO and H2, is a common by-product in petroleum refining and other chemical manufacturing processes. "In this way, low value solid fuels (e.g. inferior coals or waste) can be discretely transformed into a gaseous fuel of high quality (thermic and environmental) in a form easy to store and transport." l060p344

                The storage capacity of formate salts exceeds zeolites, glass microspheres, and some metal hydrides. The conditions for charging and discharging are too demanding and cumbersome to be used for vehicle storage but may be practical for stationary applications. Output is estimated at 30% of the weight of the salts.  "Based on the data presented, one can conclude that the storage and transport of hydrogen by the intermediate of the formate-bicarbonate cycle is promising. The transformation of low value solid fuel in high caloric gas by this method can prove itself especially attractive." l060p346

Microsphere Storage

                Robert J. Teitel, and associates of San Diego, California, developed a process under a Department of Energy grant where hydrogen is diffused into tiny hollow glass spheres. At 350C (662F) hydrogen gas passes into the glass containers where it is trapped when the glass cools. When the hydrogen is heated again, but at a lower temperature, the gas is released. Hydrogen is stored at 272 to 409 atm (4000 to 6000 psi) in a mass of tiny spheres with the consistency of powdered sugar. They are 25 to 150 microns (millionths of a centimeter) wide with walls .25 to 5 microns thick. A thimble contains 4 million. They weigh less, but require more space, than pressurized gas tanks.

The energy used to store the hydrogen cannot be recovered as with hydrides.

The 3-M company uses the trade name Fillite. It comes in two grades.

• Grade 300/ 7: needs high temperature but stores at higher pressure.
• Grade 32D/4500: lower temperature storage pressure. Automotive use.

Storing Hydrogen In Carbon

Sponge Carbon

                The disadvantages of gaseous, liquid, and hydride storage can be summarized as follows for a car with a 500 km (310 mile) range.

• Pressurized gas range: 4,500 kg (10,000 Ib.) a pressure of 200 atm requires 100 kg of tank for each pound of hydrogen stored. Range: 60 to 80 miles (96-128 mi).
• Lead acid batteries for an electric motor: 3,000 kg (6,600 lb.)
• Titanium hydride: 2,600 kg (5,700 Ib.) Hydride systems are about 18 times heavier than a liquid hydrogen system. For a 500 km (310 mile) range the hydride system would weigh 2,600 kg (5,700 lb.)
• Liquid hydrogen: 136 kg (300 lb.) Equal to gasoline in weight and range but twice the weight and four times the storage volume.
• Gasoline: 63 kg (138 lb.)

                The prospect of hydrogen power for bus fleets has resurfaced in 1992, The city of Tempe, Arizona, is planning to spend $3 million to convert 25 fleet vehicles to operate on hydrogen within two years. The project will incorporate technological modifications that overcome the difficulties encountered in the Riverside experiment. With the assistance of Arizona's Senator John McCain. federal government, through the EPA and the Departments of Energy and Transportation may fund the project. This will be largest fleet of hydrogen-fueled vehicles in the world. It will also involve research by Arizona State University on the most cost effective method to extract hydrogen from sewage and city garbage. Also, a solar thermal powered dish built by McDonnell Douglas and a Stirling engine developed by Cummins will provide electrical power for electrolyzers. The local utility will provide power by night during off peak hours. If the cost of the utility electricity can be held to 3 to 4 cents per kilowatt hour, the cost of the hydrogen will be equivalent to gasoline costing $1.00 to $1.40 per gallon ($0.26 • $0.37/liter) Considering the environmental, health and military costs of gasoline use, this would be a bargain.

                The hydrogen fuel for the Tempe bus project is stored on board the bus in carbon. Carbon has a high surface area that readily absorbs a variety of gases including hydrogen. The surface area is about 2,000 square meters (21,500 sq. ft.) per gram of storage material.  Researchers at Syracuse University in New York are developing lightweight carbon composites to store hydrogen. The hydrogen must be chilled to -123C (-190F) at a pressure of 102 atm (1,500 psi). Like hydrides, the captive hydrogen is released by increasing temperature and reducing pressure. The weight and volume of the device is similar to a full gas tank. The granules resemble what Harry Braun describes as "kitty litter." 165

                Roy McAlister, President of The American Hydrogen Association, is in the process of developing a activated carbon fabric that is capable of storing hydrogen for use on board vehicles at about one-third the energy density of gasoline.

                Carbon takes the forms of graphite and diamonds. But it can be formed in spheres of 60 atoms per molecule - C60 also called Fullerenes. The molecule is shaped like the geodesic dome of Buckminster Fuller. Hydrogen atoms can be stored inside these tiny spheres. Carbon nanomaterials can absorb hydrogen in amounts exceeding the requirements for mobile systems. 812 p. 1063. C60 can be stored in many porous conductive materials.

• porous carbon
• carbon-bearing porous material
• carbon aerogels, surface area 800 m2 / gram temperature resistant, can adapt to liquid electrolytes, low cost. 15

Applications include

• hydrogen storage
• electric battery
• durable super capacitors 905

Electrochemical Fullerene System

                A newly patented device uses a proton donor electrolyte and a C60 cathode to attract and store hydrogen as C60Hx and electricity. The anode is nickel hydroxide as in NiCd batteries, m the C60 molecule each carbon atom is combined with 3 others to form a sphere. One of the four carbon bonds is free to accept, one hydrogen atom.

During Charge:

• cathode         C60 + H2O + e- —> C60H + OH-
• anode          OH- —> 1/2 H2 + e- + 1/2 O2

During Discharge

• anode          C60H + OH- —> H2O + C60 + e-
• cathode          H2O + e- + 1/2 O2 —> 2OH-

An experiment measured the charge and discharge capacity for C60 hydride using a silver electrode with DC current in 30 KOH solution and a charging current from 5 to 20 mA/cm2. Hydrogen loaded into the carbon from 60 to 92% of capacity. A level of hydration of C60H56 at a charging density of 10mA/cm2.Theoretical Capacity of C60Hx Electrodes is given below. Nominal composition                             Specific stored capacity

                                                                (mA-hr / gram)

C60H60                                                  2250

C60H36                                                  1340

C60H56                                                  1042

C60H18                                                  551

                C60Hx compares "favorably with the best metal hydride electrodes, which is 320 mA-hr / gram." Performance may be enhanced by charging under pressure. 237

Evaluating Hydrogen Storage Systems

                The estimation of storage capacity is the first step for evaluating the efficiency of a hydrogen carrier. This property has two components.

• Volumetric density, measured in kg of hydrogen per liter (lb per cu.ft.).
• Mass density, measured in kg of hydrogen per kg of carrier (lb per lb).

                The storage efficiency of any system combines both the above measures. Exhibit 95 compares the storage capacity of some hydrogen storage alternatives. l060p342 The upper right area shows high volumetric density and high mass density. For the lower left, the reverse is true. Formate salts hold an intermediate position in the graph.

                There are about 9.2 x 1022 atoms per mole of fully charged iron titanium hydride. Solid hydrogen holds about 5.3 x 1022 atoms per mole. Liquid hydrogen has about 4.2 x 1022 atoms per mole.

                According to the latest research presented at the ninth World Hydrogen Energy Conference in 1992 at Paris, France, liquid hydrogen was compared with hydride.  Liquid hydrogen is more efficient and more expensive. BMW showed plans for a liquid hydrogen tank weighing 43 kg (95 lbs) full, with a range of 306 km (190 miles). Hydride is cheaper but heavier. For the same range, a hydride tank would weigh 295 kg (650 lbs).

On-Board Hydrogen Generation

Hydrogen From Gasoline

                Gasoline may be reformed to hydrogen and simple gases by incomplete combustion using small amounts of oxygen at a high temperature. The university of Arizona modified a 29.8 kW (40 hp) Volkswagen engine to run on 100% hydrogen from reformed gasoline. The fuel reformer had a catalytic reactor. Water and liquid hydrocarbon are reformed to produce hydrogen. l040p67 Nickel pellets were used as a catalyst at 816C (1/500F). 18.9 liters (5 gal) of water and 75.7 liters (20 gal) of gasoline were stored in separate tanks. Water was recycled from the exhaust. l070p56-57

                Pollutants were reduced to one-fourth to one-half of federal standards.

No soot was produced. Mileage increased by 50% at a slightly lower horsepower. The researchers reported smooth running over the entire range of rpm's. The design recycled exhaust heat to the reformer.

                A fuel atomizer replaced the carburetor. Exhibit shows the process. Steam and gasoline goes to a superheater (a vaporizer), then to a reactor to be burned in a small amount of oxygen (partial oxidation). The hot hydrogen decomposes the steam producing more hydrogen gas. The condenser dries the hydrogen gas before storing it. Excess water is recycled. Exhibit 97 shows another process using no water. Spiral tubes in the start-up burner impart a swirling motion to the gases to mix air and fuel thoroughly. As the hollow jacket imparts heat to the incoming air, a thermocouple activates a two-way control valve that diverts fuel to the hollow jacket surrounding the reactor (the preheat fuel chamber). Then fuel and air are mixed before burning.

Hydrogen From Methanol

                Methanol can be split into hydrogen and flammable hydrocarbons by engine waste heat according to the following reactions.

                                Heat + CH3OH —> 2H2 + CO

                                Heat + CH3OH + H2O —> 3H2 + CO2

                The first reaction uses only heat to decompose methanol, the second reaction uses both heat and steam. Carbon monoxide and hydrogen, burned together, reduce overall engine temperature. A zinc oxide or copper oxide catalyst is used. Splitting methanol requires 26.7 Wh/mole of energy. 325p485

                Engine waste heat can force hydrogen from methanol at the rate of 7,363 to 13,027 liters/hr (260 to 460 cu.ft./hr). A typical catalyst is copper chromite (70% CuO + 20% Cr2O3 + 3% graphite) at about 316C (600F) are needed. Higher temperatures damage the catalyst.

                1.8 kg (4 Ib) of catalyst is used in a typical automotive application. It would take the form of 9 tubes, each 2.5 X 17.8 cm (1 X 7 in).

                The overall size of the reactor for the above amount of catalyst is determined to be 7.5 X 7.6 X 17.8 cm (3 X 3 X 7 in). For a larger volume of hydrogen, a larger reactor would be needed. See Exhibit 98. 40pl07

                The mixture of methanol and water contains from 1.12 to 1.13 hydrogen — 1.4 to 1.5 times the amount of hydrogen as liquid hydrogen. 160

Hydrogen from Iron

                Iron reacts with water to form iron oxide and hydrogen at 700 to 900C (1,300 to 1,700F). It is best to use sponge iron, a porous form of cast iron. The iron oxide is reduced to iron and water at 800 to 1,100C (1,470 to 2,000F).

                                3Fe + 4H2O —> Fe3O4 + 4H2

                                Fe3O4 + 4H2 —> 3Fe + 4H2O.

The temperatures needed come from burning some of the hydrogen produced. Using special catalysts, H-Power Corp. has developed a process for lowering the temperature required for oxidation to 90 to 100C (200 to 212F). This is within the range of exhaust temperatures from an engine or fuel cell, making possible on-board production of hydrogen from iron and water.

                With conventional processes conversion to hydrogen is about 55%. The H-Power approach may improve this to 75 to 80%.

                A car would carry iron and water in a special tank twice as heavy as a gasoline tank. The range would be 6 kilometers (3.75 miles) per kilogram of iron (2 mi/Ib.). To cover 500 km (310 mile), the vehicle would need 83 kg (184 Ib.) of iron. Because of the oxygen, the amount of iron oxide left weighs about 1.4 times as much as the original iron. A lightweight tank made of plastic could hold 4.5 to 5% hydrogen by weight.

                H-Power assumes that the hydrogen would cost the equivalent of $0.48/liter ($1.80/gallon) of gasoline. The cost would be even less if the iron oxide could be recycled by giving cash credit for turning in used iron oxide.

                The advantage over methanol as an on-board source of hydrogen is that iron is renewable and nontoxic. 434

Chapter 5:

Engine Modifications

Benefits and Problems Of Using Hydrogen Fuel

General Considerations

                125 million cars and trucks use 16% of current U.S. energy consumption and one-third of its liquid fuel production. The per capita oil consumption in the U.S. is more than double that for Britain, France, or Japan.

                At the turn of the century, a variety of petroleum products, including naphtha, were used as fuel. Gasoline was regarded as a dirty byproduct of manufacturing kerosene, a fuel that powered some Stanley Steamers. Town gas, produced by heating coal to produce carbon monoxide and hydrogen was used in homes and in some vehicles.

                Hydrogen has 2.7 times the energy of gasoline on a weight basis but only one-third on a per unit volume. Engines converted to hydrogen get only 80% of the power normally achieved with gasoline.  Hydrogen, however, burns 50% more efficiently.

                Hydrogen has a higher flame speed than gasoline, wider flammability limits, and higher detonation temperature and produces more nitrous oxide emissions than gasoline. Water injection combustion process lowers the nitrous oxide output below that of gasoline.

                Hydrogen burns hotter, faster and takes less energy to ignite than gasoline, but carries the danger of preignition and flashback.

                With only one-tenth of the density of gasoline, pressurized hydrogen takes up 4 times the volume. A hydride forming metal like Iron-titanium stores 1.5 of its weight as hydrogen. This material usually takes an hour to recharge, at atmospheric pressure. About 40% is recovered in the first minute and 80% is recharged after 15 minutes.

                Hydrogen is similar to other gaseous fuels. The advantages of gaseous fuels apply to hydrogen, propane, butane, or liquefied petroleum gas (LPG).

• Better fuel and air mixing. No vapor lock or flooding.
• No cold wall quenching. Gaseous fuel does not precipitate on the cold walls of an engine that has just been started.
• Cooler operating temperature.
• Better engine lubrication. Gasoline dissolves oil on cylinder walls, thereby increasing engine wear.
• Less carbon deposits. Gaseous fuels burn more efficiently. The oil stays clean for a longer engine life of 480,000 km (300,000 miles).
• Less air pollution, especially with water injection.

Disadvantages of gaseous fuels include the following:

• Overheating. Faster burning fuel may overheat valves/particularly on cars designed for unleaded gasoline. The valves may need more frequent replacement. Need valves and seats designed for high temperature operation.
• Misfiring may occur if the ignition system is in poor condition.
• Lower fuel economy: Propane, for example, gives 75% of the range as an equal volume of gasoline.
• Danger of leaks. The fuel system must have an excess flow valve to shut off the fuel flow in case of a leak.
• Danger of over pressurization. The fuel system needs a relief valve on any pressurized tank to avoid stress from excess heat. Fuel lines should be made of high pressure neoprene reinforced with stainless steel, similar to high pressure aircraft hoses.

                Compared to gasoline, hydrogen's low energy per unit volume produces less energy in the cylinder. An engine running on hydrogen produces less power than with gasoline. Exhibit 99 shows that this difference is more noticeable in spark-ignited two-stroke engines than with four-stroke spark ignition or two-stroke diesels. Supercharging may help remedy this by compressing the incoming fuel before it enters the cylinder. This increases the amount of energy per volume of fuel.

                Incomplete combustion of gasoline causes carbon monoxide and other hydrocarbon emissions. The list of pollutants also includes nitrous oxides, sulfur oxides and lead oxides. 580 With hydrogen, nitrous oxides are the only pollutant. These can be brought well below government standards with proper combustion techniques. Gasoline produces more nitrous oxides even when the engine is using emission controls. With hydrogen, increasing engine load reduces nitrous oxide emissions to 10% of those at low loads. 319

                Internal combustion engines can bum hydrogen in a wider range of fuel-air mixtures than with gasoline. Hydrogen with wider flammability limits and higher flame speed makes it more efficient in stop and start driving. 940p99-129

                "The combustion and emission characteristics of hydrogen appear so favorable that research into hydrogen engine technology has expanded at a rapid rate, especially in the last few years. Results have been so favorable that all of the previously defined engine types have been operated on hydrogen with relative success." 580

Preignition and Flashback

                Hydrogen burns quickly and has a low ignition temperature. This may cause the fuel to be ignited by hot spots in the cylinder before the intake valve closes. It may also cause flashback, preignition, or knock. 201 These problems are particularly acute with high fuel-air mixtures. Uncontrolled preignition resists the upward compression stroke of the piston, thereby reducing power.

Remedies for backfire include:

• Timed port injection. Delayed injection to make sure the fuel detonates only after the intake valve is closed.
• Water injection. 1.75 water to hydrogen, by weight. 690p653

                An appropriately designed timed manifold injection system can overcome the problems of backfiring in a hydrogen engine 395p953

Efficiency of Combustion

                Hydrogen burns more completely than gasoline. The thermal efficiency of an engine running on hydrogen is 25 to 100% higher. This is means lower exhaust temperature and less waste heat. The efficiency tends to be higher at reduced load. 319

                Exhibit 100 shows thermal efficiencies using hydrogen and gasoline at different load conditions but at a constant 3,000 rpm. It is 16 greater than gasoline at 20% load. Hydrogen is seen to be more efficient through the entire load range. The figures assume an engine speed of 3,000 rpm and a compression ratio of 6.2 545p66l-668

History of Hydrogen Conversion Experiments

                In the early years of the development of internal combustion engines hydrogen was not the "exotic" fuel that it is today. Water splitting by electrolysis was a well known laboratory phenomenon. Otto, in the early 1870s, considered a variety of fuels for his internal combustion engine, including hydrogen. He rejected gasoline as being too dangerous. Later developments in combustion technology made gasoline safer.

                Most early engine experiments were designed for burning a variety of gases, including natural gas and propane. When hydrogen was used in these engines it would backfire. Since hydrogen burns faster than other fuels, the fuel-air mixture would ignite in the intake manifold before the intake valve could close. Injected water controlled the backfiring. Hydrogen gave less power than gasoline with or without the water.

                During World War I hydrogen and pure oxygen were considered for submarine use because the crew could get drinkable water from the exhaust. Hydrogen was also considered for use in powering airship engines. The gas used for buoyancy could also be used for fuel. Even if helium were used to provide lift, hydrogen gas could be used to supply additional buoyancy if stored at low pressure in a light container.

                Rudolf A. Erren first made practical the hydrogen-fueled engine in the 1920s and converted over 1,000 engines. His projects included trucks and buses. After World War II the allies discovered a submarine converted by Erren to hydrogen power. Even the torpedoes were hydrogen powered. 430

                In 1924 Ricardo conducted the first systematic engine performance tests on hydrogen. He used a one cylinder engine and tried various compression ratios. At a compression ratio of 7, the engine achieved a peak efficiency of 43. At compression ratio of 9.95, Burnstall obtained an efficiency of 41.3 with an equivalency ratio range of 0.587-0.80.

                After World War II, King found the cause of preignition to be hot spots in the combustion chamber from the high temperature ash — the residue from burned oil and dust. He traced flashback to high flame velocity at high equivalency ratios. 200

                M.R. Swain and R.R. Adt at the University of Miami developed modified injection techniques with a 1/600 cu.cm. (98 cu.in.) Toyota engine with a 9:1 compression ratio. The Illinois Institute of Technology converted a 1972 Vega using a propane carburetor. Converting to propane fuel utilizes similar technology as hydrogen.

                Roger Billings, in collaboration with Brigham Young University, entered a hydrogen-converted Volkswagen in the 1972 Urban Vehicle Competition. The vehicle won first place in the emissions category over 60 other vehicles even though the peak emissions were greater than for other hydrogen powered vehicles elsewhere.  Nitrous oxides exceeded levels obtained by other experimenters using direct injection. 580pl39

                Robert Zweig converted a pickup truck to hydrogen power in 1975. It has been running ever since. He solved the backfiring problem by using an extra intake valve to admit hydrogen separately from air. It is a simple, elegant vehicle that uses compressed hydrogen. The American Hydrogen Association displays the Zweig hydrogen pickup trucks in public exhibits.

                The Brookhaven National Laboratory converted a Wankel (rotary) engine to hydrogen. It worked better with hydrogen than conventional engines because its combustion chamber enhances the emission of hydrocarbon pollutants. 70p725

                Mazda has converted one of their rotary engine cars to run on hydrogen. The unique design of the rotary engine keeps the hydrogen and air separate until they are combined in the combustion chamber.

Modern Conversion Projects

Diesel Conversion in China

                An experiment in China demonstrates the higher efficiency of hydrogen compared to gasoline. Tests were performed on a stationary mounted, single cylinder, four stroke, air-cooled diesel engine. Specifications are below.

• Bore                                                        75 mm (3 in)
• Stroke                                                     75 mm (3 in)
• Compression ratio                                20:1
• Injection advance                                21°

Diesel Conversion In India

                The Indian Institute of Technology tested spark ignition engines converted to hydrogen and has come to the following conclusions:

• Hydrogen permits a wide range of fuel-air mixtures.
• Very little throttling, if any, is needed. The fuel-air ratio and the amount of fuel is varied instead.
• Conversion requires higher compression ratios: up to 11:1.
• Hydrogen is 30 to 50% more efficient than gasoline. "Significantly above the range of gasoline-fueled spark ignition engines."

                The Indian researchers also reached some conclusions regarding the use of hydrogen in addition to diesel fuel in diesel engines.

• They reduced the compression ratios from 16.5:1 to 14.5:1.
• Because of hydrogen's high rate of combustion only a small amount should be used mixed with diesel fuel.
• A high ignition temperature is necessary: 585C (1,021F).
• The more hydrogen is added to the fuel mix the lower is the level of toxic emissions. 8l0pl37-l45

Billings Postal Jeep

                The Billings Energy Corporation in Independence, Missouri, converted a U.S. postal Jeep to hydrogen hydride. On gasoline it got 3.9 km/liter (9.2 mi/gal). The hydrogen fuel consumption is 4.9 km/liter (11.50 mi/gal) per gasoline energy equivalent. This was an improvement of 24. A special gaseous carburetor was used.

                High flame speed and low ignition energy required narrowing the spark gap. Problems of rusting and pitting on the sparkplug tip developed. Billings replaced the plugs with Champion stainless steel plugs to eliminate the problem. Rusted plug tips can cause preignition through the valves (backflash).

                Since the firing rate was faster, they had to change the ignition timing on the straight six engine.

                The researchers added a water injection system to lower the combustion temperature and nitrous oxide production. The ratio was 4:1, by weight, of water to hydrogen. Daily fuel consumption was 1.4 kg (3 Ib) of hydrogen and 5.4 kg (12 Ib) of water. Water was injected as a fine mist directly into the manifold of the engine. This reduced backflashing into the manifold and boosted power.

                The Fe-Ti hydride tank had an internal heat exchanger - a copper tube coiled up inside the hydride tank, like the Dodge Omni tank in Exhibit 101.

Hydrogen Mining Vehicle

                In experiments with a diesel converted to run on 100% hydrogen. In 1980 the U.S. Bureau of Mines, in collaboration with EIMCO Mining Machinery, found that the nitrous oxide emission for hydrogen is one-tenth of the amount for the same vehicle on diesel. With hydrogen, the only other emission was water vapor. This is important for vehicles operating in mines and other confined spaces.

                They mounted a 63.4 kW (85 hp) engine on a 4,500 kg (10,000 lb) truck.

                The diesel required the addition of spark ignition. Compression alone would not ignite the hydrogen at the reduced compression ratio. They added a turbocharger to increase the density of the incoming fuel.

                The fuel induction system provides two intake paths: one for hydrogen and one for air. The fuel and air are kept separate until entering the cylinder to prevent backfiring.

Fuel Mixing

                Keeping the air and fuel separate until combustion is an important strategy for controlling a host of difficulties arising from the fast-burning properties of hydrogen.

                The low flammability limits and low energy required for ignition of hydrogen cause preignition and flashback when using hydrogen fuel. Preignition occurs when a fuel-air mixture ignites in the combustion chamber before the intake valve closes. Preignition can cause flashback when the ignited fuel-air mixture explodes back into the intake system. It is most prevalent at higher loads and at higher fuel-air mixtures near open throttle.

                Preignition is not a necessary precursor to backfiring and probably does not occur under normal circumstances at moderate compression and equivalence ratios.

                Because of the low volumetric energy content of hydrogen, higher compression ratios or higher fuel delivery pressures are needed to avoid reduced power.

• Supercharging spark ignition engines compresses the fuel-air mixture before being inducted into the cylinder.
• Direct fuel injection involves mixing the fuel with air inside the combustion chamber. The fuel and air are kept separate until then.

                If fuel and air are mixed before entering the combustion chamber, the arrangement is called external mixing. A carburetor usually accomplishes this. With internal mixing fuel and air are introduced separately into the combustion chamber.

External Fuel Mixing

                Exhibit 102 shows an external mixing system. When air and fuel are mixed outside the combustion chamber the light hydrogen fuel displaces air in the mixture, thereby reducing power 20 to 30% compared to gasoline.

                Hydrogen fuel passes through a pressure regulator where it is reduced in pressure for delivery to the fuel mixer.

                The German Institute for Energy Conversion (DFVLR) in Stuttgart converted a BMW with a 3.5 liter (214 cu.in.) engine to liquid hydrogen. It uses an external mixing system with timed port injection, exhaust turbo charging and variable rate water injection. Digital engine controls the fuel injection. The car runs on either hydrogen or gasoline.

                The power output at 5,000 rpm on gasoline is 170 kW (228 hp) on hydrogen compared with 120 kW (161 hp) on gasoline. 560p725 Another BMW with a 4 cylinder engine was converted to selective hydrogen or gasoline fuel. Power output on hydrogen was 67 kW (90 hp) at 5,000 rpm compared to 75 kW (101 hp) for gasoline. 7l0p72l

                Supercharging was ineffective with external hydrogen fuel mixing over a lower power range. 560

Internal Fuel Mixing

                With internal fuel mixing air and fuel are mixed internally, inside the combustion chamber. This is generally done in the following sequence.

• Air is injected. This cools any hot spots in the cylinder.
• The air intake valve closes.
• Fuel is injected.
• The fuel intake valve closes.
• The fuel-air mixture is ignited.

                Exhibit 103. shows intake ports of an internally mixed system. 690,654

                When hydrogen is inducted into the cylinder under pressure no air is displaced in the combustion chamber. This prevents the power loss from externally mixed fuel-air systems. Theoretically, 20% more power is possible with directly injected hydrogen fuel than with the same engine using externally mixed gasoline. 20lpl6 All types of engines can be modified in this way: four stroke, two stroke, diesel, and rotary. With internal mixing, high pressure is needed: up to 99 atm. (1,455 psi). 710 A fuel pump is needed to supply fuel to the cylinder under pressure.

                W.D. Van Vorst and associates conducted an experiment testing direct fuel injection. They found that high pressures up to 66 atm (6.7 MPa, 970 psi) were necessary to overcome compression in the cylinders. Hydrogen is injected immediately after the intake valve closes and before the combustion chamber pressure reaches maximum. 201

                The induction of air separately, rather than with the fuel, allows the air flow rate of a low density hydrogen engine to be essentially that of a carbureted engine operated on a higher density fuel such as gasoline. 580pl60

                Since liquid hydrogen is 10 to 20 times denser than gaseous hydrogen, direct injection of liquid hydrogen allows smaller and lighter valves. The relatively high density of liquid hydrogen, compared to gaseous hydrogen, causes it to generate pressure when evaporating. Because of this, internal fuel mixing combined with liquid hydrogen has the potential to surpass external mixing for gasoline or hydrocarbons. 7l0p653

                Experimenters at Oklahoma State University used direct injection to eliminate preignition and provide smooth operation in a wide range of hydrogen-air mixtures. 580

                There are two types of internal mixture formation: early injection and late injection. With early injection, fuel is introduced at the start of the compression stroke and continues until 90° before top dead center. With late injection, fuel is introduced at 5° before top dead center. High pressure is needed to get enough fuel into the chamber in a short time. With liquid hydrogen fuel, the fuel pump can supply some of this pressure. Fuel expansion from evaporating liquid hydrogen supplies the rest of the 99 atm (1,455 psi) pressure needed. Fuel injection in general and late injection in particular, makes fuel-air mixing difficult because of the short time involved. Uneven mixtures cause:

• Increased nitrous oxide formation.
• Erratic ignition.
• Ignition delay.
• Incomplete combustion.
• Delayed combustion.

                These problems can be overcome by increasing the turbulence in the combustion chamber. This is accomplished in one of two ways.

• Changing the combustion chamber geometry.
• Modifying the fuel injector arrangements. 700p48l-499

                Both early and late induction requires further research to overcome problems. Neither exhibits the flexibility of electromagnetically activated injector arrangements. If the problems of internal mixtures are solved, hydrogen with controlled combustion allows performance comparable to gasoline with less pollution. 700p491-492

                Hydrogen injectors must be able to handle compressible fluids and changes in engine power. They must accept varying pressures and changes in pulse duration.

                External mixing (intake port injection) gives the highest efficiency at low loads while internal mixing (in-cylinder injection) is best with high loads. Since hydrogen has a wide flammability range un-throttled operation is possible with low efficiency at low loads. Throttling external mixtures improves efficiency with high fuel-air equivalency ratios and compensates for pumping losses.

                Depending on the operating condition, the intake port injection and the in-cylinder injection should be used in parallel. The control of the intake air flow rate using a throttle valve actuator can facilitate engine operations effective and stable at all load conditions. 1033

Equivalency Ratio

                The equivalency ratio compares the fuel-air mixture in the engine with the mixture needed for the maximum energy output. This ideal mixture is called the stoichiometric ratio. It is the mixture at which all the air and fuel burns with no un-reacted air or fuel.

                                Equivalency ratio = e.r. = Actual fuel mixture / Ideal mixture.

                Generally, higher engine load requires a higher equivalency ratio. For hydrogen fuel, normal operation needs an e.r. of 0.5 to 0.65. High loads need e.r. of 0.8 to 1.00. 201 The range of e.r. for gasoline is 0.72 to 2.40. 700p7 Combustion temperature increases with e.r. At low e.r. the fuel is burned completely but some oxygen is left over to cool the combustion. Lower e.r. reduces the flame velocity of any fuel.

                The lower flammability limit for gasoline (1.3) is close to its stoichiometric mixture (1.7). The stoichiometric ratio of hydrogen is in the middle of a wide flammability range (4 to 75).  This allows lower temperature operation. 201

Engine Governing

                There are three methods of delivering fuel to an engine.

• Constant equivalency ratio. The volume of fuel, not e.r., is changed.
• Variable air - constant fuel. Varying the proportion of air while keeping the volume of fuel constant. A third valve is installed to inject the fuel. See Exhibit 104. 840
• Varying the proportion of fuel by direct injection of fuel into the cylinder. To accomplish this, the carburetor and intake manifolds are removed. Researchers at Cornell, Miami/and Oklahoma universities used this method.

Methods of Reducing Preignition

                An engine that varies e.r. in response to changes in load runs the risk of preignition with increased e.r. To avoid this, tight tolerances and quick response by the fuel injection control system is necessary. Only a digital electronic engine control system is fast enough — in less than 10 milliseconds.

                Preignition can be minimized by taking the following precautions.

• No excessive oil in the combustion chamber. Gaseous fuel needs less.
• Low temperature spark plugs.
• Sodium-filled exhaust valves avoid heat buildup in the valve. 201

                The auto ignition temperature of hydrogen is one-tenth that of other fuels. Carbon deposits and manifold temperatures too low to ignite gasoline may be hot enough for hydrogen. Hot surfaces causing preignition include:

• Spark plug electrodes.
• Exhaust valves.
• Carbon deposits from unburned lubricants. 545p662

Liquid hydrogen injected near the end of the piston stroke cools any potential hot spots. In one conversion experiment the injection valves were mounted on top of the cylinder head and opened 40° after top dead center. 710

The Musashi Liquid Hydrogen Diesel

                In 1973, a University of California researcher (Feingold) converted a vehicle to liquid hydrogen with external mixture formation. W.F. Stewart at the Los Alamos Laboratory followed in 1983. A.N. Podgorny in the U.S.S.R. and H.C. Watson in Australia conducted similar experiments in 1984.

                The Musashi Institute of Technology in Japan introduced an liquid hydrogen car in 1975. The company later experimented successfully with internal mixture formation in 1982-84 with a 2 stroke spark ignition engine and a 2 and 4 stroke diesel. 700 Their first liquid hydrogen powered car for road use was tested in a 1975 road rally for experimental vehicles. Low temperature hydrogen at -120C (-184F) entered the engine's cylinders.

                Musashi has also converted a 2 stroke Suzuki diesel to liquid hydrogen. A turbocharger uses exhaust gas pressure to pump liquid hydrogen for direct injection into the combustion chamber at a pressure of 9.9 atm (140 psi) and at 0 to -50C (32 to -58F). Direct injection and low fuel temperature both prevented preignition and reduced nitrous oxide emissions. The fuel is injected during the first half of the compression stroke.

                The combination of features employed in this vehicle increased power output 50% beyond a comparable gasoline or diesel without a turbocharger.

                Engine specifications in the experiment are as follows:

• Bore                                                        76 mm (3 in)
• Stroke                                                     80mm (3.1 in)
• Number of cylinders                            3
• Displacement                                        1,100 cu.cm.(67.1 cu.in.)
• Engine                                                    2 stroke, water cooled.
• Direct injection                     during 30° of crank angle at maximum point.

                They installed the injection device in the cylinder head. The poppet valve is opened by a cam shaft and rocker arm. Injection pressure without turbo charging is 59.2 atm (870 psi). With it, the pressure is 80 atm (1,176 psi). Exhibit 105 shows the stainless steel injection nozzle.

                The injection pipe projects into the combustion chamber to spray fuel into the cylinder away from the cylinder head. Holes in the pipe distribute hydrogen uniformly. The fuel jet is mounted in a depression in the cylinder head, as shown. They compared this arrangement with several other alternative designs and found it to be the most effective. 390p399-405

                The experimenters replaced the original manifold with a blow down type. See Exhibit 106. This modification puts the turbocharger within roughly an equal distance of each exhaust port and ensures higher exhaust velocities and increased air flow rate.

The A.H.A. "Smart Plug"

                Roy McAlister of the American Hydrogen Association is developing a means of converting almost any spark ignition engine to hydrogen power. Hydrogen fuel injectors deliver fuel to the cylinders exactly when needed. This is similar to the "stratified charge" of a diesel. The experimenters expect to exceed the performance and efficiency of gasoline. 442pl2

Compression Ratio

Spark Ignition Engines

                In addition to compressing the fuel outside the cylinder with a turbocharger or liquid hydrogen fuel pump, the piston can be adjusted to increase the compression of fuel and air inside the cylinder prior to ignition. This means increasing the compression ratio.

                The compression ratio is defined by the following. 390pl88

                                Compression Ratio = Volume of cylinder with piston at lowest point

                                                                                                Volume of cylinder with piston at highest point

Increasing the c.r. decreases the ratio of piston head area to the cylinder volume containing the fuel. A decrease of e.r. from 6.2 to 7.8 increases the area-volume ratio at maximum compression. More area per unit volume increases heat dissipation from the cylinder walls. 545 Higher compression also increases combustion and exhaust gas temperature along with elevated nitrous oxide levels. 810

                Compressing the fuel/air mixture to greater degree permits lower fuel- air mixtures to get the same output as higher mixtures. Leaner mixtures help reduce the risk of preignition. Hydrogen permits leaner mixtures at any e.r./ compared to hydrocarbon fuels. Increasing the e.r. in hydrogen fuel conversions almost always makes sense. Increasing the e.r. improves engine efficiency according to the relationship below.

                                ne = 1 - ek-1

• ne = engine thermal efficiency.
• e == compression ratio.
• k = specific heat ratio = heat increase due to compression.

                In specific tests, experimenters increased the e.r. of an engine from 6.2 to 7.8 and noticed a 19% improvement in efficiency at 20% of full load. 545 Exhibit 107 shows the relationship between thermal efficiency and two c.r.'s for the engine. It shows improvement in engine efficiency at all load conditions. This is the same experiment depicted in Exhibit 100.

                Experimenters at the Indian Institute of Technology achieved engine efficiencies of 30 to 50% significantly above the range of gasoline-fueled spark- ignition engines. 810 The e.r. was increased to just under 11.0.

                Changing the e.r. may require modifications of the piston. Not all engines are designed for higher pressure operations. Billings Energy Corp. converted a 6.6 liter (403 cu.in.) 1975 Pontiac V8 to hydrogen and changed the e.r. from 7.7 to 12.7 after shaving the piston heads 0.254 mm (0.010 in). At higher pressure in the combustion chamber, lubricating oil may leak past the piston rings. The remedy for this is to install double piston rings.

Diesel Engines

                Diesel engines have no sparkplugs. Fuel is ignited by compression. This is based on the principle that the temperature of a gas increases with pressure. If the e.r. is increased from 14 to 25%, the gas temperature increases from 700C (1,290F) to 900C (1,650F). At the right pressure, diesel fuel-air mixtures ignite spontaneously by autoignition. Fuel and air enter separately. The air is drawn in during the piston downstroke, and the fuel is inducted at the point of maximum compression.

                Hydrogen requires a compression ratio over 28 for autoignition. 20lpl9 This is impractical. Hydrogen converted diesels require an ignition source.

• Mixing hydrocarbon fuel with the hydrogen.
• Using a glow plug.

                The latter solution involves a kind of "non-spark" plug. It remains hot continuously. The hot surface ignition is conducted in such a way that combustion takes place while hydrogen is injected, which is similar to the conventional diesel engine.

                Exhibit 108 shows the glow plug used in the Musashi experiments. 380p405 It is a porcelain pipe 6 mm (0.24 in) in diameter. A 0.5 mm (0.02 in ) diameter platinum wire is wrapped around the pipe. Each pipe requires 24 W. The 3 cylinder diesel engine in the test required 23W per cylinder for a total of 70 Watts. The plug requires current at startup, idling, and low loads. Otherwise it maintains its 1,000C(1,832F) temperature by absorbing and retaining combustion heat without current input.

Fuel Dilution

Sources of Pollution

                There are two main sources of emissions problems from the use of hydrogen. They are not unique to hydrogen. Gasoline and diesel fuel combustion also produces these, and other pollutants, in greater quantity.

• Hydrocarbons from burning lubricating oil.
• Nitrous oxides from high temperature combustion of nitrogen.

Burning hydrogen in pure oxygen yields only water vapor.

                                2H2 + O2 —> 2H2O at 3,353C (6068F)

Nitrogen makes up about 70% of the atmosphere. Under some conditions, nitrogen absorbs some of the heat during combustion.

                                2H2 + O2 + 3.76 N2 —> 2H2O + 3.76N2 at 2.673C (4.844F)

With an excess of air, combustion of hydrogen forms nitrous oxide.

                                2H2 + O2 + N2x + O2x —> 2H2O + 2NOx

The combustion temperature to less than 2,673C (4,843F). 580

                In 1984, researchers in Germany tested a 3.5 liter (214 cu.in.) engine converted to run on either gasoline or hydrogen. They found that nitrous oxide emissions on hydrogen were only 7 of those for gasoline. 700 R.G. Murray and R.J. Schaeppel at Oklahoma State University tested a hydrogen- injected single cylinder engine. The nitrous oxide emissions were only one- fifth of those for gasoline engines of the same size.

                The combustion temperature and nitrous oxide emissions increase with the fuel-air mix and the equivalency ratio.  This relationship is exponential. In other words, slight increases in temperature bring much greater increases in nitrous oxide formation.

                Nitrous Oxide emissions form a hydrogen-operated spark ignition engine can be drastically reduced by way of lean engine operation. 395p965.

Water Induction

                Internal combustion engines waste about two-thirds of the combustion energy as heat. Adding water to hydrocarbon fuels allows the heat of combustion to combine the oxygen in the water with unburned carbon in the exhaust. This produces a combination of hydrogen and carbon monoxide. The hydrogen then burns, creating additional power.

                The induction of water vapor into the cylinder reduces the combustion temperature of nitrous oxide formation. "Water induction is an effective means of controlling nitrous oxide without loss of power, efficiency, or exhaust temperature. The effectiveness of water induction increases with rpm." 580pl38

                It has been found that some cylinders of the same engine produce more nitrous oxide than others. With direct injection the equivalency ratio can be varied to each cylinder in response to individual emission characteristics. This is not possible with external mixing in carburetors where a uniform mixture is delivered to all cylinders. The nonuniformity of nitrous oxide formation from cylinder to cylinder requires a similar nonuniformity in water induction to compensate for this. Direct induction mixes water vapor with hydrogen before the introduction of air.

                When the equivalency ratio exceeds 1.0 to 1.6 the possibility of preignition is greatly increased. This is because of the presence of hot residual gas or solid combustion residues such as oil ash. The cooling effect of water injection remedies this.

                As water induction reduces combustion temperature it also reduces the probability of preignition and flashback. By reducing the reaction rate of hydrogen and air in the cylinder and increasing the energy needed for ignition, a larger range of mixtures may be used. Reducing the time, as well as the temperature, of combustion greatly reduces nitrous oxide emissions. This also serves to prolong engine life. Experimenters in India used a modified Bosch L-Jetronic water injector along with a Bosch-Motronic computerized engine injection control. 690p653-659

                Higher engine rpm requires more water. German experimenters varied the water induction rate with engine rpm.   It was zero at engine speeds up to 2,000 rpm and 140 Nm (103 ft.lb.). Up to 4,000 rpm and 220 Nm (162 ft.lb.) the water input rate varied from 1 gram per sec. (0.0022 Ib per sec.) to 8 gram per sec. (0.018 Ib per sec.). 7l0p725

                A standard gas tank, carburetor, and fuel pump may be adapted for water. Exhibit 109 shows an externally mixed hydrogen-converted engine with water injection. The hydrogen fuel and water enter the gas mixer through different ports. Two spray nozzles on each side of the intake manifold enter just below the plenum chamber throttle plate. The water flow rate must be adjusted to avoid water leaking past the piston rings.

Exhaust Temperature and Combustion Efficiency

                The higher the temperature of a heat engine is compared to its' exhaust temperature, the higher the efficiency will be.

                                Thermal Efficiency = High temp. - LOW temp.

                                                                                                High temp. - Abs. Zero

• High Temp. = maximum combustion temperature,
• Abs. zero = -273C (-459F).
• Low Temp. = exhaust temperature.

The lower the exhaust temperature, the greater the proportion of combustion energy converted to work. An operating temperature of 2,670C (4,838F) with an exhaust temperature of 500C (932F) implies an efficiency of 74%. Reducing the exhaust temperature to 300C (572F) raises the efficiency to 81%.

                Exhibit 110 shows the results of an experiment on the effects of compression ratio and engine load on efficiency. Exhaust temperature is used as a measure of engine efficiency. The engine was run on gasoline as well as on hydrogen. The results for the two fuels are shown — increasing the compression ratio improves engine efficiency. More energy is converted to turning the drive shaft and less is sent out the exhaust pipe. 545

Cryogenic Cooling

                Liquid hydrogen avoids the need for water induction for both internal and external mixing. In tests for speeds up to 5,000 rpm. The cooling effect of liquid hydrogen was equivalent to water induction in reducing nitrous oxides. The liquid hydrogen tank was under a pressure of 247 atm (3,630 psi). A pressure regulator in the fuel line reduced this pressure to 19.7 atm (290 psi). A second regulator reduced the pressure further to 3 atm (44 psi).

Exhaust Gas Recirculation

                Another method to reduce engine hot spots and nitrous oxide emissions is to recirculate engine exhaust back to the combustion chamber. In experiments by Finegold, 35% of the exhaust were recycled. Combustion temperature and nitrous oxide emissions fell, but so did engine power.

                In conjunction with the development of a hydrogen fueled farm tractor the relative effectiveness of different methods of fuel dilution was measured. The engine was tested in three modes.

• No fuel dilution.
• Exhaust gas recirculation with the rate adjusted to maximize power.
• Water injection adjusted for maximum power.

                Measuring fuel consumption also indicates brake thermal efficiency. This data was collected from a gas Rotometer corrected for temperature and pressure. Power was measured at the drive shaft by a water-cooled friction type dynamometer. The fuel consumption was 7.9 kWh per kg (4.8 hp.hr per Ib). The maximum power without backfire was 19.4 kW (26 hp) at 1,800 rpm. This was 67% of gasoline power.

                Exhibits 111 and 112 summarize the test results. Water induction increased power more than exhaust gas recirculation at both full and partial loads. The thermal efficiency of the engine was lower with either water injection or exhaust gas recirculation. The highest efficiencies were achieved with no fuel dilution.

Ignition Timing

Spark Advance

                The flame speed of hydrogen is 2.87 meter per sec. (9.4 ft per sec.) - 10 times the flame speed for gasoline. The engine may backfire through the intake valve unless the ignition timing is modified for hydrogen. The spark advance is moved close to the top dead center of the cranking angle.

                With each increase in the timing, the combustion temperature goes up exponentially and so does nitrous oxide formation. Decreasing the ignition advance reduces power. It is necessary to make a tradeoff between reduced power and nitrous oxide emissions.

                Spark advance should be reduced as the equivalency ratio increases. If a fixed equivalency ratio is used, the spark timing may be fixed at all rpm and manifold vacuum settings. 330 Exhibit 113 shows the lean best torque setting for various equivalency ratio values. 1030 These figures are only approximations. Exhibit 114 summarizes results indicating an inverse relation between spark advance and the equivalency ratio. Three different compression ratios and engine speeds were tested: e.r. varied from 5:1 to 14:1 and rpm varied from 1,000 to 1,500. 560

                If the spark advance is too high, backfiring through the manifold may occur. If the spark advance is set too low, it may cause delayed combustion instead. With delayed combustion the fuel is still burning when the exhaust valve opens. This could cause overheating of the valve and preignition during the next cycle.

                Once found, the optimum spark advance can remain constant from 0 to 5,000 rpm. The optimum spark advance does not seem to depend upon fuel temperature. The advance used for mixtures over 373C (703F) is approximately the same as for hydrogen at ambient temperature, liquid hydrogen, or for internally or externally mixed fuel.

Spark Gap

                Less energy is needed to ignite hydrogen, therefore, less voltage is needed for the sparkplugs. Reduced voltage also serves to prevent preignition. W. Peschka reports on a hydrogen conversion experiment using a sparkplug gap of 1 mm (0.04 in). They uses Bosch W300 T2 sparkplugs. 690 W.C. VanVorst recommends narrowing the spark gap by one-third to one- fourth the normal gap distance, thereby reducing the spark energy needed. 200 Billings, with a 6.6 liter (403 cu.in.) Pontiac V8, reduced the gap to 0.015 mm (0.0006 in). Finegold used a width of 0.012 mm (0.0005 in).

                The researchers also recommended that the plug electrodes must have square clean edges, otherwise excess voltage is required for them to work.

                If an engine is normally used at heavy loads and is being placed in a light load condition, it may be necessary to increase the spark gap slightly.

                Increasing the spark gap may be necessary when driving extensively at high altitudes. More voltage is needed to overcome the higher electrical resistance of thinner air.

Avoiding Cross Induction

                A current in one wire may induce a current in another wire nearby. When a spark plug is being fired, the voltage in the cable may induce a voltage in a nearby spark plug cable. This is most likely if the spark cables touch each other. Several precautions are necessary.

• Shield and heavily insulate the cables. Billings used a high temperature silicone radio suppression type. Alternative: use a tygon tubing slip over the ignition cables. 1030,201
• Ground all plugs not being fired.
• Avoid parallel runs. The ignition cables must not run parallel to one another. If they must touch, minimize the contact area. Crossing the cables at right angles helps to minimize the danger.

The Ignition Sequence

                The manual vacuum switch or ignition switch is used to activate the fuel supply solenoid switches mounted on the fuel lines. This insures a fuel supply while the engine is cranking. In one experiment, a relief valve is mounted between the solenoid shutoff valve and the manual shutoff valve. The relief valve used was a Nupro SS-4CA-3. The valve is activated at 2.2 atm (32 psi). 1030

Hydrogen as A Supplemental Fuel

Diesel and Hydrogen

                Hydrogen reduces pollutants. Experiments show that mixing hydrogen with diesel fuel reduces smoke, hydrocarbons and nitrous oxides in the exhaust. The following are specifications for an engine tested with diesel and hydrogen fuel together.

• Single cylinder                                      4-stroke, Air-cooled.
• Bore                                                                        75mm (3 in).
• Stroke                                                                     75 mm (3 in).
• Compression ratio                                                20:1
• Injection advance                                                21°.
• Type of combustion chamber            pre chamber.
• Rated power                                                          4.5 kW (6 hp) at 3,000 rpm.

                                                                                                        4.1 kW (5.5 hp) at 2/600 rpm.

During each experiment, hydrogen flow was kept constant. The results in Exhibits 115,116, and 117, are for two different How rates of hydrogen:

• 35 gram per hour (0.08 Ib per hour).
• 60 gram per hour (0.13 Ib per hour).

                The effect of hydrogen is greater at lower rpm and high load. At 2,600 rpm (high load) the exhaust contains more smoke than at 3,000 rpm (low load) because of the high flame speed and reaction rate of hydrogen that shortens the diesel combustion period, increasing temperature dissipation, and increasing combustion turbulence.

                Smoke production was measured at two injection advance settings: 20 and 21.5°. Both used a 5 hydrogen mix. There was more smoke at the higher setting.

                Increasing the hydrogen content in diesel fuel was found to cause knock and reduced power output. Water induction remedied the knock by reducing combustion temperature, but further reductions were experienced.

                Hydrogen and air were injected, then compressed. Diesel fuel was injected later, near the top dead center, using conventional diesel injection equipment. Diesel conversions had smoother uninterrupted fuel selection than spark ignition engines. Specifications for the diesel used were:

• One cylinder.
• Water cooled.
• Direct injection, vertical diesel.
• Water induction.
• Bore                                                                        80mm (3.1 in).
• Stroke                                                                     110 mm (4.3 in).
• Displacement                                                        553 cu.cm. (33.7 cu.in.).
• Power                                                                     3.68 kW (5 hp) at 1,500 rpm.

                Hydrogen was delivered at 173 atm (2,543 psi). A regulator reduced this pressure to 1 atm (14.7 psi) for introduction into the manifold.

                Without water induction, the knock limit fell between mixtures of 50% and 84% of the fuel energy supplied by hydrogen. A water induction rate of 7 liters per hour (1.8 gal per hr) raised the knock limit, allowing 53.5% to 87.5% of the fuel energy to be supplied by hydrogen. Beyond the knock limit brake thermal efficiency increased. Power output was less than on 100% diesel. Temperature quenching increased hydrocarbon pollution from unburned fuel. 730pl77-l86

Mixing Hydrogen and Gasoline

                Hydrogen and gasoline can be burned together. The best mixture is about 30% by volume of hydrogen. 1050 Chinese researchers found that lean mixtures of both gasoline and hydrogen mixtures reduced pollutants. The engine had the following specifications.

• Engine                                                                                                                                    Chinese "492 Q." Four Cylinders:
• Cooling                                                                                                                                  water cooled.
• Bore                                                                                                                                        92 mm (3.6 in).
• Stroke                                                                                                                                     92 mm (3.6 in)
• Displacement                                                                                                                        612 cu.cm. (37.3 cu.in.).
• Power                                                                                                                                     56 kW (75 hp) at 4,000 rpm.
• 2 chamber carburetor for gasoline.
• External hydrogen and air mixing for hydrogen fuel.

                Either fuel may be used separately. The throttles in both the carburetor and fuel mixer are adjusted to vary the hydrogen-gasoline mix During the tests hydrogen was added at a constant 750 grams per hour (1.7 lb per hour).

                Carbon monoxide emissions decreased with the percentage of hydrogen used. The amount of hydrocarbons in the exhaust depended upon fuel temperature and the quenching effects of the condensed fuel layer on the cylinder wall. Incomplete combustion due to these and other factors increases hydrocarbon emissions.

                Increasing the fuel-air mixture reduces hydrocarbons up to the mixture at which all the air and all the fuel are reacted (the stoichiometric ratio). Beyond this point/ the mixture is excessively lean. It burns more slowly and also contributes to incomplete combustion and hydrocarbon output.

                Lowering the amount of oxygen in the fuel mix and reducing the temperature and duration of combustion lowers nitrous oxides.

                Reducing oxygen tends to increase hydrocarbon emissions. Rapid burning reduces all pollutants.

                Experiments showed that adding even a small amount of hydrogen to a gasoline can speed up burning and improve emissions. Improvements also come when hydrogen - gasoline mixed fuel is used in a multi-fuel engine. Pure gasoline always had a lower volume efficiency than hydrogen at all engine speeds than when mixed with hydrogen. Engine efficiency increased under all operating conditions, particularly under partial load conditions. This will be an effective means of improving fuel economy. 545

                The American Hydrogen Association, under the direction of Roy McAlister, shows that hydrogen can reduce polluting emissions when combined with standard hydrocarbon fuels because hydrogen breaks down larger hydrocarbon molecules, creating a larger surface-to-volume ratio and allowing oxygen to more completely burn the components. 567

Selective Use of Hydrogen or Gasoline

                In Germany, Mercedes-Benz converted a car to dual fuel hydrogen and gasoline operation. See Exhibit 118. BMW also converted a sedan to dual fuel hydrogen and gasoline. The fuel tank can be seen in Exhibit 63. Exhibits 119, 120, and 121 show the engine compartment, and the intake manifold and injectors. 7l0p727-728 Specifications for the vehicle are given below.

• Storage system                                                     LH2 tank 130 liter <34 gal). Empty weight 70 kg (1541b), boil-off rate 1.7                                                                                                                   per day. Gasoline tank 22 liter (5.8 gal).
• Engine                                                                                    3.51iter (214in3).External mixing, lean mixture, exhaust gas turbocharger,                                                                                                                 computer controlled ignition timing, fuel mixing and water injection, dual                                                                                                                        fuel
• Power output on hydrogen                                                115 kW (154 hp) at 5,000 rpm.
• Power on gasoline                                                               180 kW (241 hp) at 5,000 rpm.
• Top speed on hydrogen                                     160 km/hour (100 mi per hour).
• Top speed on gasoline                                       230 km/hour (143 mi per hour).
• Nitrous oxide with hydrogen                             0.27 gram per ECE (6 X 104 Ib).
• Nitrous oxide with gasoline                                2.5 gram per ECE (6 X 103 Ib).
• Range with hydrogen                                          400 km (250 mi).
• Range with gasoline                                                            160 km (100 mi).

                The liquid hydrogen tank was fabricated from an aluminum- magnesium alloy (A13.5Mn) by Messer Griesheim GmbH. A safety valve vents the tank if the pressure exceeds 2.5 atm (36.7 psi). The fuel is fed through vacuum insulated lines and activated by a solenoid valve. A heat exchanger vaporizes the fuel.

                A turbocharger boosts the fuel pressure to 0.5 atm (7.3 psi) at 2/000 rpm. Fuel flow rate, fuel pressure, and equivalency ratios are varied according to engine demand by an engine load management system controlled by a Motronic microcomputer. Sensors located at different points on the vehicle feed information the computer on:

• Intake air flow (an indicator of engine load).
• Engine speed.
• Crank angle. When it reaches top dead center.
• Cylinder identification.
• Intake air temperature.
• Cooling water temperature.
• Engine knock, when it begins to occur.
• Turbocharger boost pressure.

Ignition timing and the fuel injection rate are easily programmed for either gasoline or hydrogen. Either fuel, or a mixture of both, can be selected.

                A standard Motronic engine control computer was supplied with an additional memory storing the hydrogen fuel ignition sequence. See Exhibits 122 and 123. It is activated only when hydrogen is used. The electronic engine control facilitates easy switching from one fuel to another.

                With hydrogen only the fuel-air ratio is varied, not the volume of fuel. 160 The engine is un-throttled with hydrogen The throttling flap in the intake manifold is bypassed. The air input no longer automatically depends upon the fuel flow rate. With hydrogen fuel, the air flow is manually governed. The air flow meter signal indicates changing load conditions with gasoline fuel. With hydrogen it is ignored. The accelerator pedal activates a sensor that tells the control system about load conditions. Another control circuit, operating only with hydrogen, regulates the water injection rate.

                At the Ninth World Hydrogen Energy Conference in 1992 at Paris, France, BMW proposed a gasoline-hydrogen hybrid vehicle as the best near term compromise between the availability of gasoline and the environmental benefits of hydrogen. Hydrogen and gasoline would be used for stop and go driving in town while hydrogen alone would be used for long distance driving with few stops. According to the company they have the technology ready now.

Precision Spark Ignition

                Roy E. McAlister, President of Trans Energy Corporation, is developing a kit that will convert most cars to run on either gasoline or hydrogen selectively. It is called the Precision Spark Ignition System. With it, there is no power penalty for converting to hydrogen. It converts the car to stratified- charge, direct-injection with specially designed "Smart Plugs." The system permits improvements in fuel economy and engine efficiency of about 20% on gasoline. Hydrogen fuel is added by installing a new fuel storage tank, safety valves, a pressure regulator, safety sensors, and the integration of the mechanical and electronic controls of the car. PSI system Smart Plugs replace the standard plugs, Trans Energy Corporation of Tempe, Arizona, provides the PSI System, engine controllers, and Smart Plugs. Manufacturers of components for storing and regulating natural gas supply the rest of the parts. Currently Trans Energy advises the Hydrogen Racing Program under the direction of Demetri Wagner. McAlister claims PSI technology allows engines to produce more power than with hydrocarbon fuels. 566

                PSI creates a stratified-charge combustion following the firing of the spark plugs. The air is admitted un-throttled into the combustion chamber to receive the largest amount possible. Fuel is injected into the air and at the same time is ignited by an electronically timed spark plug. Some parts of the cylinder have too much air for ideal combustion while other parts have too little air. When the burning fuel reaches the excess air region of the cylinder, flame speeds increase. The flame speed is higher than with uniform fuel-air mixtures prior to spark ignition. With un-throttled intake, higher compression and power cycle pressures are developed. 565

                Fuel and air are injected separately. Fuel is injected through the center of the PSI spark injector. As the fuel enters the cylinder it passes through the spark "flame" (a plasma) and the fuel is ignited. Combustion takes place after the intake valve is closed. Air in the fuel-poor region of the cylinder surrounds the burning fuel. This serves to insulate the combustion region from the cooler cylinder and piston surfaces. A few milliseconds later the burning fuel expands into the fuel-poor, excess air region. The extra oxygen ensures complete combustion.  In stratified-charge engines, combustion occurs in one part of the cylinder before it occurs at another. The flame front progresses from a fuel-rich region to a fuel-poor region. This staged form of combustion is different from regular engines where the fuel-air mixture detonates uniformly throughout the piston. In conventional engines, the fuel-air mixture is uniform before ignition. PSI avoids the backfiring when using hydrogen that is common with homogeneous mixture engines.

                Stratified charge promotes more complete combustion, more power, and reduced emissions of unburned fuel components such as carbon monoxide, hydrocarbons and oxides of nitrogen. Diesel and spark-ignition engines that have been modified to utilize PSI technology are able to bum efficiently fuel alcohols, diesel fuel, gasoline and L-P gases, or hydrogen interchangeably. 565 This is due to:

• Fuel is injected directly into the cylinder.
• The fuel flow is electronically controlled.
• A computer automatically adjusts the injection and ignition timing according to engine speed and load and the fuel used.

                Herb Hayden of Trans Energy designed electronic controls for PSI, increasing efficiency 10% for diesels and 20 to 50% for carbureted engines. Fuel savings help amortize the cost of the system within months. 565 The unthrottled air boosts power by lowering upper-cylinder vacuums.

                The system ensures cold weather startup. Under extreme starting conditions with throttled carburetors, engine power is not limited with PSI. The burning fuel is insulated from the cylinder walls at the beginning of combustion. Heat energy is conserved. Excess air burns fuel completely, eliminating auxiliary air pumps, catalytic mufflers, and particulate filters.

                The PSI system combines the functions of a fuel injector and sparkplug. In Diesel engines this is an advantage. Diesels ordinarily don't have sparkplugs . Compression is used to ignite the fuel-air mixture. In cold weather this can lead to delayed combustion due to heat loss through the cold cylinder wall. In summary, PSI has the following advantages:

• No vacuum needed to suck in the fuel. Power is saved.
• Increased air intake promotes complete combustion.
• Reduced heat loss during early combustion.
• Ignition occurs later but combustion is faster. This prevents early detonation from pushing against the rising piston.

                According to Roy McAlister of Trans Energy Corp, combining water injection with hydrocarbon fuel to produce carbon monoxide and hydrogen boosts power and the use of PSI can improve fuel economy 50% compared to homogeneous-charge engines. 565

Continuous Flow Engines

                A Pratt and Whitney J-57 gas turbine was converted to liquid hydrogen. The researcher concluded that the stable operation of the J-57 confirmed that conventional gas turbines could be readily adapted to hydrogen fuel. 580pl40

Continuous flow engines like turbojets require only slight modification to be converted to hydrogen fuel. Compared to piston engines, continuous flow engines have the following advantages.

• Relatively low pressurization is needed.
• A simple continuous injection process is used.
• There are no intake and exhaust valves.

                A significant disadvantage is the accumulation of high temperature heat in the engine materials due to continuous unrelieved combustion. 200 However, if liquid hydrogen is used, it can be used to cool the engine.

                In another experiment, a Pratt and Whitney 304 jet engine was converted to hydrogen. The expanding liquid hydrogen helps turn the compressor while combustion energy provided thrust. All performance predictions for this engine were confirmed within the first 25 hours when the project was terminated in 1958.

                The Saturn rocket booster uses liquid hydrogen under 58 atm (852 psi). The low-temperature properties of the liquid hydrogen are used in the thrust chamber cooling jacket.

                The preliminary efforts performed to date indicate that all types of engines can run with hydrogen. All of these engines seem capable of excellent performance with very little pollution." 580pl40-l40

                Exhibit 124 gives a summary of major experiments in running internal combustion engines on hydrogen fuel. 580pl54-l64

Natural Gas Conversions

Costs

                United Parcel Service has the world’s largest private compressed natural gas fleet with over 1,000 compressed natural gas delivery vehicles in 16 states. In the 70's and 80's UPS tested methanol and multifuel engines. In 1979 a UPS Canadian subsidiary converted 735 vehicles to propane. They also studied the performance of compressed natural gas in it's vehicles from 1997 - 2000. The "Truck Evaluation Project" was part of a DOE study by the National Renewable Energy Laboratory. The trucks ran every working day with "no major complaints." Were used as much as the diesel vehicles. CNG, Connecticut supplied the fuel. Total operating costs at one site were 98 of diesel/ the other was 119. The fuel emission results for natural gas were:

• 25% Carbon monoxide
• 93% of Carbon dioxide
• 50% of nitrous oxides
• 96% of hydrocarbons

                Early CNG technology consumed 140 more fuel than diesel trucks. Newer technology can reduce this deficit to as low as 10-15% more. 32 Electronically-controlled solenoid-activated injection for compressed natural gas (CNG) has an octane rating between 120 and 130. Gasoline: 83 to 93. The self ignition temperature is 540C (1000F), for gasoline it is 260C (500F).

                For carburetion and continued manifold injection backfiring is less with CNG than for hydrogen. Timed manifold injection is best suited for hydrogen. Safety measures are needed because of hydrogen's low ignition energy and high flame speed. 255

Chapter 6:

Electricity from Hydrogen

Hydrogen vs Electric Power

                In the late 1800's electric cars were introduced to a public skeptical about any means of transportation that didn't draw flies. For a time electric cars competed for public favor with internal combustion engines. By 1920 the gasoline-powered engine prevailed. The electric car's demise was not due to the power of the electric motor. The efficiency of electric motors is between two and three times that of internal combustion engines. The weak link in electric vehicle technology is the battery. Columbia Electric produced an electric car from 1897 to 1913 in Hartford, Connecticut. One set of batteries lasted eight hours. It was used as a limo by New York City. Even with today's technology/ over a ton of lead acid batteries are needed to provide the range of one gallon of gasoline,

                In 1998 two% of all new cars sold in California must be "zero emission" vehicles. In 2001 the number is five%, and 10% in 2003. General Motors concept car. Impact, is now for sale. It has a top speed of 160 km/hr (100 miles per hour), accelerates from zero to 97 km/hr (60 miles per hour) in eight seconds and costs about $30,000. The battery must be replaced every five years at a cost of $1,500.

                Another case in point is the 1999 electric version of the Ford Ranger pickup truck. Range: 80 k (50 miles) with lead add batteries. The 200 Ranger has nickel-metal hydride batteries the range is 105 to 129 km (65 to 80 miles). 25, 12-volt HiMH batteries are mounted underneath on the chassis. Lighter than the 1999 version. Three phase A,C. motor. Single speed rear wheel drive transaxle. Direct drive, no transmission. Top speed is (120 km/h (75 mph). Acceleration: 0 to 80 km/h (50 mph) in 12.5 sec. 67.1 kw (90 hp), 623 N (140 ft/lb) torque. Able to carry payload of up to 567 kg (1,250 Ibs). Recharges in six hours, 80% in three hours. May partially charge whenever it is not in use without harming the batteries. The electric charger requires a 208 to 240 volt, 40 amp outlet (similar to clothes dryer or electric stove). Uses a conductive charging system, which features an on-board charger and an off- board Power Control Station is the interface with the power source. May be installed in garage. Used for fleet vehicles that return daily to point of origin. Regenerative braking, only 15% of energy recovered while braking or going downhill. Operating costs equivalent to gasoline powered vehicles. No oil, no spark plugs, no alternator, 3 to 5 year Ford lease includes battery replacement ($2/000 to $3,000 value). Three year year 60,000 km (36,000 mile) limited warranty same as the company's gasoline vehicles. Wheelbase: 284.5 cm (112 in.).

                Exhibit 125 presents the results of a study comparing hydrogen fuel with electric batteries. Improvements are anticipated in both hydrogen and battery technology for the years 1990 and 2010. The researchers also considered capital costs, service life, efficiency, power output, recharge time

and energy storage density.

                Considering the use of the cryogenic properties of liquid hydrogen to cool an internal combustion engine and to provide air conditioning, the researchers concluded that this fuel provided the lightest weight, cheapest operating costs, best range and lowest energy consumption (including its manufacture) of all the non petroleum fuels studied.

                They found FeTi hydride to be competitive with liquid hydrogen in 1990 but not by the year 2000. Current lead-acid batteries were worst in all categories. Future nickel-zinc and zinc-chloride batteries were best in overall efficiency in using the electric energy generated from nuclear fuel. This takes into account an electric vehicle's use of regenerative breaking. This feature uses the deceleration force during breaking to feed current back into the batteries. This strategy can increase an electric vehicle's range by 8 to 13%. However, the use of on-board battery-powered accessories can reduce the range from 14 to 25%. For the year 2000 lithium-aluminum and iron sulfide batteries were predicted to be comparable in cost of maintenance to liquid hydrogen. This assumes a 20% improvement over the efficiency of zinc-chloride batteries in 1990. 20lp70 Even with the most up-to-date technology the figures are discouraging for electric batteries.

                For an electric car with a range of 500 km (310 miles), the lead-acid batteries would weigh 3,000 kg (6,600 lb). General Motors is now marketing an electric car called the "Impact," The advanced lead-acid batteries in the car would weigh just 40% of the above figure. More advanced zinc-air batteries would reduce the weight of electric cars powered with today's lead- add batteries by one-sixth.

                Bradley makes a two-seater that gets 40 to 50 miles per charge in the city 113 km (70 miles in the country). The batteries can be recharged overnight.

                Utilities produce electricity at about 30 to 40% efficiency. They also produce 35% of the CO2 emissions; transportation produces 30%. Only about 20% of U.S. electricity production comes from nuclear energy and a much smaller% from hydroelectric plants. These produce virtually no air pollution. With coal-fired plants, cars indirectly produce pollution and operate at a much lower overall efficiency. This is in spite of the electric motor's 80% efficiency compared to the internal combustion engine's 30 to 40% efficiency.

                The only way to take full advantage of the electric motor's efficiency and low environmental impact is to use a non polluting source of energy such as hydroelectric plants, wind-driven generators, solar power, and nuclear. Although coal-fired utilities are inefficient and polluting, at least they have the virtue of using domestic sources of energy.

                Bockris proposes passing air containing C02 through potassium hydroxide, then electrolyzing the resulting carbonate solution to give H2 and CQ2. They can be combined to form methanol using extra hydrogen, possibly from photovoltaic electrolysis. Fuel cells would reform the methanol into H2 and C02. Since the gas is recycled there is no net addition to the atmosphere.

The Hydride Battery

                Perhaps the best way to store electricity is to use hydrogen. The U.S. Department of Energy, the auto industry, and several public utilities have joined together to form the Advanced Battery Consortium. They have given their first development grant to the Ovionic Battery Co. of Troy, Michigan. The company won the $18 million contract award in competition with 60 other designs. The winning design is a nickel hydride battery. The design has been tested at 80 Wh per kilogram (36 BTU/lb). An earlier Japanese design was rated at 70 Wh per kg (32 BTU/lb). This compares with 30 to 35 Wh (14-16 BTU/lb) per kg for lead add batteries. The new technology is half the volume and half the weight of nickel cadmium batteries. This gives a range of double or triple that with conventional batteries.

                Gasoline has 12,300 Wh per kg (5580 BTU/lb)- far greater than for any battery technology. But electric motors are about 2.5 times as efficient as internal combustion engines. This gives the new Ovionic technology an effective energy density of 2.5 X 80 or 200 Wh per kg (91 wh/ Ib).

                In 1987 Ovionics produced the world's first nickel hydride battery. The company has finished testing an experimental cell they plan to install and test in a car. The new technology achieves its remarkable performance from an amorphous mix of hydride materials: vanadium, titanium, zirconium, and nickel. The battery is charged when water splits into hydrogen and hydroxyl ions (OH-). The hydrogen is absorbed into the crystalline structure of the hydride. The hydroxyl ions migrate to the nickel hydroxide electrode. The electrode oxidizes to nickel-oxy-hydroxide.

                During discharge oxygen combines with hydrogen to form water releasing electrons.   At the positive terminal, nickel-oxy-hydroxide transforms back into nickel hydroxide. Ovionics has seven Japanese and eight worldwide patents on its system. An earlier Japanese design used magnesium nickel hydride (MnNi5).

                A hydride battery can store energy in the form of electricity and as hydrogen gas. A certain hydride alloy , (NiCoMgAl)5.i-xZnx, does both. The highest concentration of hydrogen is 1.58 of the weight of the hydride. The highest electrical charge is 380 mAh / gram (173,000 mAh / lb.) Both occur when no zinc is used, but some zinc is needed to improve cycle stability and discharge performance. Zinc content of less than 0.2 by weight allows 345 mAh / gram (156,000 mAh / lb.) storage.

                There is not, as yet, any means of storing electrical energy that can come close to the energy density of combustible fuels.

                In a test of reliability Southern CA Edison and Toyota ran a RAV-4 electric vehicle with a nickel metal-hydride battery pack 100,000 miles since Feb 2002. SCE has 273 electric vehicles in use by meter readers, service managers, security patrols and carpools. The fleet covered 8.5 million miles, The vehicles prevented 1,000 tons of air pollutants, including 4,500 tons of tailpipe carbon dioxide emissions, 1,700 oil changes, and 500 gallons of gasoline worth. "The test data showed eV's with advanced batteries are cost effective to operate and have an equal life cycle of comparable internal combustion engine vehicles." 292

Fuel Cells

Reactions

                Electrolysis generates hydrogen from electricity. Fuel cells reverse the process to create electricity from the combustion of hydrogen. A fuel cell is an electrolyzer operating in reverse. Exhibit 126 shows the operation of a hydrogen-oxygen fuel cell. Comparing this diagram with Exhibit 2 (Hydrogen Oxygen Electrolyzer) we see that hydrogen enters on the anode side and oxygen enters on the cathode side. Water leaves the cell. Instead of current flowing into the electrolyzer/ current flows from the fuel cell.

                Both electrical storage batteries and fuel cells convert chemical energy directly to electrical energy, but fuel cells operate as long as a supply of fuel and oxygen is available.

                The chemical reactions that govern a hydrogen-oxygen fuel cell are given below. The reaction at the anode is:

                                2H2 + 4OH- —> 4H2O + 4 electrons.

At the cathode the reaction is:

                                O2 + 4 electrons + 2H2O —> 4OH-.

The overall reaction is:

                                2H2 + O2"—> 2H2O.

                Hydroxyl ions (OH-) flow from cathode to anode through the electrolyte. Electrons flow from anode, through the external circuit, to the cathode When the external circuit is broken, the cell stops.

                If the cell is 100% efficient, the energy from one mole of water produced in a fuel cell is 66 Wh. One kWh of energy is produced from every 421 grams (0.9 Ib) of water in the exhaust. Output voltage is 1.23 volt - similar to an efficient electrolysis process. The efficiency of ideal fuel cells and ideal heat engines are the same — 100%. 555 p. 1103

                In practice, fuels cells are currently 73 to 90% efficient. Compare this with a theoretical maximum of 55% for steam power. Output voltages range from 0.7 to 1.12 volt. Typical cell voltage varies with the current density of the electrical output.

                For fuel cells up to 15kW the current output is typically 50 to 100 mA per cu.cm. (819 to 1,639 mA per cu.in.) of water produced.

                As with electrolyzers, fuel cells may be connected in series to boost voltage or parallel to boost current.

                Fuel cells were discovered in 1939 by Sir William Grove, in England. It wasn't until the NASA space program in the 1960s that fuel cells were used for a practical purpose. The Gemini and Apollo spacecraft used hydrogen- oxygen fuel cells to generate electrical power and a pure water supply.

Efficiency

                A heat engine converts heat to work. No machine yet invented converts 100% of the input energy to work output. Waste energy is produced that does not contribute to the output. The First Law of Thermodynamics states that the amount of waste caused by the process is

                                Waste energy = Heat input - Work output.

                A fuel cell converts chemical energy directly to electricity. For any process that converts energy to work, thermal efficiency is the work output divided by the heat input.

                                efficiency = Work out / Heat in

Carnot efficiency measures efficiency of heat flow from high temperature to low temperature. The greater the difference in temperatures the greater the efficiency of flow.

                                Eff. Carnot = Temp High - Temp Low

                                                                                Temp Low

                In other words, the first law states that a machine cannot put out more than it receives. The second law state that the output will always be less than input because of inevitable heat losses.

                The fuel cell is not a heat engine. It does not convert heat energy into mechanical movement. Nevertheless, fuel cells are limited by Carnot Efficiency. "Fuel cells and heat engines are both constrained by the same maximum efficiency. The limit is established by the second law of thermodynamics."

                A. E. Lutz, and others, determined that the maximum efficiency of a hydrogen - oxygen fuel cell is 93.5. For a heat engine the limit is 92.1.

                "The Carnot efficiency results from the application of the second law of thermodynamics to a perfect heat engine. If such a process gets its heat from a chemical reaction, there will not be any other process that can extract work from the same fuel at any higher efficiency. Any proposed process that did would have to violate the second law of thermodynamics,"

                Can fuel cells be more efficient than heat engines? "Heat engines cannot operate at the maximum combustion temperature, because of the materials problems of handling the working fluid. Therefore, heat engines are forced to accept operating losses that fuel cells, operating at a much lower temperature, can avoid"

                Neither heat engines nor fuel cells are able to break this law.

                The "combustion temperature" is the maximum temperature for the reaction to proceed continuously. This is not the same as the adiabatic flame temperature. The enthalpy and entropy changes during the reaction are assumed to be independent of temperature. 555

Power Density

                Discovered in the 1850's, the fuel cell has developed into an efficient competitor to internal combustion engines – 50% more efficient and 50% better fuel economy when coupled with an electric motor. Power density is less than for internal combustion engines, but improving. Power density is the power output per unit volume.

• After 1989              106 kW per cu.m.                  (3 kW per cu.ft.)
• 1990                        350 kW per cu.m.                  (10 kW per cu.ft.)
• 1995                        700 kW per cu.m.                  (20 kW per cu.ft.)
• after 1995               1770 kW per cu.m.                (50 kW per cu.ft.)

Materials

                Electrolytes may be acids, bases, or salts.  For hydrogen-oxygen fuel cells potassium hydroxide (KOH) is less corrosive and gives higher cathode voltages. Phosphoric acid electrolyte is used with hydrocarbon fuels.

                Air may be used as a source of oxygen but nitrogen and other gasses dilute the effect of oxygen at the cathode. Oxygen makes up only 20% of the air. Contaminants in the air poison catalysts, thereby increasing maintenance costs. In spite of this, the ready availability of air eliminates the cost of separating pure oxygen from the atmosphere.

                Fuel cell catalysts assist the ionization of fuel and oxygen. Many catalyst materials are precious metals such as platinum, palladium, or rhodium. Nickel is most common with hydrogen-oxygen fuel cells. Catalysts with low ion exchange current densities minimize the activation potential. In other words, these catalysts minimize the build up of charges at the electrode-electrolyte interface. l70pl5l-l57

                Electrodes are typically made of plastic bonded composites of Teflon, platinum and carbon compressed and heated into thin durable sheets. This process prevents water saturation of porous electrode materials yet allows them to remain porous to gas. In general, electrode materials should combine the properties of thickness, low electrical resistance and porosity. Minimizing thickness and electrical resistance also reduces ohmic polarization. This is a potential that builds up across the electrode due to the resistance to current flow in the electrode, Reducing the thickness of electrodes to 0.0001 mm (0.04 in) helps minimize concentration polarization. This is the build-up of concentrated charges in the electrolyte on either side of the electrode. 580

Solid Electrolyte

                The Argonne National Laboratory in Illinois is developing a solid electrolyte fuel cell. The new lightweight cell would be ideal for automotive applications. It is designed to bum hydrocarbon fuels, particularly methanol, in air at 800 to 1,000C(1,470 to 1,800F).

                At elevated temperatures, hydrocarbon fuels breakdown into hydrogen and carbon oxides in a process called reforming. The hydrocarbon fuel is a carrier for hydrogen — the actual fuel used in the cell.

                The solid electrolyte greatly reduces weight. The researchers used yttria stabilized zirconium oxide in a ceramic-type material.

                A cross-section of the cell is shown in Exhibit 127. The cells are stacked in layers like corrugated cardboard. The entire array is a "sandwich" of individual cells connected in series. Each layer adds to the voltage of the next. This voltage is tapped on both sides of the fuel cell. The negative and positive poles are on opposite sides.

                Electrons released from the anode travel to the cathode of the next cell above. The cathode releases oxygen ions through the electrolyte to the anode to repeat the process. Current flows in this zigzag path until it reaches the surface of the cell stack.

                This arrangement is an improvement on an earlier Westinghouse prototype. The new cell has shorter current pathways to reduce resistance. The main problem the researchers face is in keeping the different components with different rates of thermal expansion, together. With recent tests, this does not appear to be a problem.

                Garrett Ceramics Corp. intends to develop mass production of fuel cells utilizing this technology. A cube 38 cm (15 in) on each side can deliver 50 kW (67 hp).

Automotive Applications

                The fuel cell cannot produce torque to turn the drive wheels. Like storage batteries, a .fuel cell can only provide current to an electric motor. Unlike batteries, a fuel cell delivers far more power at a less weight penalty. Fuel cells in cars may be 60% efficient. Combined with an electric motor's 80% efficiency, the overall efficiency of a fuel cell vehicle would be 48% — almost twice that of an internal combustion engine.

                Electric motors have a higher power-to-weight ratio than internal combustion engines, and also have twice the efficiency. Fuel cells are 50 to 70% efficient compared to 35 to 38% for fossil fuel internal combustion engines, 80 to 90% efficiencies are expected with advanced technology, A fuel cell in combination with an electric motor has twice the efficiency of an engine powered by gasoline or diesel fuel, 940pl05

                The cost of hydrogen from advanced electrolysis is about one-third greater than natural gas. Adding delivery charges and other costs of making the fuel available to the consumer, the costs of hydrogen become twice as much as diesel fuel or natural gas. However, if hydrogen fuel is used -in an electric vehicle to power a fuel cell, hydrogen is equivalent in cost to premium gasoline and half the cost of using hydrogen with an internal combustion engine. 180

                In 1964 General Motors experimented with a fuel cell-powered Electrobus. The vehicle used potassium hydroxide electrolyte and liquid oxygen to avoid electrolyte contamination with carbon dioxide.

                Dr, Kari Kordesch in 1970 converted a 1961 Austin A-40 four passenger sedan. He combined a fuel cell with lead acid batteries for acceleration. The fuel cell was used for low speed and cruising. A device to remove carbon dioxide enabled the cell to use atmospheric oxygen. The electrical system is shown in Exhibit 128. Exhibit 129 presents data showing how the batteries were charged and discharged at different speeds. The fuel cell is used for speeds up to 51.3 km/hour (32 mi/hour). At these speeds, the batteries are being charged. At higher speeds the batteries contribute a larger and larger proportion of the current used by the motor. A schematic drawing of the air- breathing Kordesch vehicle is shown in Exhibit 130.

                Despite the inability of these experiments to reach commercialization, one researcher concludes that "A hybrid fuel cell-battery vehicle could meet the performance standards of a conventional internal combustion engine while providing far more efficiency and less pollution." 201,41 That assessment was made in 1977.

                A Belgian-Dutch company, Elenco NV, in 1976 converted a VW van to hydrogen-powered fuel cells.  They use a 30% solution of potassium hydroxide for the electrolyte. The electrolyte was circulated to promote cooling. It operated at 65C (149F) at atmospheric pressure. The electrodes were comprised of three layers. The first layer was a metal current collector. The second was a catalyst made up of platinum-coated carbon granules and other constituents. The amount of platinum used was 0.7 mg per sq.cm. (9 X 106 lb per sq.in.). A porous support structure formed the last layer.

                They used three stacks of fuel cell modules. Eight modules were used in each stack as shown in Exhibit 131. Each module had a plastic frame that contained 24 cells with two electrodes each. See Exhibit 132 and 133. Each electrode is 17 X 17 cm (6.7 X 6,7 in). Bach module weighed 5 kg (11 lb), including the electrolyte. The dimensions were 26 X 25 X 16 cm (10 X 9.8 X 6.3 in). The total output of the fuel cells was 12 kW.

                During the eight-year development program, the company improved the fuel cell's performance. Exhibits 134 and 135 show the voltage-current output and voltage-time relationship of a 24 cell module at 65C (149F). At 0.67 volt the specific power of the modules is about 10 kg per kW (22 Ib per kW) when using air. Performance would be higher using pure oxygen. The electrolyte was not changed during the test. Soda lime was used to remove carbon dioxide from the air. The vehicle's range was 200 km (124 mi) compared to 60 km (37 mi) with batteries alone. 9l0p47l-474

                In 1992, Dr. Paul Cherry of the American Academy of Science in Independence, Missouri, modified a compact car powered by a hydrogen fuel- cell. LaserCel 1 is a converted postal delivery vehicle. It took part in the first annual Cannonball Run, a rally for alternative powered vehicles, from Flagstaff, Arizona, to Las Vegas, Nevada. The car had to be refueled every 75 km (120 miles). It cruised at 89 km/hr. (55 mph). A grant from the Pennsylvania Department of Energy paid for the research. The car was sponsored in the rally by a special contribution from Demetri Wagner, head of the American Hydrogen Association's racing program. It won the Special Vehicle Award. Further developments for LaserCel 1 include a reversible fuel cell. When charging, the fuel cell can electrolyze the stored exhaust water to generate more fuel. 815

                Hydrogen can be extracted from more easily stored fuels, such as natural gas. Hydrogen is extracted from natural gas by partial oxidation and steam reforming:

                                2CH4 + O2 = 2CO + 4H2.

                                CO + H2O = CO2 + N2.

The first reaction is exothermic and the second is endothermic. One absorbs the heat the other produces. No additional heat is needed. The most efficient ratio of air to fuel is 3.5 and for water to fuel it is 2.5 to 4.0.185

                During the Ninth World Hydrogen Energy Conference in 1992 at Paris, France, despite many incremental advances, there were no reports of a practical working fuel system for vehicles. Experts at the conference predicted that it would be 5 to 10 years before a practical fuel cell vehicle can be available for electric cars.  BMW and Mercedes-Benz are now making progress and predict that dual-fueled gasoline and hydrogen engines will be the norm in the 21st century.

                In 1997 Arthur D. Little, Inc. developed a fuel cell powered by hydrogen extracted from gasoline. They are working to adapt the system to vehicles. Chrysler Corp. estimated that even if mass produced, the device will cost $30,000 per car. With further research the cost will decline and will be in commercial production by 2010. Because gasoline's availability and ease of storage, the conversion to a pure hydrogen economy is delayed. However, gasoline consumption will be cut in half and air pollution reduced.

                Gasoline is reformed by burning with a small amount of oxygen. The complex hydrocarbons in gasoline are reduced to hydrogen and carbon monoxide. Since carbon monoxide, above 40 parts per million, poisons the fuel cell catalyst, more oxygen is added to make carbon dioxide. Los Alamos National Laboratory devised a method of adding oxygen to the carbon monoxide without effecting the hydrogen.

                In the fuel cell the hydrogen atoms flow through a membrane, leaving an electron behind. The hydrogen ion combines with oxygen on the other side of the membrane. The trapped electrons are rerouted through an external circuit, to power an electric motor, and then flow to an cathode to neutralize the positive ions.

                The reformer delivers 84% of the energy in the gasoline to the fuel cell. The system, overall, is more than double the efficiency of an internal combustion energy and gives 50% more range. An internal combustion engine has Carnot limits to its efficiency. Fuel cells do not have the same limitations of heat engines. The costs of fuel cells have been declining as shown below.

• 1990: $5,000 per kW
• 1998: $500 per kW
• 2000: $25 to 30 per kW

                Manufacturers hope meet a $5,000 cost goal by 2004. Solid polymer or proton exchange membrane electrolyzers now have platinum catalysts. Ballard Power's automotive fuel cells each have $225 worth of platinum now. Mass production would reduce this. At least 250,000 vehicles per year are needed to make it profitable.

Mirage?

                Since 1991 several groups of companies have pooled their resources to develop infant fuel cell technology. Under the direction of Dr. Ferdinand Panik, Daimler Benz has contributed $320 million. Ford 4430 million, and Ballard Powers Systems of Vancouver B.C. lends its decades of expertise to the venture. Toyota has assigned 200 researchers to a gasoline reforming fuel cell. In a 1997 auto show in Germany they revealed their prototype - the RAV-4 sport utility vehicle.

                The predictions during the Ninth World Hydrogen Energy Conference in 1992 were for commercial fuel cell vehicles in 10 years. In 2001Daimler- Chrysler predicted 100,000 cars per year by 2004. 288 At the North American Innovation Symposium in New York City in November 2002, Daimler- Chrysler announced no "near term plans" for fuel cell or hybrid vehicles.

                Honda and Toyota are the only car makers on earth pushing hybrid passenger cars in the consumer market Ballard Power Systems of Canada has signed a supply agreement with Honda Motor Co., Ltd of Tokyo to supply fuel cells and provide support services. The Institute of Transportation Studies at UC Davis received the first of six fuel cell vehicles from Toyota Motor Sales USA. These are the first market ready fuel cells vehicles in the US. Over five years Toyota has given $2,000,000 for research to the University of California and will receive $4,000,000 more in the next four years. UC has one of the few hydrogen fueling stations in the US. Stuart Energy System built the station to use patented "intelligent" hydrogen fueling technology. 293

Thermoelectric Turbine

                A thermoelectric device converts heat energy to electricity. A thermoelectric turbine may produce both electricity and torque. Any fuel can be used. It requires no catalyst and withstands contaminants that would destroy conventional fuel cells.

                Exhibit 136 shows a cross-section of the device. It consists of a stack of several discs mounted on an axle. Only four discs are shown. Fuel and oxygen are burned at the top. The combustion gasses swirl in and around each disc.

Thermal Gradient

                The flow alternately compresses and expands the gas as it flows into towards the center and out toward the rim. The center of each disc is heated by the compressed gas. As the gas expands, the rim is cooled. This gives each disc a temperature gradient across its radius. In other words, the rim is cooler than the center. As the gas gives up its heat to the discs, the gas gets cooler. The turning stack has a temperature gradient from top to bottom. Where the gas enters is hottest and where it exits is coolest.

                The challenge of thermoelectric technology is to combine high electrical conductivity with low thermal conductivity. Each plate is made of a temperature-resistant conductive metal. The alternating compression and expansion of the gas flow maintains the temperature difference across the radius of each plate, despite the high thermal conductivity of all metals.

Radial Field Gradient

                Magnetic field coils extend between the plates. The intersecting magnetic and electrical fields cause the the stack of discs to revolve around the axis like a turbine without vanes. The magnetic field causes a circular current to flow in the discs. The difference in temperature from the center to the rim creates a difference in resistance which causes the current to go outward. Electrical currents drift toward the edge of the disc producing an electrical field gradient across the radius. The center becomes more positive and the rim becomes more negative.

Axial Field Gradient

                A wire connects the rim of each disc to the center of the one below. Diodes in the wire prevent current from flowing backwards. The current flows in an around each disc until it reaches the bottom disc. In other words, each disc is "filled" with current from the one above and overflows into the one below - like a stack of Champaign glasses forming a fountain. The current. The disc closest to the entrance becomes positive and the one closest to the exit becomes negative.

                The output terminals of the turbine provide electricity to a load to do useful work. The turbine torque may be used to turn the wheels of a car. A mix of electrical output and torque may be used. The thermoelectric turbine has the ability to use any gaseous or liquid fuel, without the reforming step used with ordinary fuel cells.

Stationary Power Generation

                The Energy Research Corp. of Danbury, Connecticut, has developed fuel cells for utility power. They operate on 58% methanol and 42% water. They tested two 3 kW units. Both were 26% efficient producing direct current and 23 with alternating current. The fuel is heated to 300C (572F) in a steam reformer and converted to a flammable gas rich in hydrogen. The fuel cell operates at 190C (374F). 60 to 65% of the output is used to produce electricity, the rest is burned to supply heat for the reforming process. A phosphoric add electrolyte is used. A microcomputer controls the fuel cell operation. 10

                Fuel cells may be in household use by the year 2000. Small units providing 7 to 70 kWh per day would operate off of utility gas lines, thereby saving electric transmission costs. With mass production, costs would drop to $300 per kW in 1987 dollars. 940

                B. Dandapani and J. O'M. Bockris, at the University of Texas, described a fuel cell that produces both electricity and hydrogen. The current density and voltage are adjusted for different outputs of current and hydrogen.

                The device has two electrodes immersed in a sulfuric acid bath. The anode is iron, the cathode is platinum. The iron electrode slowly dissolves during a series of chemical reactions producing both current and hydrogen gas. The platinum cathode does not dissolve. See Exhibit 136. The reaction at the anode generates an electrical potential.

                                Fe —> Fe2+ + 2e-. 0.041 volt

The reaction at the cathode evolves hydrogen.

                                2H+ + 2e- —> H2.  0 volt

The overall reaction is:

                                Fe + 2H+ —> Fe2+ + H2.

                At operating conditions of 10 mA per sq.cm. (9300 mA per sq.ft), 0.2 volt, and maximum power output, 10.7 kWh of current are generated for every mole (1 gram, 0.002 Ib) of hydrogen produced. An equal amount of iron is needed. One mole of iron is 0.055 kg (0.12 Ib). The electrical output of this cell in Wh per mole of hydrogen is:

                                Fuel cell voltage X 2 X9.65 X 10,000 / 3,600 = 53.61 X cell voltage.

                The maximum power point in the curve shown in Exhibit 137 occurs at about 0.2 volt. 0.2 volt X 53.61 = 10.72 Wh/mole H2. If the price of industrial electridty is $0.05 per kWh, the current may be sold back to the utility at the rate of $0.000536 per mole of hydrogen produced, or about $0.536 per kg of hydrogen produced.

                No membrane is needed - only one gas is produced. In 1985 operating costs ranged from $120 to $1,400 per kW. At low temperature $440 per kW is assumed. If 12 is amortized per year over 10 years and it runs 8,000 hours per year, the costs are $0.0127 per kWh of hydrogen produced. Electrolysis costs about 3.5 times as much. Steam reforming of natural gas is 2.3 times higher.   130pl01-l05 The researchers conclude that "taking into account the credits for the electrical energy generated, hydrogen gas can be produced at a cost significantly less than the cost of hydrogen from natural gas and by electrolysis of water."

Infrastructure

                The state of California mandates that one% of all vehicles be zero polluting by 2005. In a study by Joan Ogden 625, if fuel cell cars meet half the mandate there will be 200,000 of them by 2010. There will be 330 fuel cell buses if 10% of new buses adopt the new technology. Los Angeles will need 26 million cubic feet (736,000 cu.in) of hydrogen per day, and by 2020, 61 million (1,730,000 cu.m). This is equivalent to one steam reforming plant used by a large oil refinery. Current industrial gas supplies can meet 5 to 15 million cubic feet (0.1 - 425/000 cu.m) per day. This can match the demand of 46,000 to 138,000 cars and 700 to 2100 buses at a cost of 12 to $30 per gigajoule (GJ).

                Natural gas supplies are sufficient for 30 years to fuel several million cars. The on-board steam reformers adds $12 to 25 per GJ, greater than the cost of liquid hydrogen.

                Small scale steam reforming and truck delivered liquid hydrogen are more cost effective than hydrogen pipelines in the short term. Off peak electricity for electrolyzed hydrogen to fuel four to six million fuel cell vehicles would cost more. In the long run hydrogen pipelines would compete with on-site reformers. The study produced alternative costs for different methods of powering fuel cell cars.

• Hydrogen              $360 to 620 per vehicle
• Methanol               $350 to 1,400 per vehicle
• Gasoline                 $850 to 1,200 per vehicle

                Las Vegas, NV has the world's first refueling station. It began operation in Nov 2002. The 4 year demonstration project will cost $10.8 million through a partnership of the Dept. of Energy, Air Products and Chemicals, Inc. and Plug Power, Inc. The station provides both hydrogen and natural gas. 292

Hybrid Buses

Hybrid bus manufacturers from the Electric Vehicle Assodation.

• Advanced Vehicle Systems 423-821-3146. AVS-22 Battery Electric Bus (hybrid option) AVS-35/40 Hybrid Electric Bus (turbine-battery hybrid) Both 22 - 40 ft models.
• Ballard Power Systems / XCellsis 604-454-0900, www.BaUard.com. Zero Emission Bus (fc - battery hybrid) Demo. only.
• ISE Research 619-287-8785. www.isecorp.com. Thundervolt Hybrid Electric Bus 30-40 ft.
• NABI, Inc 256-831-4296, www.nabiusa.com. [email protected]. 30LF CNG Hybrid Electric Bus. Retail and fleet
• New Flyer 204-224-1251, www.newflyer.com. [email protected]. DE40Lf Diesel Hybrid Electric Bus. retail and fleet.
• Nova Bus, Georgetown U./ Fed. Transportation Auth.
• Nova Bus, 450-974-0111, www.novabus.com. Georgetown University, http://fuelcellbus.georgetown.edu. Methanol Reformer fc electric battery hybrid. Demo only. Nova Bus 450-974-0111. www.novabus.com. RTS Hybrid Electric Bus (diesel, CNG or LNG-battery hybrid), retail and fleet.
• Orion 315-768-8101. http://stage.freightliner.com/products/orion.html Orion VII Hybrid Electric Bus (diesel, CNG or LNG electric hybrid.
• Toyota / Hino 800-468-6968, www.toyota.com Hino FCHV-1 Low-Floor City Fuel Cell Bus (fuel cell battery hybrid) Demo only.
• TransTeq 303-382-1041. EcoMark Hybrid electric BRT Bus (CNG battery hybrid) retail and fleet.

Hybrid F.C. Kits

                An all electric hybrid provides electricity to a motor from both batteries and a fuel cell. Batteries are used for acceleration, the f.c. is used for cruising. Azure Dynamics Corp., Canada makes hybrid electric power trains available to Purolator Courier, Ltd. for up to 3,000 delivery trucks. They can be installed in new vehicles or in old ones. One demonstration vehicle has a top speed of 60mph. At 15,534 annual miles, fuel savings pay the cost in three years. Below is a comparison of hybrid and conventional vehicles.

                                                                                Hybrid                    Non-hybrid                           Savings

• Fuel                                        $2734                      $10542                    $7808
• Hydrocarbons                      83      100%
• carbon monoxide  91      100%
• nitrous oxide                         53      100%

                The test was conducted by Independent Vehicle Testing Ltd, Delta BC. Average fuel economy improvement was 129. 4 conventional delivery vehicles and Azure's single prototype were driven over urban package, mail delivery, and delivery routes and an EPA urban driving cycle.

                The power plant is "Compatible with all internal combustion engines and fuel types, and the company says the system is suitable for easy retrofit and is fully compatible with fuel cell technology."

                A vehicle emission study in Birmingham, England found that medium-sized commercial vehicles contribute 12 to the miles driven, but 25 of ground-level emissions. For this application hybrids demand reliability and economy. Performance is secondary.

                Hybrid power trains are compatible with fuel cells. They enable reduced size and performance of the fuel cell. Toyota will produce a fuel cell hybrid vehicle suv. A prototype has been driven 81,000 miles (130,000 km). It relies on hybrid technologies found in Prius and other hybrid vehicles. Both the fc and battery power the motor.

Air Batteries

                A recent development combines the operation of a fuel cell with a battery "rechargeable like normal secondary cell, but which as the advantage of also being rechargeable with hydrogen gas." Hydrogen was stored in the anode as metal hydride. It could be recharged to 87 of capacity in 58 minutes. The Anode was made of MmNia.sCoo.yAlo.yMno.i. Cathode catalyst was Lao.6Cao.4Coo.3- Cell voltage: 20 mA / cm2. Operated on air: 12 mW / cm2. On pure oxygen 34 mW / cm2. It can store electricity electrochemically, but only when using air in the process. l87p945.

                A recent study made cost comparisons between competing propulsion systems or a future city bus fleet in Las Vegas. Zinc-air batteries equaled diesel and diesel hybrids but were more cost effective than fuel cells over a five to 10 year period. The life cycle cost comparisons took into account fuel, refueling labor and equipment, maintenance, equipment and battery costs. Future costs of fuel cell and diesel hybrid are expected IP decrease with improved technology but zinc-air costs are also expected to decrease. 292.

                The Las Vegas bus uses a zinc-air battery for cruising and a regular battery for acceleration. It's a kind of two-battery hybrid. The bus in 40 feet long (12m). The Federal Transit Administration paid $2 million for the project, half the cost of the electric transit bus program conducted by Electric Fuel Corporation and GE Global Research, and Regional Transport. Commission of S. Nevada. 32

Hydrino Hydride Battery

High Voltage Battery

                According to Randell Mills, "Although billions of dollars are being spent to develop an alternative to the internal combustion engine, there is no technology in sight that can match the specifications of an internal combustion engine system." His company, Blacklight Power has produced a hydride material capable of storing electrical energy at a greater energy per unit weight than gasoline. 6l5p669 If the concept is proven/both conventional electric batteries and fuel cells will become dead end technologies.

                The internal combustion engine has three times the power per unit weight as do either batteries or fuel cells: 1800 vs 300 W/kg (816 - 136 wh/lb).258p785 Although fuel cells are 70% efficient within 80 of peak power an on-board reformer to extract hydrogen from hydrocarbon fuels lowers the efficiency to 10 to 45. Liquid hydrogen requires about 30% of its heating value for liquefaction. The energy per unit weight for an i.c.e. is 6,000 Wh/kg (2722 wh/lb) compared to 300 Wh/kg (136 wh/Ib) for the most advanced battery technology.

                The key to increasing the energy storage capacity of batteries is to increase the voltage of the stored electricity beyond the 2 volts of conventional batteries or even the 6 volts of lithium fluoride batteries. Even hydride batteries fall short. The binding energy of a hydride is 0.75 electron volts, less than the 3.4 electron volts of the fluoride ion.

                Mills claims to have discovered a hydride ion with 22.8 electron volts and is chemically stable. If so, "a battery may be possible having projected specifications that surpass those of the internal combustion engine." 615p670.

                                The cathode reaction is                      MHx+ e- —> MHx.-i + H-.

                                The anode reaction is                          MHx-2 + H- --> MHx-i + e-.

                                The overall reaction is                         MHx + MHx-2 —> 2MHx-i.

                A hydride compound with a suitably high binding energy has been found, claims Mills. Ifs formula is: KH KHC03. It is made by electrolysis using a K2CC8 electrolyte, a nickel wire cathode and anodes of platinized titanium. A single anode is placed between two cathodes.

                Mills explains the high binding energy by invoking "hydrinos". A hydrino is a shrunken hydrogen atom. The electron orbit has fallen below the usual ground state. The ionization potential of hydrogen is 13.6 eV. The hydrino is a hydrogen atom with a binding energy of

                                13.6 eV / (1/p)2

Where: p = an integer greater than one.

                A hydrino hydride ion is formed when an electron combines with a hydrino.

Binding Energy of Hydrino Hydride ion

                The observed binding energy in Mill's reported experiment is 22.8 eV. This corresponds to hydride ion with a hydrogen atom one sixth it's normal size. A hydrino is formed by reacting a hydrogen atom with a catalyst. The catalyst must have a net enthalpy of reaction:

                                m 27.21 eV

Where: m = an integer.

                Energy is released when a hydrogen atom shrinks to form a hydrino. At 1/2 normal radius the energy released is 40.8 eV.

Chapter 7:

Stationary Applications

Utilization Efficiency of Hydrogen

                Hydrogen has one-third the energy of an equal volume of hydrocarbons but gives three times the energy for an equal amount of weight. Higher combustion efficiency means that the fuel is burned completely, without residues. When burned, the combustion of hydrogen with oxygen yields only water vapor.

                Exhibit 137 was compiled by T. Nejat Veziroglu from a variety of sources. 670 It shows that hydrogen has a greater utilization efficiency than fossil fuels for transportation/ industrial, commercial and residential uses.

Overall, it takes only 74% as much hydrogen to deliver the same energy as fossil fuels.

On-Site Power Generation

The Energy Carrier

                Hydrogen fuel has been studied and applied in virtually every way in which conventional fuels are used, in domestic non-commercial use. "In all these applications, it is superior to conventional fuels and other synthetic alternatives."  201

• Cooking.
• Water and space heating.
• Cooling and refrigeration.
• Lighting.
• Farm implements.
• Transport.
• Generating electricity.

                Worldwide energy demand is increasing four times faster than the population. The problem with wind, solar, water, and nuclear power is in transporting the energy from where it is generated to where it is needed. Hydrogen can serve as a link between new sources of energy and the end uses. With engine-driven generators or fuel cells, the energy consumed in generating hydrogen can be converted to electrical power.

                A combination of steam reforming of hydrocarbons and the use of hydride-forming metals can be used to generate hydrogen on site. In a Chinese experiment a methanol and water mixture was steam-reformed to produce hydrogen at 10 m3 / hour (353 cu.ft / hour) Carbon dioxide was also produced. The mixture of gasses was exposed to a metal plate that passed hydrogen but blocked the carbon dioxide. 75% of the generated hydrogen was separated. The remaining 25 was burned to provide heat for the steam- reforming process. The overall efficiency was 85%. 405 p. 1043

Hydrogen vs. Natural Gas

Some advantages of hydrogen as compared to natural gas (methane):

• A minimum of 4% hydrogen in air is needed for combustion. For natural gas it is 5%. An explosion of 4% hydrogen has only one-fourth the energy of a 5% natural gas and air mixture. This means that if an explosion with leaking hydrogen gas occurs, it would be less damaging than a similar explosion with natural gas.
• Leaking hydrogen rises faster and dissipates more readily than natural gas. (The high density of propane makes it hazardous.)

Some disadvantages of hydrogen, as compared to natural gas are:

• Because of the small size and high kinetic energy of the hydrogen molecule, it is more likely to leak and leak more rapidly, than natural gas. Hydrogen can reach its explosive limit four times faster. This is because it has a higher diffusion rate than other gases.
• The flame is invisible and radiates less heat than a natural-gas flame. This makes it easier to accidentally contact a hydrogen flame.
• All other gases except helium and neon liquefy upon contact with liquid hydrogen. These two gases can be used as a purge gas with liquid hydrogen fuel to flush air out of storage tanks and fuel lines before fuel is put in the tanks. l40p224-226

Pipelines

                In today's economy energy from coal, hydroelectric dams, and nuclear power plants produce electricity and transmit it long distances over transmission lines. Natural gas, from underground wells, flows through pipelines to where it is used.

                Both wires and pipelines carry energy. With few modifications hydrogen could flow through the same pipelines as does natural gas.

                In 1972 D.P. Gregory, of the US Institute of Gas Technology, calculated the critical distance where hydrogen in pipelines costs less than electricity through transmission wires. For distances of at least 322 km (200 miles) hydrogen pipelines are cheaper. The cost of transmitting hydrogen in 1969 dollars is $0.93 per kWh per 100 km (1.5 mil per kWh per 100 miles). The exact cost depends on the line voltage. 392

                In 1980 J.CV M. Bockris in Energy Options described how renewable and nuclear energy would produce electricity and hydrogen. See Pipelines would carry hydrogen long distances to produce energy two ways.

• Fuel cells convert hydrogen to electricity
• Hydrogen burned for heat and as an vehicle fuel. 465

                The cost of transmitting hydrogen by pipelines at 136 atm (2,000 psi) pipeline pressure is 1.5 times the cost of an equal volume of natural gas. 580p94 Because of its low density, hydrogen gas requires larger compressors with more power. This can be offset by the lower viscosity of hydrogen, this allows a higher pressure to be used with hydrogen than with natural gas. 100 Natural gas can be piped in combination with 10 hydrogen with no modifications of the distribution system. 800

                Hydrogen pipelines can be used as a substitute for electrical transmission lines.   At the power station, hydrogen is produced by electrolysis. Hydrogen gas sent through pipelines could take the place of electricity in high voltage lines. A 1,000 kilometer (622 mile), 1 meter (3.28 ft.) diameter pipeline at 98.7 atm (1,451 psi) can replace two 400 kilovolt overhead lines. Underground hydrogen pipelines have several advantages.

• They are less obtrusive.
• Hydrogen energy can be stored in any quantity near the until needed.
• Hydrogen can provide electricity on-site in fuel cells or burned.
• The gas can be used as a chemical feed stock for ammonia or methanol.
• Hydro plants now operating at 30 to 60% capacity, can operate at full output when producing hydrogen.

                Hydrogen can be withdrawn and liquefied at various points on the pipeline with the boil-off used to maintain pressure, thereby replacing compressors. The fuel can also be stored as a liquid close to its end use. A sphere with a diameter of 100 meters (328 ft) can provide 120 MW years of energy. 660pl52 Several pipelines are now in operation.

• Air Products and Chemicals, Inc. of Texas, has a 96 kilometer (60 mile) 10 to 30 cm (4 to 12 inch) diameter buried pipeline. No line compressors are used.
• Imperial Chemical Industries of Teesside, England, operate a 16 km (10 mile) above-ground line.
• Chemische Huls, of Germany, and L'Air Liquide, of France, jointly own a 550 kilometer (342 mile) 10 to 30 cm (4 to 12 inch) line.

                A study by the Institute of Gas Technology, in Illinois, found that hydrogen pipeline operating costs exceed the cost of natural gas pipelines by $0.0004/kWh-km ($0.0006/kWh-mile). This is due to higher compression costs and leaks, which are 3.5 to 30 times higher than with natural gas. In spite of this, it was found that pipings and components used in natural gas home distribution systems should be adequate for hydrogen as well. 670plll Evan Orr concludes that "eventually, when fossil liquid fuels become uneconomic or unattractive for other reasons, the industrialized nations will probably transport energy by hydrogen pipeline." 660pl52

                During the Ninth World Energy Hydrogen Energy Conference in 1992 in Paris, France, William Hoagland, manager of the Hydrogen Program at the National Renewable Energy Lab at Golden, Colorado, described a program for making the transition from natural gas to hydrogen using existing pipelines.

Natural gas can be mixed with up to 15% hydrogen without significant modifications.  Emissions of carbon dioxide and hydrocarbons will be reduced. Hydrogen and natural gas can be easily separated, allowing users to selectively use either fuel. Liquefaction plants would supply aviation fuel, and later, be expanded to power ground transport. By the middle of the 21st century pipelines will handle hydrogen exclusively.

                For more than 50 years the petrochemical industry has stored natural gas in underground salt caverns and aquifers. Nature has stored natural gas underground for millions of years. Storing compressed air in underground caverns could be a means of storing off-peak electrical power for utilities at a cost of about $425 per kW.  Suitable sites are plentiful in most of North America and have a projected life of 30 years. 569

Harnessing Hydride

Heating and Cooling

                In the Brayton cycle a gas is compressed to increase temperature. The gas is then heated by combustion, or some other means, and allowed to expand. It is the expanding gas that does work, either by pushing a piston or turning a turbine.

                During refrigeration, the Brayton cycle is reversed. First, a gas is compressed to increase its temperature. Heat can flow out of the gas more easily. When expanded, the gas cools to a temperature lower than what it originally was. A series of such steps are used to liquefy gases.

                Heat pumps either remove or add heat to a living space. In the cooling mode it compresses a heat exchange fluid. The fluid now has a temperature higher than the outside air. Heat flows out of the fluid. The fluid is then expanded and brought into contact with the inside air. The inside air transfers heat to the cooled fluid. This heat is again transferred to the outside, and the cycle repeats. In the heating mode the process is reversed. The gas is allowed to expand outside where heat is absorbed from the air. When the gas is taken inside and compressed, the temperature of the gas increases and allows heat to be transferred to the inside air to provide heating.

                Hydrides can be used in a heat pump. Hydrides absorb heat when releasing hydrogen and give off heat when absorbing hydrogen.

                In one project the efficiency of a hydride heat pump with the cooling power of 353 kcal / kg of hydride was 1.8. The minimum cooling temperature was 6C (43F) at an air flow of 7 m3 / min (247 cu.ft. / min). 456p94l

                Pairs of hydrides can be selected for various desired heat transfer characteristics. Hydrogen gas is shuttled back and forth between these hydrides, absorbing and emitting heat in the process. "For energy storage applications, the hydrides offer the possibility of performing work over a much wider temperature range than the classical absorption engines." 250p797 Exhibit 138 compares FeTi hydride with other heat storage systems. 630

                The efficiency of a heat engine is a measure of the work done by the engine compared to the heat energy input.

                                Efficiency = work output / heat input = 1 - (Tout / Tin).

• Tout = exhaust temperature.
• Tin = temperature of the heat applied to the engine or the temperature of combustion inside the engine.

In refrigeration, work is done to remove heat. The efficiency of a cooling process is:

                                Efficiency = work input / heat removed = (Tjn /Tout) -1.

                The absorption-desorption characteristics of hydrogen hydride can be used in a chemical heat pump. This is a method developed at the Argonne National Laboratory. It uses two tanks of two different hydrides: LaNi5 and CaNi5. During the loading cycle the CaNi5 is heated to 100 to 150C (212 to 302F). Solar energy could be used for this purpose. Hydrogen is released from the CaNi5 and is absorbed by the LaNi5. Heat is then released by the LaNi5. The input-output temperature difference is about 30C (86F). At pressures of less than 0.5 atm (7.35 psi) cooling is provided at OC (32F).

                When the LaNi5 has been fully charged, heat from room temperature can cause hydrogen release. The hydrogen is released and is absorbed by the CaNi5 which then gives off heat that can be vented outside. In this way, heat is taken from the room. Researchers claim that the cost is competitive existing refrigeration technology. 190p1082

                This principle can also be employed in a hydride-driven compressor with large differences in pressure and low differences in temperature.

                Iron-titanium is not used for either of these approaches because it has a break in its absorption cycle that lowers its efficiency for heat transfer.

Complex Hydride Energy System (CHES) Project

                A hydride heating and cooling system supplements a solar-assisted heat pump and water heater for use in a university building. At night a fuel cell provides electricity for the heat pump. The thermal energy storage unit was completed in 1986. It supplies 385 kWh of heat to the building. A second stage of the project, completed in 1987, uses heat from a 150 kW fuel cell to drive a hydride heat pump with an output of 60 kW.

                Daimler-Benz, converted a van to hydrogen. Heat from the passenger compartment is used to discharge a hydride tank, and the cooled air is returned to the passengers.

Power From Hydride

                The pressure generated by hydrogen gas discharging from hydride can be used to perform work. In one possible application, solar or waste heat from industrial processes discharges hydrogen. The pressurized gas then turns a turbine, gives up its heat, and is reabsorbed in another hydride tank. Heat can then be applied to the second tank and the flow reverses. If a reversible turbine is used, continuous power is possible. Several units of this type can work in tandem so that the power output is even and continuous.

                The hydride beds can transmit heat at 0.2 to 1.0 W/m (0.06 to 0.3 W/ft.).

Aphoid Burners

                Hydrogen burned in pure oxygen produces steam at 3,300C (6,000F). Water can be added to reduce the temperature. This process produces no flue gases. This avoids the 25 to 35% heat loss from burning hydrocarbon fuel. 870

                No "boiler" is needed because steam is produced directly from combustion. This allows for smaller units. The total volume of an aphoid heating plant can be ten% of the size of fossil-fueled boilers. A six story building could be heated by a furnace that can fit into a small living room.

                Fossil fuels are typically burned at 1,600C (2,900F) to produce steam at 490C (914F) with a 44% efficiency. Pollutants include: soot, sulfur dioxide, carbon monoxide, and carbon dioxide. An aphoid burner avoids this and has an efficiency of around 90%.

                High combustion temperature can be a disadvantage. It is difficult to design economical materials to withstand these temperatures. As a partial solution, water can be sprayed into the flame to reduce the temperature and produce a larger volume of steam at around 2/200C (4,000F) and 88% efficiency. "This burner is still in the experimental stage but there appears to be no serious obstacle to either its development or the development of its associated turbine equipment." 580pl37

Open Air Burners

How a Burner Works

                The purpose of a burner is to mix air with gaseous fuel and speed up the flow of the fuel to keep it from burning back into the fuel line. The principal parts of an open air burner are shown in Exhibit 139.

                Fuel flows from the fuel line through the gas orifice. As the gas flows through the mixing chamber it draws air in through the primary air openings. The fuel-air mix emerges under pressure from the burner through the burner ports. As the velocity of the fuel increases through the burner ports, more air is drawn up through the secondary air opening.

                It takes 9.56 cu.meter (338 cu.ft.) of air to burn 1 cu-meter (35 cu.ft.) of natural gas. Typically, 55 to 60% of this is primary air. For a water heater or range oven, 35 to 40% is primary air and for a space heater it is 65%. 670

                The fuel velocity must be carefully adjusted. If the fuel velocity exceeds the rate at which the fuel burns the flame will blow itself out or combustion will take place too far from the burner. If the fuel velocity is less than flame speed, the combustion will flash back into the mixing chamber.

                Because hydrogen burns faster than other fuels, the flame has a tendency to burn back into the mixing chamber. This may cause a loud, but harmless, "pop." Hydrogen burners should be designed to minimize the space between the gas orifice and the burner ports. The primary air intake is generally eliminated in hydrogen burners. 200

Hydrogen vs. Natural Gas in Appliances

                Natural gas (methane) is the most commonly used gaseous fuel. Hydrogen is adaptable to almost every application where natural gas is now used. Some modifications are necessary to switch from one to the other. These modifications are based on the differences between the two fuels.

                The minimum amount of hydrogen necessary to burn in air is 4%, the maximum is 75% (volume). The limits for natural gas are 5 and 15% in air.

                A hydrogen flame gives off almost no visible light. Natural gas burns with a blue flame. The temperature of hydrogen combustion in air is about 2,130C (3,870F). For natural gas it is about 1,900C (3,450F).

                The combustion energy for hydrogen is 1,000 Wh per cu.meter (93 BTU per cu.ft.). For methane it is 3,000 Wh per cu.meter (290 BTU per cu.ft.). Three times as much hydrogen as methane is needed to deliver equivalent amounts of energy. However, the flow rate for hydrogen is about three times that for methane (through the same size port). This means that about the same size gas orifice is needed for hydrogen as for natural gas. In practice, the energy value of the hydrogen flow is about 10% less than with natural gas. A slightly larger fuel orifice is needed for hydrogen to compensate for this.  (Note: the fuel orifice is not the same thing as the burner port.)

                The flame speed for hydrogen is ten times faster than for natural gas. This poses a greater danger of flashback with hydrogen. Hydrogen requires smaller burner ports to prevent the fuel from burning back into the body of the burner. The burner port size for any fuel must be smaller than a certain maximum size for a quenching effect to prevent the flame from burning back beyond it. If the burner port opening is less than this diameter the flame will not pass through it. This maximum diameter is the quenching distance.

• For hydrogen the quenching distance is 0.06 cm (0.024 in).
• For methane the quenching distance is 0.23 cm (0.091 in).

Burner Port Sizing

                The diameter needed for the burner port for any gaseous fuel is determined using the Bernoulli Theorem to solve for the area of the burner port opening.

                                A= YC(h/p)0.5

                                                q

• A =   area of orifice.
• Y =   expansion factor, function of: specific heat ratio

                                                ratio of orifice diameter to inlet diameter

                                                ratio of downstream to upstream absolute pressures.

• C =   coefficient of discharge.
• h =   differential pressure across the burner port.
• p=   specific gravity of the gas. Air =1.0. Hydrogen == 0.0696.
• q =   flow rate through orifice = density of gas x velocity.

Appliance Regulators

                Fuel line pressure may vary, thereby giving an unstable supply of fuel to the burner. Laws require that gas appliances have pressure regulators installed on the fuel line to even out the pressure of gas to the burner and to vent periodic excess pressure.

                A natural gas regulator may be adapted to hydrogen. Hydrogen requires a smaller size vent because of the lower specific gravity of hydrogen. The maximum vent rate should be 0.06 cu.meters / hour (2 cu.ft. / hour). For natural gas the maximum rate is 0.07 cu.meters / hour (2.5 cu.ft. / hour) according to ANSI standard # Z21.18-1969. "This standard would apply to a regulator for hydrogen fuel.   Informed opinion is that residential gas appliance regulators designed to regulate natural, manufactured, and mixed gases would accommodate hydrogen without deterioration of the diaphragm or other working components." 670pl83-l84

Catalytic Burners

Flame Assisted

                When hydrogen burns in the presence of iron or steel, combustion takes place very close to the surface of the metal at 1,500C (2,730F) or less. This controls the combustion and the metal absorbs the heat. The hot metal surface then radiates the heat to the atmosphere. This reduces nitrous oxide emissions, allowing indoor, un-vented combustion of hydrogen fuel.

                Billings Energy Research has developed a hydrogen flame stove top for a Winnebago recreational vehicle. The project was sponsored by Mountain Fuel Supply. The Institute of Gas Technology, with the sponsorship of the Southern California Gas Company, has researched catalytic combustion for use in water and space heaters.

                Some catalytic burners use a stainless steel wire mesh over the burner ports so that the flammability zone is within the diameter of the mesh surface. The larger the surface of the mesh, the smaller is the diameter of this zone. See Exhibits 140 and 141. 201

                The catalyst requires a high temperature. A primary ignition source (such as a pilot light or glow plug) starts the combustion to increase the temperature of the catalyst.   Such burners are about 70% efficient. Conventional natural gas burners are 60% efficient.

Flameless Combustion

                Hydrogen combustion in the presence of certain catalysts (such as platinum or palladium) occurs without a flame. Water vapor and heat are the only byproducts. Flameless catalytic combustion reduces nitrous oxide formation to a negligible amount. This form of combustion is from 85 to 98% efficient. 670 Venting is required only to remove excess humidity from the air. Flameless combustion also occurs naturally, such as the body's oxidation of carbohydrates, the yellowing of old newspapers, and rust.

                No pilot lights, spark plugs or other ignition sources are needed, just the surface of the catalyst. This prevents the accumulation of unburned fuel.

                Low temperature combustion reduces nitrous oxide emissions to 0.1 parts per million, compared to conventional burners at 200 to 300 ppm. 610 The combustion temperature for catalytic combustion must be kept at less than the autoignition temperature for hydrogen: 580C (1,076F). No pilot light or glow plug is needed to initiate combustion. This helps prevent the accidental buildup of unburned gas. Although only water is produced, venting to the outside is desirable.

• Excessive moisture may build up inside, rotting building materials and promoting mold and mildew.
• Oxygen is consumed and could lead to smothering of the inhabitants.
• If the flame goes out, an explosive mixture of fuel may build up.

                Additional efficiency is possible if the water vapor from combustion is allowed to condense and release its latent heat of condensation.

                The temperature of the catalysts starts out at room temperature but, over time, increases due to accumulated heat. The rate of fuel flow, fuel velocity, and the surface area in contact with the fuel combine to influence the temperature of the catalyst.

                Temperature resistant ceramic substrates are used for the burner.

                Water heaters with catalytic burners were tested to be 80% efficient.

                The cost of catalyst material is minimized by using a thin coating of platinum over a less costly metal, like stainless steel. The estimated cost of the catalyst is estimated to be $0.34 per kWh ($0.00001/BTU). If a 110 sq.meter (1,200 sq.ft.) house uses 439 kWh/day (1.5 million BTU per day) of natural gas, only $12.00 is required as a one time cost to supply the catalyst material for hydrogen conversion. For low cost do-it-yourself projects, stainless steel wool (3 to 22 nickel) works well enough and is easy to come by, even though nitrous oxides are not as low as with more expensive catalysts. Using these low cost catalysts it is fairly simple to convert appliances that use propane.

                Exhibit 142 shows test results on nitrous oxides comparing natural gas and hydrogen for use in range burners. Open flame and catalytic combustion are also compared for both fuels. 670 In open air combustion hydrogen produces considerably higher levels of nitrous oxides than natural gas does. With catalytic combustion, the nitrous oxide emissions are lower for both fuels. For low temperature catalytic combustion, the nitrous oxides for hydrogen are lower than those for natural gas.

                Hydrogen can burn in some space heaters designed to burn propane or natural gas. The CATTM flameless catalytic radiant space-heater has forced external venting. It is approved by the American Gas Association and manufactured by Thermal Systems, Inc.. The propane version is designed for recreational vehicles. They use 12 volt DC power. The natural gas models are used with 120 volt AC for the exhaust fan and the solenoid-activated gas valve. A platinum coated silica quartz pad provided the catalytic combustion surface. In burning hydrogen, the manufacturer measured the temperature with a non-contact infrared thermometer. The temperature of the rock wool was from 580 to 780C (1000 to 1400F). It glows a dull orange in a dark room. Temperature above 590C (1100F) will damage the pad.

                Catalytic combustion from natural gas, propane, or hydrogen produces long wavelength infrared radiation, like the sun. This radiation warms objects that it strikes, but does not warm the space it travels through. The heat is felt immediately, unlike forced air convection systems.

                Reynaldo Cortez in Home Power Magazine reported on his experience with hydrogen converted CATTM space heaters. 192 The hydrogen flow rate is controlled by varying the gas delivery pressure or changing the size of the gas inlet orifice. Adjustments are necessary for maximum output.

                Installation must conform to local codes or the American National Standard (National Fuel Gas Code) NFPA 54 and ANSI Z223.11984.

                The fuel delivery line is made from 1.9 cm (3/4 inch) diameter black iron pipe. Cortez used Permatex Industrial Hydraulic thread sealer. The shut off valve was installed at the flex hose that delivers the gas to the appliance. Low temperature combustion allowed the use of 5 cm (2 inch) plastic flue pipe. This appliance is designed by the manufacturer so that the fuel gas solenoid-activated valve will not open unless the exhaust fan is on.

                A soap solution (such as Rectorseek Leak Detector) is used to check for leaks in the pipes after they are installed. Pipe joints are immersed in the solution. Bubbles in the solution mean that gas is escaping.

                In 1991 Cortez stored hydrogen in a 156.5 atm (2,300 psi) gas cylinder. A two stage pressure regulator lowered the pressure to 10cm (4 inches) of water column for use in the heater. The heater had a hot wire for igniting fuel. The wire was unnecessary with hydrogen. In tests, fuel consumption was measured at 453,100 cu.cm. (12,800 cu.ft.) per hour at 13 cm (5 inches) water column pressure. This is three times the fuel consumption of natural gas. The natural gas orifice was enlarged from the standard 1.258 atm (18.5 psi) to get the same heat output as hydrogen.

                Despite successful tests, the manufacturer does not yet approve its product for use with hydrogen. The warranty will be void if anything other than natural gas is used. The American Gas Association must approve before the heater can be marketed for use on hydrogen.   For do-it-yourself conversions the manufacturer advises:

• Installation by qualified technicians.
• Any damage to the catalytic pad may pose a fire hazard.
• Experiments with hydrogen should be done outside.
• Hydrogen gas leaks are hard to detect because the gas is odorless.
• Hydrogen-air mixtures are explosive over a wide range of mixtures (4% to 75% hydrogen in air).
• Do not store mixtures of hydrogen and air.

Lighting

                Although almost invisible, a hydrogen flame can be used for lighting. Peter Hoffman, in his book The Forever Fuel, describes using a phosphorous- coated metal screen to react with a hydrogen flame to produce visible light. This is similar to the devices used in gas camping stoves. A copper flame spreader will give a green flame. 430

Water Production

                Hydrogen combustion yields either water or steam. At 25C (77F) 0.21 Wh per meter (0.02 BTU / cu.ft) of energy must be removed from the steam to produce water. If less energy is removed, the steam remains. 330 7 kWh per day at 70% efficiency produces 2.5 liters per day (0.6 gal. per day) of water. 670 Hydrogen produces twice as much water vapor per unit energy, as natural gas. See Exhibit 143.

                The McGuire Water Purifier electrolyzes salt to chlorine. The salt water mixture is too high to measure with swimming pool meters. It kills cholera bacteria in 10 minutes and takes an hour for all types, plastic pipe and turbine, runs on car battery, water tablets, disinfect up to 55 gallons of water a minute. The waste sodium hydroxide can be used to increase electric current or for lye to make soap. The system uses 12 volt battery and chargers widely available in third world countries. Developed from 1990 to 1998 by New Life International of Underwood, IN, a nonprofit organization. Cost is form $350 to $1,000 depending on location. Contributions also help the organization send purifiers to 37 countries. New Life International 812-752-7474 or www.missionsalive.org/newlife.

The Billings Homestead

                Billings energy Corporation constructed a large home fueled with hydrogen and solar energy. The Hydrogen Homestead includes a three-level 557 square meter (6,000 sq. ft.) home and a hydrogen powered tractor and Cadillac. The hydrogen Homestead provides a glimpse of a hydrogen economy on a small scale.

                The appliances in the home have been converted to hydrogen fuel. These include a Tappan range and oven, barbecue, fireplace, boiler and water heater. The homestead has two hydrogen vehicles: a Jacobsen tractor and a dual fuel Cadillac Seville. A metal hydride container stores fuel for them.

                During the first phase, an electrolyzer produced 1.4 kg (3 lb) per day of hydrogen. It was designed and manufactured by Billings. Later, the electricity to generate hydrogen came from a commercial hydroelectric plant.

                During the second phase, all electric power was using wind turbines, solar collectors, and a small hydroelectric plant. In phase three, hydrogen was produced for the residential subdivision and an industrial park using a nearby coal gasification plant.

                In a project funded by the U.S. Department of Energy through Brookhaven National Laboratory, Billings designed a metal hydride storage system and filled it with 1,800 kg (3,970 lb) of iron-titanium hydride. A computer monitored the tests for one year.

                Solar collectors are mounted on the south-facing roof and side wall. There are ten roof-mounted collectors to heat a mixture of water and antifreeze used with the hydride vessel. Two 1/000 liter (264 gallon) insulated holding tanks collecting hot water, for each solar collector array. Experimental equipment included: a metal hydride vessel, an electrolyzer/ hot water storage tanks / and the computer monitoring system. The hydrogen system shown schematically in Exhibit 144 has been installed in the Hydrogen Homestead. Funding for planning the system came from Four Corners Regional Commission and the Mountainland Association of Governments.

The Hydrogen Delivery System

                A Billings Solid Polymer electrolyzer produces hydrogen that passes through a water trap in the electrolyzer unit, it to the Homestead or to the hydride vessel, according to demand. The gas passes through a molecular sieve dryer. Hydrogen flow pressure is 24 atm (353 psi). The recharge pressure equilibrium and the design output pressure of the electrolyzer are identical.

                Hydrogen equilibrium for the design recharge pressure is approximately 55C (131F). The entire hydride bed and vessel is maintained at this temperature under equilibrium conditions by heat liberated from the hydrogen absorption reaction as hydrogen enters. Solar heated water is used to release the stored gas. When homestead demand exceeds the electrolyzer output, the hydrogen flows from the hydride vessel and the pressure drops. The temperature of the hydride also drops as heat is used to release the hydrogen. Hydrogen flows back through the purifier at reduced pressure because of the use of large lines and few restrictions.

                In the homestead, hydrogen is used for the gas appliances, to boost the energy input to the heat pump used for space heating, and to fuel the two vehicles. The operation of each of these experiments is described below.

Hydrogen Production

                In the first phase of operation, hydrogen is generated by electrolysis using power from a commercial hydroelectric source. Later/ the electrolyzer will be interfaced with a wind machine and with several types of solar-electric generators. An industrial park south of the Homestead is available for future installation and testing of a prototype coal gasifier for hydrogen production to supply the proposed Hydrogen Village.

                The electrolyzer installed in the energy storage shed at the Homestead is designed to deliver 1.36 kg (3 lb) of hydrogen per day at pressure of 34 atm (500 psi). Hydrogen from the electrolyzer recharges the hydride vessel for the Homestead and the vehicle hydride tanks.

                The Billings electrolyzer uses a duPont membrane material known as Nafion for its electrolyte. This plastic absorbs water and conducts hydrogen ions between electrodes. The membrane, which replaces acid or caustic electrolytes, allows use of deionized tap water in the cell. The Nation membrane also acts as a separator to prevent mixing of hydrogen and oxygen within the cell.

                Disc-shaped electrodes 8.9 cm (3.5 in) in diameter are pressed against the membrane to obtain good electrical contact. 20 cells are fitted within the housing to make up a 0.5 kg per day (1 lb per day) module.

                Hydrogen evolves at a pressure sufficient to charge the hydride vessels without the use of a compressor. Oxygen is generated at atmospheric pressure. The pressure difference across the membrane forces the Nafion against the anode for better electrical contact.

                Water consumption is 12 liters (3.2 gallons) per day and electrical consumption is 6 kW. The electrolyzer operates at a high current density of 4,000 A per sq.meter. (372 A per sq.ft.) in order to minimize capital cost and size. Lower current density units may be constructed for higher electrical efficiency, if desired.

                All of the transducers, flow controllers, water circulation pumps and switches are interfaced with a Billings computer monitor system. The computer records data periodically on magnetic discs. It also controls water flow in the heat exchanger and solar collectors and performs hydrogen mass flow integrations and other data analysis. See Exhibit 146.

                As a consequence of the swelling of the hydride as it absorbs hydrogen, it is possible for the hydride to become locked up.  This reduces the effective surface area available to hydrogen. Brookhaven National Lab tested small containment vessels and revealed vessel strain beyond the elastic limit. They believe that the hemispherical shape of the Homestead vessel will be less conducive to lockup than other shapes. To insure against it, they installed a loosening jet in the bottom of the tank to lift and loosen the hydride bed with jets of hydrogen. The same port was also used to evaluate methods of hydride heat transfer with hydrogen recirculation.

Cooking and Nitrous Oxide Formation

                Nitrous oxide is formed when nitrogen and oxygen, the two main constituents of air, are heated above a threshold temperature of about 1,315C (2,400F). The higher concentrations for hydrogen are a result of the fact that the laminar flame speed of a stoichiometric mixture of hydrogen and air is 3.24 meter per sec. (10.6 ft per sec.) compared to 0.46 meter per sec (1.5 ft per sec.) for natural gas and air mixtures. This higher hydrogen flame speed results in a large fraction of hydrogen being burned in a smaller area and, consequently, a higher peak temperature with resulting increase in nitrous oxide formation. Although the combustion temperatures vary only modestly, the natural gas combustion takes place right on the bottom edge of the nitrous oxide formation threshold, so that only a modest increase in temperature makes a significant contribution to the concentration of nitrous oxide formation. Appliance conversions were accomplished using a technique developed under a contract from the Mountain Fuel Supply Company of Salt Lake City, Utah. In this technique, nitrous oxide formation is controlled by two interacting phenomena.

• Hydrogen-air mixing is inhibited by blocking all primary air input.
• A stainless steel wire mesh is placed around the burner ports.

                The placement of the wire mesh in a proper configuration will allow the gradual mixing of hydrogen and air throughout the operating flow rates of the burner design. A hydrogen-rich condition exists in close proximity with the burner. The oxygen concentration increases when moving away from the burner head. If the stainless steel material is properly placed, there will exist a region immediately surrounding the burner openings, consisting of a flammable hydrogen concentration. This region is the flammable limit zone. The flammable zone will move in and out from the burner head, depending on the hydrogen flow rate.  A proper burner design will incorporate sufficient stainless steel material so as to ensure that the flammable limit zone is always located within the outside perimeter of the stainless steel material. See Exhibit 140.

                The stainless steel provides a very important secondary function in addition to the one just described. At high temperatures, stainless steel is an excellent catalyst for hydrogen combustion.  Shortly after ignition, the burning fuel raises the temperature of the metal to the region where the catalyst starts to work. At this point, the hydrogen in the flammable zone begins to react with the dilute quantities of oxygen present on the surface of the stainless steel catalyst. In this manner, a controlled reaction occurs in the flammable zone where mixture limitations will not permit the rapid combustion of hydrogen which would occur under normal conditions. Therefore, peak combustion temperatures are maintained below the threshold level for nitrous oxide formation.

                The Hydrogen Homestead uses a Tappan Convectionaire range. The oven has the same modifications in the burner design as does the stove. The furnace, barbecue, and fireplace are similarly modified. The catalyst screen is placed directly above the burner. The metal grid glows when hot, indicating that the otherwise invisible hydrogen flame is present. The hydrogen burner heats eight times faster than with natural gas, while using 24 less energy.

The Lorenzen Homestead

                "Everybody laughed at Henry Ford, too!” says a sign hanging in John Lorenzen's workshop. The inventor found his own answer to the energy crisis blowing in the wind.  Wind-powered generators have provided electricity for his 100 acre farm since 1926. Solar panels capture the heat of the sun for space heating and hot water. An electrolyzer generates most of the fuel for two pickup trucks, the rest comes from a small amount of gasoline. Fuel for the stove and refrigerator comes from $200 worth of propane a year. He has never paid an electric bill. But, alternative energy has a price: their TV is black and white and the power system can't handle a freezer.

                Something of a legend in his hometown of Woodward, Iowa (population 1,200), Lorenzen has played host to Henry Ford jr. and President Jimmy Carter. He credits his success to learning hard lessons struggling through the Great Depression with his wife, Elva. He barely avoided bankruptcy over a $340 debt by cutting wood to avoid foreclosure. His two children Vivian and son Jerry live nearby. Jerry has his own farm but chooses to pay for his electricity.

                A habitual pack rat, his machine shop is filled from frequent forays to the junkyard — some as far away as Omaha, Nebraska 274 km (170 miles) away. From odds and ends come many useful devices. He invented a battery recharger that prolongs battery life for ten days. The battery can last through 30 charge cycles. Lorenzen doesn't bother getting patents because he doesn't manufacture his inventions. Other homebuilt projects include a post hole digger, a hay baler, a barbed-wire winder and two tractors.

                He inherited the family farm at 15. There was no electricity - so he created his own. The power is stored in 170 batteries. The newest battery was installed in 1927. By 1940 utility power was available for $3 per month, but the power company never found a customer in John Lorenzen.

Conclusions

                The Hydrogen Homestead demonstrates the application of combined hydrogen, electricity and solar energy for residential use. The production, storage, and use of hydrogen to complement the solar and electrical system.

                The electrolysis of water uses hydroelectric power. Electricity could also be generated from other renewable energy sources such as solar and wind. Future plans call for a hydrogen pipeline from direct conversion of coal. Hydrogen is stored in a vessel containing iron-titanium hydride. Operational characteristics of the vessel and hydride are being studied. Hydrogen fuel is used to replace natural gas and gasoline in the Homestead.

                The Billings Hydrogen Homestead has served as a test facility for evaluation of hydrogen systems interfacing with electrical and solar systems. 120 It has ceased operation because of technical and funding problems.

The Lorenzen Homestead still continues in operation, as it has, since 1926.

Chapter 8:

Safety

Venting

                Pressure builds inside storage vessels containing hydride or liquid hydrogen. It must be vented before the tank ruptures. This is the purpose of a safety valve.

                Once outside the tank, this vented gas must not be allowed to accumulate in explosive mixtures. It must be safely burned during the venting process. Exhibit 147 shows a cross-section of a catalytic device that is mounted on the outlet of a safety valve. 110 When the maximum tank pressure is reached, at 9.2 atm (135 psi), the built-up gas is vented until the pressure is reduced. The blow off gas enters the jet nozzle, where it is mixed with air and passed through a catalyst of platinum coated aluminum pellets. Combustion takes place at low temperatures close to the surface of the pellets. In this way, the flammable vented gas is converted to water vapor.

                Government regulations require that an outlet for vented gas be at least five feet above any nearby building opening.

Safety-Related Properties of Hydrogen

                The various properties of hydrogen that make it safer or more hazardous than other fuels are listed in Exhibit 148. 580,594

Density and Specific Gravity

                Hydrogen has a lower density than air. It rises to accumulate at high points in a building. These areas must be vented when hydrogen is used indoors to avoid fire hazards. Its low molecular weight makes hydrogen more prone to leaks than other gases.

Diffusivity

                Hydrogen diffuses in air more rapidly than any other gas or vapor.

                The safety of liquid hydrogen was tested. 1,890 liters (500 gallons) were spilled on the ground, simulating an accidental rupture of a cryogenic tank. In 60 seconds the concentration in the air was less than 18% of the explosive limit. 580

                In another test, the Billings Energy Research Corp. shot a hole in an iron-titanium hydride tank charged to full capacity. The armor-piercing incendiary bullet ripped through the casing of the tank but there was no explosion. Only burning gas escaped from the bullet hole. If a hydride tank is pierced, pressure is released and an endothermic (heat absorbing) reaction occurs as hydrogen escapes. This absorbs some of the heat required for combustion. For comparison, a gasoline tank was shot with the same ammunition. The explosion threw flaming fuel over a wide area. The advantage with hydrogen, and other gaseous fuels, is rapid dissipation. 120

                There is a special hazard associated with magnesium hydride, however. The combustion of magnesium takes place at a high temperature and is difficult to extinguish. This is why magnesium is used in signal flares.

Some finely divided powders of magnesium, aluminum, or iron will bum spontaneously when exposed to air.

                In 1937, The Hindenburg, a giant rigid-frame passenger-carrying dirigible, caught fire near Lakehurst, New Jersey.  The hydrogen cells exploded and 36 people were killed. This disaster is cited as an example of the special dangers of hydrogen fuel. However, it must be remembered that:

• Hydrogen was not used as a fuel but for buoyancy, instead of helium.
• The Hindenburg had completed 18 transatlantic trips.
• Two-thirds of the passengers survived. The passenger gondola was below the gas cells. The burning hydrogen rose as it burned. Many of the 36 passengers who died jumped to their deaths.

                In general, hydrogen is no more hazardous than other flammable substances. It does have some unique properties that require special safety considerations. Its high rate of diffusivity enables it to penetrate some materials, such as cast iron.

Heat Energy

                On a weight basis hydrogen has three times the energy content of hydrocarbon fuels. On a volume basis it has about one-third less. A given volume of hydrogen will not give off as much energy as other gases, such as methane.

Explosion Energy

                A concentration of hydrogen of 18% or more in air can cause detonation (an explosion). Only 6% is needed for methane and propane to explode. 290pll7-l24 The amount of pressure that exploding hydrogen will exert on a container depends upon the detonation velocity and the density of the unburned mixture. Since hydrogen burns quickly, it has the highest explosion potential of any gas, on a mass basis. On a volume basis, it has the lowest explosion hazard. For an equivalent storage of energy, hydrogen has a similar explosion potential as methane or propane.

Flammability Limits and Optimum Mix

                The flammability limits of hydrogen in air are from 4% to 75%. 4% to 75% hydrogen mixed (by volume) in air will support combustion. These limits are wider than for methane, propane, or other hydrocarbon fuels. In most accidents, the lower flammability limit is of particular importance. Ignition sources with sufficient energy are nearly always present. 360p595 The minimum limit of flammability for hydrogen is higher than for propane or gasoline (2%). For maximum combustion hydrogen needs three times higher concentration in air (29.3%) than methane (9.48%).

Ignition Temperature

                The temperature needed to start the combustion of hydrogen in air is slightly greater than for methane and double that for gasoline. This means that hydrogen is usually not ignited, at atmospheric pressure, by ignition sources such as a lit cigarette, but only by an open flame. Exhibit 149 gives a detailed comparison of ignition temperature ranges.

Ignition Energy

                The minimum amount of energy (not temperature) necessary to start the ignite hydrogen is about one-tenth that for any hydrocarbon fuel. Most ignition sources, such as electrostatic sparks, exceed this level. Sparks from the human body ("carpet shock") have about three times the amount of energy needed to set off a hydrogen explosion.

Flame Luminosity and Temperature

                Hydrogen gas is colorless, odorless and nontoxic. It produces a barely visible blue flame with very little radiant energy compared to hydrocarbon fuels. It is possible to come into contact with a hydrogen flame, accidentally, because of its near invisibility.

Flame Speed

                The flame speed of any combustible gas is the sum of its burning velocity and the speed with which the flame displaces the un-burnt gas mixture. The flame speed for hydrogen is ten times that for hydrocarbon fuels. Therefore, automatic check valves designed for methane must be able to respond quickly enough to prevent hydrogen fuel-air mixtures from burning back into a fuel line.

Embrittlement

                This phenomena could best be described as unwanted hydriding. Steel and other iron-containing metals become brittle and crack when absorbing hydrogen. Metal containers and pipelines designed for natural gas may not be suitable for hydrogen. Steels with a high proportion of nickel (stainless steels) are more resistant to hydriding. If the right materials are used, hydrogen presents no unique storage problems.

                Since 1940 a German pipeline has carried hydrogen with no significant embrittlement problems. The pipeline extends 220 kilometers (137 miles) to 18 industrial centers. The fuel flow is 250 million cubic meters per year (8.83 billion ft3/year). The pipe diameter varies from 15 to 30 cm (6 to 12 inch). Pressure varies from 10.9 atm (160 psi) to 24.7 atm (363 psi). Very high operational reliability and safety have been established. Even though the pipeline was designed for natural gas, the pipe material should experience negligible levels of embrittlement. Embrittlement becomes a significant problem in pipeline steel at around 100 atm (1,470 psi). Replacement of parts in the pipeline network has shown negligible deposition and corrosion compared to natural gas pipelines. 360p593

                Over 220C (430F) the hydrogen molecule (H2) splits into two atoms of hydrogen (2H). Steel is more easily permeated with single atoms than with molecular hydrogen. Corrosion or electrolysis reactions can also produce atomic hydrogen. Pressure over 680 atm (10,000 psi) promotes hydriding.

                Titanium tubing specifications require hydrogen concentrations to be below 150 ppm, otherwise the titanium becomes titanium hydride. A titanium oxide film accumulates on the metal with exposure to air, but this film protects the metal from hydriding. General precautions against hydriding include:

• Use alloy linings and vented inner liners for large containers.
• Minimize the presence of nonmetallic inclusions in metal.
• Use quenched and tempered, rather than rolled, steels. Embrittlement is lowest in 300 series stainless steels, beryllium-copper alloys, and aluminum and copper alloys. All alloys should have minimal manganese content.
• Avoid the use of water when welding, to prevent the hydrogen in the water from getting into the metal. Use low hydrogen electrodes and any other method to reduce the presence of hydrogen in the weld.
• Preheat the metal before welding, and allow the weld to cool slowly.

Regulations

                U.S. hydrogen consumption exceeds 65 billion cubic meters per year (2,300 billion cu.ft. per year) and increases about 7 per year. Hydrogen has been used in the petroleum and chemical industries. It has an excellent safety record and can be handled without significant risk. Government regulations have evolved regarding gaseous fuels, and in particular, hydrogen. The main regulations are shown in Exhibit 150. 580pl

                Containers with over 85 cubic meters (3,000 ft3) must be located outdoors. The regulations for containers over 425 cubic meters (15,000 cu.ft.) are the most stringent.

                Researchers testing hydrogen in a stationary engine located indoors used a delivery pressure from the cylinders of 1.4 atm (21 psi). They voluntarily conformed to National Fire Prevention Association standards 54(14), ANSL B31.K15), ANSL B31(16), and Canadian gas association regulations 11 and 12. Fuel flow was automatically shut off when the ignition was off using solenoid valves in the fuel line adjacent to the engine and solenoid valves in the high pressure supply to the cylinder manifolds.

                The fuel line was a flexible hose and vibration-free connection.

                Nonflammable nitrogen gas was used to flush the air out of the fuel lines prior to delivery of hydrogen.

                Gas sensors mounted on the ceiling to detected 25% of the lower flammability limit of hydrogen (1 hydrogen in air). When hydrogen was detected, the sensor activated an alarm and cut the fuel delivery to the engine. A roof suction fan was also employed.

                All piping connections were sealed to prevent leaks. High pressure material was used for the pipe material: CDA alloy 443 brass. Rexarc manufactured some of the gas manifolds and others were obtained from a gas welding company.

                The fuel tank relief valve was set to open at 44.2 atm (650 psi). The 2 cm (0.75 inch) vent pipe extended outside and rose 1.5 meters (5 ft.) above the roof level. 820p738

                Liquid hydrogen containers in many experiments are made of aluminum or stainless steel. These materials have low temperature ductility. They can stretch at low temperatures without cracking.

                To meet the lack of safety codes written specifically for hydrogen, the Canadian Hydrogen Safety Committee was formed. It is a subcommittee of the Advisory Committee on Energy of the National Research Council. Its members include representatives of hydrogen producers and consumers, those involved in research and development, and quality control and process safety specialists. It is in the process of drawing up long overdue guidelines for hydrogen safety.

Summary

                The safe use of hydrogen can be summarized as follows:

• Adequate ventilation
• Leak prevention
• Elimination of ignition sources

Chapter 9:

A New Manhattan Project

                At Pear Harbor the oil still rises from the sunken ships below. On another Day of Infamy oil, and the dependence upon it, remains a threat to world peace. The onset of World War Two instigated the Manhattan Project - a massive effort to develop nuclear weapons. After 9-11 a new symbolic "Manhattan Project" is needed to rebuild what was destroyed in New York City. In a similar spirit, a Manhattan-type effort could research and develop the peaceful uses of nuclear energy to replace fossil fuels.

Hot Fusion

Dawn of the Hydrogen Age

                There are no alternatives to fossil fuels without cost — until a safer, cleaner form of nuclear power arrives. Perhaps fusion is the sunny side of nuclear power. The process that powers the stars can be brought down to earth to make electrolyzed hydrogen cheaper than natural gas - and end the use of fossil fuel for good.

                The following list gives the energy content for equal weights of mechanical, chemical, and nuclear energy sources. 320

Advantages of Hydrogen Fusion vs Fission

• Avoids the scarcity and importation of Uranium and Thorium
• Uses less radioactive fuel.
• A million times more power output per weight of fuel.
• Short lived wastes. May be recycled.
• Can process actinides from fission wastes to shorter radioactive life.
• Space propulsion using heated hydrogen propellant.

Isotopes

                A chemical element is defined by the number of protons in its nucleus.

Some elements have one or more neutrons in addition to the protons. These are "isotopes" of that element. This doesn't significantly alter the chemical properties.

• "Normal" hydrogen dH1) occurs at 1:1,500,000 parts of air.
• Deuterium (symbolized by iH2 or iD2) has one proton and one neutron in its nucleus. It's ratio to HI is 1:6500 in both air and water.
• Tritium dH3 or iT3) has two neutrons. It almost nonexistent on earth it is produced by manmade nuclear reaction. Half decays in 12.26 years to form an isotope of helium and an electron.

                                iH3—>2He3+e-

The subscript before the element is the atomic number. The superscript after the element is the mass number (number of protons + neutrons). For example, 2He4. Atomic number 2, mass number 4. Isotopes have the same atomic number but different mass numbers.

                Helium has two protons. Helium 3 (symbolized as 2He3) has two protons and one neutron. Helium 4 (2He4) has two protons, two neutrons. 2He3 occurs in 14 atoms to every 10,000 atoms of 2He4. The half lives of 2He6 and 3Li8 are less than one second.

                Lithium 6 and 7 are stable, lithium 5,8, and 0 are unstable.

                Heavy water at $1,000 per kg ($454/lb.) is only one atom in 6,500 in water, yet thousands of times cheaper than oil. Oil has 40 megajoules per kilogram. Heavy water converted to helium in d-d reaction yields 116 million megajoules per kilogram - only 1.3 grams of matter converted to energy. All the water on Earth contain 2X1013 metric tons of heavy water, enough energy for 851 million years at current rates. 448pll

                The obstacles of nature are imposing. A strong nuclear force holds the protons in a nucleus together. Nuclear forces operate within 10-13 cm. Outside that electrostatic forces keep protons from fusing. When two nuclei are fused, much energy is needed to bring the protons close enough for the strong nuclear force to take over and hold them together.

                During fusion, two atoms are combined into a new element. Secondary reactions convert a small amount of the matter to energy according to Einstein's E = me2. 14 MeV of energy are produced. Atoms with neutrons are called isotopes. Hydrogen has two isotopes: deuterium (one proton and one neutron) and tritium (one proton and two neutrons). Deuterium makes up only one of every 6,500 atoms of hydrogen, tritium is even rarer. Because the neutrons have no charge and they add inertia to the nucleus, fusion is easier with deuterium and tritium than with ordinary hydrogen.

                The products of fusion are: helium, high energy neutrons, and gamma rays. Helium is not radioactive, but it is hard to detect and has nearly the same mass (4.02820 amu) as the deuterium molecule (4.00260 amu). It is not radioactive, but the high energy neutrons make it radioactive. Neutrons are absorbed by the molten lithium barrier surrounding the reactor and produce tritium. Tritium is radioactive.

                A fusion reaction of one watt would release a lethal dose of gamma radiation instantly, but it would take 73,000 years to produce one mole (4 grams) of helium.

                In 1932, at the Cavendish Laboratory, Cambridge, England, Sir John Cockcroft and Ernest T.S. Walton produced fusion by accelerating protons against lithium target under a force of 100,000 to 600,000 volts.

Fusion Reactions

                Nuclear reactions release more than a million times more energy than chemical reactions. The reactions below are shown in millions of electron volts (MeV). A proton with an equivalent energy would have a speed of 14,500 km/sec (9,000 miles / sec). One atomic mass unit = 931.162 MeV. Only a small portion is converted to energy in fission or fusion. Fusion of hydrogen 1 occurs in stars but is impractical and takes to long on Earth.

                The first two reactions are nearly equally probable.

                                iD2 +    iD2 -—>2He3+onl      + 3.25 MeV

                Spare neutrons from the D-D reaction may be absorbed by Lithium 6

                                1D2 +    iD2 -—> iT3 +iHl      + 4.0 MeV

                Tritium and the helium and Lithium isotopes shown below are rare in nature and must be manufactured.

                                iD2 +   iT3 —->2He4+on1    + 17.6 MeV

                This is the most common reaction used in experimental reactors. The neutron has energy of 14.1 MeV, the helium 3.5 MeV. Tritium from the D-D reaction can be recycled to produce helium, above. This is the fastest reaction and is used in the hydrogen bomb. When beryllium is struck by a stray neutrons two neutrons are produced.

                                2He3 +   iD2 -—>2He4+iHl    + 18.3 MeV

                                3LI6 +   iD2 -—> 22He4        + 22.4 MeV

                                3Ll7 +   iHi -—> 22He4        +17.3 MeV

More tritium can be bred from neutrons reacting with lithium 6.

                                oni + sLIs -—> 2He4 + ITS

Neutron losses slow the contributing reaction to stop. The tritium remains, acting like a catalyst.

Magnetic Confinement

                The most promising fusion device is the tokamak. (Russian for "toroidal chamber-magnetic") First presented in a paper by l.V. Kurchatov, "The Possibility of Producing Thermoelectric Reactions in a Gas Discharge" at I. Kurchatov Institute in Moscow under the direction of L. Artsimovich.

                At over a million degrees all the gas is stripped of its electrons and becomes a "plasma". A magnetic field is used to confine the high temperature plasma to keep it from contacting the walls of the reactor. A magnetic field bends the paths of the charged particles into tight spirals, moving along the magnetic field lines. See Exhibit 151.

                Heavy hydrogen gas is heated inside a donut-shaped container by:

• A current in the confined gas (ohmic heating). In most tokamaks this is the primary means of heating, supplemented by one of the following:
• radio frequency (rf) waves. Similar to a microwave oven. The frequency is the same as the rate the ions revolve around the field lines (cyclotron frequency). The gas absorbs and emits radiation at this frequency (becomes a black body)
• A neutral particle beam injected into the deuterium gas. They are neutralized to go across the magnetic confinement barrier, once inside they become ionized by heat and collide with the gas particles. The beam contains 10 to 100 KeV ions. The Princeton Large Torus is heated to 70 million C in a 35 kilogauss field, for 100 milliseconds. Others include JET in Europe, T-15 in Russia, and JT60 in Japan.

                A plasma current flows around inside the torus generating rings of magnetic force lines. The magnet rings exert an inward confining pressure on the particle stream, keeping it together despite the electrostatic repulsion of the particles. This is the pinch effect.

                George Gamow determined the probability of collision between two approaching light nuclei.

                                Probability of reaction = exp [-kZ1Z2/W 1/2]

where:

exp = the base of natural logarithms raised to the power of the quantity in brackets.

Z1 and Z2 = number of protons in each nuclei.

W 1/2 =    square root of the relative energy of approach.

k =        a proportionality constant.

                The heavier the nucleus, the more protons it has and the more energy is needed to fuse them. With more than 3 protons, the energy required is too large to be practical.

                The probability of a nuclear reaction is called a "cross section". It is the area that must be hit to produce a reaction. The larger the cross section the more likely the two nuclei are to collide and fuse. The cross section is measured in "barns". 1 barn = 10-24 cm

                The maximum cross section for a deuterium - tritium reaction is 5 barns. An approaching particle must have an energy of about 200 keV (200,000 electron volts) in relation to the nucleus. At 20 keV the cross section is only 0.1 barn.

                A large number of atoms are heated to speed them up and strip away the electrons from the atoms. It requires millions of° for less one in a million particles to collide.

                                nuclear power released = P = n2Rf(T)

                                Energy released = Pt

                                Energy required to heat gas = knT

Where:

n = number of nuclei per unit volume

R = energy released in each reaction

f(T) = function of the gas temperature

t = time of reaction

k = proportionality constant

T = temperature in Kelvins

                If fusion occurs the energy output will exceed the input. The temperature of the reaction will be greater than the heat required for it.

                                Pt > knT

Substituting for "P" , above and solving for nt.

                                nt>(k/R)[T/f(T)]

In other words, a given temperature the gas must be contained for a certain minimum amount of time. This amount depends on the fuel used. This is the "Lawson" criteria. For a power output of P = 100 w / cm3 the following conditions must be met.

• For D - D gas nt must exceed 1016 sec / cm3.

                                At 109K, Power output = P = 8 X 10-30 n2 watts / cm3.

                                If n = 3 X 1015 nuclei / cm3 (1000 atm, 15,000 psi).

                                Gas was confined for more than 1.0 sec.

• For D - T gas nt must exceed 2 X 1014 sec / cm3.

                                At 107K, Power output = P = 2.5 X 10-28 n2 watts / cm3.

                                If n = 1015 nuclei / cm3 (30 ami, 450 Ib / in3)

                                Gas was confined for more than 0.1 sec.

In both cases the gas density is only about 10,000 atmospheric density, requiring the reactor vessel to be evacuated to a very rarefied vacuum. The high temperature causes high pressure. Fusion reactions require high density or high confinement time, or some combination of both. Low gas density prevents heat from being transmitted to the walls of the vessel. It also prevents the sudden temperature increase from fusion reactions from causing an explosion.

Instabilities

                Collisions between the particles or electric fields intersecting the magnetic field lines will deflect the particles from their paths. Deviations from uniformity in the magnetic field (hydromagnetic instabilities) occur when particles deviate from the magnetic lines for a few millionths of a second. Heat is transferred to the container wall.

                These instabilities happen when a slight kink in a magnetic line compresses the lines on the inside of the curve causing the kink to enlarge and disrupt the plasma flow. To remedy this an axial field is superimposed on the first magnetic field. This has the effect of reinforcing the field to prevent kinks and particle drift.

                Electrostatic instabilities are caused by electric fields intersecting magnetic field lines disrupting current and particle flow.

Magnetic field patterns

                Magnets produce "lines of force" that trace the direction of the field. In a fusion generator two patterns are a:

• Toroidal (axial) field parallel to the inside of the torus and has closed field lines without north or south polarity.
• Poloidal field perpendicular to the plane of the torus. The magnetic axis is through the "hole" in the donut and has a north and south pole. Both of these fields are employed to twist the lines of the magnetic field (rotational transformation). The twist stabilizes the plasma flow to help prevent kinks.

• Current through plasma in the direction of the flow produces a poloidal field
• Windings around torus in a helical pattern. First used by L. Spitzer, Jr. in the "Stellarator" at Princeton. Confinement does not depend on the plasma current. The advantage: magnetic diverters can be built into the coil pattern to inject neutral particles and remove spent fuel without any contact with the container wall. The Stellarator was tested in Wendelstein, Germany. A 5 million degree plasma was sustained without plasma current, instead using only injected neutral particles.

Safety Factor

                The safety factor is a measure of resistance to kink instabilities.

                                q = rBt / RBp

where:

r = minor radius (thickness of the torus)

R = major radius (of the hole).

Bt = strength of toroidal magnetic field.

Bp = strength of poloidal magnetic field.

The longer the field lines are at the point where the plasma is being compressed the less chance there is of a kink instability. Stability is increased if the toroidal field (Bt) is very much greater than the poloidal field (Bp). In other words, if the value of q is greater than one. In a tokamak the toroidal field greatly exceeds the poloidal.

EImo Bumpy Torus

                Some machines have q less than 1 and Bt = approx Bp. This compresses the plasma and then allows it to expand. One application of this reversed field pinch is the EImo Bumpy Torus at the Oak Ridge National Lab. Shaped like sausage links in a circle. Heated by RF power and high energy electrons, confinement depends on plasma current.

                Other applications reverse the field lines at the center and at the outside of the plasma. The relative strength of Bt and Bp vary with radius producing a higher ratio ("beta") of energy in plasma to the confining magnet than for a tokamak.

                                Beta = Plasma pressure

                                                                magnetic field pressure from toroidal field coils

Future Tokamaks

                Continuous operation is not yet achieved. Complex magnet structures of newer designs increase cost. Larger size may improve performance (minor radius greater than 1 meter) at 60 - 80 kilogauss, and 2 million kilowatts. Requires input power in 100s of MW. Liquid nitrogen is used to cool the coils to -195 C (-319 F) or a superconducting material niobium and (titanium or tin) is employed. A blanket of lithium and beryllium absorb neutrons and transfer the heat to a circulating fluid while coils are shielded from radiation and heat.

Spherical Torus

One trend is for tokamaks to have a smaller hole in relation to the thickness of the interior. In other words, smaller aspect ratios. See Exhibit 151.

                                Aspect Ratio = R/r ss Major diameter / minor diameter

I960                         Aspect ratio =4.5 Zero Energy Toroidal Assembly (ZETA), Harwell, Eng.

1980                        Aspect ratio = 3.0 Joint European Torus (JET), Culham, England ITER

1990                        Aspect ratio = 1.25 ("Spherical Tokamaks") START (Small tight-aspect ratio tokamak) 1991-98. First high temp. spherical tokamak. UK Atomic Energy Auth. Fusion at 100 million C for 1 sec

2000                        MAST (Mega Amp Spherical Tokamak), 2 X size START Sustained high current plasma. Additional heating used. Use neutral beam injector from Oak Ridge Nat'1.. Lab. Stainless steel vacuum vessel. England, Culham. SPHEX, Manchester, England

TS-3, TST                              Tokyo, Japan

NSTX, CDX-U      Princeton, USA

HIT-2                      Seattle, U of Washington, USA

Pegasus                 Madison, U of Wisconsin, USA

Globus-M                              St. Petersburg, Russia

ETE                                         Rio de Janerio, Brazil

Sphera                    Milan, Italy

Rotamak-ST          Adelaide, Australia

Advantages of Small Aspect Ratio Reactors

• 1/3 size conventional. 3 meters vs 10 meters.
• Less vessel surface area than high aspect ratio
• Only 90% of magnetic field needed for high aspect.
• More resilient to instabilities.
• 3 x plasma pressure
• Plasma confinement time similar.
• START beta 40 = 3 X large aspect devices.

Cold Fusion

                Unlike hot fusion, some low temperature fusion experiments have produced more energy than they have consumed. Problems remain but progress continues.

                Too good to be true? That’s what some observers thought after a 23 March 1989 press conference. Stanley Pons and Martin Fleischmann at the University of Utah announced the results of a startling experiment — nuclear reactions through electrolysis. Ten times more energy output than input. At last, the Holy Grail of energy research. Speculation ran wild and the press called the new energy source "Cold Fusion".

                The nuclear reactions used an electrically charged hydride metal as a catalyst. The reactions avoided the high pressures and temperatures thought necessary for nuclear fusion.  A hydride metal cathode absorbs heavy hydrogen (deuterium) during the electrolysis of heavy water. Electrolysis was not essential, gaseous hydrogen could be absorbed into a metal hydride cathode. Palladium, platinum, and nickel are most often used as hydrides in experiments demonstrating catalyzed nuclear reactions. Hydrogen is tightly packed into the hydride. The highly concentrated atoms occasionally sustain nuclear reactions. Normal output is 1000 - 5000 W / 1 (97,000 - 484,000 BTU / cu.ft.) for palladium.

                Skeptics argued that some experiments failed to accurately measure heat output. The thermal gradients inside the cell were causing poor mixing of the electrolyte. The heat measuring thermocouples or thermistors would register only the hot spots in a cell. But, Pons and Fleishmann used two thermistors "located at completely different positions."  452p47. Others replicated their results with other calorimeter designs that record accurate heat measurements despite thermal stratification (using flow and Seebeck envelope calorimeters). Pons and Fleischmann continued their experiments measuring excess heat with more advanced instruments (an Icarus-9 cell with three sets of thermocouples). Further experimental errors of 0.2 to 20% would substantiate cold fusion claims.

                Growing evidence vindicates Pons and Fleischman. But a serious problem remains. Despite improved techniques, scientists today are able to obtain catalyzed nuclear reactions only about 25% of the time. That's not enough to convince the bulk of the scientific community. According to cold fusion researcher. Dr. Michael McKubre: "The robustness of the heat observations seems to have achieved the point where we are not talking about whether there is a phenomenon, but what the phenomenon is. The issue of replicability, however, is severe. Neither the nuclear products nor the heat are attainable under sufficiently well defined conditions that we can guarantee to reproduce them on any given day, in any laboratory, for any period of time." 446p24.

                Peter Hagelstein of MIT reports 300% excess energy. During 1993-94 Yoshiaki Arata cycled the cell on and off in cycles lasting several days. Over 4,800 hours, they produced 200-500 megajoules per cu.m. (5.7 -14.2 MJ / cu.ft.) of active material. 1035

                Mizuno, with a ceramic, SrCe03 (semiconductor), produced 50 watts of power over 20 hours. The output was 50/000 times greater than the input energy of 1 milliwatt.

                According to John O'M. Bockris, a professor at Texas A and M University: "In the last five or six years is it's been found that nuclear reactions can be made to occur as long as they occur inside solids, with rather small energies." 444p38.

                A report by Melvin H. Miles, examines "...the possible production of excess power, helium 4, tritium and radiation during the electrolysis of heavy water D20 using palladium alloys as cathodes." 28 of 94 electrochemical experiments showed excess power, using palladium or palladium alloy cathodes in heavy water. 597

                "Results from our laboratory indicate that helium-4 is the missing nuclear product accompanying the excess heat. ... Thirty out of 33 experiments showed a correlation between either excess power and helium production. There was no significant production of tritium in any of our experiments...Our results provide compelling evidence that the anomalous effects in deuterated systems are real. Nevertheless, we have not been able to solve the reproducibility problem. This research area will remain highly controversial until reproducibility can be demonstrated." 450p35

                The products of cold fusion reactions reveal that traditional chemistry cannot explain why two thirds of the gas is deuterium and why helium is only 9 parts per billion, compared with 5.4 parts per million in the atmosphere at sea level. 450p28 120 keV of hard X-rays emerge from cells, compared with 15 keV for electrons in k-shells of hydrogen atoms. The total output was 240 eV per atom of cathode material. 447p63. The "Charging" periods are exothermic — energy is not being stored. The latest experiments use calorimetry sensitive enough to measure any energy input being stored.

                The press calls the phenomena "cold fusion," but even the researchers are not clear that nuclear fusion is taking place. Skeptics cite the lack of radiation, neutrons and gamma rays, normally associated with fusion. Cold fusion takes place at temperatures from ambient to several thousands of° centigrade. Natural "hot" fusion takes place at tens of millions of°. Regardless of whether or not it's fusion, atomic or nuclear reactions are taking place. The heat output is far greater than for any chemical reaction.

                Despite experimental evidence for a new and pollution free source of nuclear energy, practical applications elude those who seek the promise of limitless energy. The reactions start and stop unpredictably.

Transmutations

                The most common cold fusion reactions involve an isotope of hydrogen - deuterium (D). It has a proton and a neutron in the nucleus.

Typical reactions include:

                                2D + 2D = 3He (0.82 MeV) + neutron (2.45 MeV).

                                2D + 2D = 3T (1.01 MeV) + proton (3.03 MeV).

                                2D + 2D = 4He + gamma ray (5.5 MeV)

                In cold fusion (c.f.) hydrogen is crucial. "If the explanation of the c.f. phenomenon based on the model is plausible, hydrogen isotopes in metals are one of the key elements in the realization of optimum conditions for nuclear reactions in solids." 489p850

                Some researchers hope to accelerate the rate of decay in radioactive isotopes by increasing the radiation output. Because cold fusion produces neutrinos, it would change radioactive substances into less radioactive ones by the process of capturing elusive particles called neutrinos. In nature nuclei capture fast moving, high energy neutrinos.   For example, potassium, colliding with a fast neutrino, may fuse with a proton. Calcium results. 451pll7-118.

                                K + neutron + neutrino --> K + proton + electron --> Ca + electron.

                Cold fusion may be able to capture low energy neutrinos. It is possible to test this hypothesis by measuring the output of gamma rays that occur during nuclear reactions.

Conditions For Reproducibility

The Patterson Cell

                Dr. James Patterson of Clean Energy Technology developed an electrolysis process that uses a unique cathode - beads (1mm) coated with hydride forming metals in a cylinder, 40 cu. cm. (2.4 cu.m). An input of 1.4 watts yields an output of 1,300 watts. The claims were verified by Professor George Miley at the University of Illinois Nuclear Engineering Department. The cell linked to a water heater delivered 120% excess energy. He found evidence of the transmutation of heavier elements from lighter ones.

                Alternating layers of metals of different Fermi energy levels creates layers of greater electron density at the interfaces. These "swimming electron layers" facilitate nuclear reactions. The cathode is made up of polymer spheres 1mm in diameter, coated with thin films of a nickel and palladium alloy, 300 to 2,000 angstroms deep. A typical cell is has 1,000 spheres, occupying a volume of 0.5 cu.m (18 cu.ft.). He uses a pump and preheater, requiring 5W. Hydride loading takes place at 70C. 448p49. Use thin films (0.1-1 micron), not solid electrodes. Consider palladium alloys (eg. palladium- nickel alloy). 80C (176 F) is the optimum electrolyte temperature. Use glass. Teflon (R) causes an increase in impurities.

Electromigration

                The Italian Nuclear Physics Laboratories finds, "Deuterium gas is loaded into a palladium plate under pressure, and a constant electric field of a few hundred millivolts per cm. is applied from one edge of the plate to the other, which moves the deuterons across it by electromigration. The ends of the plate are sealed with gold, and I think this causes the deuterium to pile up against the ends." (EBotta) Wpl5/'When the loading ratio is large enough to allow an excess power, the filling condition of neutron production has fallen off significantly. The higher the excess power, the lower the neutron flux from the cell, and vice-versa." 448p34

Alternating Current

                The open circuit voltage should be at least 1.0 V. Enhance hydride loading by periodically lowering the current to 30 mA/cm (64 mA/sq.in.) and reversing the polarity of the electrodes. Arata & Zhang found that cold fusion can be initiated by "strongly coupled plasma and a violent localized vibration of the lattice" caused by an intense electromagnetic turbulence. 448p53. Variations in current can be from 5 to 45V, with low current, less than 1.0 mA. One experiment used unipolar alternating current from IHz to 0.005 Hz with a power input of 0.5 milliwatts to 20 milliwatts. 443pl5 They charged first one side of the cathode, then the other, alternating every few minutes. Square wave current causes deuterons to pile in local hot spots with a concentration higher than average for the conductor. (Oriani and Karabut) 446pl5. According to Samgin and Vakarin, "Cooperative excitations could play a key role in proton transfer." 448p66.

                444p56 Power     output     increases     nonlinearly     with temperature.” Whatever the reason, many people have noted that high heat or rapid changes in      voltage will help trigger CF heat. Excess power production seems to be related to the average composition, the amount of excess volume, and the open circuit voltage partial unloading results in excess power production just as soon as loading has been restored. " Rothwell

443pl5

                In all parts of the cell, measure and control voltage drops, particularly within the mass   of the cathode. John O'M. Bockris 447p27.

                Also try immersing the cathode in an oscillating magnetic field. A magnetic field sometimes triggers heat burst in cell. 443pl5.There appears to be some kind of link between superconductivity, magnetism, and cold fusion. 443pl5.

Heat vs. Transmutations

                During transmutations both endothermic and exothermic reactions occur simultaneously. This is why heat output varies.445p25 Transmutations are sometimes accompanied by less heat output. 445pl2. To maximize heat production the internal metal crystal structure should be as large as possible. Annealing the metal reduces the number of grain boundaries and surfaces. If tritium and neutrons are desired, the reverse is true. Sintering produces small crystallites.

Spontaneous Neutron Formation

                It is uncertain why cold fusion works but it is clear that some sort of nuclear reactions are taking place.   Any or all of the following are possibilities.

                                proton + electron --> neutron + neutrino.

                                neutron -> proton + e- + antineutrino.

                                proton + antineutrino —> neutron + positron + neutrino.

                                neutron + neutrino --> proton + electron + antineutrino.

                Paul E. Rowe offers one explanation for cold fusion. Hydrogen atoms are converted to neutrons at the surface of a hydride cathode. The mass of a neutron is 1.67482 X 10-27 kg, approximately equal to the mass of an electron plus a proton or the mass of hydrogen 1.67343 X 10-27 kg The free neutrons are in a higher energy state than in a hydrogen atom. They enter metal atoms, participating in fusion and other nuclear reactions. 443p6 The half life of free neutron is 12 minutes. They are absorbed in .001 second when passing through materials. A hydrogen atom is converted to a neutron at the surface of the hydride. Perhaps two thirds of the neutrons are absorbed by the high concentration of hydrogen atoms in the hydride. 443p6

N - Space

                Graham Toquer envisions the shrinking electron orbit going into a fourth dimension where it picks up an elusive subatomic particle — a low- energy neutrino. This releases heat energy. Cold fusion is not fusion but the result of neutrinos interacting with compressed hydrogen atoms to release energy. Neutrinos are an elusive sub atomic particle. They normally streak through space at near light velocities. Low energy neutrinos may exist in a region of higher dimension within, or near, the nucleus.

                Electrons brought close to protons of the nucleus capture neutrinos. An electron and proton cannot combine without a neutrino.

                                electron + proton + neutrino —> low energy neutron + positron.

                                positron + electron --> gamma ray.

                                neutron + antineutrino --> proton + electron.

                A nucleus capturing a neutrino is transformed into another element. If the atom is heavier than iron it may fission. Fission produces protons and helium nuclei..

                                thorium isotope + antineutrino --> titanium + copper

                Subatomic particles have both the characteristics of waves and particles. The mass-wave characteristics of electron determines its orbit. When an electron orbit is compressed, it has nowhere else to go but into "n- space". This is a space of higher dimensions that some physicists think exists within subatomic regions. If low energy neutrinos inhabit this realm, they would be available to interact with protons and neutrons.

                Free neutrons have a half life of 12 minutes. It breaks down into an electron and a proton. A free proton must absorb electron or emit a positron and decay.

                                hydrogen + neutron —> deuterium

                                deuterium + neutron —> tritium

                                tritium —> proton + deuterium —> helium3

                                hellum3 + neutron —> helium4

In these reactions hydrogen atoms emit energy as photons, not heat. Toquer calls any device that would harness this energy a "neutrino trap." If the hydrogen is stimulated with 21 cm electromagnetic waves, the atoms would deliver their energy in unison.  An antenna converts the energy to electricity-

Underground States of Hydrogen

                According to Randall Mills hydrogen atoms may drop down to energy states below the ground state. The ground state is now thought to be the lowest energy state for a hydrogen atom. Dropping below that, it will not participate in chemical reactions as an ordinary hydrogen atom would. A hydrogen atom dropping to an "underground" state releases energy. Unlike Graham Toquer, Mills thinks the energy would emerge as heat.

                Hydrogen is drawn into a hydride-forming metal and stored there as as individual atoms in the form of atomic hydrogen. The gas accumulates until there is about one atom of hydrogen for every one of metal. At this point, the density of hydrogen in the hydride is greater than for liquid hydrogen. The electron orbits are constricted to a smaller orbit. The shrinking hydrogen atoms release energy. This energy is in the form of heat, not radiation.

                Mills calls these shrunken hydrogen atoms "hydrinos." They are from one half to one twentieth the size of hydrogen atoms and are able to escape confinement by passing between the atoms of any container. They are environmentally benign and do not burn.

                In forming hydrinos, energy is produced from the whole atom, not just the nucleus. This avoids the radioactive debris usually associated with nuclear power.

                In Mill's invention hydrogen gas collides with a heated cathode to compress hydrogen atoms. The energy released is reported to be about one thousand times greater than for hydrogen combustion. "We have independently validated now of a thousand times the energy of burning hydrogen. So you'd use very little material. ... A 200 hp car going 50 mph using this process will go a hundred thousand miles on a tank of water.... We have cells running here that produced a thousand times the energy of burning hydrogen, running now." 45lp24

                One cup of water with the hydrogen atoms shrunk to half size produces 25kWh. At 1/20 size produces 3,500kWh. enough to heat a home for a month.

                In recent experiments Mills has claimed to reconfirm his theories. The potential energy of the hydrogen atom is 27.2 eV. Elements with ionization potentials an integer multiple of this can "borrow" an electron from a nearby hydrogen atom. As the hydrogen atom recombines it forms an unusual atom half, or less, the size of the original. In experiment rubidium was used. The presence of the shrunken hydrogen atom was spectroscopically verified and had a new potential of 3.05eV. 6l6p92 7 and 7 Hydrogen mixed 3% in an Argon plasma reportedly reacted to produce 624 times as much energy as combustion in oxygen. The experiment repeated with another inert gas, Xenon, produced no results, confirming the importance of selecting a gas with the right ionization potential. 6l6p967.

Safety

                The hydrogen escaping from the electrolyzer should be ignited before it can accumulate in explosive concentrations. A catalytic combustion device similar to the one shown in Exhibit 147 promotes combustion without a high temperature flame.

                "So far, nobody has detected dangerous levels of x-rays or other emissions from a cold fusion cell. The auto radiographs prove that cold fusion does produce low levels of radioactivity, but the levels are so low that scientists have difficulty detecting them with sensitive instruments. Compared to the radiation from televisions and the natural background of radiation from space, radon and other sources, cold fusion radiation seems likely to remain so low as to be nearly undetectable." 448pl9.

                A worker was killed by an exploding cathode. The cause was thought to be the build up of harmonic resonance in the metal. The 21cm (8.3 in) waves reflected off a nearby metal surface and were reabsorbed into the cathode. This might have been prevented by using a signal generator connected directly to the cathode or by avoiding the presence of reflective surfaces to avoid feedback. 449p95 Avoid feedback from the cathode with any nearby reflective surfaces. High voltage electromigration may cause an explosion of the cathode. ll88p20 Graham Toquer, in his experiments, recommends that the cathode be stimulated by radio waves, alternating current, or an oscillating magnetic field. The optimum wavelength is 21cm (8.3 cm), the same as the hydrogen emission frequency. If reflective surfaces are nearby there is danger of feedback that can build up to an explosion.

Charge Cluster Acceleration

                Another approach to uses a stable formation of ionized gas known as charge clusters. They carry a small amount of positive ions within a larger envelope of electrons. Traveling at one tenth the speed of light and smashed against a surface, nuclear reactions may result. A neutral metallic hydride charged with deuterium would make an ideal target.

                Part of the gas is ionized, but more and more of it becomes ionized as the energy is produced from ion collisions. "Our philosophy is to accelerate some of the particles in the gas phase to a very high degree and leave the other particles relatively cool." 400p23

                Charge clusters are called "plasmoids" because they contain an imbalance of charges, unlike a plasma. Typically, they are about one micron in size with 100 billion electrons together with a million positive ions. They are shaped like a smoke ring rotating around its axis. A magnetic field holds them together despite their electrostatic repulsion.

                The cathode discharge "punches through the glow plasma layer, creating turbulence which initiates the poloidal rotation of the vortex ring. The perfect boundary symmetry from the liquid protuberance and glow plasma not only causes an abrupt scalar compression which polarizes the vacuum and ortho rotates the .flux, but it also provides the needed boundary conditions to create a tight vortex filament that is closed upon itself trapping the excess energy." 449p99.

                Charge dusters "accelerate the protons with sufficient kinetic energy to overcome the Coulomb barrier and penetrate the lattice nuclei triggering transmutation events." 449p99. High density clusters (about 2,000 volts) accelerate in a 5,000 volt electric field to one tenth the speed of light (the same as electrons in a TV picture tube). As the cluster nears the target the electrons drive off electrons in the target, exposing the positive ions. The heavy positive ions in the cluster overcome the Coulomb barrier. The impact can produce nuclear reactions in radioactive elements. Charge clusters are stable at atmospheric pressure, but only in resistive environments, not on the surface of a conductor.

                "Previously, it has been the common belief of scientists that much higher energies than a mere few thousand volts would be necessary to cause nuclear reactions.  So the effect of these electron clusters in picking up positive ions now gives us a new tool by which we can more easily explore the world of nuclear energy." Hal Fox 448p62

Chapter 10:

SOURCES

                "As most of you already realize, there is almost no area of human activity that would not be dramatically affected by the advent of new energy technology - especially matters of war or peace and health and the environment. If you doubt this, just try to imagine our world ten, twenty, or fifty years hence without the advent of a dramatic source of new energy such as cold fusion (low-energy nuclear reactions), or some other very powerful new energy source! It’s not a pretty picture. Frankly, what we have today in the menace of hydrocarbon fuels and an associated geopolitical nightmare is very ugly indeed. Furthermore, a future of abundant, clean energy has almost zero chance of emerging from the well-intentioned beneficial, but limited world of wind-power, photovoltaics, and other conventional renewables - not to mention from the so-called hot fusion program, which is lavishly funded by governments to the exclusion of new energy." Dr. Eugene F. Mallove, President, New Energy Foundation (See below)

ORGANIZATIONS AND PUBLICATIONS

Hydrogen and Cold Fusion

                New Life International. Nonprofit. 812-752-7474. online at www.missionsalive.org/newlife. Underwood Indiana. Manufacturers saline electrolyzers for water purification and donated to third world countries.

                American Hydrogen Association. Nonprofit. Sponsors annual energy exhibits and promotes its own research into using solar energy to generate hydrogen. Current research includes development of a "SMART" plug that promises to allow easier conversion of almost any car or truck engine to hydrogen combustion. Also, an activated carbon hydrogen storage system that will hold more hydrogen per unit weight than hydride.

                Director: Roy McAUister, P.E. 1739 W. 7th Ave./ Mesa AZ 85202-1906. (602)890-2444. Fax:602-967-6601. Data Bank: Updated hydrogen energy data by fax at 408-738-4014. Times: 12:00 noon to 6:00 am. pacific.

                Electric Vehicle Progress:  reports on fuel cell industry. Alternative Fuels Advisor alternative cars, hybrid, batteries for electric vehicles, hybrid. hydrogen fuel for transport, new vehicles & specs.. Fuel Cell Industry Report: applications, energy policy & regulations, marketing strategies. On line access. Published 20 years, battery, hybrid and fc. R&D, Order from: Scientific American Newsletters, 215 Park Avenue South, Suite 1301, New York, NY 10003-1603. Phone: 800-232-0376. Fax: 212-228-0376. Website: www.AltFuels.com. E-mail: [email protected]

                Hydrogen and Fuel Cell Letter, monthly, edited by Peter Hoffmann, correspondent for major news organizations in Washington D.C, Germany, and Italy. Covers major research and development in fuel cells and hydrogen energy worldwide. Grinnel St. P.O. Box 14, Rhinecliff, NY 12574-0014. Phone: 1-914-876-5988. Fax: 1-914-876-7599. E-mail: thihoff @ aol.com

                Hydrogen Now. www.hydrogennow.org

                Infinite Energy Magazine,    Bold, unique, answers questions establishment science would rather ignore generally in the field of new energy. It provides a forum for debate and discussion of frontier science. P.O. Box 2816, Concord, NH 03302-2816. 603-228-4516. Fax: 603-224-5975.

                International Journal of Hydrogen Energy. Monthly publication of the International Association for Hydrogen Energy. Provides for exchange and dissemination of ideas on hydrogen energy between scientists and engineers worldwide. P.O. Box 248266, Coral Gables, FL 33124.

                Lindsay Publications. P.O. Box 538, Bradley IL. 60915-0538. Phone: 815- 935-5353. "Unusual technical books, past and present, of exceptionally high quality revealing skills and secret processes almost forgotten."

                National Science Foundation, Comell, Ithaca, NY, cold fusion archive.

                New Energy Foundation. Nonprofit. Dedicated to new energy research. Publishes Infinite Energy, The Magazine of New Energy Technology. Presents science and technology,     P.O. box 2816, Concord, NH 03302-2816, www.infinite-energy.com. Phone: 603-228-4516. Fax: 603-224-5975.

                UK Fusion (www.fusion.org.uk) Information and downloadable technical on Mega Amp Spherical Tokamak (MAST) fusion reactor and proposed 1200 power plant.

Hybrid Power Plants

                Azure Dynamics, Steven Glaser, vice president. 1-416-367-0220 ext 105. [email protected]. www.azuredynamics.com.

                Electric Vehicle Corp. 1-212-529-9200 ext 111. [email protected]

                Fuel Sell Technologies, Decom 300-A2. Solid state H2 storage and delivery system. Size of small suitcase. Fuel cars, remote and back up power systems. Two fuel cassettes per unit. Regulates flow, pressure, demand. Mates to fc stacks. Proprietary ECE to hyd conversion system.

COLD FUSION ARTICLES

                J. 0'M. Bockris, etal., "Two Zones of 'Impurities' Observed After Prolonged Electrolysis of Deuterium on Pd.", Infinite Energy 1995, pp. 56-67.

                V.B. Brudanin, etal.. Physics Letters A 1990,146(6) p. 351.

                C.C. Chien, etal., "On an Electrode Producing Massive Quantities of Tritium and Helium", J. Electroanalytic. Chem., 1992 pp. 338-189.

                E. Conte and M. Pieralice, "An Experiment Indicates the Nuclear Fusion of the Proton and Electron Into a Neutron," Infinite Energy, 4,23, 67.

                M. Fleischmann, S. Pons, "Electrochemically Induced Nuclear Fusion of Deuterium", J. Electroanalytic Chemistry 1989:261 pp 261-301.

                J.C. Fisher "Liquid Drop Model for Extremely Neutron-Rich Nuclei" Fusion Tech.l998:34p66.

                Giori C. Borghi, etal., ^Experimental Evidence of Emission of Neutrons from a Cold Hydrogen Plasma," Phys. At. Nucl., 56,7, American Inst of Physics. 1993

                S.E. Jones, "Observation of Cold Fusion in Condensed Matter", Nature 1989:338 p737.

                H. Kozima, "Cold Fusion Experiments Generating Excess Heat, Tritium and Helium", J. Electroanalytic Chemistry; 1997,425 ppl73 and 1998,445 p 223.

                H. Kozima, etal./ "Anomalous Phenomena in Solids Described by the TNCF Model", Fusion Technology, 1998 pp. 33-52.

                H. Kozima, The Cold Fusion Phenomena: International Journal of the Society of Materials Engineering for Resources (Japan) 1998: 6(1) p 68.

                H. Kozima, "Excess Heat and He in Cold Fusion Experiments", Cold Fusion 1996:17 p.4.

                H. Kozima, "First Reliable Tritium Data by Packham, etal. Analyzed by TNCF Model", In. J. Hyd. Energy 2000:25 p 505.

                H. Kozima, N. Arai, "Localized Nuclear Transmutations in PdH Observed by Bockris", Int J. of Hyd. Energy, 2000.

                H. Kozima, et.al., "Nuclear Reactions in Surface Layers of Deuterated Solids", Fusion Technology 1999: 36 p 337.

                H. Kozima, "The TNCF Model for the C.F. Phenomenon", The Best Ever, Proc. 6th Int. Conf Cold Fusion, Vancouver, Canada p. 192 Also in Cold Fusion 1998: 26 p 4.

                H. Kozima, etal., "Tritium and 4He Data by Chien ital. Confirmed by the Cold Fusion Phenomenon", Int J. Hyd. Energy 2000:25 p 509.

                Melvin H. Miles, et al., "Anomalous Effects in Deuterated Systems", Naval Air Warfare Center weapons Division, China Lake, CA 93555-6100.

                G.H. Miley, et.al., "Quantitative Observation of Transmutation Products Occurring in Thin-Film Coated Microspheres During Electrolysis", in Progress in New Hydrogen Energy, Proc. 6th Int. Conf Cold Fusion, 1996 p.629 also in Cold Fusion 1996: 20 p 71.

                M. Rabinowitz, Modern Physics Letters B, 4, 233,1990.

                Randell L. Mills, Steven P. Knelzys, "Excess Heat Production by the Electrolysis of an Aqueous Potassium Carbonate Electrolyte and the Implications for Cold Fusion", Fusion Technology, Vol 20,1991, pp 657-781.

                Randell L. Mills, "Fractional Quantum Energy Levels of Hydrogen", Fusion Technology, Vol 29 (1995) pp. 1697-1719.

                Randall Mills, "Spectroscopic Identification of a Novel Catalytic Reaction of Potassium and Atomic Hydrogen and the Hydride Ion Product," Int. J. of Hyd. Energy. Feb 2002 pl83-192.

                Randall Mills, "Spectral Emission of Fractional Quantum Energy Levels of Atomic Hydrogen from a Helium-Hydrogen Plasma and the Implications for Dark Matter," Int J. of Hyd. Energy. Mar 2002 p301-322.

                Randall Mills, Paresh Ray, "Vibrational Spectral Emission of Fractional Principal Quantum Energy Level Hydrogen Molecular Ion," Int. J. of Hyd. Energy. May 2002 p533-564.

                Randall Mills, "The Grand Unified Theory of Classical Quantum Mechanics," Infc J. of Hyd. Energy. May 2002 p565-590.

                Randall Mills, etal., "Optically Measured Power Balances of Glow Discharges of Mixtures of Argon, Hydrogen, and Potassium, Rubidium, Cesium, or Strontium Vapor," Int. J. of Hyd. Energy. Jun 2002 p651-670.

                Randall Mills, etal., "Measurement of Hydrogen Balmer Line Broadening and Thermal Power Balances of Noble Gas-Hydrogen Discharge Plasmas," Int. J. of Hyd. Energy. Jun 2002 p671-685.

                Randall Mills, "Novel Inorganic Hydride", Int J. of Hyd. E. July 2000.

                Randall Mills, "Spectroscopic Identification of a Novel Catalytic reaction of Rubidium Ion with Atomic Hydrogen and the Hydride Ion Produced," Int J. of Hyd. Energy. Sep 2002 p.927-935.

                Randall Mills, et al., "Measurement of Energy Balances of Noble Gas - Hydrogen Discharge Plasmas Using Calvet Calorimetry," Int. J. of Hyd. Energy. Sept 2002 p967-978.

                T. Mizuno, et.al., "Detection of Radiation Emission and Elements From a Pt Electrode Induced by Electrolytic Discharge in Alkaline Solutions", in Proc. 7th Int. Conf Cold Fusion, 1998, Vancouver/Canada, 1998. p.253.

                D.W. Mo, et.al./ "The Conformation of Nuclear Transmutation Phenomenon in a Gas-Loading P/Pd System Using Neutron Activation Analysis", In: Proc. 7th Int. Conf Cold Fusion, Vancouver, Canada 1998 p. 259.

                J.R. Morrey, et.al./ "Measurements of helium in Electrolyzed Palladium", Fusion Technology, 1990:18 pp. 18-659.

                M. Okamoto, et.al., "Behavior of Key Elements in Pd For the Solid State Nuclear Phenomena Occurred in Heavy Water Electrolysis", In: Proc. 4th Int. Conf Cold Fusion, 1993 Hawaii, USA), vol. 3,1994, p.l4.

                T. Ohmori, et.al., "Transmutation in the Electrolysis of light water - Excess Energy in a Gold Electrode", Fusion Technology, 1997 p. 210.

                J.J.C. Fackham, etal., "Production of Tritium From D20 Electrolysis at Palladium Cathode", J. Electroanalytical Chemistry 1989:270 p. 451.

                T.O. Passell, "Nuclear Reaction Products in Heat Producing Pd."/ In: Proc. 7th Int. Conf Cold Fusion, Vancouver, Canada 1998 p. 309.

                I.B. Sarvatimova, "Transmutation Phenomena in the Palladium Cathode After Ion Irradiation at the Glow Discharge", in Progress in New Hydrogen Energy Proceedings of Proc. 6th Int. Conf Cold Fusion 1996 p.575.

                D.S. Silver, "Surface Studies of Palladium after Interaction with Hyd. Isotopes", in Proceedings of Proc. 7th Int. Conf Cold Fusion, 1998, p.351.

                T. Suzuki, et.al., "Neutron Skin of Na Isotopes Studied at their Interaction Cross Section", Physics Review Letters 1995:75 p 3241.

                S. Wang, etal.. Int. J. Hyd. Energy 1994:19 p. 253.

BOOKS

Alternative Energy and Cold Fusion

                Charles G. Beaudette, Excess Heat: Why Cold Fusion Research Prevailed, New Energy Foundation, Inc., P.O. Box 2816, Concord, NH 03302.

                Richard Garwin, Megatons and Megawatts (2002). History and prospects for nuclear power.

                Howard C. Hayden, The Solar Fraud: Why Solar Energy Won't Run the World, Vales Lake Pub. 2001, PO Box 7595, Pueblo West, CO 81007-0595

                Peter Hoffman, Tomorrow's Energy: Hydrogen Fuel Cells and the Prospects for a Cleaner Planet, M.I.T. Press, 2001. How the auto industry can make the transition to hydrogen fuel.

                Klare, Michael T., Resource Wars: The New Landscape of Global Conflict, Metropolitan Books 2001. Why the U.S. remains dependent on imported oil, particularly from the Middle East.

                H. Kozima, Discovery of the Cold Fusion Phenomenon — Evolution of Solid State Nuclear Physics and the Energy Crisis in the 21st Century, Tokyo, Japan: Ohtake Shuppan, Inc. 1998.

                Eugene Mallove, Fire From Ice, 1991. John Wiley & Sons, Inc., 334 pp. Nominated for Pulitzer prize.   An expose of scientific community's conspiracy to bury the evidence for cold fusion.

                Randell L. Mills, The Grand Unified Theory of Classical Quantum Mechanics, Second Edition, Science Press, Ephrata, PA 1996.

                Dr. Tadahiko Mizuno, Nuclear Transmutation: The Reality of Cold Fusion, 1998. Cold Fusion Technology, Inc.

Alternative Fuel Vehicle Group

28 W. 25th St., 8th Floor, New York, NY 10010

Fax: 212-228-0376

Email: [email protected]

Website: www.Altfuels.com

                Alternative Cars in the 21st Century, 416 pages. Hardcover. Society of Automotive Engineers.

                Alternative Fuels Guidebook, 204 pages. Hardcover. S.A.E.

                Automotive Fuel Cell Markets 398 pages. Softcover. Allied Business Intelligence.

                Electric Vehicle Battery Systems, 208 pages. Hardcover. Butterworth- Heinemann.

                Fuel Cell Power for Transportation 2001,120 pages. Softcover. S.A.E.

                Fuel Cell Technology for Vehicles, 282 pages. Softcover. S.A.E.

                Fuel Cells: The Source Book, 50 pages. Softcover. Escovale.

                Hydrogen Fuel for Surface Transportation. Background information. Advantages and disadvantages of hydrogen fuel. Describes current state of technology. 588 pages. Softcover. Society of Automotive Engineers.

PATENTS

Hydrogen and Cold Fusion

4,066,046                                Roy E. McAlister, "Method and Apparatus for Fuel Injection-Spark Ignition for an Internal Combustion Engine", 1978.

4,435,663                                IBM "Thermochemical Magnetic Generator." Heat to electricity using variations in hydrogen pressure to reversibly transform inter metallic compound from ferromagnetic to non ferromagnetic thereby inducing current in an output coil.

4,530,744                                E. Smith, "Improved Liquid Hyd Design",

5,590,031                                "System for Converting Electromagnetic Radiation to Electricity"

5,607,563                                James A. Pattterson. Commercial cold fusion device.

5,672,259                                James Patterson (Clean Energy Technologies, Inc.) "Electrolytic Cell to Produce Heat and Reducing Radioactive Material by Electrolysis" 30 Sept. 1997

FOOTNOTES

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15.           Aerogel - Fullerene Hybrid Materials for Energy Storage Application, Lamb Pat. #5698140 16 Dec 1997.

20.           Y.K. Ahn, "Production of Hydrogen from Coal and Petroleum Coke: Technical and Economic Perspectives", Int. J. of Hyd. Energy, #12,1986.

25.           Kemal Aldas, "A 3-D Model for Absorption in a Metal Hydride Bed," Int. J. of Hydrogen Energy, Oct 2002 p. 1049-1056.

30.           H.P. Alder, "Hyd. in Air Transport", Int. J. of Hyd. Energy, #18, 1987.

32.           Alt Fuels Advisor, 12 / 2002.

40.           J.C. Anphletti, et al., "Hyd. Production from the Catalytic Steam Reforming of Methanol", Chemical Engineering. Oct. 1984.

50.           MJ. Antal, "Hyd. and Food Production from Nuclear Hear and Municipal Wastes" in T. Jejat Veziroglu, Hydrogen Energy, Plenum Press. 1975.

60.           John Appleby, cited in. The Hydrogen Letter. July 1987, p2.

65.           T. Bak, "Photochemical Hyd. Generation," IntJ.Hyd.Energy, Nov 2002 p. 1185.

70.           G.E. Beghi, "A Decade of Research on thermochemical Hy. at the Joint Research Center at Ispra", Int. J. of Hyd. Energy, #12,1986.

80.           L. Peraldo Bicelli, et al., "Anodically Oxidized Titanium Films to be Used as Electrodes in Photoelectrolysis Solar Cells", Int. J. of Hyd. Energy, #10.1986.

90.           Bicelli, "Photoelectrochemical Behavior and XPS Characterization of a (Ti,Al,V)02 Film Obtained by Nonconventional Anodic Oxidation of a Commercial TiAlV Alloy", Int. J. of Hyd. Energy, #4, 1987.

100.         Bicelli, "Hyd: Clean Energy", Int. J. of Hyd. Energy, #9, 1986.

110.         R.E. Billings, "Hyd Storage for Automobiles", in First World Hyd. Energy.

120.         Billings, Performance and Nitric Oxide Control Parameters of the Hyd. Engine. Billings Energy Research, Provo, UT 1973.

125.         J.O' M. Bockris, Energy Options, New York: Wiley, 1980. E. Justi and Bockris shared an award 1989 from German Euro-Solar Society for the book,

130.         J.O'M. Bockris, et al., "Electrochemical Recycling of Iron for Hyd. Production", Int. J. of Hyd. Energy. #2. 1986.

133.         J.O'M. Bockris, Intl. J. of Hyd Energy, 1999 p. 1.

135.         J O'M. Bockris, et.al., "The Mechanism of the Evolution of Hydrogen on Palladium ...", Int. J. of Hyd. Energy, Aug 2000 p 747-765.

136.         J.O'M. Bockris, Int. J. of Hyd. Energy, 2002 p.740

140.         J O'M. Bockris, The Solar-Hydrogen Alternative. John Wiley, NY 1975.

150.         E. Borgarello, "Photochem. Water Splitting", Chemtech, 13, pp. Feb. 1983.

155.         S. Bouaricha, et.al., "Reactivity During Cycling of Nanocrystalline Mg-based Hydrogen Storage Compounds," Int. J. of Hyd. Energy, Sep 2002, p909-913.

160.         Theodore A. Brabbs, "Catalytic Decomposition of Methanol for On-Board Hyd. Generation", NASA TP-1247 (N78-23256/NSP). Available from the National Technical Information Service, Springfield, VA 22161.

165.         Harry Braun, "Hyd. Storage Systems", Hydrogen, Journal of the American Hydrogen Association, Summer 1991.

170.         J.D. Canada, et al., "A Polarization Model of Solid Electrolyte in Fuel Cells", Int. J. of Hyd. Energy. #3, 1981.

180.         C.Carpetis, "Hyd. Storage by Use of Cryoadsorbants", in Seminar in Hyd as an Energy Carrier. Commission of the European Communities, Luxembourg.1971.

185.         S.H. Chan, et.al., "Thermodynamic Analysis of Natural Gas Fuel Processing for Fuel Cell Applications", Int. J. of Hyd. Energy, May 2000.

187.         D. Chartouri, "Metal Hydride Fuel Cell with Intrinsic Capacity," International Journal Hydrogen Energy, Sep 2002, p945-957.

190.         R.L. Cohen and J.H. Wemick, "Hyd. Storage Materials: Properties and Possibilities", Science. Vol. 214.4 Dec. 1981.

195.         Douglas M. Considine, Energy Technology Handbook, McGraw-HUl 1997.

200.         K.E. Cox, ed.. Hydrogen: Its Technology and Implications, Vol 1-2. CRC Press, Inc., 1977. 18901 Cranwood Pkwy., Cleveland, OH 44128.

201.         Cox, Vol. 2.

210.         Cox, "Thermochemical Cycles: A New Method of Producing Hyd.", Los Alamos Scientific Lab., 1980.

220.         G.A. Crawford, et al., "Advances in Water Electrolyzers and Their Potential Use in Ammonia Production", Int. J. of Hyd. Energy. #11, 1986.

230.         Crawford, et al., "Electrolyzer, Inc. Advanced Hyd. Plant at Becancour, Quebec", Int. J. of Hyd. Energy. #11,1986.

235.         Cummins Power Generation, Inc., Box 3005, Columbus, IN 47202, "Dish Sterling System", May 1990. Cited by McAlister in 568.

237.         Curl et. al, "Fullerenes", Scientific American, Vol 254 # 5039 p. 1705, Dec 1991 Kratschner et.al, "Solid C60: New Carbon", Nature vol. 347 # 6291 1990 pp 354 Loutfy, 28 Nov 1995 "Electrochemical Fullerene System," Pat. No. 5470680

240.         R.P. Dahiya, "Transition to Hyd.", Int. J. of Hyd. Energy. #6. 1986.

250.         P. Dantzer, "Hydrogen ...", Int. J. of Hyd. Energy. #12, 1986.

255.         L.M. Das, et.al., "A Comparative Evaluation of the Performance Characteristics of a Spark Ignition Engine Using Hydrogen and Compressed Natural Gas as Alternative Fuels", Int. J. Hyd. Energy Aug 2000 p. 783-793.

260.         D.Davidson, et al., "Development of a Hyd - Fueled Farm Tractor", Int. J. of Hyd. Energy. #1, 1986.

270.         G. DeBeni, "Thermochemical Processes for H:yd. Production by Water Splitting", Electrochemical Society Journal. Vol.129. Jan 1982.

280.         W.Donitz, "High Temp. Electrolysis of Water Vapor Status of Development and Perspectives for Applications", Int. J. of Hyd. Energy. #5,1986.

285.         A.G. Dutton, et.al., "Experience in the Design, and Implementation of Autonomous Wind-Power Hydrogen Production Systems", Int. J. of Hyd. Energy, Aug 2000 p705.

288.         The Economist: The World at 2001, p. 102.

290.         H.Eichert, et al., "Combustion Related Safety Aspects of H:yd. in Energy Applications", Int. J. of Hyd. Energy. #2, 1986.

291.         Electric Vehicle Progress. 15 Oc 2002, vol .24 #20. Source: "Automotive Waste Heat Recovery Using Power Chips", Dr. Brian von Herzen at Global Powertrain Congress, Ann Arbor, MI 9/2002

292          Electric Vehicle Progress 1 Dec 2002

293          Electric Vehicle Progress 15 Dec 2002

300.         H.Engles, "Thermochemical Hyd. Production", Int. J. of Hyd. Energy. #5, 1987.

319.         Joseph G. Feingold, et al., "Crash Test of a Liquid Hyd Automobile", in First World Hyd Conference, 1976. Int. Assn. for Hyd. Energy.

320.         Feingold, "Engine Performance With Hyd. and Gasoline", in First World Hyd. Energy Conf. 1976.

325.         Feingold, et al., "Methanol As a Consumable Hydride for Automobiles and Gas Turbines", Hydrogen Progress, 17 June 1982, pp. 1359-1369.

330.         Feingold, et al., "The UCLA Hyd. Car: Design, Construction and Performance", Paper SAE 730507, Soc. of Auto. Engineers, NY 1973.

335.         J.A. Fillo, "Overview of the Hyfire Power Electrolysis Design" ,Int. J. of Hyd.E.

340.         J. Fisher, "Fundamentals and Technological Aspects of Medium Temperature Electrolyzers", in Seminar on Hyd. Energy Vectors. Commission of the European Community, Luxembourg. 1978.

350.         M.Fisher, et al., "The Hyd. Economy", Int. J. of Hyd. Energy. Vol.12, 1987.

360.         M.Fisher, "Safety Aspects of Hyd. Combustion in Hyd. Energy Systems", Int. J. of Hyd. Energy. #9, 1986.

370.         M.Rsher, "Review of Hyd. Production With Photovoltaic Electrolysis Systems", Int. J. of Hyd. Energy. #8, 1986.

380.         S.Furuhama, it al., "Development of a Liquid Hyd. Car", in First World Hyd. Energy conference., 1976. Int. Assn. for Hyd. Energy.

390.         Furuhama, et al., "High Output Hyd. Engine With High Pressure Fuel Injection, Hot Surface Ignition and Turbo charging". Int. J. of Hyd. Energy. #6,1986.

392.         D.P. Gregory, D.N. Long, G. Ng in J.O' M.Bockris, ed.. The Electrochemistry of Cleaner Environments, New York: Plenum Press. 1972.

395.         F. Gupta, "Hydrogen Engine: R&D Program in Indian Institute of Technology," Int.J. Hyd.Energy, Sep 2002, p953-965.

400.         William D. Gwinn, "The Lithium - Fast Proton Nuclear Reaction", Infinite Energy, Issue 18, 1998. p.23. Professor Chem. U. of California, Berkeley, Crystal Energy, Inc.. "The Li-Fast Proton Nuclear Reaction", 26   Oct 1989

405.         Jaesun Han, "High Purity Hydrogen Generation for On-Site Hydrogen Production," Int. J. Hyd.Energy, Oct 2002, p 1043-1047.

410.         O.G.Hancock, Jr., "A Photovoltaic-Powered Water Hectrolyzer Its Performance and Economics", Int. J. of Hyd. Energy. #3,1986, ppl53-160.

420.         KJ.Hartig, et al., "Production and Testing Methods of Different n-Ti02  Photo anodes", Int. J. of Hyd. Energy. #12, 1986.

430.         Peter Hoffman, The Forever Fuel, Int. Assn. for Hyd. Energy. 1980. and Westview Press, Boulder, CO, 1981.

434.         Hoffman, "Iron-Based Hyd. System", The Hydrogen Letter, June, 1992.

435.         Hoffman, "Ovionics Wins Battery Contest", The Hydrogen Letter, June, 1992.

440.         Hoffmann, "Texas A&M Expands Program", The Hyd. Letter. July 1987.

441.         S.D. Huang, et al., "Hyd Production by Non photosynthetic Bacteria", Int. J. of Hyd. Energy. #4, 1986. pp227-23L

442.         Hydrogen Today, June/July 1992.

443.         Infinite Energy Issue 7,1996.

444.         Infinite Energy Issue 8,1996. Harold Aspden, "The Reality of Perpetual Motion"

445.         Infinite Energy Issue 9,1996.

446.         Infinite Energy Issue 10, 1996.

447.         Infinite Energy Issue 11, 1996.

448.         Hal Fox, Infinite Energy Issue 12,1997.

449.         Infinite Energy Issue 13-14,1997. David Moon and Chuck Bennett "The Nucleo-Hectric Effect".

450.         Infinite Energy Issue 13-14,1997.

451.         Infinite Energy Issue 15-16,1997.

452.         Infinite Energy Issue 18,1998.

456.         Jeong, Gun-Park, "The Development of Compression-Driven Metal Hydride Heat Pump System as an Air-Conditioner," Int. J. of Hyd. Energy, Sep 2002, p941-944

460.         P. Jonville, "Metal Hydrides and Propulsion", 1st World Hyd Energy Conf. 1974.

465.         E. Justi and J.O' M. Bockris shared an award 1989 from German Euro-Solar Societyfor the book, J.O' M. Bockris, Energy Options, New York: Wiley, 1980.

470.         R.C. Kainthala & J.O'M. Bockris, "Photo electrolysis of H2S Using a n-CdS Photoanode", Int. J. of Hyd. Energy. #1,1987.

480.         K.Katuta, et al., "Photo Assisted Hyd. Production Using Visible Light and Coprecipitated ZnS.CdS Without a Noble metal Catalyst", Journal of Physical Chemistry, Vol.89, 28 Feb. 1985.

485.         F.L.Kester, et al., "On-Board Steam Reforming of Methanol to Fuel The Automotive Hyd Engine", IECEC 1997 Record, pp.1176-1183.

487.         A. Kogan, et.al., "Direct Solar Thermal Splitting of Water and On-Site Separation of the Products — Improvement of Reactor Efficiency by Steam Entrainment", Int. J. of Hyd. Energy, Aug 2000 pp 739-745.

489.         Hideo Kozima, et.al., "Local coherence, condensation and nuclear reaction of neutrons at crystal boundary of metal hydrides and deuterides". Int. J. of Hyd. Energy, Sep 2000 p845-851. Gives bibliography of 33 studies from 1990 to 1998.

Hideo Kozima, "Localized Nuclear Transmutation in PdHx ...", Int. J. of Hyd. Energy, June 2000 p 513.

490.         A.T.Kuhn, Journal of Power Sources. Vol.11, 1984.

500.         S.B.Lalvani, et al., "Simultaneous Production of Hyd. and Sulfuric Acid from Aqueous Sulfur Slurry", Int. J. of Hyd. Energy. #9, 1986.

510.         J.Lede, et al., "Production of Hyd. by Simple Impingement of a Turbulent Jet Stream Upon a High-Temp. Zirconia Surface", Int. J. of Hyd. Energy. #1, 1987.

520.         R.W. Leigh, "Photvoltaic-Hectrolyser System Transient Simulation Results, Transactions ofASME", J.Of Solar energy Engineering. Vol.108, May 1986.

530.         Leigh, "Solar Hyd Aircraft", Int. J. of Hyd. Energy. #3, 1986.

535.         Liebert, et.al., J. Hectrochem Chem 319,161 (1991)

540.         M.A. Liepa, "High Temp. Steam Hectrolysis: Technical and Economic Evaluation of Alternative Process Designs", Int. J. of Hyd. Energy. #7, 1986.

545.         Li Jing-Ding, et al., "Improvements on the Combustion of a Hyd Fueled Engine", Int. J. of Hyd. Energy. #10, 1986.

547.         G.H. Lin, "Photovoltaics in 2025", Int. J. of Hyd. Energy, Sep 2000 pp 807-811.

549.         J.K. Lomness, "Hyd. Uptake of Mechanically Alloyed Mixtures of Ti-Mg-Ni," Int. J. of Hyd. Energy, Sep 2002, 915-920.

550.         L. Loy, et al., "Photo induced Hyd. Evolution from Water in the Presence of EDTA and a pt/Ti02 Catalyst", Solar Energy. Vol 32 #6,1986.

555.         Andrew E. Lutz, et.al., "Thermodynamic Comparison of Fuel Cells to the Carnot Cycle," Int. J. of Hyd. Energy, Oct 2002 pp 1103-1 111.

560.         F.E. Lynch, "Backfire Control Techniques", in T.Nejat Veziroglu, Hydrogen Energy. Plenum Press, NY 1975.

563.         S. Lawrence, Solution to Pollution: 101 Things You Can Do to Clean Up Your Environ. Master Media Limited.215 Park Avenue South, New York, NY 10003

565.         Roy E. McAlister, Alternatives Allowing Continued Use of Fossil Fuels, Trans Energy Corp., Tempe, AZ 1992.

566.         McAlister, Conversion of Automobiles to Air Cleaners, Trans Energy Corp.,1992.

567.         McAlister, Hyd Mixed with Conventional Fuels for Improved Performance and Reduced Emissions, American Hyd. Assoc., 1992.

568.         McAlister, Prosperity Without Pollution, American Hyd. Assn, 1992

569.         McAlister, Renewable Hectricity and Hyd Using Solar Thermal Processes, American Hydrogen Association., 1992.

570.         Donald B. McKay, "Hydride Tank Design", First World Hyd. EnergyConf.,1976.

580.         D.A.Mathis.Hyd.Tech. for Energy .Noyes Data Corp, Park Ridge, NJ, 1976.

590.         LMaya, et al., "A Thermochemical Hyd Production System Based on a High Temperature Fusion Reactor Blanket", Nuclear Technology & Fusion-Sep 1983.

595.         Melvin H. Miles, et al., "Anomalous Effects in Deuterated Systems", Naval Air Warfare Center weapons Division, China Lake, CA 93555-6100.

597.         Melvin H. Miles, Benjamin F. Bush, and Kendall B. Johnson, in a report entitled, "Anomalous Effects in Deuterated Systems", Naval Air Warfare Center weapons Division, China Lake, CA 93555-6100.

600.         J.Miyake, et al., "Efficiency of Light Energy Conversion to Hyd by the Photosynthetic Bacterium", Int. J. of Hyd. Energy. #3,1987.

610.         C. Marchetti, "Primary Energy Sources for Hyd Production", in T.Nejat Veziroglu, ed., Intro. to Hyd Energy. Int Association for Hyd Energy, 1975.

615.         Randall Mills, "Novel Inorganic Hydride", Int. J. of Hyd. Energy July 2000.

616.         Randall Mills, "Spectroscopic Identification of a Novel Catalytic reaction of Rubidium Ion with Atomic Hydrogen and the Hydride Ion Produced," Int. J. of Hyd. Energy. Sep 2002 p.927-935. "Measurement of Energy Balances of Noble Gas-Hydrogen Discharge Plasmas Using Calvet Calorimetry," Same. p967-978.

617.         Nick Musachio/'Electrified Roadway .. "Machine Design 3/12/93 p. 18.

620.         J.E. Nitsch, "Large Scale Solar Energy", Int. J. of Hyd. Energy. #1,1986.

625.         Joan Ogden, "Developing an Infrastructure for Hydrogen Vehicles: A Southern California Case Study." Int. J. of Hyd. Energy, Aug 1999 pp 709-730.

630.         T. Ohta, The Solar-Hyd Energy System. Pergamon Press, Ltd., 1979. Maxwell House, Fairview Park, Elmsford, NY 10523.

640.         S. Ono, et al., "The Effect of C02, CH4, H20 and N2 on Mg-Ni Alloys as Hyd Transporting Media", Int. J. of Hyd. Energy. #6, 1986.

650.         Ono, "Hydrogen...", Am. Institute of Chem. Eng. J. Vol. 32, Nov. 1986.

660.         Evan Orr, "Hydrogen Power Transmission for Remote Hydro Schemes", Electronics and Power. Vol. 31, Feb. 1985.

670.         J. Pangbom, "Domestic Use of Hydrogen", First World Hyd. Energy Conf.

680.         W. Peschka, "Cryogenic Storage Tank for a Passenger Car", in First World Hyd Energy Conf. 1976.

690.         Peschka, et al., "Experience and Special Aspects on Mixture Formation of an Otto Engine Converted from Hyd. Operation", Int. J. of Hyd. Energy. #10,1986.

700.         Peschka, "Hyd for Future Technology", Int. J. of Hyd. Energy. #7,1987.

710.         Peschka, "Liquid Hyd Automotive Vehicles in Germany: Status and Development", Int. J. of Hyd. Energy. #11,1986.

720.         E.J. Phillips, et al., "Characterization and Optimization of Hyd Production of a Salt Water Blue-Green Algae...", Int. J. of Hyd. Energy. Vol. 11, #2,1986.

721.         Pons &Fleischman, J. Electroanalytical Chem. 287 1990 p.293.

722.         Pons, et al.. Fusion Technology, 17 (1990) 669. Respond to criticisms.

723.         Pons, et al.. Physics Letters A176 (1993) 118, Respond to criticisms.

724.         Pons, et al.. Transactions of Fusion Technology, Vol. 26, p.329. Insure that there are no stagnant zones in the electrolyte.

730.         G.P. Prabhukumar, "Water Induction Studies in a Hyd Diesel Fuel Engine", Int. J. of Hyd. Energy. #3, 1987. pp 177-176.

740.         K.H. Quandt, et al., "Concept and Design of a 3.5 MW Pilot Plant for High Temperature Electrolysis of Water Vapor", Nuclear Tech. & Fusion. Sep 1983.

750.         J.F. Reber, et al., "Photochemical Production With Zinc Sulfate Suspensions", Journal of Physical Chemistry. Vol. 88,22 Nov. 1984.

760.         J.J. Reilly, et al., "Iron-Titanium as a Source of Hyd for Stationary and Automobile Applications", Power Source Symposium, Int. J. of Hyd. Energy.

770.         Reilly, "Metal Hydrides...", in K.E. Cox, above.

772.         CA. Rohrman, et al., "Large Scale Hyd Production Utilizing Carbon in Renewable Resources", Int. J. of Hyd. Energy. Vol.2,1977. pp31-40. Cited by McAlister in 568.

780.         R. Rotenburg, "The Musashi 7", Int. J. of Hyd. Energy. #6,1987.

790.         Rotenburg, "Vibrational Effects on Boil-Off Rate from a Small Liquid Hyd Tank", Int. J. of Hyd. Energy. #11, 1986.

792.         S. Roychowdhury, et al., "Production of Hyd by Microbial Fermentation", Int. J. of Hyd. Energy. #7, 1988. pp407-410.

800.         F.J. Salzano, et al.. Hydrogen Energy Assessment, Brookhaven National Lab., Upton NY, Sep 1977.

810.         M.V.C. Sastri, "Hyd Energy Research and Development in India: An Overview", Int. J. of Hyd. Energy. #3, 1987.

812.         D.V. Schur, et.al., "The Prospects for Using Carbon Nanomaterials as Hydrogen Storage Material," Int. J. Hyd. Energy. Oct. 2002 p. 1063-1069.

813.         Scientific American (January 1986)

815.         Jennifer Suave, "LaserCel: A Fuel-Cell Car", Hydrogen Today, Apr-May 1992.

820.         L. Selvam, "Design of a Gaseous Hydrogen Supply", IntJ.of Hyd.E. #11, 1986.

830.         S. Sleyam, "Magnesium Hydrides", Int. J. of Hyd. Energy. #3, 1986.

840.         F.B. Simpson, et al., "Modification Techniques and Performance Characteristics of Hyd Powered Internal Combustion Engines", First World Hyd Energy Conf.

850.         E. Smith, "Improved Liquid Hyd Design", Patent #4,530,744.

860.         Frank Spillers, cited in. The Hydrogen Letter, Sep 1987.

865.         Irwin M. Stelzer, "Can We Do Without Saudi Oil? Alas, no." The Weekly Standard. 19 Nov. 2001, Volume 7, Issue 10.

870.         S. Suda, "Metal Hydrides", Int. J. of Hyd. Energy. #4,1987.

880.         Suda, "Transatmospheric Aircraft", Int. J. of Hyd. Energy. #11,1986.

890.         S. Tanisho, "Fermentation Hyd", Int. J. of Hyd. Energy. #9, 1987.

900.         J.B. Taylor, et al., "Technical and Economic Assessment of Methods for the Storage of Large Quantities of Hyd", Int. J. of Hyd. Energy. #1,1986.

905.         R. Taylor & D. Walton, "The Chemistry of Fullerenes", Nature, vol. 363 pp 685

910.         H. Van Der Broeck, et al., "Status of Elenco's Alkaline Fuel Cell Development", Int. J. of Hyd. Energy. #7, 1986.

920.         T. Nejat Veziroglu, "Dawning of Hyd Age", Int. J. of Hyd. Energy. #1,1987.

930.         Veziroglu, cited in P. Hoffmann, The Hydrogen Letter, p.3 Aug 1987.

940.         Veziroglu, "Hyd Technology for Energy Needs of Human Settlements", Int. J. of Hyd. Energy. #2, 1987.

943.         T. N. Veziroglu, Int. J. of Hyd. Energy, 2000 p. 1143.

945.         J. K. Vijay, et.al. 'Titanium-Coated Polymeric Membranes for Hydrogen Recovery," Int. J. of Hyd. Energy, Sep 2002 p 905-908.

950.         M. Vincenzini, "Hyd Production by Immobilized Cells III - Prolonged and Stable Hyd Photo evolution by Rhodopseudomonas Plaustris in Light-Dark Cycles" Int. J. of Hyd. Energy. #10, 1986.

960.         J.W. Wamer, et al., "Hyd Separation and the High-Temperature Splitting of Water", Int. J. of Hyd. Energy. #2, 1986.

970.         K. Watanabe, "Hydrogen...", Automobile Industry, Vol. 165, Aug 1985.

980.         M.F. Weaver, "Splitting Water With Photo Electrodes", IntJ.of Hyd.E. #4, 1986.

990.         W. Weinrich, et al., "Development of a Laboratory Cycle for a Thermochemical Water Splitting Process (Me/MeH cycle)". Int. J. of Hyd. Energy. #7,1986.

1000.       Lawrence 0. Williams, Hydrogen Power: An Introduction to Hyd Energy and Its Applications. Pergamon Press, NY 1980.

1010.       C.J. Winter, "Hyd Energy Breakthroughs", Int. J. of Hyd. Energy. #8,1987.

1012.       J.M. Woodwell, "The Energy Cycle of the Biosphere", Scientific American, Vol. 223. #3, Sep 1970. Cited by McAlister in 568.

1020.       R.L. Wooley, "Thermodynamic Considerations in the Production of Synthetic Fuels From Coal", Billings Energy Corp., Provo, UT 1977.

1030.       Wooley, "Water Injection in Hyd Powered Internal Combustion Engines", First World Hyd Energy Conference.

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1070. Zaidman, "Water-Gas Engine", Mechanical Engineering, Jan 1977.

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