Hydrogen Power Jonathan Cho Priyam Shah Period 5

Hydrogen Fuel Cells Extraction: Hydrogen fuel cells pass oxygen gas and hydrogen gas over electrodes. The hydrogen gas is converted to positive hydrogen ions. Electrical energy is created by the outward flow of electrons from the hydrogen. Fuel cells break apart a hydrogen molecule into a proton and electron. Uses include powering cars and NASA missions. Space Shuttle Orbiter uses hydrogen fuel cells.

Advantages The only byproducts of using hydrogen fuel cells are oxygen and heat. No greenhouse gases and particulates are released into the atmosphere. The excess heat produced from hydrogen fuel cells can act as a co-generator for commercial heating. Like fossil fuels, hydrogen power can be produced centrally then distributed to other areas.

Disadvantages The size of hydrogen fuel tanks is impractical for everyday use. A hydrogen fuel cell used to power a car is three times larger than a standard gas tank. Safety issues: too much pressure caused by a backup in the fuel cell can result in an explosion. Currently, the cost of hydrogen power outweighs all potential benefits.

Source and Efficiency Hydrogen power utilizes water, hydrogen gas, oxygen gas and natural gas. At equal volumes, gasoline and diesel contain much more energy than hydrogen. Steam reforming is the current industrial standard for the production of hydrogen. This process removes hydrogen from natural gas; the hydrogen produced has a lower energy content than the natural gas. The process is very inefficient and expensive. n is routed to the cell's oxygen electrode, where it reacts with the water and returning electrons to produce hydroxyl ions. The hydroxyl ions then migrate to the hydrogen electrode, where they enter into the hydrogen reaction. Hydrogen is routed to the fuel cell's hydrogen electrode, where it reacts with the hydroxyl ions from the electrolyte. This electrochemical reaction produces electrons (electrical power), water and heat. The electrons are routed through the orbiter's EPDC subsystem to perform electrical work. The oxygen and hydrogen are reacted (consumed) in proportion to the orbiter's electrical power demand. Excess water vapor is removed by an internal circulating hydrogen system. Hydrogen and water vapor from the reaction exits the cell stack, is mixed with replenishing hydrogen from the storage and distribution system, and enters a condenser, where waste heat from the hydrogen and water vapor is transferred to the fuel cell coolant system. The resultant temperature decrease condenses some of the water vapor to water droplets. A centrifugal water separator extracts the liquid water and pressure-feeds it to potable tanks in the lower deck of the pressurized crew cabin. Water from the potable water storage tanks can be used for crew consumption and cooling the Freon-21 coolant loops. The remaining circulating hydrogen is directed back to the fuel cell stack. The fuel cell coolant system circulates a liquid fluorinated hydrocarbon and transfers the waste heat from the cell stack through the fuel cell heat exchanger of the fuel cell power plant to the Freon-21 coolant loop system in the midfuselage. Internal control of the circulating fluid maintains the cell stack at a normal operating temperature of approximately 200 F. When the reactants enter the fuel cells, they flow through a preheater where they are warmed from a cryogenic temperature to 40 F or greater; a 6-micron filter; and a two-stage, integrated dual gas regulator module. The first stage of the regulator reduces the pressure of the hydrogen and oxygen to 135 to 150 psia. The second stage reduces the oxygen pressure to a range of 62 to 65 psia and maintains the hydrogen pressure at 4.5 to 6 psia differential below the oxygen pressure. The regulated oxygen lines are connected to the accumulator, which maintains an equalized pressure between the oxygen and the fuel cell coolant. If the oxygen's and hydrogen's pressure decreases, the coolant's pressure is also decreased to prevent a large differential pressure inside the stack that could deform the cell stack structural elements. Upon leaving the dual gas regulator module, the incoming hydrogen mixes with the hydrogen-water vapor exhaust from the fuel cell stack. This saturated gas mixture is routed through a condenser, where the temperature of the mixture is reduced, condensing a portion of the water vapor to form liquid water droplets. The liquid water is then separated from the hydrogen-water mixture by the hydrogen pump/water separator. The hydrogen pump circulates the hydrogen gas back to the fuel cell stack, where some of the hydrogen is consumed in the reaction. The remainder flows through the fuel cell stack, removing the product water vapor formed at the hydrogen electrode. The hydrogen-water vapor mixture then combines with the regulated hydrogen from the dual gas generator module, and the loop begins again. The oxygen from the dual gas regulator module flows directly through two ports into a closed-end manifold in the fuel cell stack, achieving optimum oxygen distribution in the cells. All oxygen that flows into the stack is consumed, except during purge operations. Previous Next Fuel Cells Hydrogen Fuel Cells How Fuel Cells Work Direct Hydrogen Fuel Cell System for Automobiles Are You An Inventor Working With Fuel Cells? Fuel Cell Program Suggested Reading Definition of a Solar Cell - History of Solar Cells The Rockets of NASA Rockets Related Articles Space Shuttle Orbiter - Fuel Cell Power Plants What is a Fuel Cell - What do Fuel Cells do - History of Fuel Cells Ideas For Alternative Fuels How Hydrogen Fuels Cells Work Switching to Alternative Fuels is Easier Than You Think - continued Mary Bellis Mary Bellis Inventors Guide Sign up for My NewsletterSign up for My Newsletter Headlines Forum Advertisement Ads Cogeneration Systems. Cogeneration Systems. Northeast Energy Systems GE Jenbacher Distributorwww.NeeSys.comwww.NeeSys.com Power Your Own HomePower Your Own HomeReduce Utility Bills by 40% Lower C02 Emissions by 1/3www.ClearEdgePower.comwww.ClearEdgePower.com Tarakhil Power PlantTarakhil Power PlantAdds 105-megawatts of power to serve Kabul and surrounding regionwww.dabs.afwww.dabs.af

The hydrogen can also be produced from other sources such as methane, coal, biomass, and water. If hydrogen is extracted from water, then the hydrogen fuel cell can be a renewable production system. However, most hydrogen that is used to power fuel cells is derived from nonrenewable sources. This results in carbon emissions and further environmental harm.

High Costs The cost of producing hydrogen is high compared to other sources of energy. Hydrogen pipelines are more expensive than long-distance electrical lines. Toyota is aiming to release a $50,000 hydrogen fuel cell powered car by Honda’s hydrogen fuel cell powered Clarity (2009) is estimated to cost $300,000 to produce.

Consumption The consumption of hydrogen as a fuel both in America and around the world is negligible due to the high cost of production and use. The viability of hydrogen power is being debated today; hydrogen power will not be practical for another few decades.