Fuel Cells Electrochemical Devices
Posted by admin on April 26th, 2009 filed in Power Articles
Fuel cells are electrochemical devices which convert the energy of a chemical reaction directly into electricity, with heat as a by-product. Fuel cells are being used now to power buses, boats, trains, planes, scooters, forklifts, even bicycles. Basically, these electrochemical devices convert hydrogen and oxygen into electricity, heat, and water. Some think they are poised to become the leading energy source of the 21st century in a range of applications such as transport, stationary power and even laptop computers.
Hydrogen is used as the fuel in this chemical reaction. Hydrogen combustion, like that of petroleum, is limited by the Carnot efficiency (a fundamental limit on the thermal efficiency of heat engines), but is completely different from the hydrogen fuel cell’s chemical conversion process of hydrogen to electricity and water without combustion. Hydrogen fuel cells emit only water during use, while the majority of hydrogen production creates carbon dioxide emissions. Hydrogen is an energy carrier, and not an energy source, because it must be produced by adding energy from other energy sources, such as petroleum, coal, or natural gas, wind power, or solar photovoltaic cells.
To some this point to an inherent inefficiency of the entire hydrogen fueling process, from generating the hydrogen with that electricity to transporting this diffuse gas long distances, getting the hydrogen in the car, and then running it through a fuel cell — all for the purpose of converting the hydrogen back into electricity to drive the same exact electric motor you’ll find in an electric car. Even so, many believe that the fuel cell engine, comprising a fuel processor, fuel cell stack and power conditioner, will ultimately take the place of the internal combustion engine as the dominant technology for vehicle power trains.
Any type of fuel cell could be used in a regenerative system, and the water electrolyser could be powered with wind, solar or hydro energy, resulting in a truly clean power system. For individuals with an existing solar, wind or hydro power system, the fuel cell could be used for backup power in place of an engine generator. A wind turbine and/or solar panels could be added to power the water electrolyzers or fuel reformer, and the entire power system would be virtually self-contained. Fuel cells cannot store energy like a battery, but in some applications, such as stand-alone power plants based on discontinuous sources such as solar or wind power, they are combined with electrolyzers and storage systems to form an energy storage system.
Fuel cells are very useful as power sources in remote locations , such as spacecraft, remote weather stations, large parks, rural locations, and in certain military applications. Use of fuel cells in small system/home power applications has so far been limited by cost considerations, but prices are falling and fuel cells should emerge as a viable home power source in the near future.
Fuel Cells are a clean and efficient technology used to generate electricity. Fuel cells are significantly more efficient than equivalent internal combustion engines (ICEs) because they convert chemical energy directly to electrical current rather than via an efficiency sapping mechanical intermediate phase. The drawback seems to be in the production of the fuel for the cells, my guess is overall that that problem can reduced to clean and green in the very near future.
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