Fuel cell is a new technology to produce high amounts of energy using direct oxidation of fuel by oxygen, without any environmental or noise pollution. As fuel cells have very high efficiencies with lower thermal energy loss, they can be a considerable replacement for Carnot cycle to produce electricity.
Due to environmental pollutions, use of fossil fuels must be reduced. Researchers have forecasted that in near future, hydrogen gas will be used as the main fuel and fuel cells as main energy production device globally.
In addition to high efficiency, fuel cells have advantages like production capacity of several watts to several megawatts, possibility of using fossil fuel instead of hydrogen, low volume occupied by the unit and easier maintenance.
Most energy production systems produce thermal energy from the fuel and then transform this energy to electricity. Since two steps are used, there will be more thermal loss, and efficiency reduces considerably. But in fuel cell technology, fuel will directly produce the electricity and therefore, high efficiencies are reachable.
It’s important to notice that high efficiency doesn’t necessarily mean high power capacity. Fuel cells can produce high powers when used in small scale, but in industrial scales will only produce powers up to 100 kW. This is one of the most important limitations of fuel cell technology which requires more research and experiments.
Fuel cell, unlike batteries, cannot store the produced energy, but it can be refueled so fast while batteries need time to recharge. Consequently, it’s more probable to use fuel cell driven cars rather than battery driven cars. Also, fuel cells have higher energy density (energy to volume ratio) than batteries, which leads to less space needed for a constant amount of energy.
by N. Ghodrati – Persian Gulf university of Iran
Director: Dr. M. Mofarahi
Translated by: P. Jowkar
Editor: M. A. Makarem