25-08-2017, 09:32 PM
Fuel Cells – Green Power
A Brief History
Although fuel cells have been around since 1839, it took 120 years
until NASA demonstrated some of their potential applications in
providing power during space flight. As a result of these successes, in
the 1960s, industry began to recognize the commercial potential of
fuel cells, but encountered technical barriers and high investment costs
— fuel cells were not economically competitive with existing energy
technologies. Since 1984, the Office of Transportation Technologies at
the U.S. Department of Energy has been supporting research and
development of fuel cell technology, and as a result, hundreds of
companies around the world are now working towards making fuel
cell technology pay off. Just as in the commercialization of the electric
light bulb nearly one hundred years ago, today’s companies are
being driven by technical, economic, and social forces such as high
performance characteristics, reliability, durability, low cost, and
environmental benefits.
Carnot Cycle vs. Fuel Cells
The theoretical thermodynamic derivation of Carnot Cycle shows
that even under ideal conditions, a heat engine cannot convert all
the heat energy supplied to it into mechanical energy; some of the
heat energy is rejected. In an internal combustion engine, the engine
accepts heat from a source at a high temperature (T1), converts part of
the energy into mechanical work and rejects the remainder to a heat
sink at a low temperature (T2). The greater the temperature difference
between source and sink, the greater the efficiency.