A typical fuel cell works by passing hydrogen through the anode of a fuel cell and oxygen through the cathode. A fuel cell is composed of an anode, cathode, and an electrolyte membrane. In a fuel cell, hydrogen and oxygen are combined to generate electricity, heat, and water.

The fuel cell does not generate energy, but just transforms the energy contained in the hydrogen and oxygen fuel into useful electrical energy output. And because this is the ideal efficiency, the actual efficiency will be even lower.ДЄ fuel cell is a device that generates electricity through an electrochemical reaction, not by combustion. The ground reality is for the range of compression ratios (the ratio of minimum and maximum volumes in the engine cylinder as it reciprocates) typical of a gasoline engine, this maximum efficiency is only about 40 to 60 percent. In other words, Carnot's theorem states that all heat engines are a function of the T cold / T hot ratio.В The smaller this ratio, the larger is the efficiency of a heat engine. The efficiency of a Carnot engine depends solely on the temperatures of the hot and cold reservoirs. The temperature at which the low-temperature reservoir operates (T cold). The Carnot Efficiency is, therefore, the theoretical maximum efficiency one can get when the heat engine is operating between two temperatures: The temperature at which the high-temperature reservoir operates (T hot). At constant volume heat capacity for air in the engine, the efficiency can also be stated as, The efficiency, О· ideal is thus, О· ideal = W out / Q in = / Q in.

In this case, Qin is the heat energy input from the fuel combusted in the engine, W out is the mechanical work output from the engine, and Qout is waste heat that is carried out of the engine in the combustion product gases. The thermal efficiency of such a cycle is the ratio of the work recovered from the cycle to the heat energy input to the cycle. The difference between the two energies (Th-Tc) О”S is equal to the work done by the engine. Since there is no volume change in either reservoir, they do no work, and during the cycle, an amount of energy Th x О”S is extracted from the hot reservoir and a smaller amount of energy Tc x О”S is deposited in the cold reservoir. During the cycle, an arbitrary amount of entropy О”S is extracted from the hot reservoir and deposited in the cold reservoir. Since the concept involves the cycle is theoretically reversible, there is no generation of entropy during the cycle entropy is conserved. (isothermal heat rejection - condenser) and Adiabatic reversible compression - pump Heat transferred reversibly to the low-temperature reservoir at constant temperature TC. Heat is transferred reversibly from the high-temperature reservoir at constant temperature TH (isothermal heat addition or absorption - boiler) Isentropic (reversible adiabatic) expansion of the gas (isentropic work output - turbine ) Isothermal compression. This difference in efficiency will be discussed in this postД®ssentially, the Carnot cycle consists of Isothermal expansion. Another advantage is the potentially higher efficiency of the hydrogen fuel cell compared to that of an internal combustion engine. Internal combustion engines produce carbon dioxide as a product of the combustion of fossil fuel with oxygen, and the release of this carbon dioxide into the atmosphere is thought to contribute to a вЂњgreenhouse effectвЂќ. These fuel cells are seen as beneficial because their operation produces no carbon dioxide. The difference is Carnot cycle sets a theoretical upper limit for heat or thermal energy to convert to mechanical energy while a fuel cell uses chemical energy to convert to electrical energy. A heat engine converts heat or thermal energy to mechanical energy,ДЄ fuel cell uses the chemical energy of hydrogen or another fuel to produce electricity. It provides an upper limit on the efficiency that any classical thermodynamic engine can achieve during the conversion of heat into work. The Carnot cycle is a theoretical ideal thermodynamic cycle. The Carnot efficiency is a ratio of temperatures, while the fuel cell efficiency is a ratio of energy changes for a reaction.

Workdone by engine vs heat exhausted