Conversion Efficiencies of Heat Engines and Fuel Cells

The Carnot cycle efficiency derived in Section 3.1 was based on the First Law, but having two definitions of conversion efficiencies gives a more accurate assessment of a power-producing device. The first definition is that of thermal efficiency, which is based on the First Law, comparing the net work output with the heat input, usually the heating value of the fuel. Using this as standard of reference, devices with different energy conversion processes can be compared against each other.

The second definition is based on the Second Law, which compares the actual performance of a device to the maximum possible work that it could produce, which, for example, is the Carnot cycle efficiency for heat engines. This shows where there is room for improvement. By using the concept of exergy, the Second Law is a measure of efficiency relative to the maximum work potential of a system.

Guide to Alternative Fuels

Guide to Alternative Fuels

Your Alternative Fuel Solution for Saving Money, Reducing Oil Dependency, and Helping the Planet. Ethanol is an alternative to gasoline. The use of ethanol has been demonstrated to reduce greenhouse emissions slightly as compared to gasoline. Through this ebook, you are going to learn what you will need to know why choosing an alternative fuel may benefit you and your future.

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