Exergy of Any Energy Except Thermal

The exergy of an amount of energy other than thermal (heat) electrical, mechanical, etc., is of course equal to this amount of energy. 

Exergy represents the real measure - the yardstick - of the ability of a system, or of a certain type of energy, to produce useful work by coming into equilibrium with the atmosphere in a flow process. 

Ideal work, on the other hand, refers to a specified final state for the system. If this final state is the atmospheric, the ideal work is the same with the exergy of the system. 

The exergy of heat - our main source of energy through fossil fuel combustion - is a strong function of the temperature it is available at. 

The exergy of steam - the major fluid for the conversion of thermal energy into mechanical - is a strong function of its temperature and pressure. 

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