ABSTRACT
This is an entry on efficiency assessment of energy systems covering energy‐ and exergy‐based efficiencies applied to various energy systems. Efficiency definitions are developed and applied to cyclic devices, mechanical energy conversion devices, steady‐flow devices, gas and steam power plants, cogeneration plants, and refrigeration systems. These efficiencies are useful in design, analysis, and performance improvement of energy systems. The confusions and inconsistencies in defining the energy and exergy efficiencies are clarified, and appropriate definitions are presented with examples. The implications of various ways of efficiency definitions for a given system are discussed. The advantages of exergy analysis and exergy efficiency use with respect to conventional energy analysis and energy efficiency use are discussed.
