Energy Balances

Abstract

Global conservation law of energy states that the total energy of a system always remains constant. Mass and energy are always conserved in a process, while exergy are not conserved. Balance equations are for both the conserved as well as for nonconserved properties, and therefore may contain a source term. For example, in an internal chemical reaction in a system, a substance may be consumed and heat of reaction may be produced. Consequently, in many engineering problems energy and mass conservations are solved together. By accounting the balance equations, energy interactions have been analyzed in turbines, compressors, nozzles, pumps, valves, mixers, and heat exchangers. Beside these, the Carnot cyclic process is also discussed briefly.