ABSTRACT
Entropy production is a key parameter in determining the maximum theoretical limits of energy efficiency of engineering devices. Inefficiencies in a fluids engineering system arise from thermal, friction, and other thermodynamic irreversibilities. The Second Law of Thermodynamics can provide a systematic way of establishing optimal performance in these systems. For example, the Carnot cycle efficiency is based on processes that require the least amount of heat input, to deliver the maximum power output by giving ideal performance without irreversibilities. Actual heat engines are often compared against this Carnot limit. The rate of entropy generation, or any related measure of efficiency based on the Second Law, such as the Second Law efficiency, can be used to quantify the magnitude of irreversibilities in thermofluid applications. Power-generation devices (such as steam turbines) deliver maximum power output, and power-consuming devices (i.e., compressors, pumps) consume the least power when the rate of entropy generation is minimized.
