An optimal endoreversible three-heat-source refrigerator

Abstract

An endoreversible three-heat-source refrigerator only affected by thermal resistance, like a reversible three-heat-source refrigerator, may be treated as a combined cycle of a two-heat-source engine driving a two-heat-source refrigerator. The theory of finite time thermodynamics in two-heat-source cycles is then used to analyze it and derive its basic optimum relation. Thus, the fundamental effect of thermal resistance on the optimal performance of a three-heat-source refrigerator is expounded. The conclusions obtained here are more realistic than those of classical thermodynamics. They provide some new theoretical bases for further exploitation of the three-heat-source refrigeration apparatus that applies to ‘‘cheap’’ heat sources, such as solar energy, geothermal energy, waste heat, and so on.