Auto-cascade absorption refrigeration(ACAR) systems are a class of new cycles that can achieve low refrigeration temperatures by utilizing low-quality thermal energy. In this study, the equivalent thermodynamic proces...Auto-cascade absorption refrigeration(ACAR) systems are a class of new cycles that can achieve low refrigeration temperatures by utilizing low-quality thermal energy. In this study, the equivalent thermodynamic processes of a reversible ACAR system are established, and illustrated in a T-s diagram. The formula of the coefficient of performance for the reversible ACAR system is derived from the first and second thermodynamic laws. And then, the equivalent cycle of an irreversible ACAR system is established. The irreversible ACAR system is optimized by minimizing entropy generation of the thermodynamic processes. As a result, the optimum distribution ratio of heat fluxes at cascade process, which is defined as a ratio of heat fluxes between a condensing reservoir and cascade reservoir, and the optimum cascade temperature are obtained. Finally, its coefficient of performance and thermodynamic perfect degree are determined with minimum entropy generation.展开更多
基金financially supported by National Natural Science Foundation of China under Grant No.51206140 and No.50890184。
文摘Auto-cascade absorption refrigeration(ACAR) systems are a class of new cycles that can achieve low refrigeration temperatures by utilizing low-quality thermal energy. In this study, the equivalent thermodynamic processes of a reversible ACAR system are established, and illustrated in a T-s diagram. The formula of the coefficient of performance for the reversible ACAR system is derived from the first and second thermodynamic laws. And then, the equivalent cycle of an irreversible ACAR system is established. The irreversible ACAR system is optimized by minimizing entropy generation of the thermodynamic processes. As a result, the optimum distribution ratio of heat fluxes at cascade process, which is defined as a ratio of heat fluxes between a condensing reservoir and cascade reservoir, and the optimum cascade temperature are obtained. Finally, its coefficient of performance and thermodynamic perfect degree are determined with minimum entropy generation.
