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摘 要 ：汽车空调压缩机耦合于车用发动机，其冷却系统的损失随着压缩机循环的增大而增加。本文从热力学第二定律的角度，分析且量化了汽车蒸汽压缩式制冷系统在压缩机循环过程中各个过程中的损失。制冷系统各部分基于熵增的损失理论上分别为：在压缩机、冷凝器、蒸发器储液器以及膨胀阀中的热力损失比率分别约为22%，10%，7%以及2%。压缩机的损失决定了整个系统的性能，可以通过提高压缩机效率来提高系统性能。比如说可以通过使用变容量压缩机或者通过不直接将压缩机与引擎联合来实现。 关键字 ：汽车空调 制冷循环 熵增 热力损失 An thermodynamics analysis of cycling in an automotive air conditioning system Pei Xiuying School of Mechanical Engineering Jimei University, Xiamen, 361021,CHINA Abstract : The compressor is a belt-driven accessory device coupled to the engine in an automotive air conditioning system, its cycling rate is directly related to the vehicle speed. The refrigeration system's losses increase with increasing vehicle speed and thus with increasing compressor cycling. This paper identifies and quantifies individual losses in an automotive vapor-compression refrigeration system during compressor cycling, and based on the second law of thermodynamics. In particular, nondimensional entropy generation, is used to quantify the thermodynamic losses of the refrigeration system's individual components under steady driving conditions at idle. Based on the ratio of entropy generation to entropic load, are 0.22, 0.10, 0.07, and 0.02 in the compressor, the condenser, the evaporator-accumulator, and the orifice tube, respectively. This analysis shows that the compressor losses dominated the overall system performance. The overall system efficiency could be significantly improved by increasing the compressor's efficiency. The compressor's efficiency could be improved by reducing or eliminating cycling, such as could be accomplished by using a variable capacity compressor or by not directly coupling the compressor to the engine. Keywords : Air conditioning; Automotive; Cycling; Entropy generation; Thermodynamic losses