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为了研究R404A/CO_2复叠式制冷系统的性能,对其进行了热力学分析。采用理论计算和熵产最小法分析蒸发温度T_e、冷凝温度T_k、冷凝蒸发器的传热温差△T等参数对该系统的性能、部件及整个系统的熵产的影响。结果表明,给定T_e、T_k和△T时,在最佳低温级冷凝温度下,系统COP取得最大值,系统总熵产取得最小值;高温级节流阀和压缩机、冷凝蒸发器和低温级压缩机的熵产约占总熵产的80%。
In order to study the performance of the R404A / CO_2 cascade refrigeration system, its thermodynamic analysis was carried out. The theoretical calculation and minimum entropy production method were used to analyze the influence of parameters such as evaporation temperature T_e, condensation temperature T_k, temperature difference △ T of the condensation evaporator on entropy production of the system, components and the whole system. The results show that, given T_e, T_k and △ T, the COP of the system achieves the maximum at the optimal condensing temperature of low temperature level, and the total entropy production reaches the minimum value. The high temperature level throttle valve and compressor, the condensing evaporator and the low temperature The entropy output of a class compressor accounts for about 80% of the total entropy production.