R404A/CO2复叠式制冷系统的熵分析

为了研究R404A/CO₂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%。

Entropy Analysis of R404A/CO2 Cascade Refrigeration System

In order to study the performance of R404A/CO₂ cascade refrigeration system,thermodynamic analysis is applied to this system.Theoretical calculation and entropy generation minimization method were adopted to get the influence of some important operating and design parameters on the performance of the system and entropy generations of each component and the whole system,such as the evaporating temperature T_e,the condensing temperature T_k and the temperature difference AT in the cascade-condenser.The results indicate that there are a maximum coefficient of performance and a minimum total entropy generation of the system at the optimal condensing temperature of the cascade-condenser when T_e,T_k and△T are constant.The total entropy generations of the throttling device and the compressor of the R404A circuit,the cascade-condenser and the compressor of CO₂ circuit are 80%of the total entropy generation of the whole system.