两种CO_2复叠式制冷系统的性能分析

Performance Analysis for Two Types of CO_2 Cascade Refrigeration Systems

为了提高复叠式制冷系统的性能,有必要对不同的复叠式制冷循环进行对比分析。本文建立了2种分别采用R290/CO_2与R404A/CO_2工质的复叠式制冷循环的计算模型,并进行理论模拟计算与对比分析。结果表明,R290/CO_2复叠式制冷循环的COP比R404A/CO_2循环高;而且2种制冷循环中,都存在最佳低温循环冷凝温度,使得系统COP取得最大值。应尽量增大蒸发温度、减小冷凝温度以及降低冷凝蒸发器传热温差,这也有利于循环的安全运行。总之,R290/CO_2复叠式制冷循环的综合性能更优,在环境保护、节约能源方面具有较好的发展前景。

In order to improve the performance of the cascade refrigeration system,it is necessary to compare and analyze different cascade refrigeration cycles.two calculation models of cascade refrigeration cycle with R290/CO2and R404A/CO2were established,and the theoretical simulation calculation and comparative analysis were carried out.The results show that the COP and of the cascade refrigeration cycle with R290/CO2are higher than that with R404A/CO2.There is an optimum condensation temperature in the two refrigeration cycle,respectively,which makes the COP of the system to achieve maximum value.It is beneficial to the safe operation of circulation by increasing evaporation temperature,reducing condensation temperature and heat transfer temperature difference of condensing evaporator.In short,the comprehensive performance of R290/CO2cascade refrigeration cycle is better,and it has a good development prospects in environmental protection and energy conservation.