R1270/CO2复叠式制冷系统热力学分析

摘要

针对R1270/CO2复叠式制冷系统,通过能量及(火用)分析的方法,分析了低温级冷凝温度、系统蒸发温度、系统冷凝温度以及冷凝蒸发器传热温差对系统COP、(火用)损Ⅰ和质量流量的影响.分析结果表明,在其他变量一定的条件下,存在确定的低温级冷凝温度使系统COP最大,总(火用)损最小;适当的升高系统蒸发温度和降低系统冷凝温度,以及减小冷凝蒸发器传热温差,可以增大系统COP和降低(火用)损;R1270高温级部件和冷凝蒸发器的(火用)损占总(火用)损比例较大,需对其进行重点优化.降低低温级冷凝温度和系统冷凝温度,提高系统蒸发温度可以减少系统中R1270的充注量.%A theoretical calculation of the R1270/CO2 cascade refrigeration system has been carried out to get a comprehensive understanding of the performance.The paper analysis the evaporating temperature,the condensing temperature,the condensing temperature of CO2 and the heat transfer temperature difference of condenser evaporator on the COP and exergy destruction with the thermodynamics and exergy analysis method.In the condition of other variables there was a maximum COP and minimum exergy destruction with a optimal condensing temperature of CO2.In order to increase the COP and decrease the loss of exergy,it is necessary to increas the evaporating temperature,reduce the ondensing temperature and heat transfer temperature difference of condenser evaporator.Therefore the main section causing the loss of exergy at high temperature part and the condenser-evaporator,need to make it optimize.Reducing the condensation temperature of CO2,the condensing temperature of the system and increasing the evaporation temperature of the system can reduce the charge of R1270 in the system.