环保型CO_2跨临界带膨胀机制冷循环性能研究  

Performances of Environmental Benign CO_2 Transcritical Refrigeration Cycle with an Expander

作　　者：谢英柏[1] 孙刚磊[1] 宗露香[1] 靳光亚[1] 

机构地区：[1]华北电力大学动力工程系,河北保定071003

出　　处：《环境科学与技术》2010年第3期41-44,63,共5页Environmental Science & Technology

基　　金：教育部重大项目(306004)

摘　　要：由于CFCs和HCFCs人工合成制冷剂破坏大气臭氧层,并产生温室效应,因此用自然工质替代合成工质越来越受到国内外制冷界的重视。文章对环保型CO2制冷工质进行了综合评价,并利用热力学原理建立模型,分析了CO2跨临界带膨胀机制冷循环的性能。结果表明:与CO2跨临界带节流阀制冷循环相比,CO2跨临界带膨胀机制冷循环明显提高了系统的性能系数(COP)。同时在保持压缩机排气压力和膨胀机等熵效率一定时,CO2跨临界带膨胀机制冷循环系统COP随着气体冷却器出口温度的增加而逐渐降低,但随着蒸发温度的增加而快速增加。在实际系统设计过程中,应综合考虑以上影响因素,以使系统设计最优化。Synthetic refrigerants such as CFCs and HCFCs deplete ozone and cause greenhouse effect. CO2 as a natural working fluids, is receiving more and more attention in the refrigeration field. The comprehensive evaluation of environmentfriendly CO2 refrigeration working fluids is carried out. The performances of CO2 transcritical refrigeration cycle are analyzed by establishing the thermodynamics model. Results indicate that the maximum coefficient of performance （COP） of the cycle with an expander is higher than that of the cycle with a throttling valve. At the optimal discharge pressure of the compressor and given expander iso-entropy efficiency, COP of CO2 transcritical refrigeration cycle with an expander increases with the decrease of outlet temperature of gas cooler, but increases quickly with the increase of evaporation temperature. For the optimization design of the CO2 transcritical refrigeration cycle with an expander, the major factors affecting the COP of the system should be considered.

关 键 词：CO2自然工质 跨临界循环 膨胀机 热力学分析 性能系数 

分 类 号：X16[环境科学与工程—环境科学]