R404A与CO_2复叠式制冷系统的热力学分析与优化  

Thermodynamic analysis and optimization of R404A/CO_2 cascade refrigeration system

作　　者：赖艳华[1] 董震[1] 邵长波[2] 吕明新[1] 王庆为[1] 孔德? 

机构地区：[1]山东大学能源与动力工程学院,山东济南250061 [2]山东商业职业技术学院机电工程学院,山东济南250103

出　　处：《山东大学学报（工学版）》2011年第2期149-153,共5页Journal of Shandong University（Engineering Science）

基　　金：山东省科技攻关资助项目(2009GG20004023)

摘　　要：为了提高R404A/CO2复叠式制冷系统的性能,对该系统开展了理论分析和优化研究。根据R404A和CO2的热物性及压缩机效率,采用热力学方法分析蒸发温度Te、冷凝温度Tk、冷凝蒸发器的传热温差ΔT等因素对系统性能的影响。通过模拟获得不同工况下低温端最佳冷凝温度、高低温端最佳质量流量比和最佳性能系数。结果表明:在一定Te、Tk和ΔT条件下,系统性能系数ε存在一个最佳值。为了提高系统性能系数ε,应尽量升高Te,减小ΔT和降低Tk。在同样工况下,R404A/CO2系统的最佳性能系数比NH3/CO2系统的稍高。In order to improve the performance of R404A/CO2 cascade refrigeration system,a theoretical study was carried out.According to the thermal physical properties of R404A/CO2 and the efficiencies of compressors,thermodynamic analysis and mathematical simulation were adopted to get the influence of the important factors such as the evaporating temperature Te,the condensing temperature Tk and the temperature difference ΔT in the cascade-condenser.The optimum condensing temperature in the CO2 low-temperature cycle,the optimum mass flow ratio of the high/low temperature cycle and the optimum coefficient of performance under different conditions were obtained by simulation.There exists an optimum coefficient of performance when Te,Tk and ΔT are definite in this cascade refrigeration system.The coefficient of performance can be improved by increasing Te,decreasing ΔT in the cascade-condenser and Tk.Under the same conditions,the optimum coefficient of performance of the R404A/CO2 cascade refrigeration system is slightly higher than that of NH3/CO2 refrigeration system.

关 键 词：二氧化碳 复叠式制冷 性能系数 最佳质量流量比 

分 类 号：TB6[一般工业技术—制冷工程]