R134a/R125混合物制冷剂性能研究

Research on performances of R134a/R125 mixed refrigerant

基于制冷剂的气液相平衡特性,建立了R134a/R125混合制冷剂二元体系模型,对其物性进行了分析。建立了蒸气压缩式制冷系统仿真模型,对混合制冷剂的循环工况和性能进行了对比研究。通过物性分析及性能对比,得到了不同比例混合制冷剂的饱和曲线和导热系数的变化趋势。对于R134a/R125非共沸混合制冷剂,在0.1 MPa压力下混合质量比为0.5/0.5时,温度滑移达到最大5.33℃。R134a/R125混合制冷剂的液相导热系数低于R134a,且随着温度的升高而减小;气相导热系数的变化趋势与液相相反。当蒸发温度较低时,制冷剂R134a在蒸发器中为负压,对系统不利,采用混合制冷剂R134a/R125(0.9/0.1)可改善这一状况,虽然COP略低于R134a系统,但可获得比R134a更低的制冷温度,且系统运行更稳定。研究结果为R134a/R125混合制冷剂的应用提供数据。

Based on the vapor-liquid equilibrium(VLE) characteristics of the refrigerant, a binary system model of R134 a/R125 mixed refrigerant was established, and the physical properties of R134 a/R125 mixed refrigerant were also analyzed.A simulation model of the vapor compression refrigeration system was established, and the cycle conditions and coefficient of performance were compared. The saturation curves of different proportions of mixed refrigerants and the trend curves of thermal conductivity were obtained. The results show that R134 a/R125 is a non-azeotropic mixed refrigerant, and the temperature slip reaches the maximum of 5.33 ℃ when the mass ratio is 0.5/0.5 at 0.1 MPa. The liquid phase thermal conductivity of R134 a/R125 is lower than that of R134 a, and decreases with the increase of temperature.The change trend of thermal conductivitt of gas phase is opposite to that of liquid phase. When the evaporating temperature is low, the evaporator of refrigerant R134 a is negative pressure, and the R134 a/R125(0.9/0.1) mixed refrigerant can improve the situation, the cooling temperature is lower than that of R134 a, and the system runs more stably, although the COP of the system is slightly lower than that of R134 a.