非共沸混合工质自复叠热泵循环试验研究

单级压缩式热泵冷凝温度与蒸发温度之差一般为40~50℃,非共沸混合工质自复叠循环具有工作温差大的优点,将其应用于热泵循环,则可产生较大的供热温差。该文通过搭建一个空气源自复叠热泵实验台,利用NIST公司的制冷剂物性数据库Refprop7,绘制出了混合工质的温度-浓度图。经过实验,分析了自复叠热泵循环工作温差的影响因素,得出了自复叠热泵气液分离器简单分离对增大工作温差的作用有限,增加工质的相对挥发度也不能显著改善热泵的运行性能等结论。并进一步得出了增设分凝设施可显著增大工作温差的结论。

Experimental study on zeotropic mixture auto -cascade heat pump

The temperature difference between condensation and evaporation is about 40~50℃ in single-stage compression heat pump,which will be larger in zeotropic mixture auto-cascade cycle.The temperature difference between condensation and evaporation of single-stage heat pump would be enlarged if the zeotropic refrigerant mixture auto-cascade cycle was applied to the heat pump.In this paper,an auto-cascade air source heat pump water heater was built.Based on the NIST REFPROP7.0,the temperature concentration diagram of a typical binary zeotropic refrigerant mixture was proposed.With a series of experiments,the influence on the temperature difference between condensation and evaporation of auto-cascade heat pump water heater was analyzed.The result showed that simple the phase separator can only increase the temperature difference between condensation and evaporation limitedly in heat pump,and the performance of the heat pump is improved limitedly by increasing the relative volatility of binary zeotropic refrigerant mixture.At last,The application of the dephlegmation separation will increase the temperature difference between condensation and evaporation evidently.