制冷剂充注量对太阳能热泵热水器性能的影响

Effect of Refrigerant Charge on the Performance of a Direct Expansion Solar Assisted Heat Pump Water Heater

在建立太阳能集热/蒸发器和冷凝器的分布参数均相流动数学模型、压缩机和热力膨胀阀的集总参数数学模型和系统充注量模型的基础上,编制了直接膨胀式太阳能热泵热水器系统性能模拟程序.将模拟计算值和实验值进行了对比.基于此模型计算了不同充注量下系统的运行参数和性能参数,分析了充注量变化对加热时间、集热器出口过热度、蒸发压力、冷凝压力、压缩机功率、集热器集热效率及系统性能系数等的影响,指出了确定系统最佳充注量需考虑的主要因素.

Simulation program of a direct expansion solar assisted heat pump water heater system was coded based on the distributed parameter and homogeneous flow mathematical models of solar collector/evaporator and condenser,the lumped parameter models of compressor and thermostatic expansion valve and the refrigerant charge model.The calculation and the experiment results were compared.Based on the calculation results,the operational parameters and the performances of the system were obtained.The effects of changing the refrigerant charge on heating time,the superheat of collector outlet,evaporating pressure,condensing pressure,power of the compressor,collector efficiency and coefficient of performance（COP） were analyzed.Some references to judge optimum refrigerant charge were proposed.