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为了研究工质R290(丙烷)在直膨式太阳能热泵系统中的分布和迁移特性,建立太阳能集热/蒸发器和冷凝器的分布参数均相流动模型、压缩机和电子膨胀阀的集中参数模型、以及系统工质充注量模型,编制以R290为工质的直膨式太阳能热泵热水器系统性能模拟程序。模拟分析环境参数和运行参数的变化对系统内部R290分布和迁移特性的影响。模拟结果表明:R290主要存在于冷凝器和太阳能集热/蒸发器内部,占系统工质充注量的80%~90%;随着太阳辐射强度和环境温度的升高,工质R290由冷凝器逐渐向太阳能集热/蒸发器迁移,系统性能系数明显增加;随着压缩机转速增快和水箱水温的增高,工质R290由太阳能集热/蒸发器逐渐向冷凝器迁移,系统性能系数明显降低;随着系统工质充注量的增加,冷凝器内工质R290质量明显增加,集热器内工质R290质量略有增加,系统性能系数先增后减,存在一个最大值;太阳能集热/蒸发器出口过热度由3℃升至8℃时,其变化对工质R290的分布和迁移特性影响很小,且对系统性能系数的影响也很小;随着环境温度、压缩机转速和工质充注量的增加,集热器集热效率不断增加;而随着太阳辐射强度、水箱水温和太阳能集热/蒸发器出口过热度的增高,集热器集热效率不断降低。
In order to study the distribution and migration characteristics of refrigerant R290 (propane) in a direct-expansion solar heat pump system, a homogeneous flow distribution model of the parameters of the solar collector / evaporator and the condenser was established, and a lumped parameter model of the compressor and the electronic expansion valve , As well as the system of refrigerant charge volume model, the preparation of R290 as the working fluid of direct expansion solar heat pump water heater system performance simulation program. The effects of environmental parameters and operating parameters on the distribution and migration of R290 in the system were simulated and analyzed. The simulation results show that: R290 mainly exists in the condenser and solar collector / evaporator, accounting for 80% ~ 90% of the system refrigerant charge; with the increase of solar radiation intensity and ambient temperature, the refrigerant R290 is condensed As the compressor speed increases and the water temperature in the water tank increases, the refrigerant R290 gradually migrates from the solar collector / evaporator to the condenser, and the system performance coefficient is obvious With the increase of system working fluid charge, the quality of refrigerant R290 in condenser increased obviously, the quality of refrigerant R290 in condenser slightly increased, the coefficient of system performance first increased and then decreased, and there was a maximum value. The solar energy set When the superheat of the heat / evaporator outlet increases from 3 ℃ to 8 ℃, the change has little effect on the distribution and migration characteristics of R290, and has little effect on the system performance coefficient. With the increase of ambient temperature, the compressor speed And the increase of working fluid charge, collector efficiency continues to increase; and with the solar radiation intensity, water temperature and solar collector / evaporator outlet overheating increases, collector heat efficiency continues to decline.