有内热源房间空调器制冷系统热力膨胀阀的匹配研究

Study on Performance of Thermostatic Expansion Valve under Variable Working Conditions

为了保持热源的降温,应用于有内热源房间的空调器一年四季都需要运行。由于热力膨胀阀特性的限制,空调器在低环境温度下,蒸发器供液不足,使得整机制冷量和COP增幅不高。为了改善整机性能,在焓差实验室对空调器进行了性能测试,得到了-5～35℃环境温度下蒸发压力、冷凝压力、制冷量和COP等热工参数变化。结合热力膨胀阀的型号和特性,研究了热力膨胀阀在变工况条件下与系统其它部件的匹配关系,旨在扩大膨胀阀的工作区间,提高低环境温度下房间空调器的效率。研究表明,兼顾较大范围环境温度变化匹配热力膨胀阀,应扩大50%～100%开度工作区间,缩小100%～120%开度工作区间,降低制冷系统设备、部件和管道阻力,避免两个震荡区进入使用范围。

To improve the performance of air-conditioners in the rooms with internal heat sources at low outdoor temperature,the performance test was conducted in our enthalpy-difference laboratory,and the evaporating pressure,condensing pressure,refrigerating capacity and COP at the outdoor temperature of -5-35℃ were obtained.The matching relationship of the thermostatic expansion valve and the other parts of the system was investigated under variable working conditions considering the different type and property of the thermostatic expansion valves.The result indicates that for greater change in outdoor temperature,the thermostatic expansion valve selected should run in larger working range with the opening span of 50%-100% and smaller working range with the opening span of 100%-120% to reduce the flow resistance in the refrigerating system.