基于CO_(2)制冷剂的空气源热泵热水器的理论分析及开发

Theoretical Analysis and Development of Air Source Heat Pump Water Heater Based on CO_(2)

以CO_(2)作为制冷剂的热泵热水器的国标GB/T 38734—2020要求空气源热泵实测能效不低于4.6,而市场上大多产品能效4.4左右,能效升级势在必行。结合实际情况分析,得出中间不冷却的双级压缩、带回热器的CO_(2)跨临界循环是热泵热水器的首选方案,并对最优高压压力的公式进行分析,得出控制气冷器制冷剂出口温度和入口水温的温差作为系统控制方式。根据CO_(2)特性,各部件设计选型,然后系统组建并测试,系统能效4.8,满足国标要求,同时也验证了系统控制方式的正确性。

The national standard GB/T 38734-2020 for heat pump water heater based on CO_(2)requires that the measured energy efficiency of air source heat pump is not less than 4.6,while the energy efficiency of most products in the market is about 4.4,so it is imperative to upgrade the energy efficiency. Combined with the analysis of the actual situation,it is concluded that the two-stage compression without cooling in the middle and the transcritical cycle of CO_(2)with heat exchanger are the preferred scheme of the heat pump water heater,and the formula of the optimal high pressure is analyzed,and the temperature difference between the refrigerant outlet temperature and the inlet water temperature of the air cooler is obtained as the system control mode. According to the characteristics of CO_(2),each component is designed and selected,and then the system is set up and tested. The energy efficiency of the system is 4.8,which meets the requirements of the national standard. At the same time,the correctness of the system control mode is verified.