超临界补气增焓高温CO_(2)热泵热风机实验研究

Experimental study on high temperature CO_(2) heat pump air heater with supercritical enhanced gas injection

针对工业上循环加热工况下,CO_(2)热泵气体冷却器出口温度过高、能效显著降低的问题,文章提出了带有超临界补气的高温CO_(2)热泵循环,并对系统进行了实验研究。主要分析了主路膨胀阀开度、压缩机频率、气体冷却器的风机频率对出风温度、性能系数COP等参数的影响。实验结果表明:出风温度随着主路膨胀阀开度的增大呈现降低趋势而COP呈升高趋势;降低气体冷却器的风机频率对出风温度的提升效果最为明显,风机频率每调低1%,出风温度最大提升5.07%。以得到最高出风温度为目标的实验数据表明,该系统在气体冷却器出口温度为75℃以上时,出风温度可达130℃以上,对应COP为1.40~1.50。

Aiming at the problem that the outlet temperature of gas cooler is too high and the system efficiency significantly deteriorates under hydronic heating condition, a high temperature CO_(2)heat pump cycle with supercritical enhanced gas injection was proposed and experimentally studied. The effects of the main loop expansion valve opening degree, compressor frequency, fan frequency of gas cooler on outlet air temperature and COP, etc. were analyzed. The results showed that the outlet air temperature decreases while COP increases with the increase of the opening degree of the main loop expansion valve. Reducing the fan frequency of the gas cooler has the most obvious effect on the improvement of the air outlet temperature. The air outlet temperature increases by 5.07% when the fan frequency decreases by 1%. The experimental data aiming to obtain the highest outlet air temperature showed that when the outlet temperature of gas cooler is above 75 ℃ and the outlet air temperature is above 130 ℃, the corresponding COP is about 1.40~1.50.