直膨式太阳能热泵制热性能的对比研究

CONTRASTIVE RESEARCH OF HEATING PERFORMANCE OF DIRECT EXPANSION SOLAR ASSISTED HEAT PUMP SYSTEM

直膨式太阳能热泵(direct expansion solar assisted heat pump,DX-SAHP)可直接吸收利用太阳能,进而提高热泵的蒸发温度和性能系数(COP),有利于改善热泵的热性能和结霜。本文在带有太阳模拟发射器的焓差实验室中建立直膨式太阳能热泵和常规直彭热泵的对比实验,对不同条件下的热泵系统参数进行测量并进行性能对比和分析。实验结果显示,直膨式太阳能热泵能够吸收太阳能,在辐照度分别为100和200 W/m^2的工况下,系统制热功率比无辐照时的制热功率分别提高9.8%和21.8%,COP分别提高11.7%和23.7%,且除霜启动延迟23 min;辐照度为200 W/m^2时,直膨式太阳能热泵在环境温度5℃下的制热功率比1℃下的制热功率提高16.92%;在室外温度为1℃,相对湿度为95%的工况下,提高太阳辐照度,可有效减小涂层蒸发器进出口温度的波动,提高蒸发器运行的稳定性。此外,直膨式太阳能热泵在运行过程中吸收的太阳辐射被用来蒸发液态制冷剂工质,导致压缩机进气量增加,系统的制热功率和COP提高。

The Direct Expansion Solar Assisted Heat Pump （DE-SAHP） can absorb and utilize solar energy for raising the evaporating temperature and improving the COP, which is beneficial to improve the thermal performance and solve the frosting problem. A comparative experiment for comparing the DE-SAHP with the conventional heat pump was built in the enthalpy difference laboratory equipped with a solar simulation transmitter, where many parameters of the heat pump system would be measured and the performance of the system could be compared and analyzed under different conditions. The results show that the DE-SAHP can absorb solar energy when the irradiation is 100 W/m^2 and 200 W/m^2, the heat power can be improved by 9.8% and 21.8% and it＇ s COP could be improved by 11.7% and 23.7% compared to 0 W/m^2, respectively; its defrost starting could be delayed for 23 minutes; When the solar irradiation was 200 W/m^2, comparing with the system performance under the environment temperature of 1 ℃, the heat power of DE-SAHP running at 5 ℃ could be improved by 16.92% ; Under the conditions which the environment temperature and relative humidity are 1 ℃ and 95%, respectively, increasing the solar irradiation intensity can effectively reduce the fluctuation between the inlet temperature and the out temperature of the coating evaporator and improve the stability of evaporator. Besides, the solar irradiation absorbed by the DE-SAHP can be used to evaporate the liquid refrigerant, which result in increasing the inflow of compressor and improving the heat power and COP.