In mobile air conditioning (MAC) systems, the secondary loop (SL) structure was usually adopted when using flammable refrigerants such as R1234yf, R290 and R152a. The introduction of intermediate heat exchangers in SL system inevitably increased the temperature difference between the condensation side and the evaporation side, thereby increased the compressor power consumption and caused the performance attenuation. To overcome the attenuation, this study designed a heat recovery device which collects the waste heat from the passenger compartment to increase the evaporation temperature and reduce the compressor power consumption. Validation experiments were completed in a secondary loop heat pump (SLHP) MAC system using R152a and was compared with a baseline direct expansion (DX) system. According to experimental results, under the -10 °C outdoor temperature, the SLHP system showed performance attenuation compared with the DX system. With the increase in indoor temperature, the attenuation gradually increased to 8.96% at the indoor temperature of 20 °C. In this case, a heat recovery design was used in the SLHP system, which increased the coefficient of performance (COP) by 9.29% compared with the original SLHP system and achieved similar performance to the DX system.

在移动空调（MAC）系统中，当使用易燃制冷剂（例如R1234yf，R290和R152a）时，通常采用二级回路（SL）结构。在SL系统中引入中间热交换器不可避免地增加了冷凝侧和蒸发侧之间的温差，从而增加了压缩机的功耗并导致性能下降。为了克服这种衰减，本研究设计了一种热回收装置，该装置可以收集来自乘客舱的废热，以提高蒸发温度并降低压缩机的能耗。验证实验是在使用R152a的次级回路热泵（SLHP）MAC系统中完成的，并与基线直接膨胀（DX）系统进行了比较。根据实验结果，在-10°C的室外温度下，SLHP系统与DX系统相比性能下降。随着室内温度的升高，在20°C的室内温度下，衰减逐渐增加至8.96％。在这种情况下，SLHP系统中使用了热回收设计，与原始SLHP系统相比，该系统的性能系数（COP）提高了9.29％，并获得了与DX系统相似的性能。