In responese to the current low temperature conditions of electric rehicle heat pump air conditioning systems, the surface of the outdoor evaporator is prone to frosting, which in turn affects the heat transfer efficiency, system performance, and driving range. Existing research has found that due to the different heat exchange capabilities of the two phases of the refrigerant in the evaporator, the frosting phenomenon is uneven, thus having a negative impact on the system performance. To address this issue, this paper proposes a solution of adding a gas-liquid separator in front of the outdoor evaporator. By adjusting the opening degree of the gas-phase bypass valve, the evaporation pressure can be optimized, and the overall performance of the evaporator and the system can be improved. By comparing the specific variation trends of the system's heat transfer efficiency, coefficient of performance (COP), and the outlet temperature of the evaporator under the conditions of the optimal opening degree of the gas-phase bypass valve and zero opening degree, at different ambienttemperatures (-5, 0, 5 ℃), evaporation pressures (0.199, 0.242, 0.291 MPa), and compressor speeds (2 000, 3 000, 4 000 r/min), the experimental results show that after adding the gas-liquid separator, the heat transfer efficiency is increased by up to 6.9%, the COP is increased by up to 7.4%, and the outlet air temperature of the evaporator is increased by 3.6% ~ 11.2%. This improved design can effectively alleviate the frosting problem under low-temperature conditions and enhance the system performance.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |