电动客车跨临界CO_(2)热泵空调系统仿真分析

Simulation analysis of transcritical CO_(2) heat pump air conditioning system for electric bus

通过MATLAB软件建立了一个电动客车跨临界CO_(2)热泵空调数学模型,分析了不同工况对系统性能的影响,并拟合了最优排气压力相应关联式。结果表明:在排气压力Pcom.out=9 500 kPa时,蒸发温度Tevp每增加5℃,性能系数COP平均增加0.2;在低Pcom.out时,提高过热度ΔT有助于增强系统性能;在Pcom.out=8 000 kPa时,随着车内空气温度Ta.gc.in从0℃增加到25℃,COP下降了1.99;增大车内空气流量Va.gc.in会导致气冷器出风温度Ta.gc.out急速下降。

A mathematical model of electric bus transcritical CO_(2)heat pump air conditioner was established by MATLAB software, the influences of different operating conditions on the system performance were analyzed, and the optimal exhaust pressure corresponding correlation was fitted. The results show that when the exhaust pressure Pcom.out=9 500 kPa, the coefficient of performance(COP) increases by 0.2 on average when the evaporation temperature(Tevp) increases by 5 ℃. At low Pcom.out, increasing superheat(ΔT) helps to enhance system performance. When Pcom.out=8000 kPa, the COP decreases by 1.99 as the air temperature(Ta.gc.in) increases from 0 ℃ to 25 ℃. Increasing the air flow in the car(Va.gc.in) will cause the air cooler outlet air temperature(Ta.gc.out) to drop rapidly.