电动客车热泵空调系统仿真与改进

Simulation and improvement of heat pump air conditioning system for electric bus

针对电动客车热泵空调系统性能优化进行仿真研究,建立热泵空调系统稳态仿真模型,利用实验数据验证及修正稳态仿真模型.小管径换热器由于管径减小,换热系数增大,基于经过修正的系统稳态仿真模型,提出换热器采用小管径的改进方法.仿真结果表明,应用小管径换热器到客车空调系统,额定制冷量(制热量)为23.2kW(20.9kW),制冷EER(制热COP)为3.14(2.75),性能有所提高但离设计要求有一定距离.分析系统的性能仿真结果可知,系统的循环质量流量低于设计值,压缩机能力不足,高效涡旋压缩机不仅排量增大,而且压缩机的制冷COP达到3.45,两个因素导致系统能效提高.将小管径换热器与高效涡旋压缩机应用于同一热泵空调系统.仿真结果表明,系统额定制冷量(制热量)为26.4kW(23.4kW),整机制冷EER(制热COP)为3.64(3.16),基本达到额定制冷量(制热量)为26kW(22kW)、制冷EER(制热COP)为3.2(2.8)的改进目标.

Heat pump air conditioning system s(HPAC S)performance enhancement was analyzed by means of simulation for 10 m pure electrical bus.The steady-state simulation model of HPAC was constructed,which was corrected and verified by the experimental data.The heat transfer coefficient increased because of the decrease of heat exchanger s diameter of the tube.Tube-fin heat exchanger withφ5 mm diameter tube was designed to the new HPAC and new design s effect on system performance was simulated by verified simulation model.The cooling(heating)capacity was 23.2 kW(20.9 kW),and cooling EER(heating COP)was 3.14(2.75).New HPAC s performance was improved,but couldn t meet improvement target.The simulation results showed that system s mass flow rate was lower than design value,and the compressor capacity was smaller than system requirement.The high efficiency scroll compressor not only increased the displacement,but also the cooling COP of the compressor was 3.45.The combination of the two factors improved the HPAC s energy efficiency.A high efficiency R410a scroll compressor was selected and applied to the same HPAC with the small diameter tube heat exchanger.The simulation results showed that cooling(heating)capacity reached to 26.4 kW(23.4 kW),while cooling EER(heating COP)reached to 3.64(3.16),which generally met design requirement that cooling(heating)capacity reached to 26 kW(22 kW),while cooling EER(heating COP)reached to 3.2(2.8).