| It’s time-consuming and energy-wasting in physical experiment of bus air conditioning system. Considering the problems of physical experiment, it’s utilized C computer language to built mathematic mode for all parts of the system based on quality-balance equation, momentum-balance equation and energy-balance equation to contact every part. Using Yutong Bus Company of 7 m type overhead type bus air conditioning system as the test platform, it simulated the impact of variation of compressor speed, air flow inside the car and environmental temperature on the whole system. It also introduced the structure of above test apparatus and test philosophy, and analyzed control method of the process parameters. According to the calculation results and test data, the paper analyzed changes of parameters including the compressor speed,air velocity in the minibus and environment temperature influence on system performance under different working conditions. The simulation results show that mathematical model of the pure electric passenger bus air conditioning heat pump system is doable and working condition of the adjusting range is big. And the maximum error between simulation data and experimental result is less than 10%. This system can not only realize heating in the low temperature condition normally, but also reduce exhaust temperature by 22℃ to 78℃ adopting complement gas of low pressure. Besides, the system can achieve high temperature cooling efficiently and lower exhaust temperature effectively comparing with common heat pump. In addition, it studied to optimize parallel flow heat exchanger inside of the minibus. The optimization of the heat exchanger increased the airside heat transfer by 9% and reduced the airside pressure drop by 60% compared to the original one. Mathematical model and physical research providean accurate idea and effective method for development and performance optimization of the pure electric passenger minibus air conditioning heat pump system. |
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