Test And Simulation Analysis Of Combined Heat Pump Air Conditioning System For Pure Electric Vehicle

With the deepening of the energy crisis and the increasingly prominent pressure of environmental protection pure electric new energy vehicles have become more prominent,which has become a new direction of development of the automotive industry,and the air conditioning system related to the comfort of the cockpit has also received more attention.Electric compressor refrigeration and PTC(Positive Temperature Coefficient)heating air conditioning system are widely used in pure electric vehicles.PTC and air-conditioning system has the advantages of constant temperature,safety and long service life,but its energy consumption is large,affecting the vehicle mileage.Compared with PTC heating,heat pump air-conditioning system has higher heating efficiency and more energy saving,but its performance decays too fast in low temperature environment.Therefore,considering the influence of energy-saving and low temperature,a PTC low temperature auxiliary heating combined heat pump air conditioning system is developed.Based on the research methods of experiment and simulation,the best way to realize the joint operation of heat pump air-conditioning system and PTC electric heater at different ambient temperatures is obtained.The specific work is as follows:(1)Based on the operation principle of the combined heat pump air conditioning system,the condition of the system is determined,and the parameters such as refrigeration capacity and heat production are obtained by thermodynamic calculation of the system performance parameters.The type selection are carried out.(2)The heat pump air-conditioning system of pure electric vehicle is set up,and the cooling test of the whole vehicle air-conditioning system and the heating test of the whole vehicle air-conditioning heat pump system with the ambient temperature of 43 ℃ and the ambient temperature of-5 ℃ are carried out.(3)The calculation model of refrigeration and heating air-conditioning system is established by using KULI software,and the refrigeration and heating conditions of the air-conditioning system are simulated when the ambient temperature is 43 ℃ and-5 ℃,respectively,and compared with the experimental data.Then the temperature range of the heat pump system and PTC is determined by simulation,and the environment is simulated.The optimum power of PTC at-10 and-20 ℃.(4)The combined heat pump air-conditioning system of pure electric vehicle is set up,and the heating test of ambient temperature is-20 ℃,which verifies the working characteristics of PTC heating and air-conditioning system at low temperature.The results show that the calculation model of combined heat pump air conditioning has higher prediction accuracy,and the experimental system of combined heat pump air conditioning for electric vehicle based on simulation results can meet the heating and cooling requirements well.To save energy,when the ambient temperature is-14℃ ～9 ℃,the heat pump air conditioning system and PTC work together,the optimum PTC power is2 k W when the ambient temperature is-10℃;when the ambient temperature is below-14 ℃,PTC electric heating is used alone to meet the winter heating demand.The optimum power of PTC is 7.5k W at ambient temperature of-20 ℃.