Experimental Study On Heating Performance Of Electric Vehicle Air Conditioning System In Cold Region

Environmental pollution and energy crisis have aroused more and more people's concern.Electric cars are used by more and more people.Electric cars are powered by power batteries,which significantly shortens the range of an electric car compared to a petrol-powered one.Electric cars have no engine waste heat to use.PTC electric heating system is widely used for heating in winter.PTC electric heating system not only consumes a lot of power but also heats up slowly,which seriously shortens the range of electric cars.The heat pump system has good heating effect,which is more than 3 times higher than PTC electric heating system.In this paper,on the basis of the electric car the original air conditioning system,by changing the line modification to the original air conditioning system design for the heat pump system,and studied the outdoor environment temperature-10? to 0?,within the scope of the system the operation of the different periods,different heat exchanger inside the car to send air volume,different outside wind speed on heat pump heating performance impact.The main findings are as follows:(1)As the ambient temperature increases,the system heat production and compressor power consumption increase gradually,and the energy efficiency ratio of the corresponding heat pump system also increases.The heat pump system requires the maximum heat load at the beginning of startup,but the heat production is the minimum at this time.The lower the ambient temperature outside the vehicle,the less the ambient heat absorbed by the external heat exchanger,the lower the system heat production,and the longer the time required for the system to achieve stable heat load.(2)As the operating time of the system increases,the heat production of the heat pump system increases and reaches the stable stage after the system runs for about 300s.The heat production and energy efficiency of the stable interstage system are larger than that at the beginning.The heat exchanger in the car has three kinds of adjustable air volume.As the air volume increases,the heat production increases.When the air volume exceeds a certain value,the heat transfer time between the cold air and the heat exchanger in the car is shortened and the heat production decreases.with the increase of wind speed outside the car,the ambient temperature decreases and the heat exchanger frosts seriously.(3)The electric car heat pump air conditioning system is composed of the original car air conditioning system design modification,the original air conditioning system condenser evaporator into a heat pump system,because of the original system of evaporator area compared to the condenser area is lesser,so after modification of the heat pump system condensing area decreases,and add a secondary heat exchanger to optimize a heat pump system.Compared with the system before optimization at the same ambient temperature outside the vehicle,the heating efficiency of the optimized system increased by about 11%.(4)Comparing the energy consumption of the heat pump system and PTC electric heating system,the heat production of the heat pump system is more than 3 times of that of PTC heating system in the same operating time.