Design For Air Conditioning System Of Electric Vehicle And Optimized Design Of Air-conditioning Duct

Now, more and more electric vehicle is used in all kinds of vehicles, people payattention to safety and comfort than others. The paper designs for air conditioningsystem of battery electric vehicle and optimizes design of air-conditioning duct, tomeet the request of using air conditioning system in BEV and to achieve comfort andenergy saving.We analyze refrigeration and heating in air conditioning system of electricvehicle. We take reliability、maturity、security and energy saving into account inrefrigeration, so we choose refrigerating system with electrically driven compressorsin the end. We consider the factor of security、stability and energy consumption inheating, so we select heat pump as heating system. From what has been mentionedabove, we come to the conclusion that using heat pump air conditioning system inBEV, and to improve it. We redefine the heat exchanger assembly, and select R134aas cycle fluid to fit heat pump air conditioning system.We make sure that thermal load is4000W and cooling load is4445W to comfortdriver and passenger through one-dimensional manipulation. The total air and freshair volume are obtained through computing air volume of duct; We get the structuresize of No.1heat exchanger, relative error of total heat transfer area is1.4%thanestimated value; We need to optimize the heat exchanger assembly of air conditioningsystem in BEV; We simulate temperature field and velocity field of the heatexchanger assembly with three-dimensional simulation. The flow of airside isthree-dimensional state of turbulence, both of the heat exchangers in the heatexchanger assembly are used as porous medium model, we use inertial and viscous toset porous medium. We analyze the angle of inlet、the depth of inlet、the shape ofguide plate、the direction of No.1heat exchanger、the porosity of No.2heat exchangerin simulation, the influence of these factors is different in temperature field andvelocity field. Considered temperature field and velocity field, we choose plan A and 0.7porosity of No.2heat exchanger as optimized design of air-conditioning duct. Wesimulate temperature field and velocity field of BEV compartment with optimizedduct, analyzed temperature distribution of driver and passenger in different travelspeed, distribution of temperature is satisfied with requirement of comfort to driverand passenger through study.We put forward three different heating patterns on the basis of plan A and0.7porosity of No.2heat exchanger. Duct is simulated to the three kind of patterns, wework out that pattern one is best than others through compared with temperature fieldand velocity field of every outlet when the vehicle only need heating. We simulatetemperature field and velocity field of BEV compartment with pattern one in heating,temperature of body surface5cm is satisfied with requirement of heating to driver andpassenger in simulation, and electric energy can be saved through less supply air ratewhen it meet requirement.The study of this paper provided a theoretical basis and reference for design forair conditioning system of battery electric vehicle and optimized design ofair-conditioning duct.