Study On Thermal Comfort Inside A Passenger Compartment

The thermal comfort of crew cabin is mainly considered from the insidetemperature and speed. It is directly related to the refrigerating capacity of the HVAC.In the earlier days of automotive air conditioning system development, through variousmethods to calculate the vehicle of heat load, to match appropriate air conditioningsystem components. The purpose of the load calculation is to forecast dynamic heat loadin the process of motor sports; the result of the calculation accuracy directly is related tothe energy consumption of the air conditioning system and in-car passenger comfort. Inthe hills or idle speed, the cooling effect of automotive air conditioning is very poor. andthe extreme cases, in which automotive air conditioning system does not refrigerateoften happen. So car air conditioning design and the match of system components justfrom a single working condition perspective is not available.This article through the real car sampling study tested physical parameters ofsamples. By taking into account the state of the car body enclosure structure beingheated, through the iterative calculation of the natural convection heat transfercorrelation about the inside plate and inclined plate, the thesis calculates the surfacetemperature and the quantity of the heat imported into the car when the enclosurestructure was stable. The iterative calculation software of the idle heat load wascompiled with Visual Basic. By analyzing the heat load calculation results of idling,medium speed, high speed, the optimization methods of lowering the heat load ofproposed.In environment lab, the vehicle air conditioning system was tested. Through theexperimental data, the cooling rate of vehicle and the temperature and humidity of airinlet and outlet in medium speed, high speed, idling conditions was analysized. it wasfound that the cooling rate of target model was good; in medium speed condition, thetemperature and humidity at the air inlet and outlet were more uniform; in high speedcondition, due to evaporator frost the temperature and humidity volatile at head sensor;in idle condition, the average temperature was higher at the head inside the car. Fromexperimental data of engine compartment and trunk wall temperature, the quantity ofheat introduced into the car was calculated and analysized, it was found that the quantityof heat from the trunk could be ignored. Through the inside and outside pressuredifference tested in idle condition, vehicle air leakage could be calculated in the air tightness laboratory.Through the CATIA, each part was assembled from the3D data model vehicle.Through ANSA, the finite element pre-processing, to clear geometry of vehicle partsmodel of data and to assemble the vehicle cabin model. On the basic of simplificationand assumption, surface mesh generation and volume mesh generation about crew cabinwas performed. Then through the FLUENT, the commercial simulation software,3-DCFD simulation on the unmanned crew cabin was carried. In the simulation calculation,the influence factors of solar radiation was considered; and the radiation model and thesun load calculation model was added.