Heat Soaks In Car Passenger Compartment And Occupant Thermal Comfort Research

The temperature of the car parked in the hot sun in summer will rise rapidly.The high temperature in the car due to the hot soak will cause harmful substances in the instrument panel,seats and other parts,and accelerate the aging of these parts.The high temperature environment will distract the driver’s attention,reduce the accuracy of work,and may cause the driver to misoperate and cause traffic accidents.At the same time,if the baby or child is forgotten and locked in the car,It will endanger their lives.Therefore,while realizing the function of regulating the driving environment,the automobile air conditioner also needs to meet the human thermal comfort and energy efficiency as far as possible.Reducing the solar radiation in the car before turning on the air conditioner can reduce the heat load of the air conditioner,so as to achieve the purpose of energy conservation.At the same time,it is particularly important to find an efficient and energy-saving air supply mode.A good air supply mode can not only quickly reduce the temperature in the car,but also meet the requirements of human comfort,which is more conducive to energy conservation.In this paper,a three-dimensional model of the passenger compartment is established,and the simulation error is verified to be within 6.7% by previous experimental data.Secondly,by using the computational fluid dynamics numerical simulation method,the influence of different parking directions on the temperature distribution in the passenger compartment and the three passive cooling methods,as well as the transmissivity of side windows and rear windscreens,are simulated to analyze the ability of the above methods to reduce solar radiation.Finally,through the simulation research on the influence of air supply speed and angle on the temperature field and velocity field distribution in the passenger compartment and the thermal comfort of drivers and children under the three air supply layout modes of front air supply,top air supply and side air supply,a air supply mode that can not only meet the thermal comfort requirements of human body,but also effectively cool and save energy is found.The research results show that in the hot soak study of the passenger compartment under different parking directions,the head,thigh and foot positions of drivers and children in the east parking direction can be 2-3 ℃ lower than those in other directions.Therefore,it is better to park in the east direction at 14:00 in summer.In the hot soak study of the passenger compartment under three passive cooling modes,it is recommended to take sunshade measures only considering the cooling effect of the passenger compartment wall temperature.For the reduction of the passenger compartment air temperature,it is best to use the front windshield sunshade+window opening gap of 2cm.The temperature around the driver can be reduced by3.4-6.7 ℃,and the temperature around the children can be reduced by 2.7-8.7 ℃.Compared with the other two arrangements,the overhead air supply has a better cooling effect.When the air supply speed is 2m/s and the air supply angle is 0 °,it can meet the thermal comfort needs of drivers and children,while the other two arrangements cannot meet the thermal comfort needs of human body.