Research On Local Cooling Method Based On Local Thermal Characteristics Of Human Body

In order to solve the thermal comfort problem of indoor human body and indoor air quality and problems,People put forward the concept of personalized air supply.In recent years,it has gradually become a research hotspot.Most of the current research on personalized ventilation is aimed at indoor air quality,but there is still no basic research to solve the problems of thermal comfort.This topic combines the local thermal characteristics of the human body and focuses on the use of personalized air supply to solve the problem of local thermal comfort.Firstly,this paper introduces the evaluation indexes of human thermal comfort,including TSV,TCV and PMV.Through literature research,the author analyzed and compared the local thermal characteristics of various parts of the human body in the thermal environment,and they are found that in hot environments,whether it is male or female,the key parts that need to be cooled are the back,thighs and calves.Next,this paper conducts a simulation analysis of the local air supply for these key parts,and discusses the difference in the impact of personalized air supply on the thermal comfort of different parts.A typical space with a size of 3.6 × 3 × 3m is simulated.Simulate a hot environment that is higher than the thermal neutral in summer,the ambient temperature is set to 29,31 and 33 ℃,the air supply speed is 0.2 ～ 0.6m / s,and the temperature difference of the air supply is 2℃ and 4 ℃.Besides,under different ambient temperature,temperature difference and wind speed,the influence of velocity field,temperature field and PMV are simulated.Research and analysis show that the ambient temperature will affect the effect of personalized air supply.The higher the ambient temperature,the smaller the effect of personalized air supply.The ambient temperature has a greater impact on the average air velocity around the human body when the wind speed is small,and when the wind speed increases gradually,the ambient temperature can’t affect the air velocity around.When the wind speed increases gradually,the average air velocity around the human body decreases.As the increase of ambient temperature,the increasing range of ambient average temperature decreases.When the parameter is set as the ambient temperature of 29 ℃,the air temperature difference of 4 ℃ and the wind speed of0.4-0.6 m/s,back air supply and leg air supply can produce very good results.But the effect of the air supply of the calf is not ideal,so it is not suggest using the air supply method for the calf.When the ambient temperature is as high as 33 ℃,using the local air supply independently may not satisfy the needs of human thermal comfort.So we need to consider the use of traditional air conditioning to reduce the ambient temperature to a suitable range.At this time,local air supply can not only satisfy human thermal comfort,but also avoid energy waste.Based on the local thermal characteristics of human body,this paper studies the key parts of human body which need to be cooled in the thermal environment by simulating the air supply.This paper analyzes the local air supply effect of different parts,summarizes the air supply parameters that make the human body hot and comfortable,which can provide some reference for the design of personalized air supply in the future.