Effects Of Human Physiological Termoregulation On Thermal Comfort In Natural Ventilation Environment In Summer

With the improvement of living standards,air conditioning is used more and more widely,which makes people over-rely on the comfortable environment created by air conditioning equipment.However,staying in the comfortable environment of conventional air conditioning for a long time not only weakens human thermal adaptability and reduces work efficiency,but also gradually degrades the immune system,which is not conducive to maintaining health.Therefore,it is of great significance to make clear the law of human physiological regulation parameters changing with thermal environment and rationally evaluate human thermal sensation in naturally ventilated buildings for creating comfortable,energy-saving and healthy thermal environment.This paper takes college students as the research object,takes physiological experiment of thermal comfort as the main research method,combines subjective questionnaire survey and other methods,and conducts experiments in the summer of 2021-2022 to study the influence of physiological regulation of human body on thermal comfort in summer.This paper investigates the influence of human physiological regulation on thermal comfort by analysing changes in physiological regulation parameters such as skin temperature,perspiration sensation and skin wetness.Firstly,by analyzing the variation of skin temperature with operating temperature,it was shown that the curve of variation of skin temperature T_skwith room operating temperature T_op was an S-shaped curve,with the most significant variation of T_sk with T_op when T_op was in the range of 28.1°C to 31.7°C.The skin sweating feeling index SFI was then analysed in relation to T_op and it was found that all subjects experienced varying degrees of sweating when T_op was greater than（31.1±0.3）°C.Finally,the relationship between SFI,skin wettedness w and thermal sensation vote TSV and thermal comfort vote TCV was analysed in conjunction with the subjective questionnaire,and it was found that TSV and TCV were all approximately quadratic with SFI,TSV and TCV increased with SFI,and the larger the SFI the stronger the sensitivity of TSV and TCV to changes in SFI,and the upper limit of skin wettability at which the human body felt comfortable was 0.4,the higher the w,the stronger the human thermal dis The stronger the comfort,the higher w increases by 0.4 scales for each 0.1 increase in TCV.In addition,the results of the subjective questionnaire were analysed and it was found that the sensation of sweating on the forehead,upper arms and thighs explained 74.3%of the variation in the overall sensation of sweating.There was a significant correlation between each local heat sensation and the overall heat sensation,with the back and forehead having the highest correlation with the overall sensation.The upper limit of acceptable operating temperature for the subjects through human physiological adaptation was approximately31.1°C.Finally,the skin temperature and evaporative heat dissipation terms of the predictive thermal sensation model PMV were modified to take into account the physiological regulation of the human body,and a modified predictive thermal sensation model m PMV for summer was proposed.The results show that the modified m PMV model meets the prediction accuracy requirements at the application level and can be used for predicting thermal sensation in the natural environment in summer.In addition,the range of thermoneutral temperature difference was also calculated based on the Griffiths method using m PMV,PMV,and TSV,and it was found that the acceptable temperature difference range at one end of the range where the human body makes 80%of people feel satisfied through physiological regulation was expanded by 0.9℃.