Study On A Thermal Regulation Model Of Thehuman Body Under Direct Sunlight Exposure

Modern buildings often use transparent enclosures,such as glass curtain walls,for aesthetic purposes and to enhance natural lighting.However,this can lead to a large amount of solar radiation entering the room,distributed asymmetrically,which can cause thermal discomfort for indoor personnel.This study aimed to simulate the thermal physiological response and thermal comfort state of personnel under direct solar radiation by establishing a thermal regulation model of the human body.This provides a reference for evaluating the thermal environment under the influence of solar radiation.Based on the two-node model,this study updated the boundary conditions for calculating thermal environment parameters by distinguishing direct and non-direct areas.It also calculated the local skin temperature distribution under the influence of solar radiation and introduced the local heat transfer coefficient to improve the accuracy of the calculation of the amount of short-wave radiation absorbed by the human body.The study used MATLAB programming to establish the thermal regulation model of the human body under direct solar radiation.The model was experimentally verified,and the study showed that the simulation accuracy was high,with a relative error between the simulated and experimental values of skin temperature within 5%.The model was also used to study the influence of different wind speeds and different activity levels on the skin temperature of personnel under solar radiation.In view of the results,this study selected the standard effective temperature based on the skin temperature change to study the solar radiation thermal comfort zone.The study adopted the PMV correction method under solar radiation and drew on the criteria of PMV thermal comfort zone division to study the thermal comfort zones of different activity levels of the human body under direct solar radiation based on the standard effective temperature.The study showed that the thermal comfort zone of personnel at a radiation intensity of 400 W/m2 was lower than that of personnel at 200 W/m2 in a sedentary state,and the acceptable ambient temperature was 2℃ lower than that at 200 W/m2.As the activity intensity increased,the thermal comfort zone shifted downward and had a wider range,and the human body could still maintain a comfortable state within a certain low air temperature range.The model was also used to analyze the heat exchange characteristics of sitting personnel in a direct sunlight room.The study showed that the greater the intensity of solar radiation,the greater the convective heat exchange between the human body and the external environment,and the radiation heat exchange decreased.When the intensity of solar radiation was the same,the overall convective heat exchange between the direct human body part and the surrounding environment was larger,and the long-wave radiation heat exchange was smaller or even negative.The model predicted changes in heat exchange of the human body in a direct solar radiation room,which were consistent with the performance of an actual human body.Furthermore,this study conducted a correlation analysis of subjective responses and physiological parameters of active persons in the direct sunlight room to investigate the significance of subjective responses and physiological parameters of the human body under the coupling effect of activity level,radiation intensity,and both.