Research On Human Thermal Comfort Under The Action Of Local Air Movement In Thermal Transient Environment In Summer

In recent years,people’s requirements for optimizing indoor environment have been increasing day by day,which will not only affect our thermal comfort and work efficiency,but also have a certain impact on our physical health.Temperature and air movement are two important parameters that determine the quality of the indoor environment.Previous research focused on the influence of the indoor environment with constant temperature on the thermal comfort of the human,but in daily life,the thermal environment in which people live is often dynamic.Therefore,it is of great significance to study the influence of sudden temperature changes on human psychological and physiological parameters,which is the key to rational design of indoor temperature.In addition,air movement as a mean to improve the quality of the indoor environment is very important for improving the thermal comfort of the human.In July 2018,this article created different temperature mutation environments(34-26-34 ℃,34-28-34 ℃,34-30-34 ℃)in the laboratory of Hunan University Building Environment and Energy Application Center.An experimental study of thermal response was carried out on 20 young subjects.We used desk fans to blow the human body locally,and then compared with the control group to analyze the changes of human psychological and physiological response under different mutati on amplitudes and directions by SPSS.At the same time,the relationship between psychological parameter and physiological parameter were analyzed to obtain a prediction model of thermal sensation.In additi on,we obtained the means for human to control the air speed and dynamic regulation of the indoor thermal environment.The results show that when the temperature drops su ddenly,there will be a phenomenon of “cold sensation overshoot”,but there was no such phenomenon when the temperature rises suddenly.Compared with the control group,the thermal response of the human body’s thermal response is more obvious when it is fa lling.Compared with the control group,using a desk fan can stabilize the thermal sensation more quickly,and can improve the thermal comfort,thermal acceptability and the perceived air quality of subjects in a hot and humid environment;compared with psychological response,changes in physiological parameters are lagging.The greater the mutation,the greater the change in the skin tem perature of the subject and the longer it takes to reach stability.After using a desk fan,when the temperature difference is 8°C,the eardrum temperature will increase significantly when the temperature drops suddenly,and decrease significantly when the temperature suddenly rises.The blood oxygen saturation of the human body does not change significantly after a sudden change in temperature.But after using the desktop fan,when the temperature difference is 8℃,a significant change occurred.Combining psychological response and physiological parameters,it was found that in the stable phase,the skin temperature can be u sed to predict the thermal sensation,but in the transient to stable phase,the skin temperature cannot be used to predict the thermal sensation.However,the skin temperature change rate and thermal sensation showed a significant linear relationship.The subject’s preferred air speed under different temperature sudden changes was obtained,which can provide a reference for regulating the comfortable air speed of local blowing under thermal transient environments.The use of desk fans expands the comfortable temperature range of the human body,and the method of dynamic comprehensive regulation of indoor thermal environment was obtained by three aspects of thermal comfort,neutral temperature and energy saving.