Study On The Matching Relation Between Indoor Thermal Environment And Bed Climate Based On Partial Body Thermal Demands

Sleep, as an essential part for human life, closely relates to human health conditions. When humans sleep in winter, the thermal sensation from their heads and covered bodies are affected by the indoor thermal environment and the bed climate, respectively. Previous studies mainly focus on how the indoor thermal environment influences the sleep comfort. Studies on the bed climate and the matching relation between the indoor thermal environment and the bed climate are rarely touched. Hence, this paper studies the matching relation between the indoor thermal environment and the bed climate based on different thermal demands from the head and the covered body. At first, the author introduces heat dissipation models of the human head and the covered body, analyzes their heat transfer processes, the PMV equation are get based on the two-node model; But in the latter, through the experimental verification, it was found that the model had an error; Due to this reason, the author introduces another method to predict the overall thermal sensation. By this method, the overall thermal sensation is predicted based on the partial thermal sensation, that is to say, the overall body thermal sensation can be determined by the head and the covered body thermal sensation. However, a human is in an Non-uniform thermal environment, the overall thermal sensation cannot be used to predict the overall body comfort. Therefore, this paper introduces the unsatisfied rate as an indicator to evaluate the overall body comfort.Later, Based on the different needs of the thermal environment of the head and the covered body, twelve schoolboys are taken as subjects for the experiment. The author tests these subjects’ skin temperature by adjusting the bedding temperature in different indoor temperature and records their thermal sensation and thermal acceptance level. After analyzing the relationship between local thermal sensation and local skin, and the relationship between local thermal sensation and temperature of the local environment, and the relationship between the sleeping thermal environment and the subjective evaluations for partial and overall human body, the author gets the following three conclusions[6]:(1)During sleeping, compared with the thermal sensation from the head, the thermal sensation from the covered body more obviously changes with the skin temperature.(2)During sleeping, the indoor thermal neutral temperature is 14.0℃ and the comfortable indoor operating temperature ranges from 7.0℃ to 21.0℃. The thermal neutral temperature of the bedding climate is 30.0℃ and the comfortable bedding temperature ranges from 27.0℃ to 32.0℃. In addition, compared with the head thermal sensation changing with the indoor operating temperature, the thermal sensation from the covered body more obviously changes with the bedding temperature.(3)Get thermal environment comfort zone based on the human needs of local thermal differences in sleep. The comfort zone considered the thermal environment parameters of indoor thermal environment and bed climate, When the overall thermal sensation is constant, the indoor operating temperature is inversely related to the bedding temperature. Not all the overall sensation between-1 and +1 match the thermal comfort.