Experiment Study On Thermal Comfort Based On Human Metabolic Rate And Skin Temperature

The research on thermal comfort originated from the Pittsburgh laboratory in 1919. The scholars all over the world made a lot of study on it for a century, from the influencing factors to the evaluation indexes, from the building environment to human psychology, thermal comfort becomes a muti-disciplinary research area and plays more and more important role in human life. There are two research directions of thermal comfort, the first is to get the variation of human thermal sensation by studying the direct relationship between human thermal sensation and environmental factors; the second is to study the relationship of human thermal sensation and physiological factors such as skin temperature. The second method is more universal and can reveal the essential law of human thermal sensation. Based on the previous research of thermal comfort, this paper studied the influence of environmental factors on metabolic rate and human skin temperature, and the correlation of the two physiological factors and human thermal sensation.During the experiment, the environmental factors influencing human thermal comfort, human thermal sensation questionnaire, metabolic rate and human skin temperature were collected, while the collected physiological factors were different during different experiment. The SPSS and Origin software were used to analyze the variance of metabolic rate and skin temperature in different environment and the influence of the two factors on human thermal sensation , the processing method include descriptive analysis, variance test and linear regression.The following conclusions are drawn as follows: (1) The measured metabolic rate is higher than that in ASHRAE 55 and ISO 7730; (2). The PMV value calculated by measured metabolic rate is more colse to human thermal sensation when sitting, while the PMV overestimated human thermal sensation at high metabolic rate, and the deviation of PMV and the mean thermal sensation becomes larger with the increasing of the metabolic rate; (3). When the subjects were stepping or sitting, the environment temperature had no significant effect on metabolic rate, while the the environment temperature influenced human metabolic rate significantly when the subjects were ascending and descending the stairs; (4) The metabolic rate increased with air pressure decreasing; (5) The prediction accuracy of PMV decreased with the increase of metabolic rate, at high metabolic rate(M>4met), PMV is not suitable for prediting human thermal sensation; (6) The environmental temperature is the most influential factor of human skin temperature, then is air pressure and velocity; (7) There is a very good correlation between human skin temperature and thermal sensation, but the correlation decreased at higher metabolic rate.