Study On The Effect Of Metabolic Rate Under The Condition Of Thermal Comfort

The objective factors that affect the human body thermal comfort including air temperature,the average radiation temperature,relative humidity,air speed,metabolic rate and clothing thermal resistance.People often have a feeling like this:in a certain thermal environment,people can keep good thermal comfort when they participate in different intensity activities,in others,human thermal comfort changes greatly even with a slight change of activity intensity.There are different thermal sensations in the different thermal and humidity environment with different activity intensity,which means that people's allowable fluctuation ranges of metabolic rate differ in different environment.As a significant physiological factor which impact human thermal comfort,studying which factors influence the allowable variation range of metabolic rate and which kind of activities are suitable for people in different thermal environment are better to guide people's actual work and living.Additionally,the fluctuation ranges of thermal and humid environment parameters also have different impacts on thermal comfort.In the case of ensure people thermal comfort,researching the interaction of relative factors is good for the setting of indoor thermal and humidity environment parameters according to different areas and different architecture with different functions.Meanwhile,the relative conclusions can provide to set a standard for air-conditioning design parameters and set indoor operating parameters according to different functional architectures which corresponding to different metabolic rate of people.The main research contents of this paper are:1)the fluctuation ranges of body's metabolic rate in different thermal environment under the condition of thermal comfort;2)the human body thermal comfort zone corresponding to different metabolic rate.Based on the body heat balance equation and Fanger's theory of thermal comfort,calculated the allowable biggest metabolic rate and the corresponding allowable variation range of metabolic rate firstly with different thermal and humidity environment under the condition of thermal comfort and analyze the factors which influence the range of metabolic rate preliminary.Then,based on the theory calculation results and preliminary analysis,the simplified mathematical model between thermal environment parameters and the allowable fluctuation range of metabolic rate was established through the adoption of orthogonal test method and multiple regression analysis.In order to verify the validity of theoretical results and simplified model,a questionnaire survey was conducted in Changsha.The theory analysis showed that the thermal and humidity environment factors affect the allowable variation range of metabolic rate in different degree.Through orthogonal test,it was found that the notable degree for metabolic rate in order is temperature,relative humidity and air velocity.There strong linear relationship was determined between these three factors and the maximum allowable metabolic rate by the uses of significant test.Combining the simplified model and the results of questionnaire survey,the comfortable ranges of temperature and relative humidity were obtained which showed that the lower of metabolic rate,the bigger of corresponding limit value of temperature and relative humidity,this simplified model provide a simple and feasible method to determine the metabolic rate of different thermal environment.Through the combination of theory and practice,the corresponding comfortable thermal and humidity environment parameters of different activity types were obtained.According to the apply of new method which determine the indoor thermal environment parameters,analyzed the energy consumption of actual project,found that the air conditioning energy consumption is different with combination of different temperature,relative humidity and air velocity.There is an optimal combination of comfort air conditioning design parameters to achieve the minimum air conditioning energy consumption.Compared with blindly reduce the design temperature,increasing the indoor relative humidity is more advantageous to reduce air conditioning cooling load.These conclusions not only can provide a simple and feasible method to determine the appropriate metabolic rate of human in a given weather condition,but can also provide valuable references to set a standard for air-conditioning design parameters and set indoor operating parameters according to different functional architectures which corresponding to different metabolic rate of people.