Influence Of Metabolic Rate And Air Movement On Human Thermal Comfort

The improvement of living standard and the development process of modernization make people have higher requirements for the quality of building environment.With the vigorous development of indoor fitness,the study of human thermal comfort under high activity volume is very urgent.Unlike sedentary office,the metabolic rate of human body increased in exercise,and the physiological parameters changed obviously.At the same time,the increase of heat storage in the body,the demand for thermal balance of the body makes the demand for heat dissipation also increase dramatically The PMV evaluation standard based on steady state experiment can not accurately judge the thermal comfort above the 4met activity level.Most of the existing research on thermal comfort is still concerned with the state of meditation,and there is few systematic research on stable motion.The only sports thermal comfort research also pays more attention to the instantaneous thermal reaction,and the thermal comfort under the influence of air flow is also aimed at the local airflow and dynamic airflow during the sit-in,which can not provide reference for the design of indoor sports place at higher activity level.China's current building environment thermal comfort standards are based on international standards,not suitable for China's national conditions.Therefore,this study tries to improve the environmental quality of indoor middle sports personnel without affecting thermal comfort,and to improve the energy saving potential of air conditioning system.Through the combination of artificial climate room experiment and subjective questionnaire,the effects of human thermal comfort and airflow on sports thermal comfort in indoor medium intensity motion were studied,and the following important conclusions were drawn: First of all,the experimental results show that the metabolic rate at three paces is 3.0 met,3.6 met,4.9met,and the standard value of 6%-7% at the same level in ISO is higher.In the experiment,the physiological parameters increased significantly with the increase of metabolic rate,in which the heart rate was the most correlated with metabolism,and the metabolic rate could be estimated by the heart rate measurement according to the obtained equation model.The core temperature has slight fluctuation in the working condition except the walking 4km/h,which increases obviously in the other two working conditions,combined with the increase of evaporation heat dissipation and skin wetting degree,the enhancement of human heat storage is greatly affected by the activity amount,and the existing dispersion heat is not enough to counteract the heat produced by the movement,so that the moderate intensity movement of the human Secondly,the statistical analysis results that the decrease trend of comfortable temperature with the increase of activity volume is obvious,and the correlation between thermal sensation,thermal comfort and activity volume is significant.After 60 mins stabilization exercise,the preferred temperature was 23.3,22.8 and 22.1 ? respectively,which decreased by 2.7,3.2 and 3.9 ? compared with the experimental initial temperature of 26 ?.At the same time,it is found that although the relative displacement of the human body makes the convection heat transfer coefficient increase and the thermal resistance of clothing decreases,the thermal sensation of human body increases with the change of motion intensity,but the heat comfort and heat acceptability are in the comfort range.Finally,it is found that airflow has a positive effect on improving thermal comfort in human active state.The results of wind speed regulation showed that the higher the activity of the subjects,the greater the wind speed of regulation.The corresponding human comfort temperature under three kinds of walking conditions increased by 1.6,1.3 and 1.5 ? respectively compared with the non-airflow state,and the increase was larger.No matter the wind,the human body on the air flow acceptability is high,and the airflow to reduce the body's own heat,improve the comfort of the effect is obvious,the perception of air quality results better,cooling and increase the air flow expectations have also been significantly reduced.