Experimental Study On Thermal Comfort Of People Under Physical Activities

Indoor Thermal Comfort is a subject which has been concerned deeply by researchers all the time.Generally,most of studies on Indoor Thermal Comfort concentrate on workers who are engaged in mild activities.While,the workshop workers often carry out repetitive physical activities in daily work.Firstly,a good work environment is conducive to improve labor efficiency and keep healthy of workers.Secondly,at present there are few studies on Indoor Thermal Comfort in a dynamic way.I written this paper because the mentioned reasons.The completion of the paper is on the basis of simulating workshop's weather condition and working situation and of testing Indoor Thermal Comfort in summer and winter operating condition.In the process of the test,we gathered the environmental parameters and workers' physiological parameters(metabolic rate,skin temperature etc.).We also made a questionnaire among some subjects and conducted a data collection.Then the main step was data processing.At the beginning,the bad values were eliminated by data processing software.Through the analysis software “Origin” and “SPSS”,the data's T test,normality test,descriptive analysis and regression analysis have been studying until now.Finally the study focused on analyzing how different physiological parameters change with the variation of metabolic rate.At the same time,the temperature intervals of indoor thermal comfort were calculated by means of regression analysis and the predictive veracity of PMV is also analyzed.The study gives the following findings through different data's analyses:(1)With the increasing of ambient temperature,the workers' metabolic rates could have a little increase in the same working condition.But the change is small and it indicated that ambient temperature has little influence on metabolic rates.Male worker's metabolic rate is higher than female worker's in the same working condition.(2)Within 1.3-2.8 met,first introduction test result is when workers are in winter operating condition.At 12?-15?,the skin temperature decreases with the increase of metabolic rate.At 18?,the skin temperature would rise at first and then decrease when metabolic rate increases.It is because the temperatures of 12?-15?are lower.Between this temperature interval,physical activities attenuate clothing thermal resistance and strengthen convective heat transfer resulting in the decrease of skin temperature.At 18?,there is less loss of human sensible heat at the beginning.So more heat is produced with the increase of metabolic rate and it makes skin temperature rise.When metabolic rate continue to increase,heat dissipation is reflected by perspiration and the skin temperature drops.In summer operating condition,skin temperature would rise when metabolic rate increase at 25?.Though metabolic rate has a rise,the slight sweating makes less heat loss and the skin temperature continues to increase.The same as at 18?,the skin temperature could rise at first and then decrease when metabolic rate increases at 28-31?.At fist when metabolic rate rises,skin temperature increases too.When metabolic rate increases to a certain degree,skin temperature has a fall on the contrary,because high-level sweat increases heat release.(3)Using PMV to analyze human thermal sensation would not work exactly right when people are in working condition.In fact,the rise of metabolic rate can enlarge the predicted deviation of human thermal sensation.(4)The study shows the comfortable interval is 14.5?-17.5?in winter operating condition while in summer operating condition the interval is 23.5?-24.5?,which is conducive to setting workshop's temperature.