Effect Of Activity Level On Human Thermal Sensation

Most research at present on thermal comfort is carried out for the low level ofactivity (sedentary activity) in the indoor environment, while the habitant in officebuilding in real life is not always in a state of sedentary.At the same time, in somebuildings (such as shopping malls, entertainment, stations, lounge, etc.), the crowd is ina state of higher activity levels, changing frequently.The applicability of the existingresearch results onthermal comfort in these cases islimited to the conditions of differentdegrees.The main reason is that at a higher level of the activity, the produce heat andheat transfer process of human body has great differences compared with sedentaryactivity, the phenomenon of unreasonable evaluation or a larger forecast deviationoccurs for the commonly used thermal sensation evaluation index and predictionmodel.Therefore, the study on human thermal comfort in higher activity levels can nolonger follow the previous conclusion under static activity level, and should pay moreattention to the effects of changes in activity level.In order to find out the physiological and psychological response to externalstimuli of human body at higher activity levels, study the influence of changes inactivity levels on human thermal sensation, use the means of experimental researchcombined with questionnaire survey, by the method of mathematical statistics andtheoretical analysis, the influence of changes in activity levels on human thermalsensation in neutral and slightly cool temperature environment is studied in thetransition season (spring).According to the analysis of experimental results, thefollowing draws the main conclusions:1) In the condition of inconstant activity rate, the mean skin temperature could notbe a thermal sensation evaluation index to describe the human thermal sensation.In aperiod of time after the mutation of activity level, the mean skin temperature can’tdescribe the thermal sensation of human bodyaccurately,and the phenomenon of"separation" between the mean skin temperature and thermal sensation occur, which isdifferent from conclusions of studiesforthe sedentary activity.Activity level changesmore frequently, it is more difficult for the average skin temperature to accuratelycharacterize the change of human thermal sensation.2) For the combination of the same level of activities, the sensitivity of thermalsensation to changes in activityis higher for activity down-steps than for up-steps. 3) For different ambient temperature, activity levels have different effect on humanthermal sensation. For the higher ambient temperature, the influence of the change ofthe activity level on human thermal sensationis smaller;while for the lowerenvironmental temperature, the influence of the change of the activity level on humanthermal sensation is greater.4) When the body is not the static behavior, especially at higher activity levels,PMV model cannot accurately predict human thermal sensation, the gap betweenthepredicted and actual values increase with the increase of activity.Therefore, thecorrectional PMV prediction model is presented according to the experimental resultsfor higher activity levels.