Effects Of Air Humidity And Velocity On Human Thermal Sensation In Summer

With the development of the rapid development of national social economy in, therequirements of indoor thermal comfort has become more and more strict. What kind ofindoor thermal environment is comfort, and how to evaluate the human thermal comfortlevel, have been the important areas of the building indoor human thermal comfortstudies. Few studies have been shown that in warm envionments, high air humidity willincrease human thermal sensation, while high air velocity will decrease human thermalsensation. And also, the impacts of air velocity on human thermal sensation haverelationship with air humidity. Therefore, it has very important and profoundsignificance to make fully understand the impacts of air humidity and air velocity onhuman thermal sensation in summer, as well as how to reasonably evaluate the impactsof air humidity and air velocity on human thermal sensation.Heat exchange between human and thermal environment influence humanphysiological parameters, thus produce different human thermal sensation. Therefore,this paper has firstly analysed the effects of air humidity and air velocity on human heatbalance in summer, which make fully understand that how the heat dissipation betweenthe human body and the thermal environment as well as human physiologicalparameters change with air humidity and air velocity in summer.Secondly, Climate chamber experiments were conducted on the effects of airhumidity on human thermal response in warm envionments. Both subjective andphysiological responses of subjects were examed in different air temperatures andhumidity. The results showed that the effects of air humidity on thermal sensation werevery little in neutral envionments, but significant in warm environments. In warmevionments, people felt warmer as air humidity inceases. It is pointed that air humiditywould play a significant important role on determining the accetptable indoor operativetempeature ranges in warm environments. And it has been preliminarily determined theindoor acceptable operative temperature under different air humidity in summer.Through analyzed the relationship between human thermal sensation and humanphysiological parameters, such as mean skin temperature and sweating degree of skin, ithas been clear about mechanism of the effect of air humidity on human thermalsensation in summer.Then, Climae chamber experiments on the influence of air velocity on human thermal response in summer were aslo conducted. Both subjective and physiologicalresponses of subjects were examed in different air velocity under different airtemperatures and humidity. The results showed that elevated air velocity not only canreduce human thermal sensation, but aslo reduce the effects of air humidity on humanthermal sensation. And it has been preliminarily determined the indoor acceptableoperative temperature under different air velocity in summer. Through analyzed therelationship between human thermal sensation and human physiological parameters,such as mean skin temperature and sweating degree of skin, it has been clear aboutmechanism of the effect of air velocity on human thermal sensation in summer.Based on the experiment study, the evaluation of air humidity and air velocity onthermal sensation in warm envionments were analyzed. The results showed that notPMV but SET can be used to evaluate the influence of air humidity and air velocity onthermal sensation in warm envonments. And it pointed that as SET did not consider theeffects of thermal adaptation, it needs to be revised. Revised SET which can be used toevaluate the influence of air humidity and air velocity on thermal sensation in warmenvonments was presented in this paper. In addition, according to the revised SETmodel, the upper acceptable temperatures at different air humidity were given, and alsothe upper air humidity and air velocities at different air temperatures.Finally, the determination methods of thermal comfort zone presented for naturallyventilated spaces were discussed. It pointed out there was a problem about the currentthermal comfort zones, namly that in the process of building adaptive model, researcherdid not cconsider the influence of air humidity and air velocity. Applicable scope of thecurrent thermal comfort zones were analyzed aspected from the air humidity and airvelocity, which indicated that a wide range of changes in the air humidity and airvelocity, as well as different climate zone data aggregation would limit the applicablescope the current thermal comfort zones. Finally, some suggestions were presented onconstructing methods of comfort zone of naurally ventilated spaces.In this paper, the determination and revised method of acceptable temperature insummer was reported that provided an important basis and reference for thermalcomfort standard in our country. Besides, recommendations proposed for thedetermination the method of indoor thermal comfort zone for naturally ventilated spacesin the study will provide guidance to improve the thermal comfort standard.