Study On Human Thermoregulation Model Based On Local Heat Exchange In Low Pressure Environment

Comfortable and healthy indoor environment has an active role in people’s living.People have been more concerned with their comfortable indoor environment with thedevelopment of society and economy growth. Thermal comfort study can not dowithout human thermoregulation model. Most of the present studies are focused onatmospheric pressure environment. In fact, people will inevitably experience lowatmospheric environment. In the meantime, the heat losses for individual body segmentsare different because of different clothes for clothed body segments and existingnon-uniform thermal environment in people’s living. This paper studies the relatedresearch on human thermoregulation based on local heat exchange in low pressureenvironment. The main contents of this study are as the followings.Firstly, the main physiology parameters of human thermoregulation in low pressureenvironment were analyzed from the standpoint of physiology. And then humanthermoregulation experiments were designed. In the experiments, metabolic rate andlocal skin temperature in different pressure, different activities and differentenvironmental temperature conditions were tested. The relation of local skintemperature with thermal sensation was deduced based on subjective questionnaire. Theregression equations of characterized skin temperature were deduced. It was found thatthe regression equation could be well applied in different pressure environments,different activities and different ambient temperatures.It was concluded that the mean skin temperature would reduced with decreasingatmospheric pressure. But the change of local skin temperature was not consistent asatmospheric pressure changed. Its significance varied with body segments. Metabolicrate increased as atmospheric pressure reduced. In accordance with the change rules ofphysiology parameters, the new expressions of convection、radiation and evaporationheat transfer for individual human body segments were deduced in low atmosphericpressure environment. The new expressions of heat exchange between human andsurroundings based local heat transfers were deduced in low pressure environment;Metabolism was revised for being used in low pressure environment and then the newrelation was introduced in two-node model and the revised two-node model could beused in low pressure environment exactly.Secondly, the change rules of the heat exchange for individual human body segments were analyzed in low pressure environment by using the new expressions ofconvection、radiation and evaporation heat transfer for individual human body segments.And the values of the new expressions and the tradition were compared. Although thevalues of two methods were not equal, the changing trends with barometric pressurewere the same. Furthermore, the heat losses for individual body segments were differentbecause of different clothes for clothed body segments; Meantime the heat lossesbetween human and surroundings for individual body segments were different. Theeffect of heat exchange for individual body segments were very significance whenresearching human thermoregulation model in low pressure environment.Finally, an human thermoregulation model based on local heat exchange wasfounded by establishing physiology parameters, founding heat exchange model throughthe human skin, caculating the values of heat production and the respiratory heat loss. Itwas proved that the new model can be applied to the low atmospheric pressureenvironment and give a more accurate result in all conditions of the experiments. Andthen using the new model, the skin temperature、core temperature and the StandardEffective Temperature of different pressure, different environmental temperature anddifferent activities were calculated. The lines of standard effective temperature in lowpressure environment were drawn. Based on analyzing the changing rules of standardeffective temperature with pressure, the relation of standard effective temperature withmean thermal sensation was deduced and the comfort area of ASHARAE comfortstandard in low pressure environment was established. It is hoped that these methodswould provide some references for thermal comfor research in low pressureenvironment.