Study On Thermal Comfort In Cold-Humid Environment And Demand For Heating

The typical weather is cold and humid and it is bad thermal comfort for people living in Hot Summer and Cold Winter.With the rapid development of China's economy,the living standards of the people have increased in this area.More and more buildings adopted split air conditioners,air source heat pumps,and capillary heating facilities.However,a few studies have been conducted to explore the effects of cold environment on human thermal comfort in cold-humid environment,heating period and suitable heating temperature in the southern region.Therefore,this study focus on the effect of cold and high humidity environment on human thermal comfort,exploring the reason that people report the sense of cold-humid,the range of acceptable air temperature and humidity,heating period and comfortable range of heating temperature in hot summer and cold winter area in winter.Prior to the experiment in climate chamber,on-site investigation was carried out in heating office and natural ventilation room in Chongqing University.The results showed that the natural-ventilated room has a harsh environment with average indoor temperature of 12.6? and relative humidity of 50-85%;people preferred to open air-conditioning for heating,the most comfortable heating temperature is about 22.5?,and indoor temperature is between 20.5? and 26.5?.When the temperature of the heating room increases,people expect elevated humidity.Then author conducted two series experimental conditions in climate room in winter.Two series recruited 24 and 20 subjects,respectively,and all subjects are college students from Chongqing University with half men and half women.Series I was designed at 14?,16?,18? and 50%,70%,90% for a total of 9 experimental cases.This experimental protocol involved two step-changes of air temperature and humidity to simulate life scenes that people enter heating room from the naturally ventilated room and then leave for non-heated room.The heating temperature of 22?,24?,26? was adopted in stepstage of series I.Series II has four experimental conditions,including two temperature levels(12?,14?),two relative humidity levels(50%,90%).In two series,the wind speed is less than 0.05m/s,the thermal insulation of the clothing is 1.2clo,and the metabolic level is 1.1met.Additionally,thermal sensation vote(overall and local),humidity sensation vote,shriving and thermal acceptancy were selected to recorder subjects' comfort perception,the moisture content of the subjects' clothing was tested during series I and skin temperature of subjects and microclimate of temperature and humidity between skin and clothing were continuously monitored.Data analysis reveals that the same air humidity level in different air temperature have different impact on human thermal comfort.High air humidity at air temperature of 12? and 14? increases the sense of coldness;however,high humidity at 16?,18? has a positive effect on human thermal sensation.In addition,when subjects enter the same heating temperature room after experiencing different air temperature of cold environments,there is a certain difference in thermal sensation vote.When subjects report 100% thermal acceptability in the heating room of 22?.After subjects experienced heating room and they went to cold and high humidity environment again,their mean skin temperature reached a lower level.The cold-humid environment increases the moisture content of subjects' clothing and the heat loss of the skin.high air humidity result in the higher moisture content of the clothing and reduce the thermal insulation performance.Finally,indoor apparent temperature was obtained by fitting the coupling effects of different temperature and humidity.Analysis of demand for heating showed that the lower limit of the acceptable winter indoor temperature in the hot summer and cold winter climate zone is 17.5 ? under 1.2 clo.After short heating experience,the acceptable temperature is 19 ?,based on this results the heating period was proposed in this study.In real heating environment,people prefer the environment of warmer and medium humidity,so the comfortable heating range based on the demand of temperature and humidity is 21.8-23.5? heating temperature,and the corresponding indoor relative humidity is about 50%.