Statistical Analysis Of Thermal Comfort Factors In Summer For Natural Ventilation Buildings In Xi'an

As one of the passive cooling method,natural ventilation can not only improve the indoor air quality, decrease the incidence of Sick Building Syndrome(SBS), but also reduce the operation energy consumption of architecture. Meanwhile, owing to its particularity of indoor thermal environment in Xi'an area, the dry climate here is great advantage for using of natural ventilation, so it is quite necessary to carry study on indoor thermal environment and human thermal comfort in natural ventilation building in Xi'an area.In this paper,the completely literature review on thermal comfort has been introduced firstly. Then the influence factors and evaluate index of thermal environment and human thermal comfort related to natural ventilation building are analyzed. During the transition season in 2010 from May till September,a practical measurement on indoor thermal environment involved 1035 people was conducted in three types natural ventilation buildings in Xi'an area: reinforced concret structure,brick-concrete structure, and raw-soil structure. The statistical results are as follows:the sex ratio is close to 1:1,indoor air temperature ranges from 24.26-34.49℃,mean radiant temperature is from 23.43-36.9℃,relative humidity is between 34%-80%,air velocity is between 0.05-0.87m/s,thermal isolation of clothing is between 0.2-0.45clo, metabolism rate is between 1.0-1.6 met, and thermal sensation vote(TSV) is between -1.01-3.00.Based on the field study of natural ventilation building and test results,the six direct factors that affect indoor human thermal comfort on the TSV and PMV are stuied quantitatively by using the partial correlation theory. The results showed that air temperature, mean radiant temperature and air relative humidity have high relativity with human thermal sensation,while the air velocity is linearly correlated at a moderate degree. The regression analysis result indicated that air temperature is of great influence in thermal sensation;while the metabolism rate is less than 1.2met and clothing insulation is less than 0.3clo,the effect of mean radiant temperature (MRT) on thermal sensation is significant; when the metabolism rate is less than 1.2met,air relative humidity has significant effect on thermal sensation; when the clothing isolation is over 0.3clo,air velocity has obvious effect on thermal sensation.Finally,the influence of indirect factors such as building type, floor position, and room direction on indoor thermal environment and human thermal comfort are analyzed in charpter 5. The results show that: 1) human thermal sensation is increasing with operation temperature,and operation temperature effect on human actual thermal sensation is more sensitive then its on the predicted thermal sensation;compared with the room facing north,the south room is more obvious influenced by solar radiation,which results to a great difference between actual thermal sensation and predicted thermal sensation; 2) The building type, floor position and room direction has little influence on relative humidity, metabolism rate and clothing isolation,however,have significant effect on air temperature,mean radiant temperature and air velocity; 3) The thermal environment in the buildings with reinforced concret structure and brick-concrete structure tend to fluctuate greatly because of its bad thermal reservation, while the masonry structure building has relative steady thermal environment and the comfort temperature is lower.