Study On Thermal Comfort And Energy-saving Potential Of Residential Buildings In Huizhou Area

With the enhancement of people’s living standard, people pay more attention on indoor thermal comfort. Subsequently, building energy consumption has increased dramatically.But it is not a wise choice in the background ofglobal energy crisis and domestic energy shortage. Currently, “energy-saving and emission-reducing” is the established principle and policy of Chinese Government, which forces people to seek strategies of saving building energy. Natural ventilation is the kind of energy-saving strategy which not only saves energy but also meets the requirement of indoor thermal comfort. But the ranges of indoor comfortable temperature accepted by people who live in different places of China have dramatic differences. So, it is very meaningful to study indoor thermal comfort and energy-saving potential for residential buildings when the ventilation mode of buildings isnatural ventilation.This paper firstly introduces and summarizes domestic and international research contentson residential buildings comforton condition of natural ventilation, meanwhilesummarizes current research on building environment and energy-saving in Huizhou area, then points out the disadvantages of these researches and puts forward the contents and focus of my study.In the second chapter, the paper introduces the basic theory of thermal comfort, including the factors influencing on thermal comfort, evaluation index, evaluation model and evaluation standards. By comparision, this paper chooses PMV-PPD and operating temperature as the evaluation index, takes the Fanger thermal comfort model for evaluation model, and uses ASHRAE 55 and ISO7730 as well as evaluation standard for indoor thermal environment in civil buildings as the evaluation standardThe third chapter summarizes the characteristics of buildings and climate in Huizhou area, noting that the climate of Huizhou area belongs subtropical monsoon climate, the annual average temperature is 15.8 ℃, annual average relative humidity is 79%, and the average annual rainfall is 1759.7mm, the average annual sunshine time is 1815.7h. Because of long time of annual sunshine, high temperature and big rainfall makes most time of all the year hot and humid in Huizhou area, and Huizhou architecture is one of the most representative building types in southern area of China, its main features include :① Its location is surrouded by water and mountain;② Its layout is compact and the distance between adjoining buildings is very short; ③ It has white wall and black roof of architectural style and patio, Matou wall and others of architectural elements that have great features.Chapter four mainly adopts questionnaire survey, field measure and CFD simulation study thermal comfort of residential building under the condition of natural ventilation. the results show that: ① the effect of humidity on the thermal comfort of inhabitants in huizhou area is not obvious, and the residents huizhou area can stand higher humidity than others;② because the wind is not big, it has little influence on the thermal comfort of local residents;③ temperature has decisive influence on thermal comfort of local residents, according to the survey on the thermal sensation, among the 82.05% of the respondents who are basicly satisfied with temperature, 74.94% of them are satisfied with the thermal environment.④ under the condition of natural ventilation, The range of comfortable temperature accepted by 90% of residents in Huizhou area is from 21.22 ℃ to 21.22 ℃, and the range of comfortable temperature accepted by 80% of residents in Huizhou area is from 16.92 ℃ to 16.92 ℃.5. The layout of traditional dwelling buildings in Huizhou area is not very conducive to natural ventilation. The CFD simulation of wind environment of the buildings shows that different directional wind has different influence on ventilation effect; the southwest wind can promote natural ventilation better than the South wind. The main ventilation codes of residential houses in Huizhou area are that: In the day wind pressure and thermal pressure drives natural ventilation; at night, the door is closed, the power drive natural ventilation is thermal pressure caused by difference of temperature inside and outside of the patio.Chapter five mainly analyzes energy-saving potential of residential buildings in Huizhou area by software. The results are as follws: ① Under the condition of natural ventilation, the time in which 80% of local residents are satisfied with thermal environment is 2463 hours, and the time in which 90% of local residents are satisfied with thermal environment is 1735 hours, which indicates that under condition of natural ventilation the number of hours to meet the human thermal comfort is small. ② The shading measure and the measure of passive solar heating + high heat capacity of materials have the great potential of energy savings, and they can increase 969 hours and 691 hours of comfortable time. ③ The shading measure has greatest effects of energy-saving in the time from May to September, and the time that the measure of passive solar heating + high heat capacity of materials has best effects of energy-saving is from January to July and September to December.④ In summer, energy consumption of air conditioning will significantly reduce with the increase of the setting temperature of air-conditioning, and significantly increase with the increase of the ratio of window to wall. When the ratio of window to wall is 0.2 and the setting temperature of air-conditioning T=26℃, energy consumption saves 17.98% than T = 24℃. ⑤ Energy-saving effect of indoor shading measure is not significant, probably saving may also increase energy consumption of air conditioning.⑥ Outdoor shading measure remarkablly saves energy consumption of air conditioning, when the air temperature T = 26 ℃,the ratio of window to wall is 0.2 energy consumption of air conditioning is smallest,and energy consumption saves 66.97% compared with energy consumption of residential buildings that have no shading measure.