| Natural ventilation, not consume non-renewable energy, is an effective passive cooling through lowering indoor temperature and taking out humidity gas for human thermal comfort. On the other hand, natural ventilation can provide fresh, clean natural air which conducives to the physical and mental health and meets the psychological demand of the natural exchanges.This shows that natural ventilation is the most economical choice for energy saving, thermal comfort and a healthy environment. So, this is a very urgent problem to research thermal comfort of natural ventilation because it is the basic task on how to apply natural ventilation. Firstly,on the basis of the work of our predecessors, a comparative study of indoor thermal environment and occupants'thermal comfort between rural and ruban natural ventilative residences has been done in the paper by questionnaire survey and field study in the hot summer and cold winter areas of China. Secondly various impact factors of thermal comfort in natural ventialted environment were researched comprehensively and systemly by the use of statistics and the artificial neural network. Finally, basing on the heat adaptation of the theory of natural ventilation environment, thermal adaptive model and thermal comfort zones were founded. In this paper, some innovative results and the main conclusions of the work are followed:(1) For the first time, a field study has been done on indoor thermal environment and occupants' thermal comfort of rural residences in the hot summer and cold winter areas and some basis data attained:①In winter, indoor operative temperature range: 6.06℃-11.24℃, mean 8.57℃. Relative humidity range 68.04%-85.57%, means 78.98%. In summer, air temperature range 28.60℃-31.60℃, mean 30.10℃, radiative temperature range: 28.40℃-31.27℃, mean 29.83℃. Operative temperature range: 28.50℃-31.43℃, mean 29.97℃. Relative humidity range: 62.97%-81.17%, mean 72.07%. Air velocity range: 0.01m/s-0.19m/s, mean 0.10m/s.②Rural residents on expectations of heat in winter are much higher than expectations of cold in summer. The frequency of rural residents accepting thermal environment is higher than the frequency of cold environment, which shows the thermal tolerance of rural residents is stronger to cold tolerance.③In summer, mean clothing insulation is 0.31 clo, metabolism rate is 1.33met and the acceptable thermal comfort temperature range is 15.65℃-30.14℃. In winter, mean clothing insulation is 2.15 clo, metabolism rate is 1.53met and the acceptable thermal comfort temperature range is 8.41℃-15.65℃. Thus, the accepatable thermal comfort temperature range of the whole year is 8.41℃-30.14℃.④Different from the urban residences, rural residences are not closed and are impacted by local weather conditions. Therefore, the thermal comfort level between rural and urban residences is different, and we can not simple extend thermal comfort level of urban residences to the rural areas because the thermal environment adaptability, thermal experience, thermal expectations, economic levels etc have obvious differences.(2) For the first time, a comparative study on indoor thermal environment and occupants'thermal comfort was done between rural and urban residences, some important results are followed:①In winter, indoor air temperature of urban residences is 3.44℃higher than that rural residences, and 2.81℃in summer. Relative humidity of urban residences is 16.2% lower than that of rural residences, and 10.86% in summer. Air velocity of urban residencs is appoximate; andaverge air velocity of urban residences is 0.22m/s in summer. From the above data of rural and urban indoor thermal environment, we can see that the urban's residential indoor temperature and radiation temperature are higher than that of rural residences, largely as a result of urban heat island effect, urban outdoor air temperature is higher than the temperature of rural area.②Thermal accepatable of urban residents in winter is better than that in the summer which was mainly due to urban "heat island". The urban outdoor temperature is higher than the rural outside temperature. Analysising the comparative results of the winter and the summer both urban and rural areas, thermal acceptability of rural occupants is higher than that of urban residents, especially in the summer, this may be due to the rural residents living in local area longer than urban residents, and rural residents are better adapted to the local climate and environment.③In winter, to improve indoor thermal environment, the main measures of urban residents are through the furnace and air conditioning, but the main measures of rural residents are through charcoal buring. So, they are different from the structure of energy consumption. In summer, to improve indoor thermal environment and thermal comfort level, the main measure of urban residents are through electric fans and air conditioners, but the main measure of rural residents are through opening the doors and windows for natural ventilation.④In winter, the neutral temperature of urban residences is 14℃,and the neutral temperature of rural residences is 11.5℃. In summer, the neutral temperature of urban residences is 28.5 ℃,and the neutral temperature of rural residences is 21.5℃.⑤In winter, the acceptable thermal comfort temperature of rural residences is 8.41℃-15.65℃, but 15.65℃-30.14℃in summer. The acceptable thermal comfort temperature of the whole year is 8.41℃-30.14℃because the summer and winter are one of the hottest and coldest season, so we take the lower end of the winter and summer.⑥In winter, the acceptable thermal comfort temperature of urban residences is 14℃-20.25℃, but 20.25℃-32.75℃in summer. The acceptable thermal comfort temperature of the whole year is 14℃-32.75℃because the summer and winter are one of the hottest and coldest season, so we take the lower end of the winter and summer(3) Basing on large samples of data from field study, the order choice model was founed by the statistics for evaluating and predicting thermal comfort of natural ventialtive environment, the main results are as follows:①Solved by the statistical software Eviews, the model was verified the correctness by the measured data. The simulated results show the overall fits well and the small difference between the actual and the predicted value.②Through analysising the data, seven main factors of impacting natural ventilation environmrnt was founded. According to the size of the affected were: indoor air velocity, indoor activity, sex, indoor radiation temperature, outdoor air temperature, indoor humidity and age.③From the analysis of the side value, people's thermal sensation votes aren't equal and asymmetry, and the more away thermal sensation votes zero, the smaller of the width, which indicates that people feel fuzzier on thermal sensation votes, so I consider five grades thermal sensation votes are more scientific than seven grade thermal sensation votes.(4) Thermal comfort in itself is a fuzzy concept, which shows the subjective satisfied feeling to the surrounding environment. It's a subjective psychological reaction under many factors.In the past, people usually want to research thermal comfort basing on measured data and use traditional mathematical method to precise define the blurred boundary of thermal sensations. Such a precise mathematical method to deal with a very vague physical phenomenon gives rise to the inaccurate results. Thermal comfort is a vague physical phenomena, which can only be determined by the fuzzy mathematical method, to describe the vague physical phenomena, and the artificial neural network approach is the most common and effective method to deal with these issues. For the first time, basing on BP neural network model, thermal comfort prediction model of natural ventilation was founfed in the paper. The model have automatic study features, and can analyze various factors on the input-output weight.Measured data shows that the model can better forecasting the human thermal comfot of natural ventilation environment.(5) Compared with the air-conditioned environment, natural ventilation environment must consider the human adaptability of human thermal comfort. A careful analysis of human thermal adaptability is conducted, and an analysis of its application in passive architectural design, the main conclusions are as follows:①Thermal adaptability model and zones were founded in the urban and rural natural ventilation environment of the hot summer and cold winter areas.Urban and rural residential natural ventilation thermal adaptation equation:T_c = 0.67 T_w +10.32T_c = 0.44 T_w +9.17 ,.②Natural ventilation design strategy of urban and rural residences are building storage (night ventilation) + passive solar heating, natural ventilation+mechanical ventilation+passive solar heating.
|
PDF Full Text Request