Study On Indoor Thermal Environment Of University Dormitories In Hengyang

Dormitory is the main activity place for students.The hot and humid environment in the dormitory directly affects students’physical and mental health and learning efficiency,and a comfortable dormitory environment is becoming an urgent need for students.This paper takes a college dormitory in Hengyang as the research object,studying and analyzing the thermal environment in dormitory by means of questionnaire surveys,field tests and numerical simulations,thermal environment problems are found and some improvement measures are proposed.The main research conclusions are as follows:（1）The result-analysis of the questionnaire survey on the indoor thermal environment in dormitory shows that the thermal comfort of the dormitories in winter and summer is low under natural ventilation,and62.63%of the students are dissatisfied with the thermal comfort in dormitory in summer;and 52%of the students are not satisfied with the thermal comfort in dormitory in winter.Most students choose air-conditioning as a measure to improve the thermal environment of the dormitory.90%of students were satisfied with the thermal comfort in air-conditioned dormitory in summer and 80%of students were satisfied with the thermal comfort in winter.（2）The field test and analysis of the thermal environment parameters in dormitory show that the temperature in dormitory on different floors in summer varies between 29℃and 35℃,and the humidity varies between 60%and 85%,The temperature in the dormitory in winter varies between 13℃and 16℃.and the humidity varies between 60%and 70%,The temperature and humidity in the dormitory in winter and summer do not meet the requirements of comfort standards.Combined with the subjective thermal comfort evaluation of the students,the necessity of improving the heat and humidity environment of the dormitory in winter and summer is verified.Secondly,the influence of air-conditioning supply air temperature,operating time and number of residents on the thermal environment in the air-conditioned dormitory is tested and analyzed.The results show that the indoor temperature and humidity are more evenly distributed under different air supply temperatures in summer.When air is supplied at 26°C,the thermal comfort in the dormitory is the best and it helps to save energy.In winter,the higher the air-conditioning supply air temperature is,the greater the vertical temperature difference in the room will be,and the lower the temperature in the lower personnel activity area will be.Only increasing the air supply temperature has no obvious effect on the lower area temperature.On the contrary,it increases the air-conditioning energy consumption and reduces the local comfort of the personnel.The CO₂concentration in the air-conditioned dormitory is directly proportional to the number of occupants and the metabolic rate,and the air-conditioning operation has a certain effect on the CO₂ concentration distribution.（3）According to the analysis of the thermal comfort of college dormitory in Hengyang,the thermal neutral temperature of dormitory personnel in summer is 26.3℃,and the acceptable temperature range is23.5℃～29.1℃.The thermal neutral temperature of dormitory personnel in winter is 19.4℃,and the acceptable temperature range is 16.8℃～21.9℃.Based on the calculation of adaptive model APMV,the summer adaptive coefficient of the dormitory in Hengyang area isλ=0.28（PMV>0）,and the winter adaptive coefficient isλ=-0.334（PMV<0）.Based on this,the internal thermal environment of the dormitory in Hengyang area in winter and summer without air conditioning and under the air conditioning environment is evaluated.（4）Fluent simulation is used to analyze the influence of individual building design under natural ventilation in Hengyang transition season and the use of air conditioning in winter and summer on indoor thermal environment.It is found that under natural ventilation in transition season,the best angle between building orientation and dominant wind direction should be 30°～60°,which is conducive to the airflow into the room.A reasonable architectural plan space design can reduce the influence of the opening of doors and windows on the windward side on the leeward dormitory,so that the leeward dormitory can obtain a better wind environment.The use of unclosed balconies can increase the wind pressure difference on the leeward side of the building,and better induce airflow into deeper indoor areas.Increasing the air supply angle of the air conditioner in winter and summer can reduce the vertical temperature difference in the room and improve the temperature of lower personnel area.The best horizontal installation position of the air conditioner in the dormitory is the middle of the room.