Adaptive Thermal Comfort Study In Prefab Construction Site Office In Guangzhou

The expanding growth in China will unarguably lead to rapid urbanization.In the process of urbanization in China,the construction of residential buildings,commercial buildings and public supporting facilities is indispensable.It can be speculated that the number of construction projects,construction area,and related employees in China will not decrease or even more in the future for a long time.Due to its convenience and flexibility,prefab buildings are employed to provide temporary office space on construction sites.The indoor environment in the construction site offices is thus of high importance as it directly affects people's comfort and health.At present,the research on indoor thermal environment and thermal comfort is mainly concentrated in conventional buildings such as residence and office,and there is a lack of research on temporary buildings such as prefab houses.Therefore,it is of considerable significance to study the indoor thermal environment and human thermal comfort of construction site offices.This study has guiding significance for the construction and evaluation of the indoor environment of prefab houses.Using the research method of combination of field test and subjective questionnaire survey,this paper conducted filed investigation on the prefab construction site office in Guangzhou,which was divided into three parts:summer,autumn and winter from June 2018to January 2019.In this study,a total number of 1505 valid questionnaires were obtained,including 694 in summer,326 in autumn and 485 in winter.After field investigation,the contents of the questionnaire would be input into the computer,and the environmental parameters of each questionnaire corresponding to the time?take the average value of one minute before and after this time?would be input together,and then the data analysis would be carried out.Firstly,the environmental parameters were statistically analyzed,and the actual situation of the thermal environment in the prefab house was revealed.It is found that the indoor temperature is higher in summer and autumn,and more comfortable in winter.The indoor relative humidity is higher in each season.And the air velocity meets the recommended value of ashrae-55 standard.There is a strong correlation between the indoor and outdoor air temperature in each season.The indoor environment is more affected by the outdoor environment than the conventional buildings.At the same time,the survey results of subjective thermal response of the subjects were statistically analyzed.The subjects'votes on thermal sensation were mainly between-1 and+1.People preferred the"cool"environment to the"neutral"one in summer and autumn,and preferred a"warm"environment in winter.At the same time,the subjects'perception of indoor high relative humidity is not obvious,indicating that the subjects have formed adaptability to high humidity environment.Secondly,the thermal comfort study was carried out.The thermal neutral temperature of people in the prefab house was calculated through three common calculation methods,and the linear relationship between the thermal sensation of the subjects and the indoor operative temperature was obtained.Through probit regression analysis,the preferred temperature of summer,autumn and winter is 26.0oC,25.8oC and 22.8oC,respectively.Compared with the thermal neutral temperature,the preferred temperature in summer and autumn is lower than the neutral value,while the preferred temperature in winter is higher than the neutral value.According to two common methods,the acceptable temperature range and comfortable temperature range of people in the prefab house are determined.Thirdly,a regression analysis of T_c on prevailing mean outdoor air temperature was performed to build an adaptive equation in each season.That show the indoor comfortable temperature has a strong linear relationship with the outdoor air temperature in the three seasons,which shows that the indoor subjects have a strong adaptability to the local climate.Then,through probit regression analysis,the relationship between the temperature off from comfort(T_diff)and the corresponding unacceptable rate was determined.And the indoor acceptable temperature range based on the adaptive equation was obtained.Thus,we build an adaptive thermal comfort model for the prefab construction site office.Finally,the adaptive model of this study was compared with the relevant research,and it was found that the adaptability of people in the prefab house is stronger than that in the conventional building.Finally,the adaptability of two kinds of thermal comfort models was analyzed.We found that the SET*and PMV model are not suitable for the thermal comfort evaluation of the prefab house.Therefore,through a variety of common calculation methods,the neutral value,preferred value and thermal grade of the two models are modified respectively.The revised results of the two models in this chapter make it possible to accurately evaluate the thermal comfort of the prefab house.This paper analyzes the current situation of indoor thermal comfort,establishes the adaptive model,puts forward the suggestion value of indoor environment construction,verifies and corrects the adaptability of PMV,SET*model in the prefab house.The results of this study have guiding significance for the design and improvement of the indoor environment of the prefab house in Guangzhou,and have certain reference value for the establishment of relevant standards.