Study On Dynamic Heat Transfer Characteristics Of Building's Exterior Wall In The Hot Summer And Cold Winter Area

Due to the widespread intermittent air-conditioning and heating operation modes in hot summer and cold winter area in China,coupled with its typical climatic characteristics,a special dynamic building thermal environment is formed in this area,which results in heat transfer boundary of the external wall often shows alternate variation characteristics,and then makes heat transfer of the external wall show dynamic variation characteristics.Therefore,the energy-saving features of the external wall in this area is significantly different from unidirectional heat transfer wall in chilling and cold area.The thermal performance design of external wall in this area should lay emphasis on seasonal change and day-night change,not only to satisfy the thermal insulation in the daytime and thermal dissipation during the night in summer,but also to ensure the heat preservation in winter.Therefore,the study on the dynamic heat transfer process and characteristics of the building external wall in summer and winter in hot summer and cold winter area is of great practical significance for the building energy conservation,which provides guidance for the energy-conservation design of external wall under different thermal environment requirements in this area.Through the continuous monitoring of building thermal environment of typical functional rooms in 2015 summer and winter in Chongqing,to get the general changing rules of building thermal environment in different seasons and different functional rooms.And then determine 6 kinds of testing-conditions,they are "summer-living room","summer-bedroom","summer-office","winter-living room","winter-bedroom","winter-office",as the input conditions of " the test platform for wall dynamic heat transfer performance ".Based on the investigation and analysis on structures and materials of 143 buildings' external walls in Chongqing,combined with the requirements for material,structure and thermal performance in relevant standards,determine 4 kinds of wall structures as the research objects,they are external thermal insulation,internal thermal insulation,sandwich thermal insulation and self thermal insulation,which have the same thickness and heat transfer coefficient.Then set up " the test platform for wall dynamic heat transfer performance ",conduct experiments on wall dynamic heat transfer performance under each condition and wall structure.According to the experimental data of wall dynamic heat transfer performance,make analysis on the wall dynamic heat transfer process under different dynamic thermal environment,make calculation and comparison on heat transfer capacity and heat storage capacity in the walls.And then obtain the dynamic heat transfer characteristics of the different walls separately in the night air-conditioning,evening air-conditioning,and daytime air-conditioning rooms,which provides guidance for the structure design of external wall in hot summer and cold winter area.