Thermal Analysis Of Thermal Bridge On Exterior Wall Of Prefabricated Steel Structure Residence In Suzhou Area

The prefabricated steel structure residence is a sustainable building form with green and environmental protection characteristics,and its structural system can fully meet the needs of residential industrialization development.The Ministry of Housing and Urban-Rural Development of the People’s Republic of China listed the promotion of prefabricated steel structure houses as one of the current key tasks in the work conference held in 2020.Due to the late start of domestic prefabricated steel structure houses,imperfect technology,high thermal conductivity of steel,and prominent building thermal bridge problems,they have a greater impact on building energy consumption.Therefore,the thermal analysis and energy-saving optimization design of the thermal bridge of the prefabricated steel structure residence need to be further studied.This paper takes prefabricated steel structure residences in Suzhou area as the research object.Through the investigation of actual cases,it is concluded that the steel structure system version 3.0 of the Fosun Cultural Tourism Taicang South Station plot project has a certain degree of universality,through the temperature control box-heat flow meter method Field measurement shows that there are thermal problems in the thermal bridge of the external wall,which needs further study.This paper uses FLUENT software to simulate the thermal bridges under different conditions,and then adopts the method of comparative analysis to find the first-rank measure to optimize the thermal bridges of exterior wall of prefabricated steel structure residences in Suzhou area.In this paper,firstly,the steady-state heat transfer simulation of the column angle thermal bridge,column thermal bridge and cross-inclined rod thermal bridge in the outer wall is carried out,and the internal surface temperature and heat flux density of the thermal bridge node under different wall materials are obtained,and the condensation analysis is carried out.As well as the calculation of the area affected by the thermal bridge and the degree of heat loss,a suitable wall material is selected through comparative analysis.Then this paper further optimizes the thermal performance of the thermal bridge of the external wall from the three aspects of thermal insulation form,thermal insulation material and local structure optimization.According to the research,in the form of external insulation,the minimum temperature of the inner surface of the thermal bridge is higher than that of the internal thermal insulation and the sandwich thermal insulation,and the affected area and heat loss of the thermal bridge are less than the other two forms.Therefore,the external thermal insulation is the best Insulation form.Form: EPS board,XPS board,SEPS,ROXUL and foamed cement board are very close to the improve thermal performance of the thermal bridge;local structure optimization adopts local external insulation methods of 20 mm and 30 mm thickness,The thermal bridge affected area and heat loss degree of the thermal bridge are significantly reduced.Finally,this paper uses PKPM green building energy-saving software to compare and analyze the energy consumption of the optimized plan and the original project plan.When all the external thermal insulation forms are adopted,the building energy saving rates under the five external thermal insulation materials are 2.5%,3.5%,3.3%,1.8% and 2.1%respectively.Under comprehensive consideration,rock wool board and foamed cement board are the best suitable materials.The building energy-saving rate when using 20 mm and 30mm-thick partial external insulation design is 2.5% and 2.8%,respectively,and the energy-saving effect is considerable.