| In recent years,China’s assembled building has been rapidly developed.However,due to the changes in the construction technology of assembled buildings,there are also a lot of problems to be solved.This paper focuses on energy-saving technologies of assembled building envelope to realize "near-zero energy building(NZEB)”,and extracts key technical issues,such as the integration of heat preservation and structure method,the thermal problems brought by new heat preservation,the realization of near-zero energy consumption index,etc.Through theoretical calculation,the paper proposes technical measures suitable for the integration of assembled buildings and NZEBs in Beijing,to solve the integration and development of the two technical systems.This paper discusses the development trend and main technical indicators of near-zero energy assembled buildings at home and abroad.It also discusses technologies on “high thermal insulation,high air tightness and high heat-breaking performance” for near-zero energy assembled buildings.In order to improve the thermal insulation performance of near zero energy fabricated building envelope,it is required that buildings should have appropriate thermal insulation materials and construction,as well as high performance parameters of the envelope structure,such as the heat transfer coefficient of the exterior wall,roof and window.The paper also explores the thermal treatment technology and solution of prefabricated assembled structure applied in NZEBs.It focuses on the thermal effect of the heat-cut scheme of the external staircase and the selection of the heat-cut material,the difference of the outer windows installed in different parts of the thermal insulation material,and the influence of the thermal insulation wrappings of the parapet wall on the heat transfer coefficient.For each typical thermal engineering case,a solution is proposed.For the air tightness of the building,the paper also analyzes two major air tightness weaknesses of the assembled NZEBs,and proposes the application technology of the assembled NZEBs envelope in air tightness treatment.Meanwhile,the paper uses De ST software for modeling,calculates the energy consumption of the main envelope structure parameters such as the heat transfer coefficient,window-wall ratio,shading coefficient,SHGC value,ventilation frequency of the building model in Beijing area,and analyses and establishes the relationship between the key parameters of the envelope and the building energy consumption.Finally,on the basis of the research and conclusion of previous chapters,the paper puts forward a set of design method and formulation process for the envelope scheme of assembled NZEBs,and carries out application analysis with a case in Beijing.The envelope performance in this cases is analyzed using EQUEST,THERM and other simulation software.A set of design schemes of assembled integral external wall,floor and roof are established.. |
