Simulation And Optimization Of Passive Building Enclosure Structure In Severe Cold Area

China is a big country with energy consumption,in which building energy consumption accounts for nearly one third.In recent years,with the implementation of building energy conservation and emission reduction,passive buildings have developed rapidly because of their low energy consumption characteristics.The practical cases of passive buildings show that after being put into use,passive buildings can not only effectively reduce building energy consumption and save social resources,but also greatly satisfy human comfort and improve the use experience.Therefore,this paper studies the passive building envelope in severe cold areas,analyzes the influence of envelope technical parameters and thermal bridge structure on the energy consumption of building itself,power consumption and CO₂emission,and puts forward the optimization range of key technical parameters and the avoidance principle of thermal bridge structure.It provides theoretical reference for the envelope structure of passive buildings in severe cold areas in China,and is of great significance to the development of green buildings and the implementation of relevant policies in China.Firstly,the climatic conditions in severe cold areas are analyzed,and based on the actual investigation,the design energy-saving measures in the studied engineering cases are summarized.The building physical model is established,At the same time,the key performance parameters of building simulation are confirmed according to the building function.Secondly,based on the heat balance method,the Design Builder software is used for numerical simulation calculation,The influences of non-transparent envelope（external wall,roof,floor and internal wall）,external window and window-wall ratio on building itself,power consumption and CO₂energy consumption were analyzed,Furthermore the key technical parameters of each envelope were optimized.Then,the orthogonal test method is used to confirm the influence degree of each envelope on building energy consumption.This paper discusses the influence law of different thermal bridge structure area ratio on parameters and building energy consumption in building envelope,studies the variation of temperature distribution and heat transfer law in walls with different insulation structures,and determines the optimization principle of thermal bridge in passive buildings.Finally,Harbin and Shenyang are selected as representative cities in severe cold areas.According to the optimized building technical parameters and structure,the energy consumption of passive buildings are simulated,the load characteristics and energy saving rates of buildings in Harbin and Shenyang respectively are analyzed,the energy saving rates by analogy method are compared,the optimized energy saving effect are confirmed,Moreover analyze the auxiliary means of passive building application.This study provides a theoretical reference for the design and follow-up study of passive house in the future,and it is beneficial to the development of low-energy buildings in the future.