Optimization Strategy For Energy Saving Reconstruction Of Existing Buildings In Hot Summer And Cold Winter Areas

China is not only a resource-consuming country,but also a resource-deficient country.How to reduce energy consumption and alleviate the energy security crisis is the direction and goal that many experts and scholars are working hard to explore.With the rapid development of urban architecture and the further improvement of residents’living standards,people have put forward higher requirements for indoor the living environment.The phenomenon of low indoor temperature in winter and high indoor temperature in summer is common in existing old buildings.The main reasons are as follows:no insulation layer is provided in the envelope structure,no outdoor shading measures,and unreasonable selection of indoor shading measures,which leads to the fact that the energy consumption of air conditioning in existing old buildings in winter and summer is much higher than that of new buildings.Building energy-saving renovation measures play an important role in improving indoor thermal comfort and light comfort,and are important measures to optimize indoor environment and reduce building energy consumption.The layout of energy-saving measures should consider the ratio of indoor environment comfort,building energy-saving and economic cost,and quantitative analysis of input-output ratio.In order to obtain high profits,more construction units have invested in energy-saving measures that are seriously inadequate.They arbitrarily choose energy-saving measures or choose low-cost energy-saving materials.The low-cost materials themselves have poor performance and not only fail to achieve the goal of energy conservation,but increases the construction cost,resulting in resources waste.In view of the above analysis,this thesis mainly has the following research content:1.Taking an old residential district in Chengdu as the research object,and sets up energy-saving measures according to the regional climatic characteristics,so as to carry on the energy-saving transformation and analysis scientifically and reasonably.2.The window and wall of the enclosure structure of the old residential area is relatively small,and the thermal insulation measures of the wall structure play a leading role in the indoor environment.Therefore,through the investigation of the commonly used thermal insulation materials,this thesis finally selects five thermal insulation materials as the thermal insulation layer of the wall,and based on Energy Plus energy consumption analysis software,the influence mechanism of different materials on indoor temperature was studied.3.The windows can exchange directly with the outdoor environment,and the outdoor sunlight can enter the room through the windows in summer,which leads to the increase of indoor temperature and heat load.Therefore,the external window shading measures can effectively block the sun and reduce indoor heat load.On the basis of the Energy Plus software,this thesis studies the influence mechanism of each shading measure on indoor thermal and light comfort environment.4.Natural ventilation strategy can be adopted,when the temperature of outdoor environment is suitable in summer.Ventilation strategy through thermal pressure and wind pressure difference for indoor and outdoor air exchange,can effectively reduce indoor thermal load,reduce indoor temperature,and reduce air conditioning energy consumption.5.At the end of the thesis,the optimal combination of various strategies is carried out,and the indoor environment temperature,humidity,CO₂ concentration,thermal comfort and comfort ratio under the combination of various strategies are analyzed and combined with economic analysis.It is found that when the combined strategy of insulation layer（roof 30mm rock wool board+external wall 30mm rock wool board）+active external shading（length:the same window length;width:1300mm）+internal shading（cloth shading）+external glazing（6+12+6,low-e insulating glass）+natural ventilation is adopted,The effect of energy saving is the best,the annual energy-saving rate can reach 30.78%,and the cost can be saved about707,000 yuan in the remaining life cycle of the building,thus effectively saving resources,protecting the environment and alleviating the energy security crisis of our country.