Research On The Energy-saving Retrofitting Path Of Existing Houses In Xi’an City Based On Ecological And Economic Benefit Evaluation

With the rapid development of society and economy,carbon peak and carbon neutrality have become a hot topic in the world.The rapid development of the early construction industry led to huge energy consumption and a large amount of carbon emissions,contrary to the carbon emission reduction commitment of the current Paris Conference of China.As the stock of urban buildings is huge,the energy-saving renovation of existing buildings will become an important measure to reduce carbon emissions rapidly,among which the stock of urban existing residential buildings takes the first place.Therefore,the energy-saving renovation of urban existing residential buildings has become the only way for China’s construction industry to achieve carbon peak as soon as possible.This paper selects the existing residential buildings in the South Campus of Xi ’an University of Architecture and Technology.There are existing residential buildings from1960 s to 1990 s in this area.Over time,most of the buildings have needed repairs or remodeling.After investigation,it is found that the renovation measures of existing residential buildings in Xi’an are all the same — "affixed external insulation",without fully considering the influence of the characteristics of the external protective structure performance,house type and shape coefficient of the existing residential buildings in different ages on human thermal comfort,energy consumption and carbon emission.(1)This paper combed the development history of building energy conservation in Xi ’an,analyzed the building materials,structure,house type,envelope structure performance,energy conservation standards and other information of the existing residential buildings in different ages,and divided the existing residential buildings in Xi’an into five stages to provide support for the case analysis of typical buildings.Based on the summary of the characteristics of existing residential buildings in Xi ’an and the open source data of map software,the distribution characteristics of existing residential buildings in Xi’an are sorted out,and the spatial-temporal data model of existing residential buildings in Xi ’an is established.(2)According to the characteristics of existing residential buildings in different ages,energy-saving reconstruction scenarios were set to meet the requirements of 30%,50%,65% and 75%.Select the typical existing residential buildings of different ages to analyze the suitability of energy conservation renovation technology with different measures.Through the evaluation of the thermal performance of the envelope structure,the energy saving target scenario satisfied by the energy saving reconstruction measures is calculated.(3)The ecological economic benefit model of energy-saving renovation of existing residential buildings in Xi ’an is established to optimize the technical suitability of energy-saving renovation measures of existing residential buildings in different ages.The results show that for existing residential buildings without energy saving measures before1989,140 mm rock wool board should be added for external wall insulation,150 mm XPS insulation layer should be added for roof insulation,and plastic steel Low-E hollow Windows should be replaced for external Windows.For existing residential buildings between 1989 and 1997,140 mm thick rock wool board should be added for external insulation,180 mm thick XPS insulation layer should be added for roof,and plastic steel Low-E hollow Windows should be replaced for external Windows.For existing residential buildings between 1998 and 2000,140 mm thick rock wool board should be added for external insulation,and 180 mm thick XPS insulation layer should be added for roof.It is suggested that buildings without exterior window reconstruction should replace plastic steel Low-E hollow Windows for exterior Windows.(4)Combined with the calculated data in Chapter 4,this paper analyzes the carbon reduction rate of the energy-saving renovation of existing residential buildings in Xi ’an.By comparing the influences of different energy-saving scenarios,renovation cost input,technical suitability and remaining life on the carbon emission reduction rate during the life cycle of the energy-saving renovation,suggestions are put forward for the renovation strategies of existing residential buildings in Xi ’an in different eras.Based on the above results and combined with the stock of existing residential buildings to be reconstructed in Xi ’an,the carbon emission reduction path for the energy-saving reconstruction of existing residential buildings in Xi’an with low cost,medium and low cost and high cost input is formulated.The results of this study can provide data reference for the energy-saving renovation of existing residential buildings in Xi’an.