Research On Carbon Emission Calculation And Emission Reduction Measures For Urban Housing Based On Life-cycle Assessment

In recent years,climate change,frequent extreme weather events,and excessive greenhouse gas emissions have warmed the global climate system,and such environmental issues have become the focus of world attention.According to the United Nations Environment Programme,the construction industry consumes about 30-40%of the world’s energy and emits almost 30%of the world’s greenhouse gases,posing a huge challenge to the global climate and environment.In his speech at the Leaders Climate Summit,President Xi Jinping emphasized that China is developing a carbon peak action plan.The construction industry,which accounts for more than 40%of the country’s total carbon emissions,has a great responsibility to achieve carbon peaking by 2030.Controlling carbon emissions from buildings is an important means to reduce the total national carbon emissions,and the large volume of construction of residential buildings,as an important component of cities,has a great impact on energy saving andemission reduction in the construction field.Based on this,this paper studies the characteristics of the whole life cycle carbon emission composition of urban housing and proposes relevant carbon emission reduction countermeasures,which is of certain significance to achieve the national carbon emission reduction target.Firstly,based on the principles and framework of Life Cycle Assessment(LCA)and the research results of scholars,the whole life cycle of a building is divided into five stages:planning and design,preparation of building materials,construction,operation and maintenance,and demolition and disposal,to determine the method and structure of building life cycle assessment and define the main sources of carbon emissions in each stage of the building life cycle.Secondly,we analyze and select carbon emission calculation methods based on domestic and international carbon emission calculation standards,and construct a carbon emission evaluation model based on LCA for the whole life cycle of a building.Then,a high-rise residential building with reinforced concrete structure in Xi’an is selected as the case building,and the carbon emissions of the whole life cycle and each stage of the residential building are calculated.Again,the carbon emissions and composition characteristics of each stage of the whole life cycle of the case building are analyzed,and the main influencing factors of carbon emissions in each stage of the whole life cycle are screened.The results of the study found that the four phases of the building’s life cycle:operation and maintenance,building material preparation,construction and construction,and demolition and disposal,accounted for 78.05%,20.59%,0.61%,and 0.75%of the carbon emissions,respectively.In the operation and maintenance stage,the carbon emissions caused by heating,air conditioning and refrigeration,and lighting were 59.59%,17.49%,and 14.31%,respectively,and in the demolition and disposal stage,the carbon emissions caused by demolition machinery,waste recycling,and waste transportation were 1.61%,92.34%,and 6.05%,respectively.Finally,based on the sensitivity analysis of the research results,the emission reduction countermeasures for urban residential buildings are proposed from the whole life cycle perspective.