Research On Carbon Emission Calculation Model Of Green Building Based On Life Cycle Assessment Theory

In China,the construction industry is one of the top three areas of energy consumption and carbon emissions.Although the ratio of carbon emissions from the construction sector to total national carbon emissions has decreased in recent years,total carbon emissions have continued to increase.In the background of carbon peaking and carbon neutrality,promoting the development of green buildings can improve the efficiency of energy resources used in buildings and promote the use of renewable energy,thus reducing building carbon emissions.With the implementation of the new standard General code for energy efficiency and renewable energy application in buildings(GB55015-2021),carbon emission calculation for buildings has become a mandatory requirement,which indicates that the calculation result of carbon emission has become a key element of green building evaluation.However,the calculation model of building carbon emission provided by the Standard for building carbon emission calculation(GB/T51366-2019)is universal,due to the numerous contents in the green building evaluation process in China,if the current calculation model is still used for carbon emission calculation of green buildings,it cannot accurately reflect the special characteristics of carbon emission.Therefore,it is of great importance to construct a calculation model applicable to calculate carbon emissions of green buildings according to the evaluation content and characteristics of green buildings.According to the standard Assessment standard for green buildings(GB/T 50378-2019),green building evaluation is divided into two stages,i.e.,design preevaluation stage and operation evaluation stage.To ensure that carbon emission values are provided at different evaluation stages,this paper proposes to construct a carbon emission calculation model for the planning and design stage and the operation stage.Firstly,from the perspective of the life cycle assessment,the green building is divided into:production and transportation of building materials phase,construction phase,operation phase and disposal phase.Then,the scope and boundary of carbon emission calculation for each stage are defined.Finally,the carbon emission calculation model of green buildings is constructed by combining the Standard for building carbon emission calculation(GB/T51366-2019)and the carbon emission factor method.In the design pre-evaluation stage,carbon emissions in the construction phase are calculated in a quantitative way,and carbon emissions in the operation phase are calculated by means of energy statistics analysis.On the contrary,in the operation evaluation stage,carbon emissions are calculated by means of energy consumption statistics or energy bills.In order to verify the correctness of the building carbon emission calculation model,this paper selects a high school in Tianjin as a case study for carbon emission calculation at different stages,and uses carbon emission intensity(kgCO2e/m2)and annual average carbon emission intensity(kgCO2e/m2 a)as the evaluation index of carbon emission results for carbon emission analysis.The carbon emissions in the design pre-evaluation stage are calculated as follows:677.04 kgCO2e/m2 in the production and transportation of building materials phase,60.33 kgCO2e/m2 in the construction phase,2222.81 kgCO2e/m2 in the operation phase and 6.93 kgCO2e/m2 in the disposal phase,and the annual average carbon emission intensity is 59.34 kgCO2e/m2·a.In the operation evaluation stage,the carbon emission is calculated mainly for the operation phase of the building,and the result is 2194.56 kgCO2e/m2,and the annual average carbon emission intensity is 43.89 kgCO2e/m2·a.Finally,in order to facilitate carbon emission calculation in the future,corresponding carbon emission calculation software is also developed in this paper,and the operation process of the software is briefly introduced.