Research On Carbon Emission And Carbon Reduction Strategies Of Primary And Secondary Schools In Central Sichuan Based On LCA

Climate warming caused by elevated greenhouse gas(GHG)concentrations has been a serious threat to global sustainable development,reducing GHG emissions has become an important task in today’s world.The energy consumed and GHG emissions generated by the construction industry account for about one third of the global total,bringing great pressure on the environment.The GHG emissions per unit area of public buildings is large,and the number of school buildings as public buildings is steadily increasing.Therefore,the implementation of GHG emissions reduction of school buildings is also one of the ways to achieve the goal of peak carbon dioxide emissions in 2030.Due to the different climate conditions and energy structure in different regions and different building types,there are some differences in carbon emissions of buildings.Based on this,this paper explores the characteristics of GHG emissions in primary and secondary schools in Chengdu,and puts forward emissions reduction strategies to promote the high-quality development of lowcarbon buildings,which plays a positive role in achieving national emission reduction targets.Based on the Life Cycle Assessment(LCA)theory and carbon emission theory,this paper divides the primary and secondary school buildings into four phases : material production and transportation phase,construction phase,operation and maintenance phase,demolition and recycling phase.On this basis,the process-based carbon emission coefficient method is used to establish the LCA model of primary and secondary school buildings.EnergyPlus and OpenStudio energy simulation software are used to obtain the air conditioning energy consumption inventory data in the operation phase.Other inventory data are obtained through field research,engineering drawings,standard specifications and literature.The GHG calculation and composition analysis of a primary school building in Chengdu are carried out.The sensitivity analysis method is used to identify the main factors affecting the GHG emission of buildings.The degree of GHG reduction under different emission reduction measures is discussed.Based on this,the GHG reduction strategies for primary and secondary schools are proposed.Through the research on GHG emissions of primary and secondary schools in Chengdu,it is found that the GHG emissions of building materials production and transportation phase,construction phase,operation and maintenance phase,and demolition and treatment phase account for 37.53%,0.4%,60.45% and 1.62% of the carbon emissions in the whole life cycle,respectively.Among them,the GHG emissions in the building materials production phase accounted for 99.36% of the building materials production and transportation phase;the GHG emissions of construction machinery accounted for 95.24% of the construction phase;the GHG emissions in the operation phase accounted for 88% of the operation and maintenance phase,of which the carbon emissions from lighting accounted for the largest.,accounting for 39.19% of the carbon emissions in the operation phase,and the carbon emissions of equipment and air conditioners accounted for 25.48% and 23.33% respectively;the absolute value of emission reduction brought by recycling building materials waste accounted for 95.98% of the demolition and recycling phase.Qualitative and quantitative analysis was carried out on the influencing factors of GHG emissions at each phase,and it was concluded that there are 14 main factors affecting the GHG emissions of primary and secondary schools.The annual average GHG emissions per unit area was used as the evaluation functional unit,and different influencing factors and emission reductions were calculated.The degree of emission reduction under the measures is found by calculation:(1)extending the service life of the building to 80 years can minimize the carbon emission of the building,and the emission reduction degree is 9.5%;(2)the emission reduction degree of reducing the lighting density is 5.8%;(3)the emission reduction degree of using coal gangue hollow bricks is 2.3%;(4)the emission reduction degree of optimizing roof insulation is 0.29%;(5)the emission reduction degree of optimizing building orientation and reducing transportation distance are both 0.27%;(6)The emission reduction degree of optimizing external wall insulation is 0.25%.Finally,22 GHG emission reduction strategies for primary and secondary schools are proposed.