Research On The Impact Of Three-dimensional Greening On Carbon Emissions Of Public Buildings In Xi’an

In the context of the long-term goal of carbon peaking and carbon neutrality,controlling greenhouse gas emissions has become a hot spot today.The building sector has always been a key sector for carbon reduction and emission reduction,and as the scale of public buildings grows,CO₂ emissions during their operational phases have become an important part of China’s construction industry’s carbon emissions.Three-dimensional greening provides a new option for carbon emission reduction in the construction industry:three-dimensional greening of buildings aims to reduce carbon dioxide emissions of the building itself,save energy,improve the thermal environment of the building and beautify the environment,etc.Therefore,three-dimensional greening of buildings has become more and more popular in recent years.This paper conducts research and exploration on the impact of three-dimensional greening on carbon emissions and emission reduction potential of public buildings in Xi’an,mainly from the following aspects.Firstly,the concepts related to three-dimensional greening,the calculation methods and models of building carbon emissions are sorted out and reviewed.By analyzing the carbon reduction mechanism of three-dimensional greening,the main influencing factors of three-dimensional greening on carbon emissions of public buildings are obtained.The three-dimensional greening of public buildings in Xi’an was investigated,and the current situation and existing problems of three-dimensional greening in Xi’an were sorted out.The survey results show that office buildings in Xi’an often adopt vertical greening form,and the plant is selected as creeper.The large shopping mall buildings mainly adopt the form of green roofs,and the plants are selected as"arbor and shrub herbaceous"hybrids,and the thickness of the planting soil is between 25-35 cm.Then,the building model was constructed and parameterized,and the Design Builder simulation software was selected and the accuracy of the software and model was verified through audit data.Secondly,the impact of key parameters of three-dimensional greening on the carbon emissions of public buildings（multi-storey offices,high-rise offices and large shopping malls）in Xi’an was analyzed by simulation.The results show that in the simulation scheme,the annual carbon emissions of public buildings are negatively correlated with the leaf area index（LAI）,and the optimal range of leaf area index carbon reduction effect is 2.0-3.0;the annual carbon emissions of buildings have a non-monotonic relationship with the increase of soil thickness（D）,and the optimal range of soil thickness carbon reduction effect is 0.3-0.5m.Finally,six different three-dimensional greening schemes are simulated by Design Builder software to obtain the optimal orientation of three-dimensional greening and the overall carbon reduction of the building.The results show that after the use of three-dimensional greening in the three public buildings,the optimal orientation of the overall carbon reduction effect of the buildings is as follows:north side,north side and south side.The optimal orientation of carbon reduction effect per unit area of building is:east side,north side and roof.According to the statistics of public building area and roof usable area in Xi’an,by 2020,the use of green roofs in all operating public buildings in Xi’an will bring 274,900 tons of carbon reduction,accounting for 3.87%of the carbon emissions of all public buildings.The research results can be used to evaluate and quantify the actual effect and carbon emission reduction potential of urban building three-dimensional greening on carbon emissions in the building operation stage,visually reveal the relationship between three-dimensional greening and carbon emissions of buildings with different indicators,and provide reference for building three-dimensional greening design.