Study On The Effective Influence Distance Of Urban Grey-green Space Compact Form On Building Energy Consumption And Optimization Strategies

As the urbanization of China process continues to accelerate,the growth of Building Energy Consumption Carbon Emission（BECCE）will have a negative impact on the construction of low carbon cities.Urban is a complex socio-economic-natural ecosystem.It has been shown that four main factors influence carbon emissions from building operations:building characteristics,socio-economic conditions,regional climate and local microclimate;Some studies have also shown that the external space of urban buildings,including green space and grey space of building,drives the change of carbon emissions of urban building energy consumption by influencing external microclimate conditions（e.g.temperature and humidity environments）.Although microclimate will not contribute significantly to the energy consumption of energy buildings,the difficulty of retrofitting through the external greenness and greyscale spatial form of buildings is relatively low compared with cost.Therefore,it is important to investigate the most effective carbon emission influence distance of building energy consumption for urban green space and grey space of building.Then to explore the optimal urban gray-green space compactness within the range of the most effective influence distance will be great significance to reduce carbon emissions from building energy consumption and assist in the achievement of carbon peaking and carbon neutrality goal.With the rapid development of cities,there is a more significant compact trend towards urban grey space.In this context,this study analyses the impact of carbon emissions from energy consumption in urban building operations by taking the compact form as the main urban spatial form.Firstly,the green space compactness index（GSCI）was established to represent green space compactness.Three-dimensional building space compactness（3D-BSCI）was developed to characterize building space compactness.Secondly,135 typical office buildings in China are taken as samples to construct a buffer with the building as the center and a step length of 50m.A total of 20 buffers are established within 1km,and the city GSCI and 3D-BSCI within each buffer are calculated.Thirdly,for 20different buffers,the partial least squares regression（PLSR）and Geo Detector（GD）were used to explore the driving relationship between urban form and building energy consumption carbon emission and to obtain the effective distance.Fourth,the application of geographic detectors and other methods to analyze how to achieve building energy consumption carbon reduction through form optimization within the range of effective distance.The main conclusions of this study are as follows:（1）Using PLSR and GD,the most effective spatial influence distance of urban grey-green spatial compactness on BECCE was determined based on the different contributions of green space compactness and building space compactness on BECCE in different buffer zones.The most effective emission reduction buffer distance of urban green space compactness for BECCE is 250m.The most effective emission reduction buffer distance of urban building space compactness for BECCE is 150m.Urban green space compactness and grey building space compactness have nonlinear enhancement effects on BECCE and the buffering distance is the strongest at 250m.Therefore,the most effective emission reduction buffer distance of urban gray-green space compactness for BECCE is 250m.（2）Based on the boosted regression tree（BRT）analysis,it is found that the interaction of urban grey-green space compactness has a common effect on BECCE.Under the combined action of urban green space compactness and grey space compactness,BECCE is the lowest when urban GSCI is in the range of 0.33-0.37 and 3D-BSCI is in the range of0.004-0.01.This range is the optimal urban grey and green compact form,which will achieve the highest carbon emission reduction ability to reduce building energy consumption.（3）GSCI and 3D-BSCI with 250m buffer distance are divided into five categories.Class I is the lowest compactness,and Class V is the highest compactness.The results of risk detector based on geographic detectors put forward reasonable optimization strategies for urban grey-green space compactness:green space compactness Class I to Class II,III,IV and V,and Class III to Class IV can effectively reduce 650-750 t CO2within 250m buffer.The optimization of urban building space compactness from Class II to Class I in 250m buffer zone can effectively reduce 550 t CO₂.By optimizing the grey-green space compactness around the office buildings,the Building energy consumption carbon emission can be effectively reduced and the low-carbon sustainable development strategy of the city can be realized.Using multiple sources of data and various methods,the most effective spatial influence distance of compact form of urban green space,compact form of grey space and compact form of coupled grey green space on building energy consumption carbon emission and the optimal urban grey-green space were determined compactness.In addition,within the influence range of effective space,the most efficient urban operation energy consumption carbon reduction can be achieved through effective grey-green space compactness adjustment.This study provides a path based on the compact shape pattern of urban greenness and grey space for the carbon emission reduction of building operation energy consumption.The research results will provide data and strategy support for the optimization of urban spatial form and the win-win situation of low-carbon city construction.