Research On The Optimization Of Street Configuration Planning In Xi'an's Main Urban Area Based On Evaluation Of Solar Potential

The built-up environment area of global cities occupies 3% of the total surface area of the earth,but consumes 75% of natural resources and produces 60-80% of global greenhouse gas emissions.As the main battlefield of carbon reduction goals,cities face imminent energy transformation issues.Improving the utilization efficiency of renewable energy in the urban built environment is the key.Solar energy is the most available type of renewable energy in urban built environment.As an important space type in the urban built environment,the street canyon accounts for up to 30% of its space.Compared with the solar potential of the roof of the building,the facade of the street canyon building also has huge development space for solar potential.In the field of urban planning,the use of planning techniques to control the shape of the street to increase the solar potential of the facade of the street canyon building will help the overall efficiency of renewable energy utilization in the urban built environment.This paper takes the sample of street canyons in typical cities of Xi'an as the research object,quantifies the planning elements of the street canyon geometry and simulates the solar energy potential of the street canyon building facades,expressed in terms of solar radiation.On this basis,the correlation between the two is further analyzed to determine the key geometric shape planning factors and optimal parameter ranges that affect the solar energy potential of street canyons.Finally,combined with the current urban planning system,the solar energy potential-oriented street morphology planning optimization method is summarized,and an empirical study is carried out by taking the main urban area of Xi'an as an example.The purpose of this study is to provide a technical basis for the optimization of urban street morphology planning based on solar potential assessment during the planning phase.The content of this research mainly includes the following four parts:Firstly,a parameterization method for planning elements of street canyon geometry based on the real built environment of the city is proposed.Using ArcGIS and SkyHelio to quantify the five street canyon geometric morphology planning elements of street width,street length,street aspect ratio,street orientation and street sky view factor respectively,the geometric spatial characteristics of street canyons in the main urban area of Xi'an are summarized for the study of street canyon The correlation between geometric planning elements and solar energy potential provides data support.Secondly,the city energy simulation software CitySim was used to simulate 8760 hours of hourly solar radiation from a sample of 552 typical urban street canyons in the main urban area of Xi'an.Summarize the characteristics of the annual total solar radiation and the monthly solar radiation changes in the street canyons of the main urban area of Xi'an.Thirdly,the SPSS bivariate model,least squares regression analysis method,and stepwise regression analysis were used to verify the correlation between the street canyon geometric form planning elements and solar potential,and the key geometric morphology planning elements and the best influence on the street canyon's solar energy potential were obtained.Parameter range.Finally,the street shape planning optimization method based on solar energy potential assessment is summarized.It is elaborated from three aspects: the planning and control path,the connection and transformation of the street form planning and control indicators and the empirical application,to ensure that the method can be connected with the current urban planning system.Through the above research,the following research conclusions are obtained:1.The average annual total solar radiation in a sample of typical urban street canyons in the main urban area of Xi'an is 437.4 KWh/m2.Judging from the characteristics of the changes in the solar potential level of street canyons,the total monthly solar radiation shows a trend of "increasing first and then decreasing",and the total radiation level shows a "double peak" characteristic.Among them,the total monthly solar radiation in December is the smallest,about 20.76 KWh/m2;the largest total monthly solar radiation is in August,about 54.23 KWh/m2.2.Street orientation,street aspect ratio,and street width are the key geometric planning elements that affect the solar potential of the street canyon in the main urban area of Xi'an.From the perspective of correlation,street orientation,street aspect ratio are negatively correlated with street canyon solar potential,and street width is positively correlated with street canyon solar potential.3.The optimal street orientation range of solar potential in the street canyon of the main urban area of Xi'an is clockwise from 10 ° north west to 40 ° north east and 20 ° north west to 30 ° north west;the best street aspect ratio Between 0.1-0.5 or 1.7-1.9,the annual average solar radiation in street canyons is at the highest level;the average annual total solar radiation in street canyons with street widths between 70m-80 m reaches the maximum.4.The optimization method of solar potential-oriented street morphology planning includes two parts: quantitative simulation and planning application transformation.Based on the principle of improving urban energy efficiency,the implementation of three levels of "element-street-area" planning and control methods,including specific implementation Flexible control of street morphology planning elements;formulate street morphology planning and control methods that combine street classification and functional classification;establish street zoning management and control mechanisms to coordinate the requirements of urban area construction.At the same time,it is necessary to consider the transformation of street canyon geometric form planning elements and street form planning management and control indicators to better link the existing urban planning system.