Research On Space Optimization Of Urban Street Canyons In Old City Based On Thermal Comfort Evaluation

As a famous historical and cultural city of China,Xuzhou has a history of 5,000 years of civilization and a history of 2,500 years of city construction,and is rich in historical and cultural resources.However,with the continuous development of modern urban construction,the urban structure of the old city of Xuzhou is continuously disintegrating,and historical buildings on the ground are gradually disappearing.As for today’s old city,there are not many historical sites on the surface of the old city,resulting in the current unfavorable situation of lack of historical and cultural heritage in the old city of Xuzhou.On October 23,2020,the Xuzhou Housing and Urban-Rural Construction Bureau announced the “Xuzhou Historic and Cultural City Protection Plan(2020-2035)”for soliciting comments,and proposed a more systematic historical and cultural planning plan for the old city,which reflects the great importance of government departments to the history and culture of Xuzhou old town.At the same time,after investigation,it is found that Xuzhou old town basically retains the historical street framework.But the internal environment of many preserved old streets is deteriorating and makes pedestrians uncomfortable.It has become an urgent problem to be solved in the urban regeneration process.In this study,the old streets of Xuzhou old town were arranged through field research,historical literature,satellite map research and other methods.7 typical old streets were chosen for research and analysis.Rhinoceros 6 modeling software and ladybug +honeybee parametric environment simulation plug-in are used to simulate the thermal comfort of each street,and the law between the thermal comfort and the street canyon space form is obtained,which is applied to the street micro-regeneration design,in order to improve the internal comfort of the street canyon.This article is divided into 5 chapters:The first chapter is the background and significance of the research,the introduction of basic concepts and so on.It expounds the problems faced by the Xuzhou old town and the long-term planning,and explains the concepts of urban street canyon,block,urban micro-regeneration,urban heat island effect,etc.The second chapter is the theoretical research on the spatial form and thermal comfort of urban street canyons,explains the definition of the parameters related to the spatial form of the street canyon and thermal comfort.And related calculation formulas are introduced.In the third chapter,the preserved old streets in Xuzhou old town are divided into different zones,and the position information of the preserved old streets in the old town is acquired by superimposing and comparing of the historical map and the current satellite map,and the historical evolution of the old streets in each zones is sorted out.Finally,7typical old streets are chosen as the research objects for detailed analysis.In the fourth chapter,the thermal comfort parameters and spatial form parameters of the 7 selected streets are simulated by computer,and the Universal Thermal Comfort Index(UTCI),wind speed and wind vector distribution map of each street are obtained.At the same time,the average width,surrounding building average height,interface density and near-line rate of each street are calculated.Finally,the comfort parameters are compared with the spatial shape parameters through regression analysis to obtain the correlation between the two kinds of parameters,so as to explore the influence of street space form on comfort,and provide theoretical support for the optimization process.In the fifth chapter,Kaiming street is selected as the optimization object,and the corresponding regeneration measures are put forward by using the laws obtained from the above chapters,and the optimal extent of various regeneration measures is compared and simulated.Finally,it is known that the comfort in the street canyon can be better optimized by changing the aspect ratio of the street canyon.Finally,it shows the rendering effect of the optimization scheme,which shows the feasibility of the research results.To sum up,this article systematically studies and analyzes the environmental comfort of old streets in Xuzhou old town through computer simulation software,and obtains the relationship between the street canyon space form and thermal comfort,which provides more reliable suggestions for the future urban regeneration process.