Optimized Design Of Urban Open Space Based On Performance- Driven Climatic Adaptability

Since the beginning of the 20 th century,along with the continuous boosting of the global urbanization process,cities have become an important external environment for the survival and development of human beings.In this process,environmental deterioration,energy shortage,climate warming and other ecoenvironmental problems have been gradually emerging,and the contradiction between people and cities and the nature has been becoming more and more prominent.In such a context,the idea of sustainable development and the corresponding theory of green city design have begun to become a frontier topic that has aroused the extension attention of the field of urban design.Climate-adaptable urban design is an important research part in the field of green city design.It can help to create a desirable micro-climatic environment,save resources,reduce energy consumption,alleviate the contradiction and confrontation between cities and the nature to a certain extent,and build a poetic habitat for human beings.Launching theoretical exploration and research against climate-adaptable urban design strategy boasts a positive theoretic significance and application value.At present,domestic and overseas researches on the relevant climate-adaptable urban design focus on the macro scale(e.g.urban heat island,urban wind corridor,etc.)and micro scale(e.g.single street,single building,etc.),and few researches choose middle-scale urban street zones as their research objects,and particularly rare researches focus on the research achievements and practical cases connected with performance-driven design which has been becoming the mainstream gradually.Accordingly,this paper chooses the regions with hot summer and cold winter and with austere outdoor comfort both in summer and in winter as its research area.First,the paper introduces the climatic features of these regions,and summarizes the basic urban design strategy of these regions according to the theory of climate-adaptable design.With the urban open space as the breakthrough of the research,this paper sorts out the basic theories of the impact of open space form on micro-climate,further abstracts the factors of open space form at the macro,middle and micro level related to micro-climate,laying a foundation for the unfolding of later research.In terms of technique,this paper brings in the technique of performance simulation and optimization in the current frontier field of parametric design.This performance-oriented technique enables the integrated development of design and evaluation,and explores the mechanism of impact on micro-climate by automatically optimizing the process of open space's response to environment with the help of computer.After analyzing the advantage,disadvantage and technical features of various software platforms,the paper chooses Rhino Grasshopper as the parametric modeling technique and the platform of software integration,selects its plug-in Ladybug series for performance simulation,and makes a detailed introduction to this presently-advanced analytic software.This paper uses the built-in Galapagos genetic algorithm as an optimizing technique,and formulates a process framework for the optimized design of open space based on climatic adaptability.Based on the above-mentioned technical strategy,this research sets up a street zone of 250mx250 m in Nanjing as a case of experimental object,as well as two seasons(winter and summer),two basic climatic conditions and optimizing ways,totaling 6 groups of optimized experiments of open space integrating design and evaluation.A desirable result has been achieved in each.By analyzing the optimizing process,evolution trend and optimal solution of open space in various experiments,this paper reveals the mechanism of the impact of the vertical distribution and horizontal distribution of urban open spaces and their formal factors on micro-climate,and get the quantitative value of each factor's influence on microclimate using multivariate linear regression analysis method.This paper compares the similarity and difference of the impacts in different seasons and climatic conditions,summarizes the design strategy of open spaces adaptable to regions with hot summer and cold winter,and abstracts it and forms a set of basic model language.By validating the case at such three levels as building combination,street zone and overall planning,this paper preliminarily testifies its universality and reliability.In addition,this research has also provided climate-adaptable urban design with a complete set of brand-new practical solution generation methods and optimizing strategies,summarizes its advantage and restriction and provides further prospect for future development.