Study On Landscape Environment Renewal And Optimization Of Guangdong Old City Blocks Based On Microclimate Performative Design

With the transformation of China’s urbanization process from quantity expansion to quality improvement,the old city blocks in Guangdong Province are undergoing large-scale renovation under the guidance of high-quality development.Many cities are trying to shape the old city blocks into new urban economic vitality,cultural experience and image benchmarking areas.At present,most of the renewal strategies of old city blocks take value continuation and style shaping as the main goal,while ignoring the micro-climate environmental factors that directly affect the health and comfort of pedestrians,which is very unfavorable to the renewal goal of building high-quality living environment and ensuring human health and life.Based on the above issues,the performance-based design method of microclimate is introduced into the renewal of the old city,and the research methods of combining morphological typology analysis with microclimate environment simulation,forward simulation and reverse simulation are used to focus on exploring the correlation law between the landscape environment renewal and the microclimate environment of the old city blocks in Guangdong.On this basis,the parametric software Rhino & Grasshopper is used to build a system platform that integrates the functions of old city block shape analysis,microclimate simulation,automatic evaluation of thermal comfort and evolutionary optimization,providing optimization strategy services for rapid evaluation of outdoor thermal comfort of old city blocks at the initial stage of the scheme.In this study,firstly,106 old city blocks in Guangdong Province were investigated and analyzed on the spot,multi-source data were collected,and 39 typical old city blocks with complete historical map evolution data were selected to establish a spatial database,63 landscape environment survey areas(LESA)were extracted,and the spatial characteristic indicators as well as Landscape environment type of each area were calculated and classified.(Chapter II)Secondly,based on the field measured data of microclimate in typical old city blocks,the differences of thermal environment in various landscape environment space(main street,tunnel,courtyard and square)and different block sections and their correlations with spatial element indexes are analyzed.By comparing the measured data with the simulation data of Envi-met4.6 software,the reliability of the software to simulate the microclimate of the old city block in Guangdong is verified.(Chapter III)Thirdly,the quantitative relationship between the spatial elements and outdoor thermal comfort of the old city blocks were studied.Physiological equivalent temperature(PET),Universal thermal climate index(UTCI)and Thermal feeling vote(PMV)were selected as the thermal comfort evaluation indicators.Envi-met 4.6 software was used to simulate the outdoor thermal comfort on typical weather days in summer in 63 LESAs.Through the correlation analysis and multiple regression analysis between the spatial shape parameters and outdoor thermal comfort,a prediction model of outdoor thermal comfort based on the spatial element index of the old city(building density,floor area ratio,sky view factor,building height dispersion,greening plot ratio,hard pavement ratio,and external wall area ratio)was established.(Chapter IV)Fourth,the coupling analysis of the correlation parameters of thermal comfort in the old city blocks.According to the evolution of historical maps and the analysis of morphological typology,three types of simplified models for the renewal of old cities are derived,namely,conservation type,renovation type and reconstruction type.Through the parametric iteration of the three simplified models and the coupling analysis of their corresponding outdoor thermal comfort,the correlation law and parameter threshold of landscape environment renewal and thermal comfort in Guangdong old city blocks are proposed.(Chapter V)Finally,research on the construction and application of the thermal comfort optimization platform for old city blocks.Based on the parameterized software Rhino & Grasshopper,the calculation code of the prediction thermal comfort equation and comprehensive thermal comfort evaluation index TCI for old city blocks are compiled and developed,the threshold range of Grasshopper-Galapagos optimization parameters is set,and the automatic evaluation and optimization system platform for thermal comfort improvement is constructed.The technical features and functional modules of the platform are shown by the demonstration cases of the old city blocks such as Donghuali in Foshan.Finally,taking three different types of old city renewal areas,including Shantou Xidi,Foshan Donghuali and Chaozhou Paifang Street,as practical cases,the platform are used to complete the automatic evaluation of thermal comfort,spatial parameter optimization and visual output of optimized parameter sets for the three renewal schemes,and calculated and generated TCI cloud maps and optimal target values that conform to the designer’s cognitive logic.(Chapter Ⅵ)The main innovations of this paper are as follows:(1)The quantitative relationship between landscape environment renewal and thermal comfort of old city blocks in Guangdong is revealed,and a prediction model of thermal comfort is established;(2)The simplified models and parametric iteration relations of three types of old city renewal are summarized and deduced,and the correlation rules of thermal comfort and the threshold values of correlation parameters are proposed;(3)An integrated platform of automatic evaluation and evolutionary optimization of thermal comfort for landscape environment renewal of old city blocks in Guangdong is constructed.The above innovative achievements provide a technical platform for the in-depth exploration of the "two-way mutual feedback" relationship between the old city block renewal and the microclimate environment,and also provide a guiding theoretical and scientific basis for the evidence-based design of landscape architecture,,which is of practical significance for parallel promotion of microclimate performance improvement and optimization of spatial schemes,and improvement of traditional human settlements.