Study On Thermal Comfort And Microclimate Enhancement Strategy Of Commercial Block Morphology In Harbin

With the rapid urbanization process,urban heat island effect directly affects the comfort level of urban residents.Commercial blocks are densely populated,with high building density and obvious urban heat island effect.Users spend a long time outdoors and have higher requirements for outdoor comfort,making it in need of improvement in micro-climate.Especially for the severe cold areas in the northeast,the winter is long and the use efficiency of commercial blocks is low.It is necessary to improve the efficiency of the block through climate adaptation planning of the commercial block to improve the outdoor microclimate comfort.At present,domestic and foreign studies on urban climate environment and built environment have been more in-depth,but the study on block scale is less.In particular,there is a lack of systematic theoretical research and guidance standard for the regulation of block morphology based on the climate in severe cold regions.In view of these problems,this study based on the urban cl imate conditions in typical cold regions of Harbin,explores the correlation between the morphological elements of commercial blocks and the micro-climate environment as well as the thermal comfort of outdoor human bodies.Established quantitative relation ship and through the multi-objective comprehensive optimization,the paper puts forward the optimal design strategy of the form elements of commercial blocks with climate adaptability.Firstly,this study systematically investigated and analyzed the morpho logical characteristics of commercial blocks in Harbin,extracted the morphological parameters of blocks by GIS,measured the microclimate of typical blocks,and analyzed the spatial and temporal distribution characteristics of microclimate of commercial blocks.Through the questionnaire survey,the expectation and comfort index of outdoor micro-climate environment were obtained,and the corresponding relationship between the block morphological parameters and thermal comfort was established.Secondly,based on the test data,the influence of the morphological parameters of each block on the temperature was analyzed.At the same time,through sensitivity analysis,multiple regression and neural network optimization methods,the multiple regression equations of reference temperature,sunshine radiation,total wall area,building coverage rate,average building height,vegetation greening rate,street coverage rate and temperature were established.Thirdly,CFD platform was used to conduct wind environment simulation analysis on the simplified block shape model,extract the block morphological parameters with higher weight on the wind environment,and establish the correlation equation between block shape parameters and wind speed.Finally,the comprehensive optimization of temperature,sunshine and wind speed was taken as the objective,and the obtained outdoor thermal comfort index of human body was taken as the evaluation standard.The multi-objective optimization method in mathematics(SPEA2 genetic algorithm)was adopted to carry out the multi-objective comprehensive optimization.According to the optimal solution,the layout rule is extracted.This paper proposes feasible optimization strategies in six aspects: street aspect ratio,orientation,block building density,plot ratio,average building height and building layout.