Research On The Optimal Design Of Residential Green Space Based On Thermal Environment Simulation

The continuous urban expansion has stimulated social development and ecological protection demands,and the resulting urban ecological problems have attracted much attention.The urban microclimate is an essential part of the human living environment and the urban ecological environment.Appropriate planning and design lay the foundation for improving the microclimate environment.As a space carrier inseparable from the leisure activities of urban residents,green space in residential areas has an irreplaceable effect on enhancing the summer micro-climate of residential areas and improving the quality of urban human settlements.This article took the urban thermal environment as the breakthrough point combining the basic characteristics of the green space in Xi’an residential area,used the microclimate simulation software ENVI-met to simulate and analyze the green space scenarios in different residential areas,and explored the thermal environment and summer microclimate characteristics of residential green space under the green space combination pattern and green space plant configuration type in different residential areas.The outdoor thermal environment comfort evaluation index UTCI was applied to evaluate the green thermal environment of the residential regions under various scenarios.The scenario simulation was taken to carry out the corresponding case empirical research combining a real case to reconstruct the green space environment of the existing residential area.The optimal design strategy of green space and plant collocation of residential areas based on the improvement of the thermal environment was proposed based on the analysis of the simulation results before and after the reconstruction of the case.ENVI-met software ENVI-met software was determined to be the research tool for thermal environment simulation,and the Universal Thermal Climate Index(UTCI)was selected as the evaluation index of outdoor thermal environment comfort through combing research on microclimate simulation methods and thermal environment evaluation methods.Based on the classification research of the residential green space in the main built-up areas of Xi ’an,three basic combination modes of residential green space were summarized.According to the three models and the combination of the different configurations of plants in the residential green space,a total of nine simulation scenarios were set for simulation research.The analysis and simulation results showed that,under the same initial simulation conditions,the combination mode of "central green space +inter-house green space" had the best microclimate environment in summer,followed by the combination mode of "cluster green space + inter-house green space." The effect of "inter-house green space" was the worst.In terms of plant configuration,the model of "lawn,shrub,and tree," the model of "lawn and shrub," and the model of "lawn only." The improvement effect of shrubs on the comfort of residential green space is not significant.According to the empirical study of the selected cases,the high intensity of development in residential areas had a greater increase in green space temperature.In contrast,the low rate of green space in residential areas had a higher air temperature and a lower relative humidity.The spatial location of green space in residential areas had a minor impact on the thermal environment of green space.The simulation and comparison results of residential green space reconstruction cases showed that the vertical spatial configuration of plants in residential green space had a significant effect on the thermal environment of residential green areas,and the impact of giant trees was noticeable.As a result,it is suggested that the green space combination mode of "center + house" should be preferred in the planning and design of residential green space and plant planting collocation,and the improvement effect of plants on the thermal environment of green space should be fully considered.The reasonable collocation should be taken into account.In addition,the dominant wind direction and other climatic factors should be fully utilized to create a comfortable ventilation environment for the residential green space.