Revealing Urban Morphology and Outdoor Comfort through Genetic Algorithm-Driven Urban Block Design in Dry and Hot Regions of China

Xiaodong Xu,Chenhuan Yin,Qi Li,Wei Wang,Ning Xu,Tianzhen Hong

doi:10.3390/su11133683

Xiaodong Xu, Chenhuan Yin + Show 4 more

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https://doi.org/10.3390/su11133683

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Abstract

In areas with a dry and hot climate, factors such as strong solar radiation, high temperature, low humidity, dazzling light, and dust storms can tremendously reduce people’s thermal comfort. Therefore, researchers are paying more attention to outdoor thermal comfort in urban environments as part of urban design. This study proposed an automatic workflow to optimize urban spatial forms with the aim of improvement of outdoor thermal comfort conditions, characterized by the universal thermal climate index (UTCI). A city with a dry and hot climate—Kashgar, China—is further selected as an actual case study of an urban block and Rhino & Grasshopper is the platform used to conduct simulation and optimization process with the genetic algorithm. Results showed that in summer, the proposed method can reduce the averaged UTCI from 31.17 to 27.43 °C, a decrease of about 3.74 °C, and reduce mean radiation temperature (MRT) from 43.94 to 41.29 °C, a decrease of about 2.65 °C.

Highlights

Urban climate is determined by a city’s spatial structure, block texture, building form, open space layout, and so on [1]
Grasshopper and genetic algorithms, and the results of this study show that it is possible to mitigate urban heat island (UHI) by manipulating urban form based on sky view factor (SVF)
Based on the study of urban morphology and urban climate elements, this study attempts to explore a design method for the automatic generation and optimization of blocks based on the outdoor thermal comfort, and puts forward the urban design strategy and method based on climate adaptability in dry and hot areas

Summary

Introduction

Urban climate is determined by a city’s spatial structure, block texture, building form, open space layout, and so on [1]. Urban climate influences building cooling and heating loads, and outdoor thermal comfort, influences the building performance [2], and it is one of the most significant factors considered in urban design. Sustainable urban design plays an important role in the improvement of the urban climate, pointing to the need for more climate-responsive environments [4]. Along with the rapid development of the global economy and the unprecedentedly rapid process of urbanization, the scale of cities has been expanding continuously, which has had direct impacts on urban morphology. Urban morphology in the design phase has become an important ecological factor in highdensity and high-intensity urban development, gradually becoming the focus of architects and planners [10,11].

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