Parametric study on solar control of urban spaces

Abstract

Spaces between buildings constitute the crucial module of the city fabric and have a great influence on the performance of the buildings abutting them. The geometrical parameters of urban spaces influence widely sun penetration, shading requirement, and outdoor thermal comfort. However, these spaces are given a little importance in the design process and urban planning. Moreover, in developing countries, urban regulations frequently are founded on imported rules and they are poorly adapted to their local climate. In this regard, the present research work attempt to assess the Algerian urban planning rules, in accordance to solar movement and outdoor thermal comfort in the main climatic zones of Algeria. The present study attempt to develop a parametric solution, which allows urban designers to determine the proper geometrical parameters of urban spaces in accordance with solar right, outdoor thermal comfort. In addition, we pursue through this research to assist urban designers in linking between fulfilling greater built density and guaranteeing solar rights of spaces between buildings. To achieve the goal of this study, an evaluation and generative method has been used. The first phase of the process, focused on the evaluation effect of obstruction angle, orientation and geographical latitudes on solar radiation dropped on ground surface of urban spaces and outdoor thermal comfort during both of times summer and winter. Whereas, in the second phase, the generative approach based on twofold steps; the application of parametric solar envelope to optimize the results of the first phase, and the application of the Comfort Cover model to determine the urban areas for future urban densification in accordance with the desirability of shade and outdoor thermal comfort (UTCI). Afterward, the parametric solar envelope is applied on the blocks reserved for future urban densification. The findings of this research reveal some guidelines; low obstruction angle safeguard solar right of urban spaces in both high and low latitudes. However, high obstruction angle mitigate outdoor thermal comfort during summer period in both high and low latitudes, while during winter periods high obstruction angle leads to drop outdoor thermal comfort in high latitudes. In addition, the generative algorithm of parametric solar envelope permits urban planners to fulfill greater built density and safeguard solar access in urban spaces and mitigate winter outdoor thermal comfort. Moreover, the generative algorithm of Comfort Cover model permits urban designers to define the area of future urban densification in accordance with shading requirement and outdoor thermal comfort.