Effect of Urban Form on Outdoor Thermal Comfort of Governmental Residential Buildings: New Aswan as a Case Study, Egypt

Abstract

The climate change has several influences on the environment such as the Urban Heat Island phenomena (UHI) and increasing the heat waves intensity and frequency. Within a city, the outdoor spaces occupants can be impacted severely as a result of urban climate, which, in its essence, is directly linked to the buildings attributes and its configuration. the urban climate is directly linked to the configuration of buildings, building heights and their attributes. The Egyptian government's work program includes the implementation of residential units' projects for low-income citizens called "Social Housing Project". The government seeks to complete the implementation of 700,000 units within that project by the end of 2019. It has successfully undertaken more than180.000 housing units of them by end of 2017. Most of the project exists in new cities in arid areas. While the urban planners ought to be aware of ensuring better thermal performance for outdoors urban spaces, in this project, multiple urban forms and orientations have been used. This study presents the observed and estimated relationship between the used building configurations in the case study and changes in microclimate. The study aims to extract the most effective building configuration that can improve the thermal performance of outdoors urban spaces during the summer. The data introduced in the study were based on site measurements and microclimate simulations using ENVImet. The study evaluated the impact of urban form and its orientation on air temperature and on daytime occupants' thermal comfort level. Since Sky View Factor (SVF) represents the fundamental factor controlling outdoor space diversity on the microclimate scale, it has been used to represent the urban form, and to connect between the form, sun path, and thermal behavior of the outdoor spaces. The study was conducted for the 24 hours during October assuming average climate conditions. The results showed quantitatively that there was a wide range of PET values (20 °C) at 12 PM, between the difference spaces owing to its shape (SVF) and orientation. These variances led to relatively comfort spaces, especially clusters which are oriented to North or Northwest , and discomfort spaces with extreme heat stress, especially clusters which are oriented to South or Southwest. Findings confirmed that the main parameters affect the outdoor thermal behavior are the solar radiation and shading patterns so the urban form which gives more shade to its spaces gives more thermal comfort.

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