Mitigating Urban Heat Through Extended Cantilever Building Shading: A Street-Level Analysis

Abstract

In hot regions, high street temperatures can be a significant impediment for pedestrians. It can also negatively impact the urban heat island and increase the energy required for cooling. Street shading can assist in mitigating these problems. This research examines the effect of extended building projections beyond the building plot and over the pavement on street shading and the resultant thermal conditions in a hot, arid urban environment employing the ENVI-met simulation tool. Several projection configurations were analyzed in a Dubai mid-rise residential district. Projections extended beyond the real estate plot boundaries but not the walking pavement, to a maximum of 6 m. Two streets were analyzed within the selected neighborhood: a side street 10 m wide, building-to-building, and a main street 56 m wide. The simulations showed a direct correlation between configurations of larger building projections with improvements in outdoor air temperature, both ambient and radiant, and thermal comfort. The average temperature for the entire block dropped almost two degrees from 41.0 C° to 39.1 C°. Significantly, the radiant temperature decreased significantly from 63 C° to 57 C°. The PMV, according to Envi-met’s scale, remained out of the comfort zone but still showed a significant improvement from 7.2 to 6.5. These results demonstrate that well-designed building projections can effectively reduce high temperatures, improve livability, and assist in mitigating the urban heat island effect of mid-rise urban sectors in hot regions.

Keywords

• street shading
• street thermal conditions
• urban heat island
• urban microclimate
• outdoor thermal comfort