Urban geometry and the microclimate of street canyons in tropical climate

Abstract

The objective of this study is to assess whether geometric parameters of urban street canyons affect their microclimates and pedestrian thermal comfort. Understanding the effect of these parameters on the microclimate of urban street canyons is crucial for achieving sustainability between urban occupation and thermal comfort. This study used the computational tool ENVI-met 4.0 preview. The study was conducted in the city of Campinas, São Paulo, Brazil, which has Cwa climate. A total of 36 scenarios, with and without space between buildings, were simulated for winter and summer. The scenarios differed in their aspect ratio (H/W) (avenue (H/W < 0.5), regular (H/W = 1.0), and deep (H/W > 2.0) canyons) and length-to-height (L/H) ratio (short (L/H < 3.0), medium (L/H = 5.0), and long (L/H > 7.0) canyons). Canyon performance was assessed by comparing the air temperature, wind speed, and physiological equivalent temperature (PET). The results revealed that canyons with a higher H/W aspect ratio increase the wind speed and shading by buildings, thereby improving the thermal comfort at the pedestrian level, especially in the summer. Conversely, an increase in the L/H ratio had no significant effect on the thermal comfort sensation at the pedestrian level, which was similar to the scenario without space between buildings.