Impact of Urban Densification on Outdoor Microclimate and Design of Sustainable Public Open Space in Residential Neighborhoods: A Study of Niš, Serbia

This research examined changes in the microclimatic parameters affecting thermal comfort in three residential settings with various urban forms in the city of Niš, Serbia, that underwent intense post-socialist urban densification. Outdoor microclimate was modeled for summertime conditions in two scenarios, before and after transformation, by using ENVI-met software. The obtained results offer quantitative data on microclimatic conditions in the chosen settings and comparisons between scenarios. Findings revealed significant variations in the transformed scenarios, with distinct patterns in specific open spaces: a single mid-rise development forming a square in a high-rise setting showed a wind speed decrease, a daytime mean radiant temperature increase despite lower temperature, and an increase in humidity; extensive low- and mid-rise development in a green high-rise setting generated the highest temperature increase at night, notably reduced daytime and slightly elevated the nighttime mean radiant temperatures, and presented inverted temperature and humidity patterns in urban canyons during the day and night; dispersed densification in low-rise setting manifested the highest wind speed increase, significantly increased the daytime temperature, and mostly raised the nighttime mean radiant temperature. Urban design strategies for sustainable public open space that enhance the resilience of densified areas include using shading from transformed western/southern-edge buildings, avoiding small partly-framed spaces and fragmented grassy surfaces, implementing urban gaps to support nighttime cooling, and framing public open space with trees.