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Relevance of Ground and Wall Albedo for Outdoor Thermal Comfort in Tropical Savanna Climates: Evidence from Parametric Simulations

 Abstract:

High-albedo ground and wall materials are promoted to mitigate heat stress in tropical climates, yet conflicting evidence driven by climatic and metric variability make their impact on Outdoor Thermal Comfort (OTC) unclear. This study employed parametric simulations to assess how ground and wall albedo affect OTC, measured via the Universal Thermal Climate Index (UTCI) in typical urban canyons. Using ENVI-met, we tested ground albedo (0.2–0.8) and wall albedo (0.05–0.90) with emissivity fixed at 0.9. Findings reveal that ground albedo had a minimal impact on the UTCI (mean amplitude 0.44 °C), while wall albedo reduced the UTCI by up to 2.80 °C, prioritizing wall material selection for heat mitigation. It was also found that the increase in ground albedo offsets the cooling potential of high-albedo walls. Furthermore, differences in the impact under shaded and unshaded areas were observed. These results question assumptions of universal high-albedo benefits, recommending case-specific simulations in urban design.


Authors
Komi Bernard Bedra and Jiayu Li

Keywords
albedo; outdoor thermal comfort; sustainable urban design; tropical savanna; parametric simulations; ground material; wall materials

Publisher 
Sustainability 2023, 15(11), 8902, 31 May 2023

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