The influence of building coverage ratio on building surface reflectivity in reducing building heat release and energy consumption under current and future weather scenarios

Previous studies have explored the effectiveness of highly reflective materials in reducing anthropogenic heat release from buildings; however, the role of building coverage ratio (BCR) has been less examined, particularly for buildings with reflective coatings under both current and future weather scenarios. This study investigates the impact of BCR (while reducing BCR up to 50 %) on heat release from buildings equipped with conventional low-reflectivity coatings (with 0.3 albedo) and high-reflectivity coatings (with 0.5 albedo for wall and 0.9 as that of roof). EnergyPlus is used to evaluate these scenarios across 12 diverse cities representing various global climate zones. The findings indicate that in scenarios using conventional coatings, future heat release from buildings decreases by up to 44 % compared to that under current weather conditions, accompanied by an increase in energy consumption of up to 24 % due to increased air outdoor temperature (future weather). Additionally, in the case of conventional coatings, buildings with higher BCRs exhibit increased heat release for both current and future weather scenarios; thus, taller buildings release less heat than shorter buildings with equivalent floor areas. In contrast, buildings with high-reflectivity coatings demonstrate a reverse pattern: shorter buildings release less heat than taller buildings, owing to their greater efficiency in reflecting solar radiation. These results suggest that building regulations should prioritize higher BCRs combined with high-reflectivity surfaces in new construction to mitigate heat release and reduce urban air temperatures.