Urban Building Shadow Exposure Metric (UB-SEM): Quantification of urban building compactness for cooling energy demand prediction

Urban morphology greatly influences cooling energy demand in buildings. However, limited understanding and quantification of compactness-related factors such as inter-building shading and solar exposure undermine the accurate prediction of cooling energy demand. This study presents a comprehensive multi-scale framework that integrates geometric, spatial-statistical, fractal, and point-pattern measures to capture urban building compactness and its relationship with cooling energy demand. Central to this framework is the Urban Building Shadow Exposure Metric (UB-SEM), a novel, climate-responsive indicator that quantifies cumulative inter-building shading using sun-path dynamics, building geometry and inter-building spacing. Applied across India’s five climatic zones, UB-SEM demonstrates moderate to strong associations with Cooling Energy Use Intensity (EUI), revealing the influence of climate, sun-path, and building geometries. UB-SEM is further evaluated as a surrogate for surrounding-building effects in Urban Building Energy Modelling (UBEM). When used to approximate radiative interactions, UB-SEM-adjusted Cooling EUI shows high agreement with full-context energy simulations with surrounding buildings’ effects, yielding r = 0.88, R² = 0.78, and a low percentage RMSE of 8.33%. These results demonstrate that inter-building effects can be captured efficiently using a shadow-based compactness indicator like UB-SEM through a simplified formulation. This substantially reduces the need for computationally intensive radiative modelling in many UBEM applications focused on cooling energy demand. The study provides a scalable, transferable, and computationally efficient framework for urban building compactness-energy analysis. By incorporating climate-aware shadow dynamics into compactness assessment, UB-SEM supports efficient UBEM workflows and offers a robust foundation for evidence-based urban design across diverse climatic contexts.