BIM integrated sun-path and energy analysis to evaluate self-shading and cooling and heating demand of a G+3 residential building model in four different climate zones in India

Purpose: This paper presents a reproducible Building Information Modelling (BIM) workflow that couples sun-path and floor-by-floor shadow analysis with whole-building energy simulation, applying one geometrically invariant residential prototype across the four climatic zones of India to give architects, builders and code authorities indicative, climate-graded shading guidance. Methods: A G+3 reference model of 391.52 m², created in Autodesk Revit 2025, was replicated without geometric change in Chennai (Warm-Humid), Jodhpur (Hot-Dry), New Delhi (Composite) and Shimla (Cold). Shadow plots were generated at nine Indian Standard Time instants per city, and annual energy performance was simulated with the Revit-integrated OpenStudio and EnergyPlus engines using ISHRAE typical-year weather data. In parallel, cast ground-shadow areas were derived analytically for all 36 instants from a rectangular-prism projection, with solar positions from the NREL Solar Position Algorithm. Results: Annual site energy-use intensity (EUI) falls from 479 to 396 kWh m⁻² yr⁻¹ with internal loads held identical, and cooling takes 74.5–81.3 % of site energy in every zone; these are ideal-load results for a fully conditioned scenario, not predictions of metered consumption. The cooling-to-heating ratio falls from infinity at Chennai to about 26 to 1 at Shimla but never inverts. Cast shadow area spans 30–733 m², and the city-mean shadow area correlates inversely with site EUI (r = −0.98, 95 % CI −1.00 to −0.34, p = 0.019, n = 4). An independently built EnergyPlus model verifies the workflow within +6.3 % to +14.2 % of site energy at the three lowland cities and shows that the cloud weather data behind the BIM runs do not resolve Shimla’s 2,202 m highland climate. Conclusions: The indicative shading recommendations and the closed-form shadow-area model give practitioners a reproducible, early-stage design aid for setting façade-specific shading and estimating cast-shadow extent at any Indian site from latitude, orientation and date alone.