The diverging indoor, outdoor, and power implications of different rooftop photovoltaic system designs

Extensive photovoltaic (PV) deployment is essential for future net-zero energy systems. In dense urban areas, rooftop PVs offer a promising solution to space constraints, but their thermal implications for indoor and outdoor environments require consideration. Previous studies have examined single or similar designs, leaving impacts across the full layout parameter space underexplored. This study presents a flexible physics-based model simulating energy exchanges between the atmosphere, PV panels, and building interiors for various configurations (adhered or elevated, ventilated or enclosed, tilted or flat). The model is validated with field data from Princeton, NJ, and San Diego, CA. Results show that geometry affects thermal behaviour more than typical panel or material property variations. All four configurations reduce building heat gain (G) by 50–90 % relative to a black roof, comparable to cool roofs but with added electricity generation. Power output aligns with peak cooling demand and can offset increased heat gains versus cool roofs, especially when paired with heat pumps. Urban atmospheric effects vary: ventilated designs increase daytime sensible heat flux (H) by 40–100 %, while adhered and enclosed designs reduce H by 50–55 %. At night, adhered, enclosed, and tilted systems reduce H by about 93 % due to lower daytime storage, helping mitigate nocturnal urban heat islands. An elasticity analysis quantifies the sensitivity of results to meteorological parameters, demonstrating the qualitative generalizability of the main conclusions. Findings offer actionable guidance for urban planners and building designers to optimize rooftop PVs for climate and urban context, balancing indoor, outdoor, and power benefits.