BIPV Yield Assessment for Transparent Envelope Applications in Early-Stage Building Design: A Cross-Tool Comparison

Building-integrated photovoltaics (BIPVs) can expand the available photovoltaic area on buildings, especially in dense urban contexts with limited roof surfaces. For transparent-envelope applications, such as photovoltaic shading devices (PVSDs) and semi-transparent photovoltaic glazing (STPV), PV-yield assessment is particularly challenging because PV elements also function as part of the building envelope. Their energy yield depends on multiple interacting factors: irradiation, orientation, shading, incidence-angle effects, operating temperature, and, for STPV, glazing thermal behavior. In early-stage building design, however, these effects must be assessed while system characteristics are still evolving, and detailed product or module data are often unavailable. To address this gap, this study develops and evaluates an EnergyPlus-based approach for PV-yield assessments for transparent-envelope BIPV applications. The approach replaces fixed PV efficiency with a time-dependent effective efficiency that accounts for incidence-angle reflection and temperature-related efficiency losses. It is evaluated through a cross-tool comparison with established PV-yield assessment tools. For PVSD, the comparison separates unshaded conditions, louver self-shading, and urban-context shading. For STPV, it includes an analysis of the PV cell-temperature estimation and the link between electricity generation and glazing heat balance. Results show that PVSD yield differences are mainly governed by shading representation, while STPV results are more sensitive to cell-temperature assessment than to thermal coupling effects. Overall, the approach provides a consistent basis for comparing PVSD and STPV yield under early-stage input constraints, while including selected AOI- and temperature-related efficiency effects.