Performance assessment of bifacial photovoltaic modules mounted on highly reflective building skins: Experiment test and coupled optical–thermal–electrical modeling

Bifacial photovoltaic (BPV) modules, which harvest irradiation from both sides, typically benefit from highly reflective surrounding environments that enhance their bifacial gain. Meanwhile, highly reflective building skins are increasingly adopted in urban architecture, yet they often result in significant solar energy waste. Parallelly mounting BPV technology on such reflective skins offers a flexible strategy to improve PV efficiency by utilizing reflected irradiation in various building applications. To gain a deep understanding of this configuration, this study conducted the investigation through both experimental and theoretical analyses. First, the performance of customized small-scale opaque and semitransparent BPV prototypes was experimentally tested. The results revealed a significant increase in electricity generation on highly reflective surfaces compared to lowly reflective counterparts, exhibiting an approximate 36% boost for semitransparent modules and a 26% enhancement for opaque modules. Subsequently, a generalized optical–thermal–electrical coupled model was developed and rigorously validated against experimental data. Based on this model, a case study was conducted on an extensive-scale 1×10 BPV array installed on reflective building skins to assess their energy performance on vertical walls, tilted roofs, and horizontal roofs. Across China, the estimated annual bifacial gains are 6.6–14.1% for opaque modules and 14.5–21.4% for semitransparent modules. However, the electricity generation per occupied area of semitransparent modules falls below that of opaque modules. The proposed model and findings provide valuable insights and methodological references for optimizing and evaluating BPV systems applied to highly reflective building envelopes.