Adaptive spectral control for thermal regulation and efficiency enhancement in hybrid CPV/T systems

High-concentration photovoltaic/thermal (CPV/T) systems are frequently limited by cell overheating and the rigidity of static spectral partitioning. This study introduces an adaptive beam splitter for CPV/T systems, utilizing a control strategy where the splitter cutoff wavelength is tuned hourly to maintain the photovoltaic (PV) cell temperature below 358 K while maximizing electrical yield. An electro-thermal model was calibrated and verified against outdoor measurements of a system using a fixed cold-mirror splitter and subsequently used to simulate adaptive operation. Results indicate that under high concentration, the optimal cutoff wavelength relaxes to ~950–1000 nm during morning and afternoon hours but shifts aggressively to 450–600 nm at midday to mitigate thermal loads. Unlike fixed splitters, which plateau at a daily yield of ~ 19 kWh/m², the adaptive scheme surpasses this limit at concentration ratios (CR) >5, achieving over 35 kWh/m² at CR = 9. Exergy analysis shows that the energy gain is accompanied by a strong rise in utilization factor at high CR (e.g. UF peaking at 57.57% at CR = 9 around noon), while exergy efficiency depends critically on the assumed thermal delivery temperature (e.g. 10.95% at 85°C versus 15.49% at 120°C at the same peak hour). A techno-economic assessment based on the adopted component-level CAPEX indicates improved levelized metrics for the adaptive scheme, with LCOE decreasing from 0.1880 to 0.1760 and LCUE decreasing from 0.0869 to 0.0285. Overall, tunable spectral management can simultaneously preserve PV thermal safety, enhance total recovered energy, and improve system value when the recovered heat is utilized at sufficiently high temperature.