Mitigation of non-uniform thermal loading in concentrated photovoltaic/thermal systems using spectral filtering and phase change material-based energy storage

Concentrated photovoltaic/thermal (CPV/T) receivers are vulnerable to non-uniform concentrated illumination, which promotes localized hot spots, thermal gradients, electrical mismatch risk, and accelerated photovoltaic (PV) degradation under harsh climates. This study develops a hybrid CPV/T-SBS/PCM receiver that combines spectral beam splitting, Therminol VP-1-based bypass cooling, and phase change material (PCM) buffering to improve PV protection and dual electrical-thermal recovery. The work advances CPV/T modelling by integrating non-uniform optical concentration, spectral filtering, active cooling, PCM phase change, and temperature-dependent PV generation within a transient optical-thermal-electrical framework. Monte Carlo ray tracing of a parabolic trough concentrator is coupled with a three-dimensional CFD model to resolve flux distribution, fluid flow, heat transfer, PCM melting, electrical output, heat recovery, and energy-exergy performance. The analysis considers flow layout, PCM type, PCM thickness, realistic weather condition, receiver configuration, optical-flux sensitivity, concentration-ratio effects, and PCM cycling degradation. Results show that bypass flow normal to the irradiance gradient is optimal, achieving 17.2% electrical efficiency, 58.4% thermal efficiency, and 39.5% total primary efficiency. PCM selection is governed by latent heat, melting range, and thermal resistance: RT35HC improves PV cooling; 5 mm RT42 enhances energy-exergy performance through useful heat recovery; RT47 provides the best harsh-daytime balance by remaining active during peak irradiance; and RT50 is preferable for prolonged high-temperature exposure. Increasing CR from 10 to 50 raises electrical and thermal outputs but increases PV temperature by 28 K, indicating the need for stronger cooling at high CR. The proposed design provides a balance between PV durability, heat recovery, and stability against other designs.