Synergistic Heat and Illumination Management in Phase Change Material Assisted Spectral-Splitting Photovoltaic/Thermal Collector Design

Concentrated photovoltaic/thermal (CPV/T) systems remain limited by incomplete spectral control and inadequate thermal decoupling between the photovoltaic cell and the thermal absorber, while most existing models do not fully resolve phase change material (PCM) optical transitions or compare receiver designs under consistent conditions. To address these gaps, this study develops and validates a three-dimensional transient multiphysics CFD model of a CPV/T receiver incorporating a hybrid spectral filter composed of a selective liquid filter (water or propylene glycol) and a PCM layer (RT25 or S27). The model incorporates non-gray radiation and temperature- and phase-dependent optical properties to accurately capture the transient coupling of optical, thermal, and electrical processes during PCM melting. Parametric analyses are conducted to assess the effects of SLF/PCM material selection, Reynolds number, concentration ratio, seasonal boundary conditions, filter thickness, and alternative receiver topologies on system performance. Results show that accurately accounting for PCM optical evolution is essential for realistic prediction of spectral beam splitting and system transients. Propylene glycol accelerates PCM melting and enhances gross thermal recovery, while water provides stronger infrared shielding and negligible pumping penalty; PW-S27 at higher Re is recommended for practical operation, reaching about 48.3% net efficiency. Increasing CR from 10 to 40 improves PCM activation and energy yield while the air-gap-assisted design limits PV temperature rise. Topology analysis confirms that the proposed hybrid filter above the PV cell provides the best durability-oriented performance, reducing degradation acceleration factor by 5.69 compared with the filterless case while maintaining high useful heat recovery. This work provides design guidance for durable, high-flux CPV/T spectral filters.