Design and performance optimization of non-imaging concentrating photovoltaic thermal systems using grey relational analysis and response surface methodology

Non-imaging concentrators enhance photovoltaic thermal system efficiency by improving solar energy capture. However, selecting the optimal concentrator geometry remains challenging due to efficiency, cost, and acceptance angle constraints. This study optimizes concentrating photovoltaic thermal (CPVT) design using compound parabolic (CPC), V-trough, and compound hyperbolic (CHC) concentrators with varying truncation levels and incidence angles. By integrating Grey Relational Analysis (GRA) and Response Surface Methodology (RSM), forty-eight CPVT configurations were uniquely analyzed to identify the best balance between performance, geometry, and cost. The results indicate that V-trough achieved the highest thermal efficiency (66.2% at 0 degrees) and was particularly effective at small angles. CPC maintained stable efficiency across configurations, with moderate truncation (55%), reducing material costs while preserving performance making it a cost-effective option. CHC exhibited the steepest efficiency decline (64.9% to 30.0%) as the incidence angle increased. Due to lower PV temperatures, electrical efficiency improved with incidence angle and smaller reflectors, peaking at 30 degrees with 0.42 truncation. Truncation effects varied by concentrator type, with CPC being the least sensitive. GRG analysis shows that CHC remains more stable at higher incidence angles. RSM identifies incidence angle as the most influential performance factor, indicating that sun tracking may be necessary at larger angles. These findings provide a structured framework for CPVT system optimization, offering insights into the role of truncation and incidence angles in enhancing efficiency and economic feasibility, supporting large-scale adoption by reducing material costs while maintaining energy output, and making it a sustainable solution for enhanced solar energy utilization.