Solar thermal radiation and Cattaneo–Christov heat transport in magnetohydrodynamic photovoltaic-thermal cooling systems under rotating flow

The integration of photovoltaic-thermal (PVT) systems with advanced cooling techniques is crucial for improving energy efficiency and overcoming performance limitations in solar energy conversion. This study investigates the combined effects of solar thermal radiation, Cattaneo– Christov non-Fourier heat transport and magnetohydrodynamic (MHD) rotating flow on PVT cooling performance. The purpose is to provide a deeper understanding of how thermal and electromagnetic interactions influence heat transfer and system efficiency, particularly under conditions where conventional Fourier-based models fall short. A carboxymethylcellulose (CMC)–water-based base fluid enhanced with nanoparticles zirconium oxide (ZrO 2 ), copper (Cu) and aluminum oxide (Al 2 O 3 ) is employed as the working medium to further boost thermal conductivity and system efficiency. A mathematical model is developed to capture the dynamics of radiative heat flux, magnetic field, rotation and nonlinear thermal relaxation effects. The governing equations are transformed into dimensionless form and solved numerically using a Chebyshev collocation method. The results demonstrate that the inclusion of ZrO 2 , Cu and Al 2 O 3 nanoparticles in the CMC–water base fluid significantly improves thermal conductivity, thereby enhancing the system’s cooling capacity. Under solar thermal radiation, ternary hybrid nanofluids demonstrate approximately 20% superior thermal regulation. The novelty of this work lies in the synergistic analysis of MHD rotating flow, Cattaneo–Christov heat transport and nanoparticle-engineered CMC-based fluids for PVT cooling, providing new physical insights and practical guidelines for the design of high-performance renewable energy systems.