Hydrothermal and entropy analysis of micro-polar NEPCM with exothermic reactions and magnetic fields

Efficient thermal energy storage systems in solar collectors require enhanced heat transfer mechanisms. This study examines convective heat transfer in a partially porous evacuated tube solar collector manifold using phase change materials, magnetic fields, and porous media. The investigation focuses on heat transfer, mass transfer, and system irreversibilities. Results show that convective intensity dominates system performance, with a threefold increase in dimensionless convective flow strength enhancing heat transfer by 138 % and mass transfer by 304 %. Phase change material concentration shows opposing effects: a 13.7 % improvement in thermal transport but an 8.3 % reduction in mass transfer at higher flow intensities. Porous media characteristics significantly affect transport processes when permeability increases. Species diffusion and buoyancy forces demonstrate complex interactions affecting system behavior. Magnetic field application enables precise performance control. These findings provide design guidelines for optimizing solar collector efficiency through balanced parameter selection. • Combined NEPCM and magnetic fields enhance heat transfer by 138 % in solar collectors. • Rayleigh number dominates system performance with 304 % increase in mass transfer. • NEPCM concentration shows dual effect on heat/mass transfer and entropy generation. • Porous media and exothermic reactions offer precise control of transport processes. • Magnetic field orientation enables fine-tuning of system performance.