Enhancement of cold thermal storage performance via the synergistic integration of hybrid nanofluids, radiative cooling, and porous foam

The present study evaluates the performance of a cold energy storage unit composed of a trapezoidal chamber filled with porous material and cooled through a sinusoidal boundary. The analysis is carried out numerically using the Galerkin method combined with adaptive mesh refinement to improve solution accuracy. The freezing process is modeled by incorporating multiple thermal enhancement strategies, including porous foam, hybrid nanoparticle-enhanced phase change material (PCM), and radiative cooling, while the effect of gravity is neglected to simplify the physical model. The results indicate that porous foam significantly enhances thermal performance and ensuring more isotherms. In addition, the inclusion of hybrid nanoparticles modifies the thermophysical properties of the working fluid, leading to an accelerated freezing process. According to the simulation results, porous foam increases the solidification rate by approximately 75.22%, mainly due to the dominance of conduction over natural convection within the porous structure. The addition of hybrid nanoparticles further improves the freezing performance by about 5.11%, highlighting their contribution to enhanced thermal diffusion. Incorporating radiative heat transfer strengthens the overall cooling mechanism, which significantly accelerates solidification and lowers the total freezing period by approximately 38.29%.