Optimization of fin design and nanoparticle doping for accelerated PCM melting

Latent heat thermal energy storage (LHTES) represents a promising renewable energy technology that can help alleviate the global energy shortage. This work numerically investigates the thermal charging process in a n-octadecane PCM-based double-pipe LHTES using a 2D COMSOL Multiphysics model. The study evaluates and analyzes the performance enhancement of the LHTES with various metallic fins, different distributions, inner tube placement, and Cu nano-additive concentrations. The study examines five fin arrangements, C 1 to C 5, three positions of the inner tube, P 1 to P 3, and three concentrations of Cu nanoparticles, 0%, 2%, and 4%. Results showed that among the five arrangements examined, C5 had the lowest melting time, up to 18.5% lower than the worst-performing configuration (C4). The inner tube position P2 outperforms P1 and P3, obtaining 99% melting in 24 min. Moreover, the 4% Cu concentration was superior, resulting in complete melting in 21 min, which is an improvement of 12.5% compared to the pure PCM.