Analyzing and optimizing the melting process by applying external forces and adjusting the geometry and material composition offers significant advantages for various industrial applications, including energy storage systems, thermal management components, and casting processes. This study focuses on the enhancement of the melting process in a latent heat thermal energy storage system (LHTES) by applying both passive and active techniques. The LHTES chamber containing nanoparticle enhanced phase change material (NEPCM) is partitioned into several sections (1, 2, 4, 6, and 8). Furthermore, a cylindrical permanent magnet is used to manipulate the magnetic nanoparticles motion in the liquified PCM. It is shown that increasing the number of partitions improves the heat transfer and melting by intensifying the natural convection and increasing melting fronts and the interface between solid and liquid phases. Moreover, applying the magnetic field further accelerates the melting by enhancing flow circulation within the NEPCM, particularly around the heated surfaces. Results also indicate that the total melting time is reduced as the magnetic field intensity increases, demonstrating the synergistic effect of chamber partitioning and magnetic field application in optimizing LHTES performance. At the highest magnetic field intensity considered, the total melting times for 1-, 2-, 4-, 6-, and 8-chamber configurations are 900 s, 565 s, 445 s, 382.5 s, and 310.5 s, respectively. Furthermore, relative to the 1-chamber case without an external magnetic field (melting time: 994 s), the 8-chamber configuration reduces the melting time by 53.93 % (to 458 s) in the absence of a magnetic field and by 68.77 % (to 310.5 s) when a magnetic field of 1.38e5 A/m is applied.
