Effect of Hybrid Nanoparticles on Melting Process in Annular Thermal Storage System

This study investigates numerically the melting performance of a hybrid nano-enhanced phase change material (NePCM) composed of lauric acid with silver (Ag) and copper oxide (CuO) nanoparticles inside an annular latent heat thermal energy storage system. The novelty of this work lies in the combination of Ag–CuO (50%–50%) hybrid nanoparticles with a periodically varying inlet temperature to evaluate the synergistic thermal behavior under dynamic conditions. A finite volume method, coupled with the enthalpy-porosity technique, is used to model the phase transition process, and the Boussinesq approximation is applied for buoyancy effects. Validation against experimental and numerical data confirms the model’s reliability with deviations below 8%. The results show that the hybrid NePCM significantly improves thermal conductivity, reduces melting time by up to 27% compared to pure PCM, and improves convective heat transfer and energy storage capacity. Optimal performance is observed at a 2% volumetric concentration of Ag–CuO nanoparticles. This work provides valuable insight into designing more efficient, compact, and responsive thermal storage systems for energy applications.