Investigation of phase change material solidification process in a LHTESS in the presence of fins with variable thickness and hybrid nanoparticles

Present study deals with performance improvement of Latent Heat Thermal Energy Storage Systems (LHTESS) with Phase Change Material (PCM) during the solidification process. The released thermal energy during the solid-liquid phase change is stored in LHTESS. Due to poor thermal conductivity of conventional PCMs, Al2O3 - Go hybrid nanoparticles are dispersed into the pure PCM to make Hybrid Nano-Enhanced Phase Change material (HNEPCM). Moreover, fins with variable thickness are applied to expedite the solidification process. In this paper, separate analyzes are investigated for evaluating the effects of adding fins and hybrid nanoparticles. At first, the influence of fin geometric parameters on the solidification acceleration is analyzed, and the best fin configuration is determined using Response Surface Method (RSM) optimization. Then, the influence of dispersing hybrid nanoparticles with different volume fractions into the pure PCM on the solidification rate is reviewed. Also, the outcomes of accelerating the solidification process by using fins and hybrid nanoparticles are compared together. In this study, the unsteady governing equations of the solidification process are solved numerically using standard Galerkin Finite Element Method (FEM). Results depicted that employing optimized fin results in higher solid fraction rate in comparison with dispersing hybrid nanoparticles into the PCM.