Solidification acceleration in a triplex-tube latent heat thermal energy storage system using V-shaped fin and nano-enhanced phase change material

•Solidification process of PCM and NEPCM in the triplex-tube LHTESS are studied.•Effect of V-shaped fin on the solidification acceleration is investigated.•Geometric parameters of V-shaped fin are optimized using RSM.•FEM is used to simulate the solidification process.•V-shaped fin causes faster solidification process than nanoparticle dispersion. This study deals with solidification expedition of Phase Change Material (PCM) in a triplex-tube Latent Heat Thermal Energy Storage System (LHTESS) by employing V-shaped fins and nanoparticles as enhancement approaches. The application of such systems is to balance the energy supply and requirement. Both approaches are used to compensate for the insignificant thermal conductivity of pure Phase Change Material and preventing the solidification process from weakening. In first enhancement approach, Response Surface Method (RSM) is used to optimize the geometric parameters of V-shaped fins to achieve best fin arrangement. The objective function of fin optimization is minimizing the Full Solidification Time (FST) to achieve the accelerated phase change process. In the second approach, SWCNT nanoparticles are dispersed to the water as Phase Change Material, and Nano-Enhanced Phase Change Material (NEPCM) is formed. Both approaches are performed separately and their results are compared. The simulation of solidification process is carried out utilizing Standard Galerkin Finite Element Method (SGFEM) along with adaptive grid refinement strategy. Results exhibited that using V-shaped fin in the system causes higher acceleration to the procedure, in comparison with nanoparticles dispersion.