Hybrid nano improved phase change material for latent thermal energy storage system: Numerical study

The phase change materials (PCM) are widely used in several applications, especially in the latent heat thermal energy storage system (LHTESS). Due to the very low thermal conductivity of PCMs. A small mass fraction of hybrid nanoparticles TiO2-CuO (50%-50%) is dispersed in PCM with five mass concentrations of 0%, 0.25%, 0.5%, 0.75% and 1 mass % to improve its thermal conductivity. This article is focused on thermal performance of the hybrid nano-PCM (HNPCM) used for the LHTESS. A numerical model based on the enthalpy-porosity technique is developed to solve the Navier-Stocks and energy equations. The computations were conducted for the melting and solidification processes of the HNPCM in a shell and tube latent heat storage (LHS). The developed numerical model was validated successfully with experimental data from the literature. The results showed that the dispersed hybrid nanoparticles improved the effective thermal conductivity and density of the HNPCM. Accordingly, when the mass fraction of a HNPCM increases by 0.25%, 0.5%, 0.75% and 1 mass %, the average charging time improves by 12.04 %, 19.9 %, 23.55%, and 27.33 %, respectively. Besides, the stored energy is reduced by 0.83%, 1.67%, 2.83% and 3.88%, respectively. Moreover, the discharging time was shortened by 18.47%, 26.9%, 27.71%, and 30.52%, respectively.