Melting Process Enhancement in Double Pipe Storage with Multiple Latent Heat Storage Materials and Oriented Fins

Combining more than one passive enhancement method can significantly improve the latent heat storage performance. This paper investigates the effect of multiple PCMs (phase change materials) used in the same storage unit as well as fins and their orientation for improving the performance of LHTES (latent heat thermal energy storage) in a double pipe storage configuration. A 2D mathematical model based on the enthalpy-porosity method is used for simulations along with finite volume techniques. Validation is conducted by comparing the numerical predictions with both numerical and experimental data available in the literature. Liquid fraction, temperature distribution, energy storage, and charging time are analyzed for the melting process considering the fin number, fin orientation, and dual-PCMs positions. Results show that adding two horizontal fins reduces the charging time by 16 %, while using dual PCM with fins reduces the charging time by 25 %. Furthermore, orientation of fins (inclination of 120(degrees)) leads to 46.5 % shorter melting time compared to the horizontally finned unit. These results help in designing of efficient and cost-effective thermal energy storage systems.