Hydrothermal and irreversibility numerical analysis of helical coil energy storage tank with nano-encapsulated PCMs: A comprehensive study with magnetic filled, Soret/Dufour, and metallic foam effects

<p dir="ltr">This paper numerically studied double diffusive free convection in a 2-D helical coil energy storage filled with nano-enhanced phase change material and a layer of porous foam. While previous studies have examined various aspects of energy storage systems, the combined effects of NEPCMs, magnetic fields, Soret/Dufour effects, and metallic foam in helical coil energy storage systems remain unexplored. This study presents the first comprehensive investigation of these combined effects, providing crucial insights for optimizing thermal energy storage systems. The cavity is rectangular with four circular heat sources on the right which are attached to a porous layer (0.1 W) while the cold is by the right wall. The considered parameters are Rayleigh number (103–105), fusion temperature (0.1 ≤ θf ≤ 0.9), Stefan number (0.1 ≤ Ste ≤ 0.9), the volume concentration of nanoparticles (0 ≤ ϕ ≤ 0.035), Darcy number, (10–4 ≤ Da ≤ 10–1), bouncy ratio (1 ≤ Nz ≤ 5), Lewis number (0 ≤ Le ≤ 10) and Hartmann number (0 ≤ Ha ≤ 50). The numerical analysis has exploited the finite element method. The main results state that the value of the Nusselt average increases with the increase of the volume concentration, bouncy ratio and fusion temperature while the Sherwood average shows reverse behavior to these numbers. On the other hand, average values of Nusselt and Sherwood are decreased with the rise of the Hartmann number. Furthermore, Nusselt average and Sherwood’s average decrease by 21.4 % and 24.9 % respectively when Darcy’s number increases from 0.1 to 10^-4.</p><h2>Other Information</h2><p dir="ltr">Published in: Applied Thermal Engineering<br>License: <a href="http://creativecommons.org/licenses/by/4.0/" target="_blank">http://creativecommons.org/licenses/by/4.0/</a><br>See article on publisher's website: <a href="https://dx.doi.org/10.1016/j.applthermaleng.2025.125651" target="_blank">https://dx.doi.org/10.1016/j.applthermaleng.2025.125651</a></p>