Numerical investigation of melting process enhancement in shell and coil latent heat storage tanks by the simultaneous use of conical coil and conical shell

Efficient energy storage rates are crucial for latent heat energy storage units. Building on previous studies highlighting the benefits of shell and helical tube configurations, which enhance energy storage rates through increased heat exchange areas, this research introduces a novel configuration featuring a combination of conical shell and conical coil. Various geometric variations, including conical/cylindrical shells and conical coils, are explored to assess their impact on charging performance using numerical simulations based on the enthalpyporosity method. The study investigates three different numbers of coil turns (4, 6, and 8) for each configuration. Results demonstrate that the proposed conical shell and conical coil configuration significantly accelerates the melting rate, achieving a liquid fraction of 0.897 within 160 min-an improvement of 7.6 % compared to the conventional shell and helical tube configuration with the same phase change material quantity. Additionally, increasing coil turns from 6 to 8 yields an 8.8 % rise in the liquid fraction for the simple cylindrical case, comparable to the 7.6 % increase achieved by the proposed conical configuration. The findings underscore the preference for geometry modifications over increasing coil turns, as the latter leads to greater space occupation within the tank, resulting in reduced energy storage capacity and a concomitant 30 % undesirable increase in heat transfer fluid pressure drop.