Super-fast charging/discharging using a coil configuration: A comparative study on phase change dynamics and thermal performance

This study examines the thermal efficacy of Phase Change Materials based heat exchanger using diverse coil designs to improve heat transfer efficiency in latent heat thermal energy storage systems. The investigation examines the influence of geometric alterations on the melting and solidification processes. The system examined consists of a double-pipe heat exchanger with a rectangular duct including inner tubes configured in various coil arrangements to optimize phase change phenomena inside the PCM domain. Essential measurements encompass melting duration, thermal storage rate, temperature distribution, and velocity profiles of the phase change material. The phase change material employed is RT 35, with a mass of roughly 1 kg, contained within a square enclosure of 40 mm × 40 mm. Three principal scenarios are examined: a single coil cycle (Case 1), two coil cycles (Case 2), and three coil cycles (Case 3). The findings indicate that augmenting the number of coil cycles markedly improves heat transfer rates, decreasing the melting duration from 494 s in Case 1 to 81 s in Case 3, while elevating the heat storage rate from 485.57 W to 2951.13 W. Moreover, the examination of velocity distribution reveals intensified natural convection currents with increased coil cycles, leading to a uniform temperature distribution and expedited phase transitions. Research on solidification indicates that although a larger surface area improves melting, the efficiency improvement differs for solidification processes. These findings highlight the necessity of optimizing coil shape in PCM-based thermal energy storage devices to get enhanced thermal performance. • Design a novel coil configuration for super-fast charge/discharge • Enhance charging rate from 133 W to 4830 W compared with conventional systems • Enhance discharging rate from 7.6 W to 469 W compared with conventional systems • Optimized coil design enhances PCM charging and discharging efficiency. • Novel LHTES system enables faster thermal energy storage and retrieval.