A new design to enhance the conductive and convective heat transfer of latent heat thermal energy storage units

Abstract

• Evaluation of latent heat TES assisted by twisted-wavy tube and conical container. • Lower charging time using twisted-descending wavy elliptical tube. • The maximum use of natural convection by employing conical container. • A decrease of 43% in charging time using appropriate conical container. • Improvement in melting time by dispersing nano particles into the PCM. The gap between the existing energy demand and supply is of immense significance worldwide, suggesting the need to develop highly effective storage technologies. This study concerns an innovative design for Phase Change Material (PCM) thermal energy storage suitable for solar energy applications. The proposed configuration for the tube benefits from the wavy profiles with different amplitude characteristics and the twisted shape. The impacts of the simultaneous implementation of the wavy and twisted tube are also examined to achieve an optimal model. The best design for the thermal energy storage is then integrated with the ascending and descending conical container shapes to gain the potential advantage of natural convection. Ultimately, the best case is treated with the nanoparticles (1, 3 and 5 vol%) to enhance thermal conductivity in the storage. The results reveal that the descending wave amplitude is the most effective profile when the least charging time is needed. Furthermore, the ascending conical shape container enhances the charging process (68 min for the complete charging process), taking full advantage of the natural convection phenomenon. Overall, the ultimate heat storage design offers nearly 83 % faster charging time than conventional straight tube heat storage units.