Melting of phase change materials in thermal storage unit with uniform and non-uniform distribution of fins

Utilizing solar energy to provide sustainable and clean energy requires a thermal energy storage (TES) system as a bridge between an energy source and energy demand. The phase change materials (PCM) are effective TES mediums. Inserting the fins within the PCM system is considered an effective thermal augmentation technique. In the current investigation, the influence of uniform and non-uniform distributions of four longitudinal fins in the bottom portion of the shell and tube TES cavity on the PCM charging is examined experimentally and numerically. An agreement of more than 91.2% is shown between the computational and experimental outcomes of the melt fraction. Inserting the fins decreases the fluctuation and produces more stabilization of the PCM temperature. Compared to the unfinned TES cavity, the charging duration declines by 78.1% and 60.4% by using a TES unit with non-uniform and uniform fin distributions, respectively. Additionally, the HTF temperature has a critical influence on melting duration. Raising the HTF temperature from 60 to 80 °C lowers the melting duration by 44.2%, 47.3%, and 49.1% unfinned, uniformly finned, and non-uniformly finned TES units, respectively. Moreover, utilizing a non-uniform fin distribution increased the stored thermal energy within the TES compared to the unfinned TES and the TES with a uniform fin distribution. Overall, the non-uniform fin distribution demonstrated superior performance compared to the uniform distribution. Therefore, future research can be conducted to investigate the impact of non-uniform fin distribution configurations, layouts, arrangements, and combinations with other PCM thermal conductivity enhancement techniques.