Enhancement of heat transfer through the incorporation of copper metal wool in latent heat thermal energy storage systems

Abstract

The design of thermal energy storage (TES) tank is the key part that can limit charging and discharging process. Most research findings highlight that the use of fins augments the heat transfer rate. This work experimentally investigates the use of aligned copper wools as fillers to enhance the thermal performance of a lab-scale shell-and-tube TES tank filled with phase change material (PCM). Two copper wools with different fibre thicknesses were chosen and discretely laid around the TES tank tubes in two design patterns. Accordingly, five shell-and-tube TES tank configurations were obtained, including the reference, for performance evaluation. The TES tank was loaded with n-octadecane as PCM for all the cases studied. The results showed up to a 16 % reduction in melting time with the inclusion of copper wool. The TES tank significantly increased the mean power during charging (53 %) and discharging (205 %). The addition of metal wool into the TES tank enables the PCM to release the heat at a constant temperature during the entire phase transition process. And the overall efficiency of the TES tank was found to get improved. Therefore, a copper wool integrated TES tank would be a beneficial addition to thermal energy storage systems.