Development of copper metal wool incorporated in a latent thermal energy storage tank for improved charging and discharging

Abstract

The thermal energy storage tank is an essential component of a conventional thermal energy storage system. Nevertheless, low charging and discharging rates is one of the different problems associated with them. Many research studies were conducted to improve the charging and discharging characteristics of thermal energy storage tanks. Those include the addition of nanoparticles, heat pipes, metal foams, and encapsulation of the phase change material. Even though those approaches improved the thermal performance of the storage tank, they also promoted some problems, like nanoparticle deposition, suppression of natural convection, and reduced energy density. This study, used a different approach to improve the thermal performance, integrating copper metal wool of two discrete thicknesses perpendicular to the heat transfer fluid carrying tubes. Accordingly, with two different packaging factor four different configurations of metal wool-packed tanks were developed and compared against the reference, i.e., a conventional shell and tube tank. The thermal performance of the developed cases was tested using a custom-built test rig. The integration of copper metal wool reduced the charging and discharging time significantly. However, the fully stacked fine fibre wool packed tank showed a remarkable 85% reduction in solidification time and a 37.4% reduction in melting time compared to the conventional shell and tube tank. Moreover, it showed a higher mean power than all the developed cases, with 414% enhancement during the discharging cycle and 42% during the charging cycle. Thus, the incorporation of metal wool into a tank is an effective way to enhance its thermal performance.