Thermal Performance of Aluminum Oxide Nanoparticles-Enhanced Latent Thermal Storage Heat Exchanger of Spiral-Wired Tube

Renewable energy sources are more acceptable and reliable by using efficient and well-design thermal storage. Therefore, enhancing the thermal performance of thermal storage is extensively studied. In the current work, the latent heat storage is a shell and a finned tube heat exchanger, the end of the fins being connected by a coiled spiral. Numerical investigation of the latent heat storage was performed by a three-dimensional model, with experimental validation. The heat transfer in the latent heat storage is improved by dispersing aluminum oxide nanoparticles with concentrations of 1%, 4%, 7%, and 10%. The outcomes confirmed that the distinguishing design of spiral enhances the heat transfer by convection, consequently rising the temperature of paraffin and accelerating the melting process. Nanoparticles increase the paraffin's low thermal conductivity, thus reducing the time required for completing the melting process. The higher the nanoparticles concentration, the greater the reduction in melting time and the improvement in thermal conductivity, whereas the highest concentration of nanoparticles gave 19.5% and 33% reducing in melting time and improvement in thermal conductivity, respectively.