Numerical investigation of performance enhancement in a PCM-based thermal energy storage system using stair-shaped fins and nanoparticles

This study numerically investigates the melting performance enhancement of phase change material (PCM) in a latent heat thermal energy storage (LHTES) unit using a novel stair-shaped fin and nano-enhanced PCM. Different fin configurations are designed and their thermal performance is compared to traditional straight fins, while the total mass of fins is kept constant. Nano-enhanced PCM is prepared by the inclusion of CuO nanoparticles into RT82 as PCM. The simulation results reveal that the stair-shaped fins can notably enhance the efficiency of phase change compared to the traditional straight fins. The configuration with more extended fin close to the lower zone of the latent heat thermal energy storage unit had the best thermal performance. The full PCM melting time for the most efficient stair-shaped fin configuration is reduced by 52% compared to the straight fins. The combined impacts of the most effective stair-shaped fin design and nanoparticles on the phase change melting performance are evaluated. The inclusion of nanoparticles with volume concentrations of 2% and 5% into the pure PCM leads to 61% and 65% reduction in charge rate, respectively, as compared to the straight fin with pure PCM.