Influence of Angular Orientation of Fins on Thermal Charging and Discharging Performance of Latent Heat Storage Unit

this paper, numerical and experimental investigations of influence of fin orientations on thermal performance of a horizontal shell and tube latent heat storage unit having were performed for charging and discharging cycles. Stearic acid was used as a phase change material which was placed between annulus of shell and tube. A buoyancy driven transient numerical methodology was adopted to analyze three different angular orientations of external fins of tube carrying heat transfer fluid (30 degrees <= theta <= 90 degrees). The angle theta = 90 degrees produced A-fin configuration while theta = 30 degrees yielded Y-fin configuration. During charging cycle, a significant increase in heat transfer rate was observed for Y-fin configuration due to enhanced natural convection effects. The Y-fin configuration, for an heat transfer fluid of 358 K, improved the complete charging process by 51% along with 10% enhancement in total heat storage capacity of the latent heat storage unit as compared to lambda fin configuration. The Y-fin latent heat storage unit also resulted in augmentation of overall charging and dis-charging heat transfer rates by 13.7 and 4.8%, respectively. The heat transfer fluid temperature increase of 7.6% intensified the charging and discharging performance of Y-fin latent heat storage unit correspondingly by 80 and 12.9%. Lastly, correlations of charging and discharging time and Nusselt numbers were proposed as functions of Stefan number and Rayleigh number, respectively.