Considerable attention is being paid in recent years to develop and improve alternative technologies to replace fossil fuels due to pollution problems and limited conventional energy sources. Solar thermal energy has been considering as one of the most attractive renewable sources to provide solution to the aforementioned problems. In recent years, latent thermal energy storage systems using phase change materials (PCMs) have been developed to aid energy supply and demand of solar thermal power plants. As one of the obstacles of these systems is the low thermal conductivity of PCMs, ceramic fin has been used in this study to enhance heat transfer rate between the PCM and heat transfer fluid. To assess the heat transfer characteristics of the triplex-tube thermal energy storage system with ceramic fin, a numerical model has been developed and the effect of fin for various Stefan numbers has been studied numerically. The heat transfer and solidification rates are significantly enhanced when connecting the fins between the inner and outer tubes.