Developing a self-made composite phase change material (PCM) of 1% XG + 90% SAT + 9% EG has resolved the phase separation issue of sodium acetate trihydrate (SAT) composite PCM and prevented the deposition of SAT, thereby enhancing the stability of the energy storage and release process in thermal energy storage units. The study focuses on a casing PCM thermal energy storage device filled with 1% XG + 90% SAT + 9% EG. A novel rotating longitudinal fin structure composed of F-type fins for the composite phase change material (CPCM) casing is proposed to improve the charging and discharging performance of the latent heat thermal energy storage system (LHTES). The phase change heat transfer process was simulated through numerical simulation. Designs of 3F, 4F, 5F, and 6F fin structures were all capable of reducing the charging/discharging time, with the 6F fin structure having the shortest charging/discharging time. Compared to the finless structure, the 6F fin structure reduced the complete melting/solidification time by 63.83% and 68.45%, respectively. Compared to the conventional straight fin structure, the 6F fin structure reduced the complete melting/solidification time by 28.56% and 33.27%, respectively.