Experimental study of a latent heat thermal energy storage system assisted by variable-length radial fins

Societal demands for energy are only increasing due to the global increase in electronics, infrastructure, and transportation. With this demand, it is necessary to improve the storage and retrieval techniques of renewable energy. Latent heat thermal energy storage (LHTES) may be an effective storage method, but the low thermal conductivity of phase change materials (PCMs) hinders their response time. In the current study, the use of variable length radial fins was experimentally compared against uniform length radial fins on the charging and discharging processes of a LHTES system with RT-55 PCM. Four cases of variable radial fins, two with four fins and two with eight fins, were analyzed against four equivalent thickness uniform length radial fin configurations. The fin configurations were attached to a central copper pipe in a shell and tube LHTES system where the PCM was contained. The charging and discharging times of the PCM when enhanced with fins were compared to a benchmark case with no fins. The benchmark case with no fins took 47.87 h to fully charge and 42.50 h to discharge. The configuration with four variable length fins extending the furthest into the PCM decreased charging and discharging times by 79.34 % and 49.53 % compared to the benchmark which was the highest decrease in total time compared to all fin configurations.