Abstract
This study examines the effect of packing fraction on shell- and tube-based latent heat energy storage units. To determine the performance of these systems, a three-dimensional transient numerical analysis has been carried out using Ansys, Fluent. This study address flow, heat transfer, melting, and solidification processes. The K-Omega SST model has accounted for turbulent flow regimes in the heat transfer fluid (HTF) and the phase-changing material (PCM). The HTF’s inlet temperature was set at 495K during the charging cycle, while it was set at 285K during the discharging cycle. A velocity boundary condition has been applied at the HTF inlet, with a Reynolds number of 5,000 considered. Furthermore, a symmetric boundary condition has been applied at the outer boundaries of the PCM to reduce the size of the shell and tube system.
The packing fraction values of 0.1, 0.2, 0.3, and 0.4 were considered while maintaining a constant volume of PCM across all cases. The performance characteristics, such as melting and solidification rates, total energy stored and discharged, and average PCM temperature, were analyzed. Although all four cases stored similar amounts of energy, the packing fraction 0.3 exhibited slightly higher thermal energy absorption at the end of the charging cycle, about 8.2% more than the 0.1 packing fraction. The packing fraction 0.4 demonstrated the fastest melting and solidification rates and the highest energy absorption and discharge rates at any given time. Meanwhile, the packing fraction 0.1 had a lower energy absorption rate but remained more consistent throughout the charging cycle when compared to higher packing cases.
