Optimizing solidification process in phase change energy storage units with sinusoidal wave-shaped fins

Abstract

Phase change energy storage units have attracted considerable interest in the field of energy storage technology. To overcome the challenge of low thermal conductivity associated with phase change material (PCM) employed in these units, researchers have implemented fins with various shapes. In this study, a two-dimensional numerical model of a phase change energy storage unit with newly designed sinusoidal wave-shaped fins is developed. The analysis is done using commercial software ANSYS-Fluent in the transient state. The solidification process of the PCM is evaluated with enthalpy–porosity method. The validation of the model is done against an experimental result from a published article. The study focused on increasing the surface area of sinusoidal wave-shaped fins, achieved by increasing its crests and troughs counts, and to analyse its impact on the solidification process of the PCM. The thermal performances are evaluated quantitatively by analysing the solidified portion of PCM, temperature distribution, rate of heat release, and velocity variation. The result shows that the total solidification time predicted for straight fin is 115.34 minutes. This duration reduces for wave-shaped fins, and it reduces even further as the crests and troughs counts of wave-shaped fins increases. The maximum reduction in total solidification time is observed as 19.93% for wave-shaped fin with 10 crests and troughs counts. It is also observed that rate of reduction in total solidification time initially decreases then marginally increases with the increase in crests or troughs counts. The effect of buoyancy on the PCM flow velocity is analysed at different locations within the phase change energy storage unit. It is observed that with the increase in crests and troughs counts the movement of PCM near the crest or trough decreases.