Investigation on Melting Process of Finned Thermal Energy Storage with Rotational Actuation

Phase-change thermal storage is essential for renewable energy utilization, addressing spatiotemporal energy transfer imbalances. However, enhancing heat transfer in pure phase-change materials (PCMs) has been challenging due to their low thermal conductivity. Rotational actuation, as an active method, improves heat transfer and storage efficiency. This study numerically examined the melting behavior of finned thermal storage units at various rotational speeds. The influence of speed was analyzed via melting time, rate, phase interface, temperature, and flow distribution. Results showed that rotational speed effects were non-monotonic: excessive speeds may hinder complete melting or reduce efficiency. There existed an optimal speed for the fastest melting rate and a limited speed range for complete melting. At the preferred rotation speed of 2.296 rad·s⁻¹, the utilization of PCMs in a finned tube could mitigate the risk of local overheating by 97.2% compared to a static tube, while improving heat storage efficiency by 204.9%.