Numerical simulation on phase-change thermal storage/release in a plate-fin unit

The fluid flow and heat transfer in a plate-fin unit with a characteristic length of 2 mm used for rapid heat storage/release by paraffin (phase change material, PCM) are investigated numerically. Transient simulations are performed using a commercial computational fluid dynamics (CFD) package, Fluent, based on the finite volume method. The effect of temperature differences on the fluid flow and heat transfer in the energy storage/release system is analyzed. It is found that temperature differences play a key role in the performances of energy storage when temperature differences are less than 20 °C. It is noted that part of not solidified PCM can be observed clearly during energy release, and a vortex in the air region is formed remarkably at the moment of complete thermal energy release. The correlations are developed as a function of the associated variables. The obtained correlations are useful for future component design and system optimization. Additionally, Experimental data taken from the literatures are conducted to validate the model. The numerical results show a good agreement with the experimental ones. Part of not solidified PCM can be found throughout the energy release process. A vortex appears in the air region at the end of thermal release in comparison with smaller velocity of air and stronger nature convection of PCM at the end of thermal storage. [Display omitted] ► Numerical study the latent thermal storage/release processes. ► Temperature differences play a key role during energy storage process. ► Part of not solidified PCM and a vortex appear during energy release. ► The correlations are established for future design and optimization.