Review of PCM charging in tabular latent heat thermal energy storage systems

This paper includes a review of several previous studies associated with the charging behavior of phase-change materials (PCM) in horizontal and vertical tabular (annular) Latent Heat Thermal Energy Storage (LHTES) units. The effects of various factors on charging, such as heat transfer fluid (HTF) inlet temperature, the eccentricity of the inner tube, the inclination angle of the storage unit ( −90◦, −60◦, −30◦, 0◦, 30◦, 60◦, 90◦), and the mass flow rate of HTF are investigated. Natural convection controls the charging process in the upper part of the thermal storage unit, while thermal diffusion dominates the melting in the lower part. Also, the HTF inlet temperature has a clear and significant effect on reducing the melting time of PCM. In addition, increasing the inner tube eccentricity results in a reduction in the charging time.