Partial charging/discharging of bio-based latent heat energy storage enhanced with metal foam sheets

Abstract

Due to the intermittent/volatile nature of renewable energy resources, they may periodically fail to provide enough energy to complete the charging/discharging processes of Latent Heat Thermal Energy Storage (LHTES) systems. However, only a limited understanding is available for the implications of partial charging/discharging. To address this knowledge gap, the present study numerically analysed the performance of a circular LHTES under partial charging/discharging modes. Three sheets of aluminium foam (all spaced equally at 120°) were added to enhance the thermal response of the storage. Sixteen different storage configurations were studied and revealed that the angle of the right-most metal foam sheet (θ) and their thickness (wmf) considerably affect the charging/discharging process. According to the proposed capacity-based and time-based charging/discharging powers, it was found that the configuration with maximum complete charging power (case no.7, θ=π/6 and wmf=7 mm) does not necessarily exhibit the best performance during partial charging mode. Instead, case no.7 has up to 6% lower charging power than the other cases when partially charged. Finally, it was revealed that a Y-shaped design can achieve optimal performance if it is charged in the upright orientation, but rotated 60° (i.e., to a ⅄-shaped orientation) to maximise the discharging process.