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

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 degrees) 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 (theta) and their thickness (w(mf)) 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, theta = pi/6 and w(mf) = 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 degrees (i.e., to a lambda-shaped orientation) to maximise the discharging process.

Automated summary

This study numerically analysed the performance of a circular LHTES under partial charging/discharging modes, revealing the significant impact of the angle and thickness of metal foam sheets on the charging/discharging process. The configuration with maximum complete charging power may not exhibit the best performance during partial charging, and a Y-shaped design can achieve optimal performance by charging in the upright orientation and then rotating 60 degrees.