Bubble-driven flow enhancement of heat discharge of latent heat thermal energy storage

In this paper, the use of bubble-driven flow on phase change material (PCM) is proposed to improve the discharge performance of a latent heat thermal energy storage system (LHTES). The upward momentum of bubbles due to its density difference can agitate liquid PCM and increase the flow velocity of liquid PCM to enhance heat transfer between the heat transfer fluid (HTF) and the PCM. To analyze the mechanism of enhanced heat transfer, visualization techniques of particle image velocimetry (PIV) and shadowgraphy were used. The result showed that the discharge time of LHTES decreased by 6%-12%. The increased flow velocity by bubble-driven flow could be observed and the expanded phase change region away from the solid/liquid interface could be identified. The average convective heat transfer coefficient is increased by maximum 1.79 times during the heat discharge period. This mechanism could accelerate the solidification process and enhance the energy discharge rate of the LHTES. Bubble-driven flow could be successfully applied to PCM to improve LHTES discharge performance.(c) 2022 Elsevier Ltd. All rights reserved.

Automated summary

This paper proposes the use of bubble-driven flow to improve the discharge performance of a latent heat thermal energy storage system (LHTES) by enhancing heat transfer. Experimental results show that bubble-driven flow can reduce the discharge time of LHTES and increase the convective heat transfer coefficient. The study demonstrates the successful application of bubble-driven flow to phase change materials for improved LHTES discharge performance.