Expedited energy charging of water using natural graphite flake for cool thermal storage.

This study investigates the solidification characteristics of deionized water dispersed with natural graphite flakes (NGF), called micro-particle enhanced phase change material (MePCM), in two spherical capsules of '64 mm' and '52 mm' diameter. Heterogeneous nucleation factor of deionized water reduces from 0.0531 to 0.0001 due to reduction in contact angle with addition of NGF. Thermal conductivity results show an enhancement of 25% in the MePCMs with 5 wt. % over the base PCM and the enhancement is not proportional to increase in mass fraction of NGF. The presence of NGF in deionized water eliminates the subcooling and expedites the solidification rate. The MePCM stores almost 94% of cool energy in a shortened duration compared to the base PCM in both capsules. In summary, the NGF can be a promising thermal enhancer to prepare the MePCMs in large scale at an affordable cost for the cool thermal energy storage applications. [ABSTRACT FROM AUTHOR]