Characterising phase transition and thermal behaviour of phase change material with nanobubbles: A comparative molecular dynamics study

Abstract

Global warming and the rising demand for sustainable energy have intensified interest in efficient thermal energy storage. Phase change materials (PCMs) offer high latent heat storage capacity but have poor thermal performance. By incorporating nanoscale additives, nano-enhanced PCMs can improve overall efficiency in renewable energy applications. Nanobubbles (NBs), gaseous cavities under 1 μm, have unique properties that make them promising candidates for various industrial applications, including in the energy and power sectors. Molecular-level approaches can provide valuable insights into the thermal effects of NBs. In this study, molecular dynamics simulations were employed to simulate the phase transition behaviour and thermal properties of NB enhanced dodecane. This study explored different NBs of hydrogen, nitrogen, and oxygen and compared with the pure dodecane in comparative analysis. The findings demonstrate that the incorporation of NBs, particularly hydrogen NB, depresses the liquid-to-solid transition temperature of dodecane. Additionally, the presence of NBs enhances both thermal conductivity and specific heat capacity, with nitrogen NBs yielding the highest increase in thermal conductivity by approximately 14 %. Furthermore, nitrogen and hydrogen NBs were identified as promising candidates for high-temperature applications due to their stability over a wide temperature range; however, their presence also results in an increase in viscosity.