Nanoscale insight into the thermal properties of lauric acid and CuO based phase change material used for thermal energy storage

Abstract

Lauric acid (LA) based phase change material (PCM) has been broadly used for thermal energy storage, whereas its poor thermal performance limits its practical application. In this paper, the microscale structure of LA as the PCM and CuO nanoparticles based composite PCM was established, the thermal properties including density, thermal diffusion, thermal conductivity, melting enthalpy were predicted by means of molecular dynamics (MD) simulations. The microscopic structure evolution and phase transition characteristic of the CPCM system were observed and investigated by structure snapshots and thermal diffusion behaviors. The addition of CuO nanoparticle makes the self-diffusion coefficient of LA based PCM decreased by 15.13 %, and addition of CuO nanoparticle is an effective way to enhance the thermal conductivity of LA based PCM significantly, and it can lead to a 33.765 % increase on average in thermal conductivity with an addition fraction of 6.86 wt%, the melting enthalpy was decreased by 17.57 %, and possible mechanism was revealed at nanoscale. This study is expected to be helpful for the preparation, performance enhancement and practical application of LA based PCM.