Myristic acid-hybridized diatomite composite as a shape-stabilized phase change material for thermal energy storage

Abstract

This study was aimed at developing a shape-stabilized composite phase-change material (PCM) for thermal energy storage. Raw diatomite was first purified via thermal treatment and acid-leaching to enhance the adsorption capacity of the PCM. The composite PCM was fabricated using myristic acid (MA) to hybridize diatomite via the vacuum impregnation method. Activated carbon (AC) was added to enhance the stability and conductivity of the composite PCM, and it could also be used to prevent the leakage of MA from the supporting materials. The maximum loading capacity and melting enthalpy of MA/H-diatomite-2 reached 72% and 124.3 J g⁻¹, respectively, and its thermal conductivity was as high as 0.58 W (m K)⁻¹. Note that the introduction of AC obviously reduced the melting and freezing periods and enhanced the heat transfer of the composite PCM. Furthermore, MA/H-diatomite-2 exhibits excellent thermal reliability after 200 cycles and could be potentially used in thermal energy storage systems.