Expanded vermiculite supported capric–palmitic acid composites for thermal energy storage

Abstract

In this study, the potential application of expanded vermiculite (EVM) as the supporting material and capric–palmitic acid (CA–PA) binary eutectic as the adsorbent mixture to fabricate a form-stable composite CA–PA/EVM by a vacuum impregnation method was investigated. The prepared form-stable composite CA–PA/EVM was then characterized by scanning electronic microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TG), differential scanning calorimetry (DSC) and a thermal cycling test. The maximum loading capacity and melting enthalpy of CA–PA/EVM could reach 51.84% and 67.5 J g⁻¹. Meanwhile, the thermal physical and mechanical properties of the CA–PA/EVM-based thermal energy storage mortars were examined to determine if the composite material based on the newly invented CA–PA/EVM material can be employed for energy conservation and efficiency in the building field. In addition, the law of full-field deformation evolution of CA–PA/EVM-based thermal energy storage mortar under uniaxial compression failure was studied based on digital image correlation (DIC) technology, which provides certain guiding significance for the application of CA–PA/EVM-based thermal energy storage mortars in practical engineering.