Preparation and properties of lauric acid/diatomite composites as novel form-stable phase change materials for thermal energy storage

Abstract

The lauric acid (LA)/diatomite composite phase change materials (PCMs) were prepared using a direct impregnation method, in which LA was chosen as PCM. The chemical structure, chemical compatibility, element composition, crystalline structure, thermal properties and thermal stability of LA/diatomite composite were extensively investigated by Fourier transform infrared (FTIR) spectroscopy, energy dispersive spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry and thermal gravimetric analysis. FTIR and XRD results indicate that there are only physical interactions between LA and diatomite in LA/diatomite composite. The decrease of XRD intensity of composite PCM confirms the reduction of the crystalline size of LA in LA/diatomite composite. The melting and freezing temperatures of composite PCM are 40.9°C and 38.7°C respectively. The latent heat of composite PCM is 57.2J/g. LA/diatomite composite does not decompose when the surrounding temperature is lower than 157°C, indicating that the composite PCM has a good thermal stability.