Direct impregnation and characterization of Colemanite/Ulexite-Mg(OH)2 paraffin based form-stable phase change composites

Paraffin is mainly preferred as an organic phase change material (PCM) in thermal energy storage (TES) systems especially for cooling and heating of buildings implementations. In order to develop form-stable and thermally stable blends natural minerals (Colemanite, Ulexite and Mg(OH)2) were used to prepare composites via direct impregnation method. These mineral compounds are abundant locally and known to be thermally stable as they show multi-step thermal decompositions. Thermal, morphological and chemical properties of these composites were characterized by thermogravimetric analysis (TGA), the differential scanning calorimetry (DSC), Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscope (SEM). Results of analyses indicate that the introduction of mineral phase to the paraffin is achieved adequately despite of minor mixing problems that show a form-stable behaviour. Comparing energy storage abilities of these composites, Mg(OH)2 or Colemanite containing blends are found to be the promising composites. •Boron-based PCM Composites of non-toxic nature were prepared.•A simple direct impregnation method was used.•Colemanite, Ulexite, Mg(OH)2 composites are developed for TES building applications.•Thermal and physical analyses are carried out to determine mineral influence in PCM.