Mixed mill-heating fabrication and thermal energy storage of diatomite/paraffin phase change composite incorporated gypsum-based materials

•Diatomite/paraffin composites is fabricated by the mixed mill-heating method.•The fabricated gypsum-based phase change composites have high thermal stability.•Thermal storage composites is improved with increase of paraffin/diatomite content. The thermal energy storage of gypsum-based material was developed by incorporating diatomite/paraffin composite phase change materials. A diatomite/paraffin composite was first fabricated using mix proportions (paraffin:diatomite) of 0.6:0.4, 0.55:0.45, 0.5:0.5, and 0.45:0.55. The diatomite/paraffin composite was then incorporated in a gypsum based composite at 10%, 20%, and 30% of the gypsum weight. The scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FT-IR) and X-ray fluorescence spectrometer (XRF) results show that paraffin can be effectively impregnated into diatomite pores and has good compatibility. The differential scanning calorimetry (DSC) results reveal that the diatomite/paraffin composite has phase transition and latent heat temperatures of 70°C. High thermal stability is observed for this fabricated diatomite/paraffin composite according to the thermo-gravimetric analysis (TG) method. The laser particle-sizer, X-ray diffractometer and laser Raman spectrograph results also show that the gypsum-based composite can be effectively stabilized. The strong thermal energy storage performance of the gypsum-based composite is clearly suggested by the results of the specific thermal performance test.