Thermal conductivity and mechanical properties of a shape-stabilized paraffin/recycled cement paste phase change energy storage composite incorporated into inorganic cementitious materials

In this study, paraffin/recycled cement paste phase change energy storage composites were fabricated by mixing paraffin and recycled cement paste at 4 ratios of 0.4:0.6, 0.45:0.55, 0.5:0.5, and 0.55:0.45 by a mixed mill-heating method. The microstructure was characterized by the pore size and surface area analysis and laser particle size method. Chemical stability was characterized by laser Raman spectrograph (LRS), Fourier transform infrared (FT-IR) and X-ray diffraction (XRD) analyses. Differential scanning calorimeter (DSC) and thermo-gravimetric (TG) analyses were used to evaluate the latent heat and thermal stability. Finally, the paraffin/recycled cement paste composites were incorporated into gypsum and cement-based materials. The effects of the phase change composites on the thermal conductivity and mechanical properties of the inorganic cementitious materials were analysed. The results reveal that the phase change composites had good chemical stability and stable thermal properties. The paraffin/recycled cement paste phase change energy storage composites had a large influence on the flexural strength. The thermal conductivity of gypsum and cement-based composites incorporating phase change energy storage composites were significantly reduced.