Improving the Supercooling Degree of TiO2 Suspensions by Coupling With Zirconium Phosphate Nanoplatelets

Abstract

Phase-change materials (PCM) with low supercooling degree (SD) are important in cold thermal energy storage (CTES) applications. The SD of nanosuspension PCM usually decreases with increasing nanoparticle concentration. However, the performance variation of nanosuspension PCM at high concentrations has been rarely studied, though it is important because nanoparticles tend to aggregate. In this paper, the SD and dispersion stability of nanosuspensions of TiO2, zirconium phosphate (ZrP), and TiO2 coupled with zirconium phosphate (TiO2-ZrP) were investigated at nanoparticle concentrations up to 5.0 wt %. Results show that the SD of TiO2 suspension did not remarkably varied with mass concentrations above 2.0 wt %. In contrast, the SD of TiO2-ZrP and ZrP were low and continuously decreased with increasing mass concentration of nanoparticles. The dispersion stability of TiO2-ZrP suspension improved compared with that of TiO2 suspension. Hence, TiO2-ZrP suspension provided more nucleation sites than TiO2 suspension to induce heterogeneous in water.