Preparation and characterization of NaNO3 shape-stabilized phase change materials (SS-PCMs) based on anorthite ceramic and cordierite ceramic for solar energy storage.

In the current study, molten NaNO 3 shape-stabilized phase change materials (SS-PCMs) based on anorthite ceramic and cordierite ceramic were prepared by cold-press sintering method. Chemical compatibility and wettability were considered simultaneously to determine whether the ceramics were qualified as supporting skeleton and the enhancement of the thermal properties of NaNO 3 by the ceramics was also investigated. It was found that both anorthite ceramic and cordierite ceramic have good chemical compatibility with NaNO 3 and no chemical reaction occurred between them. Physical compatibility was evaluated by measuring the contact angle of molten NaNO 3 on a ceramic substrate. Cordierite ceramic exhibited better wettability than anorthite ceramic, although both of the contact angles decreased gradually with increasing temperature. The supercooling of the prepared anorthite ceramic-based SS-PCMs with 45 wt% NaNO 3 (45ASS-PCMs) was only 0.7 °C, which was less than 2.5 °C for pure NaNO 3 and 2.0 °C for cordierite ceramic-based SS-PCMs with 45 wt% NaNO 3 (45CSS-PCMs). The phase transition enthalpy loss of 45ASS-PCMs after 100 thermal cycles was less than 2%, while 45CSS-PCMs reached more than 5%. Anorthite ceramic showed better capabilities than cordierite ceramic in terms of thermal reliability and stability, while cordierite ceramic was better than anorthite ceramic in enhancing thermal conductivity. The evaluation method proposed in this study provided favorable guidance for the matching of PCMs and ceramic supporting skeleton. • Evaluating supporting skeleton for PCMs based on chemical and physical compatibility was proposed. • Wettability of NaNO 3 on cordierite ceramic was better than that of anorthite ceramic. • Cordierite ceramic has better shape-stabilized performance but poorer thermal cycle stability than anorthite ceramic. • Thermal conductivity of 45ASS-PCMs and 45CSS-PCMs was enhanced by 2 and 3 times compared with NaNO 3 , respectively. [ABSTRACT FROM AUTHOR]