Experimental study of erythritol - SiO₂ phase change nanocapsules for medium temperature thermal storage

Erythritol holds significant potential for medium-temperature solar energy heat utilization. However, its phase change process is susceptible to issues such as leakage, and adhesion to the container. Nanoencapsulation is considered an effective method to mitigate these challenges. Until now, progress in erythritol nanocapsulation with excellent phase change properties has been limited. This study is dedicated to improving the phase change properties of erythritol nanoencapsulation. The authors innovatively synthesized erythritol nanocapsules with a silica shell using the Sol-gel method at ambient temperature. The nanocapsules were characterized to validate the encapsulation effect and to uncover the mechanism through which thermal cycling affects the thermal storage performance of nanocapsules. The results show that the nanocapsules are mostly fabricated at 46-70 nm in diameter, have a melting enthalpy of 294.3 J/g, and a thermal storage efficiency of 78.3 %. Continuous thermal cycling leads to aging degradation of erythritol and damage to the shell layer of the nanocapsules. These factors are the primary reasons for the reduction in the phase change enthalpy of nanocapsules. The nanocapsules studied in this research have broad applications in solar medium-temperature heat utilization, waste heat recovery, and various other fields.