Preparation and characterization of polyethylene glycol (PEG) hydrogel as shape-stabilized phase change material

A kind of PEG8000 hydrogels as shape-stabilized phase change materials (SSPCMs) were prepared by using a simple sol-gel technique. Their thermal characteristics were studied under the modified mass ratio of PEG and water. The optimized PEG hydrogel (PEGH) was placed at high temperature of 70 °C to remove excess liquid water. This temperature was less than the apparent melting temperature (74 ± 1 °C) but over its phase transition temperature of about 9 °C. Obtained PEG gel displayed an excellent thermal energy density of 154.2 J/g, and the value was twice that of reported form-stable composite PCM in literature. Therefore, it can be remarkably noted that the PEG hydrogel provides a new way for the preparation of SSPCMs, and has an important potential for heating/cooling applications in buildings.