Preparation and thermal properties of sodium acetate trihydrate as a novel phase change material for energy storage

Highlights: • A new composite phase change thermal storage material of sodium acetate trihydrate. • Na₄P₂O₇·10H₂O as the nucleating agent to control undercooling. • Polyacrylamide as the thickening agent to avoid phase stratification. • Thermal properties via Differential Scanning Calorimetry scanning. -- Abstract: As phase change thermal storage material, sodium acetate trihydrate (CH₃COONa·3H₂O) exhibits large thermal capacity and holds tremendous promise. However, main problems of undercooling of solidification and phase stratification constrained its application in energy storage. Thus, present work prepared a new composite phase change thermal storage material of sodium acetate trihydrate mixed with nucleating agent and thickening agent. The initial research results showed that addition of an appropriate proportion of nucleating agent tetrasodium pyrophosphate decahydrate led to a good restrain to the undercooling of CH₃COONa·3H₂O. A certain amount of thickening agent polyacrylamide could also avoid the phenomenon of phase stratification and maintain the heat storage capacity of samples. Meanwhile, the additions little affected the melting point and would not decrease the enthalpy of fusion of sodium acetate trihydrate as established from Differential Scanning Calorimetry study, which indicated that this novel composite material possessed excellent and stable performance suitable for its application for thermal energy storage systems.