Phase change materials with enhanced thermal stability

Abstract

Sodium sulfate hydrate is used as a phase change material (PCM) for thermal energy storage due to its high energy storage capacity, low cost, and abundance. However, there are two major problems, supercooling and phase segregation upon cycling. To address supercooling, various nucleating agents can be added. This method promotes formation of crystals and reduces formation of a metastable supercooled liquid. Phase segregation occurs when a PCM undergoes repeated melting and solidification cycles, leading to a separation of the material into its constituent phases. In the case of sodium sulfate hydrate, this can lead to the separation of the anhydrous form of the material from the hydrated form, resulting in a loss of energy storage capacity and reduced thermal performance. To address these issues, this invention provides a phase change hydrogel comprising sodium sulfate, alginate, and molecules of glycine, wherein the molecules of glycine are zwitterions.

Dependencies are inferred from the claim text.