Thermophysical Properties of Some Fatty Acids/Surfactants as Phase Change Slurries for Thermal Energy Storage

Capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and their eutectics are chosen as phase change materials to constitute the phase change slurries for the first time. Under the emulsification of span20/SDS, phase change slurries with 30 wt % fatty acids are then fabricated by high-speed shearing. Thermophysical properties of phase change slurries are characterized by means of DSC. Results indicate that eutectic phase change slurries exhibit lower freezing/melting peak temperatures than corresponding fatty acids slurries. In the melting, peak temperatures from 22.36 °C to 55.61 °C and the freezing peak temperatures from 14.61 to 48.97 °C, latent heat fusion of eutectic phase change slurries are between 36.32 J/g and 51.82 J/g, 34.35 J/g and 48.58 J/g in the endothermic/exothermic processes. Heat fusion has not demonstrated obvious changes under the heating and melting processes, and these values are approximately equal to those of pure fatty acids multiplied by the mass fraction. Additionally, supercooling of phase change slurries are between 0.55 °C and 6.55 °C, and this phenomenon might be induced by the crystal structures formed in fatty acids eutectics.