Supercooling and Solidification Behavior of Phase Change Material

Supercooling and subsequent solidification behavior of phase change materials (PCM) of sodium acetate trihydrate (SAT) and erythritol were studied by using a thermal analysis technique. A molten SAT specimen easily supercooled below 0°C and the observed maximum degree of supercoolimg was 89°C. Three changes due to phase transformation were observed in the cooling curve of the SAT. First change corresponds to the precipitation of sodium acetate (CH3COONa), and second change is the recalescence due to the solidification of supercooled SAT. It was considered that third change corresponds to the solid state transformation of SAT. From the maximum degree of the supercooling of SAT, the solid/liquid interfacial energy of SAT was evaluated as 5.56×10−2 J/m2. The observed maximum degree of the supercooling of erythritol was 91°C. An experiment to induce the nucleation in supercooled liquid of SAT was carried out and the effectiveness of the combination of the ultrasonic irradiation and the addition of nucleation catalysts was demonstrated.