Effect of Copper Electrode Geometry on Electrofreezing of the Phase-Change Material CaCl2·6H2O

Abstract

Abstract The development of effective active thermal energy storage systems requires an understanding of how electrode geometry affects the electrofreezing process. This study aimed to observe the nucleation behavior of an inorganic phase-change material, CaCl2·6H2O, using a DC electric field and various copper electrode geometries. The effects of both the electrode diameter ( d = 0.5 d=0.5 and 0.7 mm) and the tip shape (flat and sharp end surfaces) were investigated. Data analysis was performed to reveal the nucleation temperature, freezing temperature, supercooling degree, supercooling time, and crystallization time period. The copper electrode with the larger diameter was found to result in a higher nucleation temperature, a smaller supercooling degree, faster nucleation, and a shorter crystallization time period. Moreover, changing from a flat tip to a sharp tip decreased the nucleation temperature and increased the supercooling degree. This study showed that the electrode geometry plays an important role in the phase-change behavior of CaCl2·6H2O.