The Effect of Static Electric Field and Nucleator Agent on the Solidification of CaCl<sub>2</sub>·6H<sub>2</sub>O and Ca(NO<sub>3</sub>)<sub>2</sub>·4H<sub>2</sub>O

The addition of energy from the electric field is one way in the active method to overcome the nucleation barriers of inorganic phase change materials (PCM) e.g. salt hydrate. The effort is to aim at improving the performance of PCM as a thermal energy storage system. Moreover, the passive method commonly uses a chemical substance called nucleator agent to induce the nucleation and to reduce the phase separation that typically occurs during the freezing-thawing cycle of salt hydrate PCM. In this paper, we report an experimental study to conduct the effect of the static electric field (DC voltage) and nucleator agent as a combination of passive and active methods on the nucleation of salt hydrates consisting of CaCl 2 ·6H 2 O and Ca(NO 3 ) 2 ·4H 2 O. In general, the nucleation temperature of CaCl 2 ·6H 2 O and CaCl 2 ·6H 2 O+BaSO 4 (0.1 wt%) become higher with the increase of the intensity of the electric field, leading to the decreases of supercooling degree. Besides that, the electric field also induces the increase in the nucleation rate, as measured by the shorter induction time. Meanwhile, the case for Ca(NO 3 ) 2 ·4H 2 O and Ca(NO 3 ) 2 ·4H 2 O+Ba(OH) 2 ·8H 2 O (1 wt%) show that the nucleation temperature tends to become smaller with increase the intensity of the electric field, leading to increases the supercooling degree. However, the addition of the nucleator agent, Ba(OH) 2 ·8H 2 O (1 wt%) to Ca(NO 3 ) 2 ·4H 2 O has not provided a significant result in terms of nucleation probability.