An experimental investigation of nucleation probability of supercooled water inside cylindrical capsules

This article experimentally investigates the nucleation probability of supercooled water inside cylindrical capsules with or without nucleators during a cold storage process. The nucleation probability curves of initial appearance of dendritic ice as a function of coolant temperature, size of capsule, and mass of different heterogeneous nucleators are characterized, respectively, by performing a number of experiments. The results show that the lower the coolant temperature, the greater the nucleation probability. The larger the volume of water contained, the higher the nucleation temperature. The addition of nucleating agents, such as iron ore, iron chips and silver iodide, into the water container can effectively improve the nucleation probability, and thus increase the coefficient of performance (COP) of a thermal storage air-conditioning system. Since the crystal structure of silver iodide is very similar to that of ice, the comparison among three types of agents indicates that it has the best effect in facilitating nucleation. (C) 1999 Elsevier Science Inc. All rights reserved.