Pressure effect on the release of supercooled water with dissolved air

• In supercooling type cold thermal energy storage, stable and low supercooling degree is required during cooling.
• Supercooling was carried out to the pure water with three types of dissolved air, experimentally.
• The goal was to find the relation between the pressure and the supercooling degree in water.
• Maximum supercooing degree of water tends to increase with the increase of dissolved oxygen and with the increase of pressure.
• Smaller size of the formed bubble in pure water related to the larger pressure.

It is proposed that vapor has been elucidated to having relation to the release of supercooled water.In this study, considering that the vapor has a relation to dissolved air, a supercooling experiment is performed to test tubes of pure water with three patterns of initial dissolved oxygen (DOi = 4.1, 7.5, and 12.6 mg L−1), i.e. dissolved air. The initial DO in each test tube is kept to the value as constant as possible during supercooling. And the pressure effect on supercooling release of pure water is observed by measuring supercooling degree and by visualizing bubbles enclosed to the ice after full crystallization of the pure water.From this study, it appeared that the factors such as cooling rate, initial DO and pressure of pure water are related to the release of supercooling (supercooling degree and supercooling time). Moreover, the initial DO was confirmed to the confined bubble in fully frozen ice of pure water.