With CALMAC's ice storage cooling, a glycol solution runs through a chiller at night. The liquid coolant then passes through a tube in a tank of water, freezing its contents over a period of six to 12 hours. During the day, the cold glycol solution runs through a heat exchange coil, chilling the air. A fan blows the cool air into an air duct. The coolant continually passes through the tank of ice to stay chilled.