Buildings are turning to 'ice batteries' for sustainable air conditioning

Every night some 74,000 gallons (280,000 liters) of water are frozen at Norton Audubon Hospital in Louisville, Kentucky. The hospital used to get all of its air conditioning from a conventional system found in most U.S. buildings, but now 27 tanks of ice sustain a network of cold-water pipes keeping operating rooms at safe temperatures and patients comfortable. This type of thermal energy storage, also known as ice batteries, is being added to buildings in the U.S. for its ability to provide cool air without releasing planet-warming emissions.