Every night, some 74,000 gallons 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 US 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, which uses what's known as "ice batteries," is being added to buildings in the US for its ability to provide cool air without releasing planet-warming emissions. As the AP reports, these systems cut electricity usage and lower the strain on the grid. With rising temperatures and the growing demand for electricity in the US, ice thermal energy storage offers a sustainable option for cooling buildings.
Trane Technologies, a company that makes heating and cooling equipment, says it has seen a growing demand for this technology over the past few years. Its ice batteries are mostly used in schools, as well as in commercial and government buildings. Nostromo Energy, another company that makes ice batteries, is pursuing customers among energy-intensive data centers that have high cooling demands. Smaller systems are also made for homes by companies such as Ice Energy.
- How it works: Ice thermal energy technology varies but follows a similar concept: At night, when electricity from the grid is cheapest, water is frozen into ice that thaws the next day to cool the building. The ice chills water that's circulating through pipes in the building, absorbing heat from rooms and creating a cooling effect. Trane said its ice batteries are often used alongside traditional AC components, which are typically left in place or downsized.
- The savings: Norton Audubon's energy costs were $278,000 lower the first year that the ice battery system was in operation in 2018. The hospital estimates the system and other energy-saving measures have saved it nearly $4 million since 2016. "The technology has been awesome for us," said Anthony Mathis, a Norton Healthcare executive who oversees sustainability.
- Other options: Some commercial buildings use lithium batteries, which can store excess solar or wind energy. Dustin Mulvaney, environmental studies professor at San Jose State University, said ice batteries are a sensible option for health care settings and senior homes because lithium batteries can pose a fire risk.
- Other applications: Manufacturers also see opportunities in data centers, which are increasing exponentially to support AI and have high energy and cooling needs. The Energy Department said in December that data centers consumed more than 4% of US electricity in 2023, a number that could hit 12% by 2028.
More here.