Each night, around 280,000 litres of water are frozen at Norton Audubon Hospital in the US state of Kentucky. The hospital previously used a regular air-conditioning system. Now, it has a system with 27 ice tanks that uses cold-water pipes to keep the operating rooms at safe temperatures.
This type of thermal energy storage is often called ice batteries. It is starting to be used in buildings across the US. It helps provide cool air, uses less electricity and eases demand on the power grid.
As temperatures go up and the need for electricity grows, ice thermal energy storage offers a better and more eco-friendly way to cool buildings.
Trane Technologies is a company that makes heating and cooling equipment. They noticed more and more people wanted their products. Their ice batteries are mainly used in schools and in commercial and government buildings.
Nostromo Energy makes ice batteries and is looking to sell them to data centres that need a lot of cooling.
There are also companies like Ice Energy that create smaller systems for homes.
Revolutionising energy storage solutions
Experts say that using ice to store energy is a good way for businesses to use less electricity. At night, when people don’t use much power, water is frozen into ice. The next day, this ice melts and helps cool the building.
The ice makes the water in the building’s pipes cold. It takes away heat from the rooms and helps cool things down. The cool air is then sent through vents to bring the inside temperature down.
Ice thermal energy storage technology is different between companies (see graphic).
The ice that is stored does not need energy to melt. This reduces stress on the energy grid during busy times and lowers electricity use.
Substantial cost savings
Energy costs at Norton Audubon were US$278,000 (HK$2,160,000) less in the first year the ice battery system worked. The hospital estimated that the system and other ways to save energy saved it almost US$4 million since 2016.
“The technology has been awesome for us,” said Anthony Mathis, a Norton Healthcare executive who oversees sustainability. He said he received inquiries from other buildings about the technology and thought more facilities would adopt it.
How do ice batteries compare to lithium batteries?
Some commercial buildings use lithium batteries, which can store excess solar or wind energy.
Dustin Mulvaney is an environmental studies professor at San Jose State University in the United States. He said ice batteries were a sensible option for healthcare settings and senior homes because lithium batteries can pose a fire risk.
