Most commercial buildings with climate control needs use chillers during the warmer months. These large systems cool water and pump it throughout the building to regulate temperature. This approach works well when electricity rates are low, but when rates spike during peak demand hours, operators end up paying more out of pocket. Now, building managers across the country are turning to ice to help lower their energy bills.
When electricity bills are low, vats of water are frozen into ice. When energy costs rise during the day, the chiller's power is reduced and ice is used to cool the building's circulating water. Just rinse and repeat every night when your energy bill goes down.
These ice batteries effectively allow operators to change the times a building uses energy, drawing power from the grid only when electricity is cheapest. According to the Washington Post, large construction operators can save hundreds of thousands of dollars annually.
Until now, ice batteries have been largely limited to commercial properties with enough space to accommodate giant blocks of ice. For example, one system in the basement of a New York City bank building has 100 ice tanks, each about the size of a traditional parking space. However, future designs may scale down the concept to make it suitable for smaller businesses or even residences.
You ask, why not just use traditional batteries to store power during off-peak hours? Cost is a factor. Traditional lithium-ion batteries use expensive chemicals that degrade over time and eventually need to be replaced at additional cost. However, water is plentiful and cheap.
Allison Mahvi, an assistant professor of mechanical engineering at the University of Wisconsin-Madison, said that in theory, something could be frozen and thawed an unlimited number of times, and the only ongoing cost of such an energy storage system would be components that wear out over time, such as heat exchangers, valves and water pumps. , but even these parts can last for decades before needing replacement.