“Ice-based energy storage is the low-hanging fruit in energy cost reduction that can pay enormous dividends,” said Calmac CEO Mark MacCracken. “Even if a building is using what is considered a ‘flat rate,’ the daytime energy is usually twice as expensive as the nighttime equivalent due to demand tariffs. Once you understand these price differences, the value in storing cooling during off-peak hours for later use becomes clear.”

The decision to install the new system came with the decision to replace the library’s antiquated HVAC chiller. By using 125-kilowatt of Calmac’s energy storage tanks, and retrofitting the building with less heat-intensive lighting, the facility was able to downsize its new chiller from the previous 195-ton unit to a 150-ton unit. The combined upgrades are on track to save the library district $40,000 annually in energy costs.

The tanks also allow the building to separate when cooling is made from when it is needed. Ice is created overnight during off-peak hours and stored in the thermal energy storage tanks. The next day, the ice is used to cool the building when energy costs are highest.