Elements Collide: Ice Storage Helps Use Wind Energy Onsite

A new ice energy-storage system better integrates wind energy at a campus in Ireland.

At Dundalk Institute of Technology, tanks of ice store wind energy produced at night and cool classrooms during the day. A thermal-energy-storage system designed by Calmac maximizes the amount of renewable energy that can be used onsite for the university’s PJ Carroll building—a renovated cigarette factory, now a creative arts building.

The school is home to an 850 kW wind turbine that was installed in 2005—the first large commercial turbine on a college campus in the world, according to Dundalk. The turbine generates an estimated 1,500 MWh for the campus annually, but because the availability of wind power does not always match peak demand times, energy was often sold back to the grid. After equipping just one building with thermal energy storage, the university now uses 79% of the energy it produces (see “Buildings On Ice: Making the Case for Thermal Energy Storage”).

Eight ice tanks are installed in the basement of the PJ Carroll building, each with a capacity of 162 ton-hours of cooling and a volume of 6.25 m³ of ice, according to a study published in the Journal of Sustainable Engineering Design. With a higher cooling capacity than that of chilled water storage, the “ice banks” run the chiller when there is excess electricity from the turbine and circulate chilled water as the ice melts during the day.

The university plans to renovate the remaining 64,000 ft² of the PJ Carroll building, and energy modeling calculations show that continuing to pair ice storage with wind energy could ensure 96% of the building’s electricity demand is met by power produced onsite.