Denmark’s supermarket turns waste heat into energy

In Nordborg, Denmark, a revolutionary supermarket showcases how technology can reduce energy use and save costs. Partnering with engineering firm Danfoss and local supermarket association Brugsforeningen for Als and Sundeved (BALS), this “Smart store” serves as a testing ground for innovative energy solutions. Covering 750m², with a 250m² technology centre, the store is designed to maximise energy efficiency.

Through a glass window, shoppers can see the advanced cooling machinery that powers the entire store. Danfoss calls it a “live” test centre, where engineers fine-tune technology in real-world conditions. The director of strategic marketing at Danfoss Climate Solutions, Henry Steffensen, highlighted that each day brings unique challenges, making it an ideal testing space.

The store is about 50% more energy-efficient than a conventional supermarket. A standout feature is its ability to recycle excess heat generated by refrigeration. Typically, such heat is vented outside, but here it’s captured and stored in tanks to provide heating and warm water for the shop. The system has proven so efficient that the store sold 33,380 kWh back to the local grid, while only purchasing 90 kWh since opening in May 2023.

Solar panels on the roof generate 100,000 kWh annually, further supporting operations. On sunny days, energy is stored by cooling freezers below usual levels. A 1 km-long ground loop under the store also creates additional heat. These technologies have potential applications in stores worldwide, from Denmark to warmer climates.

Steffensen noted that investing in these energy solutions could pay off in under a year, offering sustainable heating without the need for gas boilers.