Keeping things cool produces heat. In a home, the amount of this waste heat is minimal. In a modern supermarket with aisles full of refrigerators and freezers, the amount of heat is significant—and enough to heat the entire supermarket and its hot water if it can be properly recycled.

According to Morten Birkebæk, store manager at MENY’s Fredericia supermarket in Denmark, making better use of waste heat was a “win-win”. “As a merchant with responsibility for the store’s bottom line, I’m of course interested in cutting unnecessary costs wherever possible,” he explains. “But if we can reduce our carbon footprint at the same time and do it all in a way that is hassle-free for our customers and employees, then count me in.”

The business case for recycling heat from the store’s CO₂ refrigeration system was clear. “The calculations were straightforward,” Birkebæk recalls. “We knew how many kWh we needed to heat the store and provide it with hot water, and we knew what we were paying the district heating company for that energy. Danfoss and the installer, Dansk Varmegenvinding, proposed a turnkey solution that included everything: the hardware, connections, installation, and a service agreement.

After a full year of operations, Birkebæk can now see precisely how much energy, money, and CO₂ the store has saved. During the first year, MENY in Fredericia reduced its energy consumption by 135 MWh in total, with 56 MWh coming directly from the Danfoss Heat Recovery Unit (HRU) and 79 mWh through a year-long Danfoss EnergyTrimTM contract. What’s more, the store reduced its carbon footprint by 6.7 tons of CO₂, close to that of a car driving around the equator.