Danish HVAC giant Danfoss is running an innovative pilot project that raises the bar for urban energy efficiency, as they funnel excess heat generated from supermarkets’ refrigerators to local district heating networks. 20 SuperBrugsen grocery stores in Høruphav on the island of Als, Denmark, have technically become heating suppliers, as homes in each store’s immediate vicinity are part of this groundbreaking experiment. “Calculations show that the surplus heat from SuperBrugsen will supply 16 so-called standard homes of 130m² annually,” explains Jan Due Kristensen from Sønderborg District Heating. 

Meanwhile, the supermarkets themselves set to benefit from reduced heating costs when the same energy is transferred within the building, as well as a reduced CO2 footprint. “The local supermarket close to the Danfoss’ headquarters in the south of Denmark now saves more than 31,000 USD annually on gas for heating. CO2 emissions are reduced by 34% by using the surplus heat from the refrigeration system to heat the supermarket and neighboring buildings,” writes Niels B. Christiansen, Danfoss’ President and CEO.

Supermarkets are notoriously big consumers of energy: in Germany, supermarket cooling equipment is responsible for 3% of all electricity consumed in the country. “The potential of adding the flexibility of supermarkets to the smart grid would equal up to 30% of the total electricity produced by wind across the whole European Union,” explains Christiansen on the untapped potential of food retail facilities as a source for energy. “This is a great example of how to incorporate district heating as a two-way energy infrastructure to distribute and thereby utilize energy, which would otherwise have been lost,” adds Danfoss Heating’s Head of Development Jan Eric Thorsen. Additionally, there is even more untapped potential in connecting supermarkets to energy networks – using unused cooling compressors, supermarkets could even store their surplus heat.

The largest cost incurred by the setting up of a district heating network is the digging for the district heating pipes and the purchase of a pump. The refrigeration system takes care of the rest and Danfoss estimates that a supermarket owner will see a return on investment within 18 months. “We need to rethink our business models, and maybe instead of only selling groceries, heat will be yet another item in a supermarket’s portfolio,” adds Christiansen.