SUPERMARKETS


Turning cooling into heating


Retired Smart Store ADC manager Ejnar Luckmann explains how CO₂ refrigeration systems can deliver 100% of a supermarket’s space heating, and why the waste heat you’re already generating may be your next unexpected revenue stream.


I Ejnar Luckmann "In the


Danfoss Smart Store, our CO₂ refrigeration system has done more than preserve refrigerated food; it has completely covered the store’s space heating needs."


n the pursuit of effi ciency and sustainability, the modern supermarket is a battleground of competing demands. Retailers face the dual challenge of keeping food fresh and customers comfortable, all while battling rising energy costs and increasingly stringent environmental regulations. The refrigeration systems that form the backbone of these operations are energy-intensive, traditionally venting valuable thermal energy directly into the atmosphere. But what if this waste wasn’t a liability? What if it was your greatest untapped asset?


A whitepaper from Danfoss, Heat Recovery in Supermarkets, explores this very question, revealing how modern heat recovery technology is transforming this wasted energy into a powerful source for heating, hot water, and even new revenue streams. By capturing and repurposing the thermal energy that is a natural byproduct of the cooling process, retailers can dramatically reduce their carbon footprint, slash operational costs, and create more resilient, profi table stores.


The scale of the problem: a river of wasted energy


A typical medium-sized supermarket can easily have a cooling demand of 100-150 kW. To achieve this, its refrigeration system works like a heat pump, extracting thermal energy from display cases and cold rooms and moving it elsewhere. For decades, ‘elsewhere’ has simply meant the roof, where condensers and gas coolers release this heat into the ambient air. This represents a signifi cant amount of wasted potential. The whitepaper highlights that the total amount of heat rejected from a refrigeration system is the sum of the cooling load and the electrical energy consumed by the compressors. For a system with a 150 kW cooling demand and a COP (Coeffi cient of Performance) of 3, the compressors would consume 50 kW of electricity, resulting in a massive 200 kW of rejected heat – enough to provide heating for approximately 20 residential homes. In a world focused on decarbonization, there is great potential here to become even more energy-effi cient.


18 April 2026 • www.acr-news.com


The solution: capturing and reusing thermal energy Heat recovery is the process of capturing this rejected heat and repurposing it for useful applications within the store or the surrounding community. Modern refrigeration systems, especially those using CO₂ as a refrigerant, are uniquely suited for effi cient heat recovery. The whitepaper details how this works. In a transcritical CO₂ system, the refrigerant leaves the compressors at very high temperatures (120–140 °C), making it incredibly eff ective for heating applications. This high-grade heat can be transferred via a heat exchanger to a water circuit, which can then be used for:


Space heating: By circulating the hot water through radiators or underfl oor heating systems, heat recovery can cover a signifi cant portion, and often all, of a supermarket’s heating demand. This eliminates the need for separate fossil fuel-based heating systems like gas boilers, leading to direct energy savings and emission reductions. Hot water production: The system can easily heat sanitary hot water for taps, cleaning, and staff facilities to temperatures of 60°C to 65°C, with the potential to reach up to 90°C without needing a supplemental heat pump. Air curtains and air handling units: The recovered heat can be used to supply warmth to the air curtains at the store entrance, preventing cold drafts and improving customer comfort.


The technology at the heart of this process includes specialised heat recovery units, advanced controllers, and 3-way valves that intelligently direct the fl ow of heat. These systems can prioritise where the heat goes, fi rst satisfying any internal store demand before rejecting any excess to the atmosphere.


Quantifying the impact: a powerful business case The fi nancial and environmental benefi ts outlined in the whitepaper are compelling. By fully integrating heat recovery,


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