How does heat recovery work?

When you cool something down, you generate heat somewhere else. Just think about your fridge or freezer, they feel warm on the outside. This also applies in a supermarket. To cool something down, you literally extract the heat from it. That’s what a refrigeration system does. A traditional refrigeration plant expels the heat into the open air. But what if you could use that residual heat? To heat a shop for example. We’re testing this in a few of our shops.

The refrigeration plant makes cold glycol for the fresh produce section and chiller cabinets. This releases heat. The refrigeration plant transfers that residual heat to ‘warm’ glycol. Glycol is water with a food-safe anti-freeze. So you can use this product perfectly safely in a shop.

We use the warm glycol to heat the shop via different heaters and radiators, and the fresh outside air that flows into the shop. The process is called heat recovery.

Heating a shop with heat recovery alone works best if the shop is well insulated and airtight. Otherwise too much heat will escape.

The refrigeration plants run on propane or propene as a refrigerating gas. We made a conscious decision to use this technology because it is exceptionally suitable for heat recovery. The major challenge lies in linking the cooling and heating systems. One of the modifications our engineers carried out, for example, was installing larger radiators so that the heating also works at lower temperatures. Propane and propene refrigeration is also a lot more environmentally friendly.


With this initiative, we contribute to the following Sustainable Development Goals of the United Nations.

Affordable and clean energy Industry, innovation & infrastructure Sustainable cities and communities Climate action