Swiss retail giant Coop uses CO2 (R744) exclusively in all new-build stores and restaurants; 60% of its existing stores have already been retrofitted too, bringing its CO2 installation total to more than 700.
These numbers were presented by Dr. Aikaterini Boulamanti, Energy Specialist at Coop Switzerland, who shared Coop’s journey with CO2 during the ATMO Europe Summit that took place in person in Brussels on November 15–16. ATMO Europe was hosted by ATMOsphere, the publisher of R744.com.
Coop is one of the largest retailers in Switzerland, and it also owns wholesale and production facilities and restaurants. They have nearly 3,000 stores, 93% of which are in Switzerland with the remainder in the EU. Commercial refrigeration systems are used in 955 supermarkets, 31 department stores and 192 restaurants (1,178 total facilities).
To date, 60% of these installations have already been converted to CO2 – more than 700 in total. Of the rest, 30% still use R134a, and 10% use R449A. “The goal of Coop is to replace all fluorinated refrigerants by 2030,” said Boulamanti. She confirmed that there is no minimum store size for this – they are converting to CO2 refrigeration in all relevant stores.
Growing CO2 since 2007
The use of HFCs in Switzerland has been restricted by legislation since 2013. R404A has been prohibited in new cooling systems since 2020 with a total ban from 2030. As of 2022, R134a is prohibited in new cooling systems as well as systems smaller than 40kW (total ban from 2030) – this was the main refrigerant Coop used previously. Government subsidies are available in Switzerland to replace these systems.
Coop’s journey with natural refrigerants started long before the policy restrictions though. It has been replacing refrigeration installations with CO2 since 2007 and since 2010, it has been installing 100% CO2 in all its supermarkets – both new and renovated. The restaurants have been slower to convert as these are generally smaller installations. Still, even here, Coop has exclusively been using CO2 in new builds since 2020.
Coop chose CO2 specifically because it can totally replace the f-gases in their systems and has a GWP of 1, which decreases their emissions massively, explained Boulamanti. Other advantages include reducing plant complexity, reducing energy demand, being able to use waste heat and lower life cycle costing. Disadvantages were mainly the higher pressures leading to higher leak percentages, which was managed with improved controls.
Integral systems for improved efficiency
Since 2017, Coop started installing integral CO2 cooling systems. These systems fulfill three needs of the systems in parallel: refrigeration, heating and air conditioning with the same system. The system includes parallel compressors and a gas cooler with heat pump evaporator integrated into the cooling system. Today, Coop has around 70 of these integral systems installed.
Two different kinds of integral systems are installed. For the standard CO2 system (used in sales outlets smaller than 1,000m2/10,764ft2) the heat exchange takes place directly with the refrigerant, while in the integral CO2 water system (for outlets larger than 1,000m2), the heat is transferred to a secondary medium (water) for storage.
The waste heat captured from the cooling system is generally able to cover the heating required by the sales outlet, eliminating the need for fossil fuels, said Boulamanti.
“The goal of Coop is to replace all fluorinated refrigerants by 2030.”Dr Aikaterini Boulamanti, Coop
Outperforming fossil fuels
German engineering consultancy Frigo-Consulting did a study for Coop to compare the equipment needed for a fossil fuel system versus a heat pump, CO2 integral and water integral system. The integral systems had a significantly smaller footprint than the other two systems.
The four systems were then deployed in four different buildings, each with its own heating and cooling requirement to also compare the performance. In all four buildings, the integral CO2 system was the most energy efficient because the heat exchange takes place directly with the refrigerant, and there are no heat transfer losses, need for a secondary medium nor storage losses.
When analyses of the life cycle costs were compared, the CO2 systems had a lower cost in all four buildings, with the integral water system being the lowest. “In larger stores, the advantage of an integral store with a secondary medium like water outweigh the disadvantages because the components of the system are more economical, and there is less need for controlling of the system,” explained Boulamanti.
Emissions were up to 82% lower for all the options not using fossil fuels.
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