Extremely quiet replacement system with a sustainable refrigerant

Cooling for the Migros hardware and specialist store  

Since summer 2024, a Secon propane chiller has been cooling the Migros hardware and specialist store in Schönbühl. CTA likes to maintain long-standing partnerships with its suppliers, and one such partnership was the backbone of this project. The replacement chiller, which uses the natural refrigerant propane, was supplied, installed and commissioned in record time. During the summer months, this standard chiller supplies the entire shopping area with cold water via the ventilation system. When the temperatures start dropping as the winter approaches, the heating takes over and heats the hardware store via the district heating network.  

Sustainable refrigerant: propane R-290 

As the owner, Genossenschaft Migros Aare deliberately utilises natural refrigerants to fulfil its sustainability goals. This affects the investment costs and the safety precautions. Propane-powered chillers are currently approximately 20 to 30 per cent more expensive than chillers that use synthetic refrigerants. However, over the entire service life of a well-maintained system, the costs are comparable to those of a chiller using a conventional refrigerant. 

Standard safety concept 

The chiller’s cooling circuits are filled with the natural and thus sustainable refrigerant R-290. Propane does present one challenge, however: it is flammable. Cooling systems using propane as a refrigerant must therefore meet stricter safety requirements. A standard concept is followed here. In contrast to the previous chiller, the propane-powered chiller has been installed outdoors. Sensors in the machine housing monitor the system to detect any potential refrigerant leakages while they are still far below the explosion limit and to switch off the system electrically. This monitoring ensures that no ignitable mixture is created. If the refrigerant nevertheless leaks, a fan draws in fresh air and discharges the gas/air mixture into the environment. This standard concept works well in this case. 

Extremely quiet 

This chiller boasts a low-noise design and is therefore exceptionally quiet. Thanks to the larger air registers, the sound pressure level at a distance of ten metres is 54 d(B)A. Normally and with smaller air registers, the sound pressure level is between 60 and 65 d(B)A at a distance of ten metres.

Contributors

• Design: SSP Kälteplaner AG 

• Building owner and installer: Genossenschaft Migros Aare 

• Chiller manufacturer: Secon GmbH

• Chiller and system supplier: CTA AG