A new generation

Transcritical CO₂ refrigeration systems have now established themselves as standard in most Northern European countries in retail refrigeration. Despite innovative developments, such as parallel compression, further potential for increasing efficiency still remains. With the world's first transcritical CO₂ system with multiple ejectors, a new generation is now available. In terms of efficiency, these systems overshadow synthetic refrigerants even in southern regions.
 

Expectations exceeded

For two years, data was collected and evaluated at the Migros pilot system in Bulle. In 2014, despite a cool summer, the predicted efficiency increase of 15% was achieved. During the extraordinarily hot summer of 2015, the system was able to reach its full potential. The evaluations of the current year show an efficiency increase of approx. 20% versus comparable CO₂-booster systems with parallel compression. The predicted efficiency increase for the southern countries was thus achieved.
 

A wave throughout europe

The pilot system installed two years ago at Migros Bulle caused a stir in the entire industry. The great opportunity to operate CO₂ refrigeration systems with this technology — even in warm regions — has motivated various manufacturers to drive their research in this area forward. The first standardized solutions are expected to be available in less than a year. With this, there is nothing standing in the way of CO₂'s victory march into Southern Europe.
 

The optimization continues

However, with the success of the pilot system in Migros Bulle the door was only cracked open. There remains much potential to refine the technology and save additional energy. A follow-up project was started at Migros Ibach in Schwyz as early as fall 2014. Thanks to the experiential values from Bulle and an enhanced system with additional flooding of the evaporators, the bar in efficiency was raised once again.

Worth mentioning is the fact that at the Migros in Ibach two identical systems were installed to cover the cooling load. This provides a unique opportunity to compare a traditional system using parallel compression with an ejector-based system. Initial measurements in November 2014 already showed a decrease in energy consumption of 20% as compared to a CO₂-refrigeration system with parallel compression. Over the whole year 2015 we are expecting a reduction in energy consumption of over 25%.
 

The role of Frigo-Consulting International Ltd.

Frigo-Consulting International Ltd. offers assistance in the field of innovative refrigerating systems and energy concepts for buildings:

• Design of energy concepts for buildings
• Engineering and realisation of sustainable refrigerating systems
• Design efficient and innovative heat recovery systems
• Worldwide unique innovations to save primary energy
• Training and audits