“We knew that if this project [to install a parallel compression CO2 system with ejectors] would fly, others – including our competitors – would benefit from this, too. That’s alright for us – others should be able to do so,” argued Daniel Duss, head of building and technology at Migros Luzern, at the close of his meeting with Accelerate Europe at the firm’s Luzern headquarters.
Duss paints a picture of Migros – Switzerland’s largest retailer, the country’s largest supermarket chain and its largest employer – as a group with well-defined reasons to invest in refrigeration technology as a crucial part of its drive to place long-term financial success on a sustainable footing.
The Migros Group’s energy and climate commitments are primarily guided by a strategy that binds all Migros companies and includes ambitious targets to reduce energy consumption and environmentally harmful emissions by 2020. Chief among its 2020 goals are reducing electricity consumption by 20% and fossil fuel consumption by 55%, as well as reducing the climate impact from refrigerants by 60%.
“Migros’s sustainability programme ‘Generation M’ signifies a balanced approach towards our activities concerning economic, ecological and social consequences with the target to ensure the long-term success of the Migros Group,” explained Duss.
A green cooling leader
Mindful of the harmful effects of synthetic refrigerants, the Migros Group is committed to using natural refrigerants in its supermarkets and in other Migros companies. Migros phased out a large proportion of HCFCs in 2014. As an alternative to synthetic refrigerants, it is focusing strongly on the natural refrigerant CO2.
Migros has made R744 applications a standard across its supermarkets with the aim of adopting the technology in new and existing stores. By 2014, Migros was using CO2 in 455 of the 2,000 systems in operation throughout its stores. Around a third of Migros stores have at least one CO2 cooling system. For its work with environmentally friendly refrigerants, Migros was named a Green Cooling Leader by the Environmental Investigation Agency in 2014.
“Our aim remains 100% CO2. But knowing when we will have reached this goal would be to read tea leaves. I only know that we have an ambitious five-year plan, and that for every single construction project we will discuss the question of which type of CO2 system we will best use,” said Duss.
The importance of a progressive partner
Migros has partnered with refrigeration system engineering expert Frigo Consulting to carry out innovative projects in Switzerland. The fact that Frigo Consulting has engineered a greater number of CO2 transcritical than subcritical installations has gone hand-in-hand with the drive of far-sighted customers such as Migros. “It was our conscious decision to take the risk and move towards transcritical systems, and there was also a smooth pressure coming from progressive customers,” explained Marcus Hoepfl, managing director of Frigo Consulting International Ltd.
“When testing new technologies, there is a big need for brave customers ready to invest in the latest technologies and who do not solely look at the very short-term return on investment. Migros is a good partner for this, and it was in a Migros store that Frigo-Consulting installed the world’s first CO2 ejector system in 2013,” Hoepfl said.
Migros Ibach store: a blueprint to follow
Being aware of the importance of further establishing CO2 technology and of eliminating its drawbacks in warmer climates, Frigo Consulting was looking for a partner to take the ejectors one step further.
The refurbished Migros store in Ibach, Switzerland, provided such an opportunity to install and optimise a CO2 system with parallel compression and ejectors. The advanced CO2 refrigeration system supplies 170 metres of medium and low-temperature cabinets and 280m2 of cold rooms and freezers with cooling capacity. Two identical CO2 booster units provide a total of 250 kW of refrigeration capacity.
Results are highly encouraging after one year of operation. The facility has achieved an increased efficiency of at least 25% compared to traditional CO2 systems, and of 45% compared to the HFC-based previous system.
“This is a quantum leap for CO2 refrigeration systems in terms of efficiency not only in Switzerland but beyond, especially in wiping away the so-called ‘efficiency equator’ for CO2 transcritical systems in warmer ambients,” enthused Hoepfl.
He is convinced that it is only a matter of time before ejector technology becomes more widespread and will ultimately become state-of-the-art in retail and industrial refrigeration.
