Gruppo Maxi Di Srl , a discount retailer operating across northern Italy, has equipped its new Famila store in Lonigo, Vincenza province with a CO2 transcritical compressor rack – complete with electronic modulating ejectors – to supply over 50 refrigerated cabinets. The store opened in 2018.

Italian firm Arneg supplied the CO2 rack, which is equipped with eight compressors. The rack features electronic controls and ejectors supplied by CAREL, another Italian company. The system serves a 2,300 square-metre supermarket.

CAREL’s pRack pR300T (a controller for managing centralised CO2 refrigerating units) and three electronic modulating ejectors (EmJ) control the CO2 compressor rack, which delivers a total cooling capacity of 185 kW.

Launched at the ATMOsphere Europe conference in April 2016, “the electronic modulating ejector is capable of increasing system efficiency by up to 25% – with annual averages of 10% in the typical climates of southern Europe,” according to CAREL’s Alessandro Greggio.

The CO2 transcritical system system supplies over 50 refrigerated cabinets; 44 of which are medium temperature and 13 low temperature. When operating in ejector mode, the compressor rack can reduce the superheat set point of the cabinets to 0.5°K.

Summer energy savings of up to 25%

The system has recorded energy savings during the summer of up to of 25% compared to traditional CO2 transcritical systems. Even in winter’s lower temperatures, it delivers energy savings by virtue of recovered heat, which is used to heat the building.

One essential feature of the ejector solution is continuous modulation that, through dedicated control algorithms, allows the system to continuously adapt to the variations in operating conditions that are typical of refrigeration systems.

Arneg tracks the system’s operation at its IRIS energy control centre.

“For years, Arneg has been working effectively with CAREL, in a partnership based on mutual exchange. Research and technological innovation have allowed us over time to offer increasingly efficient and environmentally-friendly solutions, just like the one at the Famila supermarket in Lonigo,” said Enrico Zambotto, Arneg’s refrigeration engineering director.

“As evidence of how much we are investing in this technology, we also now adopting ejectors in other installations, always using natural refrigerants, at numerous stores in Italy,” Zambotto said.

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