Coop Italy, a network of seven large consumer-led cooperatives, and more than 90 smaller ones, constitutes the largest retail food chain in the country, with more than 1,000 supermarkets, and more than 100 hypermarkets.

It has a long history, with the first shop opening in 1854 in Turin.

As part of their mission statement, the coops are committed to “safeguard the environment.” This commitment includes taking measures to “optimize performance and retrieve  heat,”  according to Coop Italy’s environmental policy, adopted in 2005.

This environmental mission led the Italian coops to become early adopters of natural refrigerants. The first system with CO2 in a secondary circuit was installed in 1999, and the first using CO2 as the primary refrigerant in a low-temperature circuit in 2003.

Transcritical CO2 is now the system of choice for INRES-coop, the company responsible for the design and commissioning of refrigeration systems for the coops. The only exceptions are very small systems and retrofits, which use R448A.

As of December 2019, the company had installed 46 transcritical systems, with eight new ones expected in the next few months, according to Fortunato Della Guerra, Technical Director of INRES-coop.

Della Guerra outlined Coop Italy’s refrigeration strategy last month at a networking event during EuroShop in Düsseldorf, Germany. The event was organized by Epta and shecco (publisher of Accelerate Magazine).

“Today, CO2 is the standard for us for larger supermarkets; we are still trying to find a good solution for smaller ones,” he said. “Just last Saturday, we had a new opening with a less-than-40kW (11.4TR) transcritical CO2 plant, so we are interested in developing this technique.”

INRES didn’t settle on a specific transcritical CO2 technology from the start, but used several different types over the years, installing its first system with parallel compression in 2015, its first Epta FTE system in 2017, and the first with ejector technology in 2018. The company also has installations with sub-cooling and heat-recovery features.

“We had at first a test base to try different types of plants and techniques,” Della Guerra said. “Then three years ago we started with a fully developed CO2 system.”

As an example of INRES-coop’s willing- ness to embrace and integrate a number of different technologies, Della Guerra shared a case study from Modena, Italy, where INRES carried out a full refurbishment of an existing 1,500m2 (16,146ft2) supermarket.

New features in the supermarket include transcritical CO2 refrigeration integrated with HVAC, mechanical free cooling using an existing air handling unit, adiabatic cooling and parallel compression, heat recovery for hot-water production, and cold recovery for the AC system.

All these features, combined with LED lighting, passive insulation, and the use of intelligent Building Energy Management System (iBEMS) software, produced a 36% reduction in energy consumption for the refurbished store.

Energy-saving techniques

Della Guerra stressed that the underlying reason for the better performance of CO2 is that it’s new technology that refrigeration technicians “pay more attention to” and use optimal set points to guide their work. By contrast, servicing of older HFC systems often descends into “anarchy,” where the technicians use their accumulated know-how, but not optimal set points, leading to poorer maintenance and decreased system performance.

“Therefore, it’s not important only to build a plant, but it’s super important to run it, because each plant in our experience runs for more than 15, sometimes 20 years, and we don’t want to change for 20 years,” Della Guerra said.

To underline his point about the importance of set points, Della Guerra gave two examples of medium- and low-temperature systems, where changing the evaporation set point from -14°C to -10°C (6.8°F to 14°F) and from -35°C to -33°C (-31°F to -27.4°F), respectively, reduced the daily energy consumption in the medium-temperature system by 6%, and by 9.2% in the low-temperature system.

Della Guerra also stressed the importance of cabinet doors when addressing potential energy savings, telling his audience that INRES-coop has been using doors on frozen cabinets since 2006, and on medi- um-temperature cabinets since 2011. New coop stores now use closed cabinets as standard, and in a medium temperature system the energy savings are typically 7%-20%, he said.

This story originally appeared in the March issue of Accelerate Magazine.

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