A supermarket in northern Italy has reduced its energy bills by an estimated €18,000 (US$19,500) per year by installing a CO2 (R744)-based rack that integrates the store’s refrigeration, HVAC and hot water production requirements into a single system.
Previously, the store had a direct expansion R404-based refrigeration system, a methane-fueled boiler for heating and hot water and no air-conditioning.
Installed in 2020 as part of a refurbishment project, the integrated CO2-based system has also helped the supermarket’s decarbonization efforts by removing the need for a gas boiler for heating and hot water.
Details of the project were presented by Stefano Mistrello, Key Account Manager at Frigoveneta – the system’s Italian manufacturer – and Giacomo Pisano, Business Development Manager for CO2 Compressors at Dorin – the Italian manufacturer of the system’s 11 compressors.
The case study was shared by Mistrello and Pisano during a refrigeration session at the ATMOsphere (ATMO) Europe Summit on natural refrigerants. The conference took place November 15–16 in Brussels and was organized by ATMOsphere, publisher of R744.com.
The 1,140m2 (12,000ft2) supermarket’s integrated system incorporates refrigeration for low- and medium-temperature applications, thermal comfort in both summer and winter and hot water production through heat recovery, explained Pisano.
Meeting a requirement of 17.5kW (5TR) and 72kW (20TR) for low- and medium-temperature applications, respectively, 130kW (37TR) for AC in the summer and 100kW (28TR) for space heating during the winter, while also supporting hot sanitary water, the single CO2 rack can “completely fulfill the shop’s needs,” he added.
For HVAC, Frigoveneta installed 10 air-conditioning/space heating cassettes in five zones around the supermarket. Each zone can be independently controlled to ensure optimal thermal comfort and energy use, explained Mistrello.
Frigoveneta’s CO2 system contains 11 Dorin compressors: three CDS301B for low temperature, one CD1200M and three CD1500M for medium temperature and one CD1200H and three CD2400H for the HVAC parallel compression.
According to Mistrello, Frigoveneta has installed similar integrated systems at 10 stores.
In total, in 2021, the integrated CO2 system cost the supermarket around €119,000 (US$128,900) in electricity for its refrigeration, HVAC and hot water production.
For its previous R404-based system, in 2019, the supermarket paid around €102,000 (US$110,900) in electricity for its refrigeration needs and around €10,000 (U$10,900) in gas for heating and hot water, totaling €112,000 (US$121,700). However, Mistrello and Pisano estimate that at 2021’s electricity costs, the previous systems would have cost the supermarket over €137,000 (US$148,900) per year.
Not only is the supermarket’s integrated CO2-based system cheaper to operate than its previous R404-based system, but the supermarket now also benefits from air-conditioning for thermal comfort during the summer.
Results from this project correspond to findings from a similar installation at a supermarket in nearby Verona, Italy. By integrating the 1,670m2 (17,975ft2) store’s air-conditioning, heating and hot water production into its CO2-based refrigeration system, Italian OEM Arneg cut the site’s energy consumption by 40% compared with operating independent HVAC and refrigeration systems.