CO₂ refrigeration in small retail outlets: why it is growing

CO₂ (R744) is now a consolidated technology in large-scale distribution, but its use is also starting to gain greater interest in small and medium-sized stores , where condensing units, autonomous systems and solutions with smaller loads traditionally find space.

Technological advances in components, electronic controls, and compact units are expanding the potential for using CO₂ beyond large supermarkets. At the same time, the European F-Gas framework is making it increasingly important to adopt refrigerants with very low GWP and evaluate solutions that can maintain compliance over the long term.

For convenience stores, small supermarkets, grocery stores and other commercial activities , the choice of refrigeration system is therefore increasingly linked not only to the initial cost, but also to efficiency, safety, maintenance and regulatory perspective.

CO₂ even in small shops: what's changing

Historically, transcritical CO₂ systems have been associated primarily with large supermarkets and industrial applications . However, the reduction in available sizes and the development of more compact condensing units are expanding their scope.

The European Commission itself indicates condensing units as a solution typically used in small shops and supermarkets and includes CO₂ among the non-fluorinated alternatives currently available for this type of commercial refrigeration.

The greater availability of components designed specifically for R744 therefore allows the creation of systems that are closer, in terms of configuration and operation, to traditional remote architectures with synthetic refrigerants.

Among the elements that are favoring this evolution are:

• compressors and components available in smaller sizes;
• more advanced electronic controls;
• more precise pressure regulation;
• greater availability of components;
• condensing units dedicated to commercial applications;
• greater experience of designers and technicians.

CO₂ also has a GWP of 1 and is classified as A1 , meaning it is non-flammable according to the industry safety classification. This makes it particularly attractive when the goal is to avoid future transitions to refrigerants with progressively lower GWPs .

R290 and CO₂: different solutions for different applications

The growth of CO₂ in small retail outlets does not mean it will become the only solution for commercial refrigeration. In stand-alone appliances , such as refrigerated display cases, beverage coolers, and small freezers, propane R290 and isobutane R600a have already assumed an important role in Europe . The European Commission highlights how hydrocarbons have progressively replaced high-GWP HFC refrigerants in many stand-alone appliances.

However, when it is necessary to power cold rooms, remote cabinets or multiple users through a centralized circuit or a condensing unit, CO₂ can represent an interesting alternative.

The two technologies have very different security features:

• R290 : Extremely low GWP, but A3 classification for high flammability;
• R744 : GWP 1 and A1 classification, but significantly higher operating pressures.

The choice must therefore depend on the configuration of the store, the required refrigeration capacity, the quantity of refrigerant, the available space and the skills required for installation and maintenance.

The market seems to be evolving towards greater diversification of architectures, rather than a single solution applicable to all stores.

External temperatures and pressures: design remains crucial

The main technical element that distinguishes CO₂ from many traditional refrigerants is its behavior at high temperatures . The critical point of CO₂ is just above 31°C. When the heat rejection temperature exceeds this threshold, the system operates in transcritical mode and pressure management becomes particularly important for efficiency.

Modern control technologies allow operation to be adapted to external conditions, but climate and operating profile remain fundamental elements in the design.

For applications located in areas characterized by high summer temperatures, the following may become relevant:

• high blood pressure optimization;
• modulating fans;
• adequately sized gas coolers;
• adiabatic systems where appropriate;
• advanced control strategies;
• heat recovery.

It is therefore incorrect to evaluate CO₂ solely based on the refrigerant . System architecture and control directly impact overall performance. Technician training also remains crucial. R744 requires specific knowledge of operating pressures, charging, recovery, start-up, and diagnostics.

F-Gas: Commercial refrigeration seeks ever-lower GWPs

The European framework is one of the main factors driving the market towards natural refrigerants. From 1 January 2025, stand-alone refrigeration equipment, excluding chillers, may generally not be placed on the market if it contains fluorinated gases with a GWP of 150 or more , except for specific safety requirements.

For other fixed refrigeration equipment not included in the specific categories, the GWP 150 limit will come into force from 2030 , again with the exceptions provided for safety reasons. Furthermore, for centralized commercial multipack systems of at least 40 kW, the GWP 150 limit has already been in force since 2022, with the specific exception provided for the primary circuit of cascade systems.

In this scenario, CO₂ offers the advantage of being well below the thresholds set by the Regulation and not affected by the HFC phase-down. For small retail outlets, this issue is therefore becoming increasingly strategic: choosing a refrigeration system today means evaluating not only its immediate efficiency, but also its compatibility with a regulatory framework that is set to become progressively more restrictive.

The growth of compact CO₂ units could thus further expand the role of R744 in European commercial refrigeration, bringing a technology already established in large supermarkets to increasingly smaller stores.