6 reasons why to choose CO2 (R744)

CO2 (R744), as a natural refrigerant, is increasingly applied in refrigeration systems. The market transition from high-GWP refrigerants to eco-friendly solutions goes hand in hand with technological developments like CO2 transcritical inverter units. To meet the growing interest in natural refrigerants technology, the refrigeration market members need awareness-raising, training, and reliable knowledge.

In the following material, we have compiled the main reasons why you should consider R744 refrigerant.

Reason 1: F-gas Regulation restrictions

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The previous European Regulation No. 517/2014 (F-gas Regulation) aimed to reduce the use of harmful HFCs by 79% by 2030 [1]. The law is successively and gradually phasing out the HFC refrigerants, moving towards more eco-friendly solutions. The new F-gas Regulation (EU) 2024/573 was adopted on 7 February 2024, and started to apply on 11 March 2024 [more info].

From January 2020, prohibition is applied to “Stationary refrigeration equipment, that contains, or whose functioning relies upon HFCs with GWP of 2500 or more, except equipment intended for application designed to cool products to temperatures below -50 °C” [2], so for example R404A (GWP = 3922) or R507A (GWP = 3985) in such equipment may not be used.

At the beginning of 2022, further bans were introduced – it is now prohibited for “Refrigerators and freezers for commercial use (hermetically sealed equipment) that contain HFCs with GWP of 150 or more” [2].

Additional and current restrictions are applied to “Multipack centralized refrigeration systems for commercial use with a rated capacity of 40 kW or more that contain, or whose functioning relies upon fluorinated greenhouse gases with GWP of 150 or more, except in the primary refrigerant circuit of cascade systems where fluorinated greenhouse gases with a GWP of less than 1 500 may be used” [2].

More information on the current and expired bans can be found on the official website of the f-gas legislation.

Moreover, on the 5th of April 2022, the European Commission made a legislative proposal to update the current F-gas regulation. The amendment establishes a more accelerated phase-down schedule for hydrofluorocarbons and a significant reduction in the use of HFC refrigerants in the coming years.

Currently (August 2023), the European Commission, the co-legislators in the European Parliament, and the Council of Ministers are negotiating the proposal [3].

Each side has already presented its initial position on the issue [4], and the European Parliament’s proposal is the most restrictive (read about it). It is clear that if the proposal is adopted, there will be a complete phase-out of HFCs and mixtures, and only natural refrigerants, such as CO2 (R744), can be used for most applications.

The consumption of hydrofluorocarbons (HFCs) will be completely phased out by 2050, and the production of HFCs, in terms of production rights allocated by the Commission, will be phased down to a minimum (15%) as of 2036 [more here].

The law’s update accelerates the timetable for phasing out HFC refrigerants and significantly reduces their use in the upcoming years. According to the regulation, the quota of HFC refrigerants will be completely banned by 2050.

New restrictions were also presented on stationary refrigeration, specifically: “Refrigeration equipment, except chillers and equipment covered in points (4) and (6), that contains, or whose functioning relies upon: fluorinated greenhouse gases with a GWP of 150 or more, except if required to meet safety requirements at the site of operation [page 54 in the source]”. The ban will take effect on January 1, 2030.

All information is included in the original file of the agreement.

Reason 2: Advantages of CO2 over HFCs

Several R744 myths require clarifying. Despite many claims that law restrictions forcing sustainable solutions are the only serious reason for switching to CO2, this natural substance is characterized by several unique thermodynamical and functional features, allowing energy-efficient cooling and significantly benefiting its users and final customers:

80% lower refrigerant price

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50% smaller pipeline diameters

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10x higher vol. capacity (kJ/m3)

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3x higher heat transfer coefficient

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Thousands of times lower GWP

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CO2 as a long-term refrigerant

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R744 is a safe refrigerant

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R744 is homogeneous

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These features of the CO2 refrigerant result not only in its user-friendliness, availability, and long-term use but, thanks to its efficiency, may bring significant cost savings and increased quality of the final product.

Reason 3: High potential for heat recovery

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The discharge temperature for R744 quickly reaches over 100oC. It brings excellent potential for heat reclaim in retail systems, which can be used for central heating or obtaining domestic hot water.

The heat recovery system can reduce the overall energy costs as an optional function of the primary cooling operation. It also increases the efficiency of a system at high ambient temperatures. Nowadays, it has become standard in European supermarkets. It should be used everywhere when possible.

The heat recovery option in the iCOOLTM CO2 transcritical inverter units is a complex, controller-managed system integrated into the unit, with safety features and an optimally sized plate heat exchanger.

Example of the heat recovery circuit for iCOOLTM 15 CO2.

Reason 4: Cost savings

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Refrigeration systems operating with CO2 transcritical inverter units offer great potential for savings. Thanks to the energy-efficient inverter technology, advanced control automation, and high efficiency of the transcritical unit, the total annual operating costs can be about 20% lower compared to a standard HFC refrigeration system [9, 10]. With the heat recovery option, it could even be lower.

There are installations where it has been confirmed that by changing the system from R507A and R404A to CO2, energy consumption has been reduced by 30% compared to the last five years with the old system [11].

The actual kWh/year energy consumption is mainly reduced by the possibility of fluid refrigeration capacity modulation in a wide range, optimized temperature regulation (case study – click here), decreased quantity of defrost cycles, and the elimination of the costs associated with the conventional fuels consumed by the heating system (when the heat reclaim is used).

The total investment cost of a CO2 refrigeration system may be higher, but with proper configuration of the system based on transcritical inverter units, thanks to the increased efficiency and lower operating cost, the return on investment time for this additional cost over an HFC system can be very reasonable.

Reason 5: Proven CO2 technologies

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CO2 technology is already very advanced at this point, and yet it is still developing. More and more transcritical CO2 systems with advanced automation can be found in the market, even in applications with large capacity demand (case study – click here). On the refrigeration market, there are different available components dedicated to working with CO2: evaporators, expansion valves, pipes, liquid receivers, and other instrumentation and tools that meet special strength and quality requirements.

For supermarkets and retail stores, Area Cooling Solutions offers several high-efficiency and high-performance transcritical iCOOLTM CO2 inverter units featured with remote monitoring as standard from factory. The remote monitoring feature helps observe the unit’s operation, even at extremely high ambient temperatures, reducing issues during maintenance and emergency situations.

CO2 condensing unit operating during heat waves

Recordings of our built-in remote control system confirm the reliability of iCOOLTM CO2 units, especially at high ambient temperatures. Despite exceeding the guaranteed working range, which is set up to 43oC degrees, our units continued the smooth operation without any alarm notifications (case study – click here).

Reason 6: Knowledge, experience, and support

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Area Cooling Solutions has been developing CO2 technology in refrigeration units since 2016. iCOOLTM CO2 transcritical inverter units are operating in various worldwide locations. Our production staff is highly qualified and constantly developing their skills.

To support refrigeration market members, the Areacademy team organizes specialized presential or online training in inverter and CO2 technology (check the video). Each training course ends with the provision of a certificate for each participant. We also share knowledge by creating helpful articles (Troubleshooting, Routing of CO2 installation), interactive materials (Virtual Reality), and videos (iCOOLTM CO2 commissioning).

Our training programs offer a practical and dynamic approach, ensuring faster and easier learning. During the training, participants can expect detailed answers from experienced R&D designers, technical support engineers, and automation and electrical engineers.

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