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CO2 as refrigerant  R744

Why CO2 technology? Well, for starters, it's a natural, non-toxic, and non-flammable substance that offers significant advantages over other refrigerants. Plus, it's environmentally friendly and helps companies reduce their carbon footprint.


CO2, by definition, has a GWP of 1 regardless of the time period used, because it is the gas being used as the reference.

High temperature

The ability to reclaim heat, which means you can use waste heat to provide high-temperature grade heating energy. In some cases, you can even cover 100% of your heating demand with heat generated by the refrigeration system.


Smaller components and more effective evaporators, which can save you money on installation and maintenance costs.


Improved energy efficiency, especially when combined with heat recovery. This is becoming more and more attractive for a wide variety of applications, from commercial to industrial.

CO2 one of the first refrigerants used

The history of CO2 can be divided into two parts. The first is part is during the 19th and 20th centuries when systems evolved and developed. This era ended when the interest in CO2 virtually disappeared in the 1950s since synthetic refrigerants were introduced and took over.

​At the end of the 1980s, Norwegian professor Gustav Lorentzen brought up the idea of using CO2 again, which introduced the second era of the history of CO2. He investigated how CO2 technology could be used in different applications and published many articles. In 1993 he stated that “CO2 is as close to the ideal refrigerant as it is possible to come….” One aspect of CO2 that he discussed was how heat may be reclaimed, as well as the associated control strategies to optimize the process.

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Carbon dioxide is a natural, non-flammable, and non-toxic substance that offers technical advantages when compared to other natural alternatives. Regarding toxicity, codes such as the European corresponding EN378 do impose certain safety measures in order to use CO2 as refrigerant, nevertheless, safety measures are simple and do not impose a high cost.
The historical challenge with CO2 basically stems from the fact that it has high pressures in the system, reaching 120 bar. Because of the rapid CO2 technology development since the 1990s, today high pressures are no longer a valid argument against the favor to CO2.
Actually, it is the opposite - the unique characteristics of CO2 offer significant advantages over other refrigerants, such as smaller components and effective evaporators. A special advantage is when there are simultaneous cooling and heating demands, where CO2 heat reclaim offers high-temperature grade heating energy. In some applications, 100% of the heating demand can be covered with heat generated by the refrigeration system.

Growing interest

Throughout the last decade, a growing interest to use CO2 as a refrigerant in many applications has been seen, especially in the commercial sector. The energy efficiency improvements that are achieved with CO2 refrigeration combined with heat recovery is becoming more and more attractive for a wide variety of applications. Since a few years back this trend has entered the industrial sector as well which has considerable implications for the business.

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EKA's skills

At EKA, we're proud to be members of, which showcases our expertise in CO2 technology. We've been working with CO2 since 2004, and we've completed some groundbreaking projects in the years since.

For example, we designed Europe's first full CO2 ice arena, which became self-sufficient with heat from its own recovery system. And we're thrilled to have played a part in the NSSO Speed Skating Oval for Beijing Olympics 2022, which is also a 100% CO2 ice arena.

If you're interested in learning more about how CO2 technology can benefit your business, we're here to help. Contact us today to find out how we can help you save energy and money while reducing your environmental impact.

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