In the search for the next big thing in sustainable cooling and heating, there is always a risk that we can overlook an existing solution. That is certainly sometimes true of the group of gases known as natural refrigerants.

Carbon dioxide (CO₂) and propane are experiencing a revival in the HVACR sector, while ammonia is used widely in industrial refrigeration, demonstrating that some long-standing refrigerants can still be the way forward for certain applications.

CO₂ is a prime example. In use as a refrigerant since the 1880s, it lost out to synthetic alternatives in the 1930s. According to manufacturer Danfoss, this was due to factors including energy efficiency, complexity and technological limitation before a comeback thanks to improved system and component design, as well as manufacturing processes.

The resurgence continues, particularly in commercial refrigeration but also in chillers for comfort cooling in commercial settings. The refrigeration trend was evident in research published at the end of 2023 by independent global clean cooling and natural refrigerant accelerator ATMOsphere. Its market report revealed that 68,500 food retail stores across Europe were using transcritical CO₂ refrigeration, a market penetration of 22.9% in 2023 compared to 14.1% in 2021.

It is important to note that the benefits of CO₂ as a refrigerant make it equally attractive in other applications, such as healthcare cold rooms, so let’s take a closer look at exactly what natural refrigerants have to offer.

What Are Natural Refrigerants?

The term refers to substances which are present in nature, although refrigerant-grade versions of the gases are manufactured. Refrigerant-grade CO₂ (R744) is a byproduct of the industrial production of ammonia, alcohol and fertilizer. Although it then has to be processed for use as a refrigerant, CO₂/R744 is still widely regarded as an environmentally friendly and future-proof option for refrigeration, air conditioning and heat pumps. It is not subject to phase down or phase out under government regulations.

What is CO₂/R744?

CO₂/R744 is an odourless and colourless gas rated by ASHRAE as an A1 refrigerant, meaning it is non-flammable and non-toxic. It operates at higher pressures than other refrigerants, from 13bar in low-temperature equipment to 113bar in medium-temperature systems. The higher pressures enable more compact component and system designs for installation in restricted spaces. Above the critical point of 31°C and 73.8bar, CO₂ operates in transcritical mode as a fluid that cannot be condensed into a liquid, offering greatly improved thermodynamic properties and increased efficiencies.

What makes CO₂/R744 Environmentally Friendly?

CO₂/R744 has a global warming potential (GWP) of 1, showing it is much less powerful as a greenhouse gas than synthetic HFCs. It is actually used as the benchmark against which other gases are measured. CO₂ also has an ozone depleting potential (ODP) of zero and is not a PFAS, a group of more than 14,000 synthetic ‘forever chemicals’ used in consumer products since the 1950s, meaning it is not contributing to chemical pollution of the environment.

We can help

CO₂ is ideally suited to many commercial refrigeration applications, including healthcare cold rooms. If you are ready to take the next step on the road to a sustainable future, please get in touch.

Let us, at Batchelor Air Conditioning & Refrigeration help find the right solution for your next project.

Use the contact form, call 01234 712 901 or email info@batchelor.co.uk

If you would like to find out more about refrigerants and the UK F-Gas regulation, read our blog your key questions answered on the F-Gas Regulation.