Natural Refrigerants

What are natural refrigerants?

Before we go any further, let’s answer the question: what exactly are natural refrigerants? The simple answer is that they’re naturally occurring chemicals which don’t deplete the ozone layer. Since they have a low or negligible Global Warming Potential (GWP), these sustainable gases are the best alternative to traditional synthetic refrigerants that are banned by the F-gas regulations.

Before the 1950s, refrigeration systems would use naturally existing gases such as carbon dioxide, propane, and ammonia as refrigerants. These fell out of favour by the 1970s with the introduction of cheaper synthetic fluorocarbon gases. However, now that we know the environmental impact of F-gases, the industry is making the switch back to more efficient and ‘green’ natural refrigerants.

What is the best natural refrigerant to use?

The experienced team at Ryan-Jayberg specialises in the application of natural refrigerants in systems of many different sizes and types. We support the industry changes to environmentally friendly solutions, and actively promote the use of natural refrigerants over traditional F-gases.

As mentioned above, the primary natural refrigerants used in commercial chilling applications are carbon dioxide, ammonia, propane, and other hydrocarbons like isobutane and propylene:

• ⦿ Carbon dioxide (CO₂, R-744)
• ⦿ Ammonia (NH₃, R-717)
• ⦿ Propane (R-290)
• ⦿ Isobutane (R-600A)
• ⦿ Propylene (R-1270)

Air (R-729) and water (H2O, R-718) are other examples of natural refrigerants, but these aren’t common due to their low efficiency. The most popular options are actually carbon dioxide and ammonia. They have a low GWP and are widely available, making them accessible and affordable.

Though we think of carbon dioxide as a big contributor to climate change, CO₂ refrigerants are actually the coolant of choice for many commercial refrigerant systems. With a GWP of just 1 and an abundant supply, it’s a cost-effective alternative to keep equipment running reliably. It’s also seen as ‘future-proof’ as CO₂ refrigeration systems comply with current and future environmental laws.

Natural refrigerants vs synthetic refrigerants

Once considered the most stable and safe option, synthetic refrigerants are provably causing real damage to our planet. With the F-gas regulations introducing a GWP limit on refrigerants from 2020, gradually tightening restrictions until the complete phase-out target in 2030, it’s past time for businesses who use commercial or industrial refrigeration systems to use natural refrigerants.

Restricted and/or banned F-gases include hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulphur hexafluoride (SF₆). So, if your old refrigeration system uses any of these, you’ll find getting a top-up difficult and expensive. If you continue using banned F-gases or handle them irresponsibly, the Environment Agency could hit your business with a hefty fine of up to £200,000 per offence.

For the sake of the longevity of both the environment and your business, it’s best to take steps to upgrade F-gas refrigeration systems now. If you choose a natural alternative like a CO₂ refrigerant for your refrigerated display cabinet or multi-temperature storage room, you can comfortably continue to use it well after all F-gases are completely banned. It’s definitely worth looking into.

What are the pros and cons of CO₂ (R744) as a refrigerant?

While carbon dioxide (CO₂) is a known contributor to the build-up of greenhouse gases that are warming the globe, refrigerants are rated according to their Global Warming Potential (GWP) – and CO₂ only has a GWP of 1. Compared to the main offenders with GWP scores of 1500 to 4000, you can see why carbon dioxide is a better choice of refrigerant than hydrofluorocarbons (HFCs).

As a safety group A1 refrigerant, it’s safe to use CO₂ in public locations like supermarkets, as it’s non-toxic and non-flammable and won’t corrode copper or brass fittings. As the F-Gas Regulations and taxes on HFCs increasingly affect the commercial and industrial refrigeration industry, more manufacturers are investing in single-stage or two-stage systems that use carbon dioxide.

In recent years, the preferred option for most UK supermarkets is trans-critical carbon dioxide systems. The site installation is similar to a conventional HFC system, without the complications of a cascade design. All the components and controls are contained in a specially manufactured ‘pack’.

Here are some of the main pros and cons of using carbon dioxide as a refrigerant:

Carbon dioxide refrigerant pros:

• ➕ Stable molecule with a low potential for decomposition within the system.
• ➕ Environmentally benign, non-toxic, non-corrosive, and non-explosive.
• ➕ Far less expensive than synthetic refrigerants.
• ➕ Has good miscibility with compressor lubricants for oil return.
• ➕ Very dense with a high volumetric efficiency (allowing for a smaller pipe size and compressor swept volume than an equivalent HFC system).
• ➕ Less noticeable pipeline pressure drop than with HFC refrigerants.
• ➕ Higher heat transfer efficiency (heat exchangers can be smaller or operate at a lower TD than an equivalent HFC unit).
• ➕ Trans-critical carbon dioxide packs are supplied with pressure relief valves that do not discharge when the power is turned off or the equipment shuts down.
• ➕ Trans-critical carbon dioxide packs also run with a very high discharge temperature, offering a better opportunity for efficient heat reclaim than HFC systems.
• ➕ With no impending legislation to phase out carbon dioxide refrigerants, they can have significant long-term value in reducing company carbon footprints.

Carbon dioxide refrigerant cons:

• ➖ Operates at a higher pressure than HFC refrigerants, increasing the component cost and potential for leaks.
• ➖ Carbon dioxide packs and condensing units require more special components, controls, and safety features than a HFC equivalent.
• ➖ Can change from a gas directly to a solid at 4.2 bar pressure, requiring more care when charging the system and designing PRV vent lines (to allow for possible freezing when approaching atmospheric pressure).
• ➖ Very sensitive to water contamination, so can form unusual compounds if there is a leak in a water heat exchanger (cannot allow moisture into the system when charging).
• ➖ Has a ‘practical limit’ value of approximately 25%, so gas leak detection equipment is 4x more likely to be required than HFC refrigerants.

Contact Ryan-Jayberg about natural refrigerants

Many businesses have already made, or begun the process of making, the transition to using natural refrigerants. Not only is this action critical for legal compliance, but also for the future of the planet.

At Ryan-Jayberg, we recognise our responsibility to help our commercial refrigeration clients with navigating the law and installing efficient and environmentally friendly systems. If you’re looking for guidance on the F-gas regulations or further information on the best natural refrigerants for your business, please contact us. As a leading UK refrigeration company, we’re well-placed to assist you.

To discuss converting an existing refrigeration system using the latest technology, or designing a new system using natural alternatives such as CO₂ refrigerants, give our team a call on 02089 446 288 or send us an email at info@ryan-jayberg.co.uk. Alternatively, click here to fill out our online enquiry form or to find the details of your nearest branch, where you can speak with an expert in person.

Natural Refrigerant FAQs

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