The rise of natural refrigerants: all you need to know

Natural refrigerant heat pumps are on the rise in Europe. But what are natural refrigerants? And how can they benefit both you and the environment?

Here, we’ll explore the rise of natural refrigerants and answer all your questions. But first…

What are refrigerants?

Refrigerants – also known as cooling agents – are the working fluid in heat pumps.

These fluids have very low boiling points. As they absorb heat from the outdoors, they boil and turn to gas. Then, as they release heat to warm up a room, they turn back into liquid, ready to start the process again.

This is known as the vapour compression cycle. The process can be repeated in reverse to cool down a building in the summer.

However, not all refrigerants are created equal. Generally speaking, refrigerants are characterised by being either chemical (synthetic) or natural.

A big part of the debate on how to deploy heat pumps at scale in the UK is around which refrigerants to use.

The problem with chemical refrigerants

When we talk about chemical refrigerants, we’re mostly referring to HFOs (hydrofluoro-olefins) and HFCs (hydrofluorocarbons) – often branded ‘climate killer refrigerants.’

These chemicals are mainly made especially for refrigeration rather than heating.

Many are patented and increasingly expensive. Yet they’re still the most widely used refrigerants in heat pump installations right now.

Why? Well, the global manufacturers have mass production set up to use them for either cooling or heating. It’s in their interest to keep the chemical refrigerants going for as long as possible to maximise profit.

BUT they come with big problems.

High GWP (global warming potential) HFCs are currently being phased out because they have an impact on climate change that’s thousands of times bigger than the same amount of carbon dioxide.

Meanwhile, HFOs are now the subject of litigation as they contain environmental toxins known as PFAS (Perfluoroalkyl and Polyfluoroalkyl Substances). These don’t break down naturally. In fact, they show up in many watercourses where they poison wildlife and in some areas endanger human health too.

Let’s say that 600,000 heat pumps (the government’s target) are installed in the UK each year using HFO or HFC refrigerants. This could generate the same emissions as running a 500kW boiler flatout continuously for 656 years!

Not only is this scary for the planet. But it also means that any company installing one of these heat pumps would have to add to their carbon footprint the refrigerant losses – bad news if you’re installing a heat pump as part of a green initiative.

Head over to our blog about avoiding killer chemical refrigerants to learn more about the negative impact of these substances.

What are natural refrigerants?

Natural refrigerants are widely available and they aren’t subject to any patents. So, they’re more secure.

The refrigeration sector has already transitioned to naturals and we believe that they’re the future of heat pumps too. This can be confirmed by the number of R290 (propane) heat pumps coming onto the market recently.

Natural refrigerants are better for the environment, more efficient and they even cost less than synthetic refrigerants. So, they’re a win for everybody!

There’s a range of natural refrigerants available, but the most common are CO2 and propane.

Why use natural refrigerants in heat pumps?

Since natural refrigerants are an effective alternative to chemical refrigerants and are widely available in Europe, perhaps we should reframe the question. Why not use natural refrigerants in heat pumps?!

Here are some of the main benefits of natural refrigeration heat pumps.

1. Environmental

Unlike synthetic refrigerants, natural refrigerants have low global warming potential (GWP). They don’t use harmful F-gases or release ‘forever toxins’ like PFAS into the environment.

For this reason, opting for these heat pumps over one that uses synthetic refrigerants is a fantastic way for companies to reduce their carbon footprint and have a positive impact on the planet.

It’s also worth noting that some synthetic refrigerant heat pumps – especially HFO – can’t be topped up after refrigerant losses. That’s because they’re made up of a blend of gases that have a critical proportion of each constituent. This means you’ll only be able to carry out a full replacement, which not only means more waste, but will also cost more.

2. Regulatory

Even if you’re not concerned about your business’ impact on the environment, bear in mind that climate change forces legislation to change too.

Regulations restricting the use of HFCs are increasing in severity – especially as carbon footprints reduce and the proportion contributed by F-gases rises.

With HFOs currently the subject of litigation for environmental toxins, it’s likely there will be more regulatory action in relation to PFAS too.

Although heat pumps should last for around 15 to 20 years, there’s a real risk that a high GWP refrigerant heat pump could become a stranded asset in the near future. Opting for natural refrigerants could be seen as the best way to safeguard your heat pump’s longevity.

3. Performance

Natural refrigerants actually perform better than synthetic refrigerants when it comes to heat pumps.

• More efficient. In heat pumps, natural refrigerants achieve higher coefficient of performance (COP) at low ambients and high flow temperatures.
• No glide. Glide is a thermodynamic behaviour found in some synthetic refrigerants. It can be useful in refrigeration, but it’s a bad thing when it comes to heat production.
• Wider delta temperatures (DT). Natural refrigerants offer wider DT (that’s the difference between the temperature the heat pump puts out and the temperature that returns to it from the heating system). The smaller DT often required by synthetic refrigerants can lead to large pipe diameters, excessive flow rates and pump costs.
• Higher temperatures. Natural refrigerant heat pumps can produce very high temperatures – CO2 has proven itself at over 100°C.
• Fewer heating system amendments. Any heat pump will require adjustments to your existing gas heating system. However, the wider DT and higher temperatures offered by natural refrigerants often result in the need for fewer amendments.

At Clade, we only use natural refrigerants in our heat pumps, as we want the best for our customers and the planet. Just get in touch to find out more about our natural refrigerant commercial heat pumps.

Are there any downsides to natural refrigerants?

While natural refrigerants are to us a no-brainer, they still come with some challenges.

However, with good engineering and careful management, the benefits far outweigh the negatives.

Here are the main things to mitigate against.

1. Flammability

Hydrocarbon refrigerants like propane are very flammable.

That said, most buildings have a gas connection, so gas risks aren’t a new problem. You can help to reduce the risks through:

• Preventing leaks (using methods like pressure testing, good commissioning and servicing, fit detection and ventilation)
• Situating heat pumps in clear, open areas
• Using CO2 (a natural refrigerant that’s non-flammable)

2. Temperatures

The natural refrigerant CO2 needs a lower-than-normal return temperature.

The best way to achieve this is through proper design and specification – as well as good installation and commissioning. Of course, these are all things you would expect on any project regardless!

Check out our case studies for examples of CO2 being used for heating and hot water.

Choosing the right refrigerant

Choosing the right refrigerant for your heat pump is all about balancing the performance of the heating system with the performance of your refrigerant.

Some of the main things to consider include:

• Environmental factors. The GWP of the refrigerant and its toxicity should be high on your priority list when selecting a refrigerant.
• Flow temperature. Not all refrigerants can generate domestic hot water or process heat.
• DT. A higher DT will make for a more efficient system and should help you to avoid pipework changes if you’re retrofitting.
• Ambient conditions. Check the refrigerant’s functionality within expected ambient conditions.
• Cost to top up or replace. Some refrigerants can be topped up, but blends need to be fully replaced and safely disposed of.
• Flammability. Refrigerants can be flammable, semi-flammable or not flammable at all.
• Efficiency. As well as the COP, consider the Seasonal Coefficient Of Performance (SCOP) so you know how efficient you can expect your heat pump to be given your circumstances.
• Regulatory risks. Restrictions are tightening on F-gases and harmful toxins. So, harmful chemical refrigerant heat pumps risk being replaced before the end of their lifespan.

As you can see, choosing the right refrigerant for your heat pump isn’t an easy formula – every business and use case will be different.

However, we think that opting for clean natural refrigerants over environmentally harmful killer refrigerants is a no-brainer. Not only are they more efficient, but there’s also a range of natural refrigerants to choose from, meaning there’s something for everyone.

Here’s a quick lowdown on the most common kinds of natural refrigerants you’re likely to come across.

CO2

CO2 is non-corrosive, non-toxic and non-flammable. So, it’s clear why it’s the natural refrigerant of choice for many!

On top of its safety credentials, it’s also high-performing and the total cost of owning a CO2 heat pump is low.

Head over to our dedicated guide to learn more about the benefits of using CO2 in a heat pump.

Propane

Propane is a gas that’s highly flammable and explosive. However, it’s a great refrigerant and has low climate impact. Plus, safety procedures and good engineering make it exceptionally safe to use as a refrigerant.

As a refrigerant, propane is pretty similar to CO2. However, it’s ideal for medium temperature requirements.

Learn more about its benefits on our page about propane heat pumps.

Discover Clade’s leading natural refrigerant heat pumps

At Clade, we take the wellbeing of our planet seriously, so all our heat pumps use natural refrigerants.

Not only does this help to reduce your business’ carbon footprint, but it also ensures an efficient heating system that’s going to stand the test of time.

Get in touch to learn how we can help your business with a natural refrigerant heat pump, designed and manufactured in the UK to your exact requirements.