What you probably don’t know about global warming potential (GWP)

Heat pumps are known for being an environmentally friendly heating method.

But what many people don’t consider is the impact of your choice of refrigerant on the planet.

Without a refrigerant gas, your heat pump wouldn’t be able to harness heat energy from the environment outside – which would mean no heating for your commercial building.

But the global warming potential (GWP) of refrigerant gases can vary hugely – in many cases, they can be extremely detrimental to the environment, despite a heat pump having been chosen by a business precisely for its environmental credentials.

Here, we’ll cover some little-known facts about GWP. But first…

What is GWP?

GWP stands for global warming potential.

It can be defined as a measure of the relative global warming effects of different refrigerants.

Essentially, it assigns a value to the amount of heat trapped by a certain mass of a refrigerant, relative to the amount of heat trapped by the same mass of carbon dioxide over a specific period of time.

However, GWP isn’t as clearcut as you might think!

Things that might surprise you about GWP

Think you know about GWP? Think again!

Here are some interesting facts that you probably weren’t aware of until now.

GWP values vary by source

You may not have noticed that GWP values often vary by source.

This is because of the details, methodology and data used by different sources to derive the GWP.

For instance, R32 is often quoted as 677. However, the UN uses the value 749.

GWP values are constantly changing

GWP values change as knowledge improves.

So, don’t be surprised to find that a refrigerant suddenly looks a lot worse for the environment than it initially seemed.

A good example is R22. In 1995, this refrigerant had a GWP of 1500. But in 2016, this value had increased to 1810!

Blends of refrigerants can be misleading

Some refrigerants are given low GWP values because they are a blend.

However, they may still contain high GWP components.

Take R454C as an example. This is promoted as a low GWP refrigerant with a GWP of 162. However, it contains R32 and R1234yf.

R32 has a GWP of around 700, while R1234yf is an HFO that breaks down into TFA, leading to groundwater pollution.

GWP is measured over time

GWP is measured over time – the usual number for GWP is over 100 years.

However, 20-year values are available too.

When considering climate change, a 20-year horizon certainly feels more appropriate.

This chart shows that the important 20-year climate impact of refrigerants is much higher than you might think (values are taken from the International Institute of Refrigeration).

Natural refrigerants and GWP

Natural refrigerants are those that occur naturally in the environment – like R290 (propane) and R744 (carbon dioxide).

Opting for these refrigerants for your heat pump takes away the risk and uncertainty related to GWP.

• The GWP of CO2 is 1 and always will be
• The GWP of propane is 3 over 100 years – or less than 1 over 20 years

This is in contrast to synthetic refrigerants like HFOs (hydrofluoro-olefins) and HFCs (hydrofluorocarbons), which commonly have GWPs in the thousands.

Not only do natural refrigerants come with very low GWPs –  making them the natural choice when it comes to protecting the planet we live on. But they’re also cheaper, have a secure supply chain, produce high temperatures efficiently, and outperform chemicals.

Which brings us onto…

Choosing the right refrigerant

At Clade, we strongly believe that your refrigerant’s impact on the environment should be a key factor in which refrigerant you choose.

However, there are, of course, other important factors to consider too.

Here are the main ones.

Efficiency

Efficient refrigerants will help your heat pump use less energy and therefore reduce your running costs.

Luckily, natural refrigerants tend to be particularly efficient in heat pumps, as they have no glide (this is a thermodynamic behaviour found in some synthetic refrigerants).

In fact, natural refrigerants achieve higher coefficient of performance (COP) in heat pumps at low ambients and high flow temperatures than synthetic refrigerants!

Cost

The price of different refrigerants can fluctuate over time.

However, as a general rule, natural refrigerants tend to have the lowest prices and are readily available.

As pure gases (rather than blends) they can also save you money when you experience refrigerant losses. This is because you can easily top up levels.

On the other hand, blends of gases have a critical proportion of each constituent, meaning you’ll need to carry out a full (and expensive!) refrigerant replacement after losses.

Suitability

Every business is different, so it’s important to think about your own unique needs and which refrigerant gas is best suited to them.

As an example, when it comes to natural refrigerants, propane is well-suited to medium temperature requirements and is easy to retrofit (although it can also be used for high temperature requirements in a heat pump like our new Elm).

Meanwhile, CO2 is a great fit for higher temperature requirements.

Your system designer will take the time to understand your needs and determine the right fit.

Regulations

The decarbonisation of heating is slowly moving up the government’s priority list.

So, we can expect regulations restricting the use of F-gases to increase in severity over time.

With that in mind, steering clear of synthetic refrigerants, which are mostly F-gases, could be a wise way to future-proof your commercial equipment and prevent it from becoming a stranded asset anytime soon.

Safety

Safety is an important factor that building owners have to consider when investing in new equipment.

Some people are wary of the natural refrigerant R290 because it’s highly flammable. However, propane is exceptionally safe to use as a refrigerant – it just needs the appropriate safety procedures in place (for instance, pressure testing, fit detection and ventilation).

It’s also worth remembering that gas risks aren’t a new problem. After all, most buildings have a gas connection — and LPG tanks and bottled gas are also common.

Make the choice to go natural

As you can see, the important 20-year climate impact of refrigerants is much higher than you might think.

So, natural refrigerants are a real no-brainer.

Not only are they clean and non-toxic, but they’re also highly efficient and even outperform synthetic refrigerants!

At Clade, we’re leading the way in natural refrigerant heat pumps and refrigeration equipment and our team has over 35 years of experience. So, you’re in safe hands.

As a certified B Corp, you’ll also know that, when you work with us, you’re having a positive impact on our employees, the communities we serve and the planet.

So, what are you waiting for? Get in touch to learn how we can design, manufacture and install a natural refrigerant heat pump for your business.