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Solstice N41 – a blessing or a curse?

Honeywell’s announcement of a new non-flammable, lower GWP alternative to R410A is perhaps seen as the answer to an air conditioning contractor’s prayer. But does it also create problems for the industry? Neil Everitt poses a few questions.

The announcement on Tuesday that Honeywell had developed a new non-flammable refrigerant blend as an alternative to R410A created a huge amount of interest. During one of the UK’s biggest heatwaves the Cooling Post servers had to deal with traffic levels four times greater than normal as visitors poured onto the website to learn more.

Solstice N41, or R466A, to give it its preliminary ASHRAE number, is said to possess a lower GWP than R410A and, more importantly for many, the new refrigerant is said to be non-flammable. Because, like it or not, many air conditioning contractors are not keen to be handling flammable refrigerants, even if those refrigerants, like R32, are categorised as only “mildly flammable”.

Flammable refrigerants will mean investing in new equipment and, importantly, training, as well as requiring a range of issues to be addressed, including insurance, transport and storage.

The European HFC phase down has put enormous pressure on the higher GWP refrigerants. Burdened with a GWP of 2088, the price of R410A has skyrocketed. Over and above the cost, there have been genuine concerns amongst contractors whether sufficient R410A can be obtained to service existing equipment, let alone secure enough for new installations.

So it’s no wonder that air conditioning contractors should view the introduction of a new non-flammable refrigerant with a lower GWP as the answer to all their problems.

The situation is of particular concern to VRF systems, the dominant air conditioning technology in Europe, where, until now, there have been no alternatives to R410A. While the A2L refrigerant R32 was deemed safe for smaller splits, its flammability precludes it from use in the larger systems.

Now, it appears, the industry could have its answer. N41 is an exciting and intriguing prospect, particularly if it is found to be economically retrofittable to existing systems. That is something we have not yet been told.


Before we all get too carried away by the potential of this new blend, however, there are a number of key issues to be considered and answered.

It is generally accepted that in order to meet the requirements of the European HFC phase down, and the forthcoming global phase down under Kigali, the roster of future, long-term refrigerants will inevitably contain a number of flammables with very low GWPs.

If that is correct, it is essential that engineers become conversant with and confident in handling flammables. News of the potential introduction of this new R466A refrigerant could provide some with the excuse to ignore R32, or delay training or any preparations for a flammable future. If the industry pundits’ predictions are correct, that attitude could be hugely damaging for the industry. 

In an effort to alleviate the pressure on demand for R410A, all the air conditioning manufacturers of note have finally got on board with R32 this year, offering R32 alternatives across their smaller system ranges. It is generally accepted that smaller splits must switch to R32 as a matter of urgency.

However, R32 is not a long-term answer. Even Daikin admits that R32, with its GWP of 675, is not a long-term answer. We require refrigerants with far lower GWP come 2030. By the same token, N41 can also only be considered a medium-term answer, even if it does potentially plug an immediate and pressing requirement.

And “potential” is the key word here. While N41 has been in Honeywell’s development programme for some while, and could be the product that Honeywell was threatening to introduce at this year’s Chillventa, the announcement and its timing came as a shock. Certainly there is a pressing need for such a refrigerant. Is this an indication that the new refrigerant is being fast-tracked?

However, it is still undergoing ASHRAE standards approval, and for N41 to make a serious impact it still needs to be approved by OEMs. That would normally take a considerable length of time.

Then it’s the question of whether manufacturers will adopt this new refrigerant? While Honeywell is likely to have been working with one or more manufacturers on the development of this gas, it will have come as a complete surprise to the rest. Under normal circumstances it could be a few years before we see an extensive range of products on the market with N41.

Then there’s the question of whether it will be suitable to retrofit existing equipment? If it can, N41 will become a real game changer but, again, the necessary approvals from equipment manufacturers could severely delay its use in existing systems.

The future

Despite the legitimate concerns, there are other potential positives to take from the launch of N41.

We have previously been told by experts that there was no “silver bullet” single component answer. As previously stated, we have also been told that any blend under a GWP of 1000 is likely to be flammable to some degree. N41 challenges that thought.

Based on this new refrigerant, are the chemical engineers going to confound us all with long-term blends that are both low GWP and non-flammable? Or will the future rely on some new technology?

Mitsubishi has recently introduced an R32 version of its hybrid VRF and Daikin is thought to be working on larger R32 systems that satisfy the requirements of EN378 by employing new leak detection and ventilation technology. But, again, these rely on R32 – a medium-term solution.

Further ahead, there has been talk of the development of new technology for air conditioning, employing the HFO 1233zd, a low pressure refrigerant, combined with a high-speed compressor.

Whatever happens, the future is an exciting one, but it will require a measured and pragmatic approach.

Like it or not, R32 is still vital to ensuring that air conditioning is a sustainable business. Nobody in Europe should now be installing R410A splits where R32 versions are available. Do not wait for a refrigerant which may, or may not, supersede R32. The switch to R32, where applicable, is vital to ensure we can continue to service existing and new VRF systems with 410A.

It’s an extra cost, and time consuming but, if you’re an engineer, it’s in your best interests to undertake a relevant flammables handling course. Even if you have no intention of installing a flammable system yourself, you will undoubtedly come across one in the future. The training will broaden your knowledge and will prove to be invaluable.

Related stories:

Honeywell announces R410A breakthrough – 26 June 2018
USA: Honeywell has announced the development of a new lower GWP non-flammable alternative to R410A in stationary air conditioning systems. Read more…

Secret of Honeywell’s new refrigerant – 27 June 2018
USA: Honeywell’s development of a non-flammable low GWP alternative to R410A has created huge interest, but what’s in it? The Cooling Post may have the answer. Read more…

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