Still using Refrigerants >750 GWP? It’ll be OK, I’ll retrofit it later. Or can you?
Climalife UK
Are you still being asked to install new systems with R-448A or R-449A or any other refrigerant with a GWP >750? If yes, then what is your strategy for keeping those systems operational to the end of their useful lives? Having previously successfully navigated the changes from either CFCs, HCFCs or the more recent move from high GWP HFCs like R-404A to lower GWP refrigerants such as R-448A or R-449A, you are probably thinking the next phase of the transition to lower GWP will be just as straight forward, but that may be a big mistake.
The refrigerant landscape is about to change again, but this time it is going to be different, this time there will not be long term retrofit options that will allow an easy transition. A plan on how to get from where you are today with refrigerant usage to where you need to be to comply with legislation will be crucial to avoid unpleasant surprises and potentially could save a lot of unnecessary cost.
Why is it different this time around?
Until now every time legislation has restricted the use of certain refrigerants, a range of direct replacement products have been available to replace the old refrigerant whilst maintaining the use of the same equipment with no or minimal hardware changes. This was possible because the replacement refrigerants had similar performance, similar physical properties and had the same safety classification as the product being replaced (table 1).
Table 1 - Examples of previously available retrofit options
Defra (Department for Environment, Food and Rural Affairs) published an assessment report in 2022 which compared different scenarios with the F-Gas HFC phasedown. Although products such as R-448A or R-449A are still easily available today, data from the report warns that without a significant move to using lower GWP refrigerants, within two years demand could exceed the quantities available under the F-Gas quota (Low ambition in figure 1).
The phasedown in the current F-Gas legislation, let alone any future accelerated HFC phasedown, means the GWP of the next round of potential replacements needs to be at a level where the only products available either have significantly different performance characteristics, significantly different physical properties or a different safety classification making a retrofit at best very difficult and in most cases completely impractical.
Therefore, systems with a significant expected useful lifetime, that are using refrigerants with a GWP >750 GWP, are going to need a refrigerant strategy probably based on using reclaim refrigerant. Using a low or very low GWP refrigerant is only likely to be possible in equipment that has been designed and certified to use such refrigerants. As previously mentioned, in most cases retrofitting a system designed for a refrigerant with a GWP >750 to a low or very low GWP refrigerant will be at best very difficult and in most cases completely impractical.
Figure 1 – Possible scenarios for HFC usage - Source data from 2022 Defra F-Gas assessment report
The same but different!
Fundamentally the requirements for using the new low GWP refrigerants are no different than using the previous and current A1 safety class refrigerants but if the equipment has not been designed for use with the low GWP options it is unlikely to be suitable or compliant with standards and legislation.
Refrigerant Charge Size
Even before the current range of low GWP refrigerants were introduced EN 378 has given guidance on refrigerant charge size limitations. All refrigerants have a maximum charge size allowance either based on toxicity or flammability.
EN 378 compliant charge sizes (without additional protective measures) for the low GWP options are often significantly lower than for the previously used higher GWP refrigerants. This is likely to require a change in the design of the system. Designing new equipment with smaller charge sizes, using a modular system rather than larger centralised systems or employing additional protective measures to allow larger charge sizes are all considerations to be incorporated into choosing the most suitable refrigerant.
This article will not go into the details of EN 378 but as can be seen in figure 2, in applica
tions using remote condensing units and additional protective measures as detailed in EN 378, relatively large maximum charge sizes up to a charge size of 84kg can be used in spaces that are normally occupied. In spaces which have no or low occupancy, much larger charge sizes are possible, for example a 15,000m³ chill store operating in East London since 2022 has 414kg of <150 GWP R-454C in a single circuit centralised system. This opens up the opportunity to consider A2L refrigerants for many applications where a remote condensing unit is used, the compliant charge sizes for A3 refrigerants are insufficient and the cost or energy efficiency of a R-744 unit is prohibitive.
Dangerous Substances and Explosive Atmosphere Regulation (DSEAR) Risk Assessment
A DSEAR risk assessment has been a requirement for all refrigeration systems, even those using non-flammable refrigerants, since 2015. When using a flammable refrigerant, compliance with EN 378 ensures there is a very low risk of forming a flammable atmosphere and therefore beyond showing compliance with EN 378, there are no additional requirements compared to using an A1 safety class refrigerant.
Pressure Equipment Safety Regulation (PE(S)R)
Many people refer to the Pressure Equipment Directive (PED) but the UK Statutory Instrument implementing PED is PE(S)R. As with EN 378 and DSEAR, PE(S)R applies to all refrigeration systems with a PS above 0.5 bar. The fluid group of the low GWP refrigerants which have flammability limits at 20°C is fluid group 1 as opposed to fluid group 2 for the non-flammable refrigerants at 20°C. In some cases, especially when using the higher-pressure flammable refrigerants, the system will be rated in a higher compliance category (see table 2) but the requirements for each category are the same irrelevant of the refrigerant.
Table 2 - Examples of PE(S)R categories for a pressure vessel on the high-pressure side with different refrigerants
Minimising the size of pressure vessels or removing completely may limit the impact of the change in refrigerant. Where systems are rated as Cat II or higher it is necessary to involve a notified body and for any piping designated as Cat II or higher a notified body approved brazing qualification will also be required.
The data in table 2 clearly shows all the high pressure or flammable low GWP options will move into higher PE(S)R categories at much lower vessel volumes than the previous higher GWP refrigerants and this is the main reason why in many cases it will be impractical to use these products as retrofit options.
No Retrofit options, what’s the answer?
Whilst availability of moderate to high GWP refrigerants is still good, it’s easy to be lulled into the false sense of security that the time to change is somewhere in the future, but already systems being installed today run a very high risk of not fulfilling their expected lifetime due to the choice of an unsustainable refrigerant.
Low GWP refrigerants are readily available, and the availability of suitable equipment is rapidly increasing meaning there is no reason why a sustainable low GWP options can’t be installed today. In many cases improved energy efficiency can be achieved lowering operating costs as well as reducing emissions for the expected lifetime of the equipment.
It may all seem very daunting changing to something new but the team at Climalife have the expertise to help guide you to a more sustainable refrigeration strategy.
It is human nature to try to avoid change but this one is inevitable so while there’s still time, why not get ahead of the legislative curve and steal a march on your competition.
