ACR Journal

32 Volume 7 No.5 August | September 2021 REFRIGERANTS When discussing refrigerant options, I’m often reminded of a joke that involves somebody asking for directions and receiving the answer, “Well, I wouldn’t have started from here!” But here is where we are, and to get to where we need to be may not be as difficult as it is often believed. So why use A2Ls? It’s a very good question, but maybe initially, we should be asking why move to lower GWP alternatives? The answer is, of course, to reduce the emissions of climate-changing gases significantly. For our industry, that reduction is driven by the F-Gas regulation encouraging the adoption of ever-lower GWP refrigerants, but is that the full story? Is the lowest GWP refrigerant the best refrigerant to use? Well, the lowest GWP refrigerant widely in use today is ammonia, the only refrigerant with a zero GWP. Still, I don’t think I would be alone in not wanting ammonia in the split air conditioner cooling my office, so clearly there are other considerations in play other than just GWP. In the case of ammonia, it’s evident that toxicity plays a part in the decision-making process, but there are also many other less obvious criteria to take into account. Not least of which is the system’s energy efficiency, which through the indirect emissions from power generation has a huge effect on total emissions over the system lifetime. When the current F-Gas legislation was first introduced, an EPEE study concluded that a 10 per cent increase in energy consumption would effectively negate any benefits gained from the eventual 79 per cent reduction of refrigerant GWP dictated by the F-Gas regulation; it would be a case of all pain and no gain. So, energy efficiency is definitely something to be considered. Refrigerant classification Then there is flammability. Flammability has not been an issue for most users as the refrigerants they have been using have had the safety classification A1 (lowest toxicity, practically non-flammable). However, many of the very low GWP refrigerant options come from the A2L (low toxicity, lower flammability) or A3 (low toxicity, high flammability) safety groups, so they do have a degree of flammability. Initially, this may seem to be a significant barrier to use, but in many situations dealing with flammable refrigerants should be covered by existing processes, e.g. risk assessment, compliance with EN378 and P.E.D. However, the results of these processes are likely to require some additional actions to mitigate the increased risk of using a flammable refrigerant. Neil Roberts, senior technical sales manager at Climalife, discusses why further considerations other than GWP need to be considered when selecting a refrigerant. Low GWP refrigerants: why use A2Ls? Neil Roberts