REFRIGERANTS
Splits second decision
Chris Chisman, technical director at Marstair talks about the benefits of the one-stop-shop for compliant A2L split system.
T
he refrigerant Global Warming Potential (GWP) quota and its effects are now very much understood within the industry. We
know the traditional higher GWP refrigerants are ultimately going to become less available and more expensive, we also know there are many low GWP alternatives in various sectors of the industry, either well established, or being trialled. For instance, R32 for small air- conditioning splits is now more common than
R410A. Meanwhile CO2 packs, or hydrocarbon- based refrigerant solutions, are now the norm for larger supermarket refrigeration applications. However, one area where there has been very little progress, despite being a good proportion of the market, is the small refrigeration split market. These are small packaged remote refrigeration condensing units matched with cold room evaporators or refrigerated cabinets, for small retail outlets. While there are now some small CO2
condensing units available on the market, this has not yet become mainstream, mainly due to the large cost investment which is difficult for the small independent retailers to afford. There is also the issue that many systems are installed by smaller refrigeration contractors who don’t currently have the experience, skills
and training required to offer CO2 as an option. A2L refrigerant alternatives to R404A are available and the skills and cost leap to using
these is much smaller than CO2, so why are the refrigeration splits behind other sectors? Large supermarkets have the size and
infrastructure to be able to plan, see the potential problems the F-Gas GWP quota will cause and work with manufacturers and the larger refrigeration contractors to find the best solutions for their businesses. The small split
30 March 2020
air conditioning market, on the other hand, had different factors which drove this area to change early.
First there is a specific ban in this sector on refrigerant with a GWP over 750 GWP after 2025, so the big brand manufacturers knew they had to ultimately make the change. The bigger factor, however, was that the whole system is manufactured by a single manufacturer. A2L refrigerants are flammable, this requires extra regulatory factors such as tighter limits on the refrigerant charge relative to room volume. This is much easier to control when the whole system is supplied by the one manufacturer. So, what’s different about small refrigerated split systems? Well, there is a ban, but only for refrigerants with a GWP over 2500 and there are R404A equivalent refrigerants available at 1300 GWP such as R448A and R449A, so there is no immediate legislative driver. The end user customer base tends to be small
independent retailers who cannot be expected to drive change and generally rely on the industry to inform them of the best solution for their needs. Similarly, the installer base tends to be smaller contractors in a viciously competitive market who individually can’t be expected to change the industry on their own. Finally, there is the equipment itself, where individual parts are supplied to the market by different manufacturers. Refrigeration condensing units, cold room evaporators, controls, valves and refrigerated cabinets all tend to be made by different companies. This is understandable in a world where manufacturers need specialist focus to be successful. The skills and expertise required for each of these parts are very different. For instance, the customer requirements of a
refrigerated cabinet such as shelf space, product presentation and aesthetics are very much different to that of a condensing unit. So now we know why refrigeration split systems have not advanced as quickly as other sectors within the market, but where are we now? What is the best way forward? And when will a solution be available in the market? Suitable A2L refrigerants with a sub 150 GWP (R454C & R455A) have been available for some time, long enough for there now to be some appropriately sized compressors to start becoming available. So, you would think that all the manufacturers of the current parts of a split refrigeration system could launch A2L variants and they would quickly take over the market. Well not quite, as there is the main issue of the regulations, specifically the amount of refrigerant allowed in a complete system relative to a room size. The relevant standard is EN378 and the allowable refrigerant is determined by certain criteria. Firstly, location criteria. For a split system the location classification must be based on Class II, “Compressors and pressure vessels in a machinery room or open air with the coil and pipework allowable in the occupied space.” Secondly, access category. This should be assumed as category ‘A’, general access, to cover all potential applications. Based on these criteria within the standard, the refrigerant limit becomes 20% X LFL X room volume and not more than 1.5 X 26 X LFL. The LFL translates to the ‘Lower flammability limit’, this is the lowest percentage mix where the refrigerant can maintain its own flame in air. Allowing only 20% of this, gives a good safety margin but severely limits the overall refrigerant charge.
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