07 February 2018
A-Gas Product Manager for Refrigerants Roger Smith on why mildly flammable refrigerants will have a major impact on the industry.
At A-Gas we’ve been keeping a close watch on the progress of A2L refrigerants as we believe they can make a real impact on the industry. In the right circumstances, A2Ls, or mildly flammables as they are often known, give users a great deal of breathing room in terms of the F-Gas Regulations. At A-Gas we are encouraging businesses to try out some of these new refrigerants, gain experience of using them and ultimately understand how they perform.
It’s no secret that R32 has been championed as an A2L alternative for use in air conditioning split systems. R32 is widely available on the market in a variety of cylinder sizes and from a practical perspective is a good replacement for R410A – a high GWP gas which, like other high GWP products, is under scrutiny as the quota system begins to take effect.
Manufacturers already supply equipment which is R32 ready and the message is reaching engineers and end users that this single component gas with a GWP of 675 is a winner – especially when you consider that the commonly used R410A has a GWP of more than 2000. What’s more, R404A, the go-to gas for refrigeration systems, is as high as 3922. Elsewhere, R455A (an A2L) has a GWP of 148 and in the case of water chillers R1234ze has a GWP of 7. So, by simply looking at the GWP you get huge benefits with A2Ls, giving the industry a chance to grow.
There is no guarantee that any refrigerant is future proof but it is a good bet that R32 will be a preferred option in air conditioning systems for many years to come. This year’s 37 per cent cut in quota for GWP will affect the availability of virgin HFC refrigerants and this is putting a further squeeze on the industry. What also makes A2Ls such excellent alternatives to the high GWP gases is that typically you will use up to six per cent less product in the system.
Change of thinking
Add to this the smaller line sizes and a potential cut in running costs by three per cent a year and you have savings that cannot be ignored. Remember that there will be a lot less of the high GWP gases around and what is available will continue to rise in price. So low GWP A2Ls will become more attractive to the industry as the F-Gas phasedowns continue.
Mildly flammable refrigerants do require a change of thinking. They are not drop-ins and engineers need to be more aware of how to handle them and also ensure that they have the right tools to do so. Recovery units and vacuum pumps have to change but the good news is that recovery units and recovery cylinders are available off the shelf for use with mildly flammable products. Suitable manifolds and hoses are already on the market and able to do the job safely, but whatever the task, make sure that you only use approved equipment. If in doubt, always ask.
They might be known as mildly flammable but A2Ls are very difficult to ignite. Only a naked flame – and not a spark – will ignite them as there’s not enough energy in the spark for ignition. The amount of refrigerant which would have to escape into the atmosphere also has to be on a much larger scale to reach low flammability limits. Having said that, A2Ls have to be treated with the same respect as all refrigerants.
Charge calculations should be approached in the same careful way you would tackle any job. You will need to refer to BS EN 378:2016 for the full calculation methodology. There are several mitigating factors to consider with A2Ls which will include location of equipment, leak detection and ventilation, but you will be getting smaller charge sizes and this in turn will reduce the risk of gas escapes reaching the lower flammability limit.
Smaller charge sizes
Ask yourself, is the equipment in a secure place or is it open to the public? Keeping the equipment outside in a secure plant room can help to get the most from your refrigerant. Piping calculations can be scaled down too because you don’t have to pump so much refrigerant around the system. These factors need to be considered when you are aiming for that maximum refrigeration capacity. If you have all the boxes ticked you can have up to 60kgs of refrigerant in a single system. There aren’t major hurdles to overcome and the British Refrigeration Association currently has a working group putting together guidance notes on A2Ls – so watch this space.
Care should also be taken when transporting mildly flammables as the ADR Regulations do not recognise them as a classification. They should be treated in the same way as you would other flammable gases and this requires a ventilated vehicle and full documentation to accompany them.
A2Ls with their greater energy efficiency, smaller charge sizes and reduced equipment footprints have a lot to offer the industry. The lower GWP is a huge bonus and so too is the reduced TEWI (Total Environmental Warming Impact) figure as the environmental warming impact by default will also come down. This is the calculation based on the GWP of the product and its energy costs over its lifetime. With an R404A system the TEWI will come out at 2500 but by using an A2L refrigerant you can reduce this to little more than a 1000 – so the figures speak for themselves.
Overall, A2L refrigerants are the next step in refrigeration technology and will be instrumental in our industry surviving through the phase down of available quota.
Content continues after advertisements