REFRIGERANTS
There are also the single component HFC refrigerants, such as R32 (GWP 675), and HFO/ HFC blends such as R471A, R448A and R449A, which have GWPs of 677, 1270 and 1280 respectively. Their future post-2030 is in doubt, and work is underway to establish safe, efficient and affordable alternatives. Ultra-low refrigeration (< -50°C) is one area where HFCs have continued to dominate, with refrigerants such as R23 and R508A. These have very high GWPs of 12400 and 11700 respectively, but have exemptions due to the critical application.
Q: How close are we to filling the current gaps?
A: For ultra-low refrigeration there is now WT69 / R469A. It is a mixture of R32, R125 and CO2
,
with a GWP of 1250 and classified as A1 (non- flammable).
Q: Are A2L refrigerants now widely accepted as mainstream? Or does the industry have to keep making the case?
A: A2L refrigerants have been used successfully in some parts of refrigeration for many years. Their use is now growing in smaller retail and cold storage applications, although take-up so far has been modest. Installer training is key, as the maximum charge limit for each installation requires calculation of the Lower Flammability Limit (LFL). Installers must also have a good understanding of the Pressure Equipment Directive (PED), and from our own research there is still some work to do in this area. Given their ‘mildly flammable’ classification there is a case for having a dedicated course for handling HFO refrigerants, as distinct from other fluids, such as highly flammable A3 refrigerants (HCs), and mildly flammable and highly toxic ammonia, which is classified as B2L.
Q: Following Brexit, are there any signs that the UK might start to diverge from the EU on refrigerants policy?
A: It’s a good question, but hard to answer with absolute certainty. What we know is that EU standards have been adjusted to BS EN standards, and will remain valid for some time. Some non-EU countries, for example Iceland, Norway and Switzerland, have aligned their national laws with the EU F-Gas Regulation. Also, we shouldn’t forget that UK scientists played a key role in discovering the hole in ozone layer in the 1980s.
www.acr-news.com Q: The (re)emergence of CO2 as a mainstream
refrigerant – for use in particular in retail – has been a key development. Do you think CO2 has wider application, say in commercial heat pumps, and perhaps even building air conditioning?
A: Absolutely. Modern CO2 systems are blurring
the line between industrial and retail refrigeration. Larger Bitzer reciprocating systems, based on 140hp transcritical compressors, are being used for chill and cold storage applications in Regional Distribution Centres. Historically this sector has been dominated by ammonia systems. However, CO2
has advantages in terms of whole-life costs, plus the safety benefits. On a wider front, CO2
chillers and heat pumps
can deliver simultaneous heating and cooling for HVAC applications and district energy schemes. The heat can be used for clean in place (CIP) systems, produce warm water for sanitary requirements and hot water for multiple uses. This will be a growth area for the future as part of the decarbonisation of heating.
Q: On heat pumps, how far do you think have we come to date in realising their potential?
A: Obviously we have not been as quick off the mark as trailblazers such as Switzerland and Scandinavia. However, the Government’s plan to achieve net-zero carbon by 2050 is a big step forward. Installing 600,000 domestic heat pumps a year to replace gas boilers is certainly a stretching target. On the commercial and industrial front, high efficiency heat-pump based technology already exists for the creation of district energy centres, and recovering waste heat from industry and supermarkets.
Q: What needs to happen to accelerate the application of heat pumps?
A: A big strategic issue is the need to upgrade the UK’s electrical supply and transmission system. Replacing gas with renewable electricity will mean a big increase in electrical demand, and this means investing in the grid. For our own industry, we will need many more
trained people with the skills to design, install and maintain heat pumps. And, crucially, end users need to be incentivised through long-term government policy and grants, to reduce upfront installation costs and support costs over the equipment life-cycle.
Q: District heating and cooling schemes are another area where significant efficiencies and carbon reductions can be achieved.
Do you see this as a growth area for Bitzer in the years ahead?
A: Yes, very much so. Our semi-hermetic screw compressors using A2L refrigerants can produce up to 1000kW of heating, evaporating at 35°C and 80°C condensing temperature in economiser operation. District energy schemes tied in with heat recovery from data centres is another promising application. As society moves ‘on line’ and digitalisation
increases, the rapid growth in data centres will continue. The waste heat these facilities generate can be harnessed very effectively using heat pumps, for use in homes, manufacturing and industry. ‘Closing the loop’ in this way will help create a 360° sustainable economy, with reduced carbon emissions and waste.
Q: On the equipment side, Bitzer has achieved great success with its Ammonia Compressor Packs (ACP). Is this development – from manufacturing compressors to producing complete packs – something we are likely to see more of, perhaps in the HFO and A2L areas, in the future?
A: We already manufacture dressed condensing units suitable for A2L refrigerants. For the foreseeable future, however, we will continue to manufacture large and – possibly larger – natural and A2L refrigerant-based reciprocating and twin-screw compressors, and let pack designers do what they do best, and integrate this technology into their own equipment.
Q: What do you see as the ‘next great leap forward’ for the industry in the next decade?
A: Digitalisation is already beginning to transform the way the industry operates, as a result of the unprecedented access to information now possible and the ability to ensure a first-time fix. But this revolution has only just begun. Intelligent compressors connected to the Bitzer Digital Network, for example, offer an extraordinary window into the performance of systems in real time, that previous generations of refrigeration engineers could only dream of. This rich data can be analysed in an infinite variety of ways, to yield valuable insights to optimise performance, cut running costs, reduce emissions, and further improve reliability and resilience. It is an exciting new field opening up before us,
and I am excited that Bitzer and our customers are in the vanguard of this revolution. It will be one of the keys to achieving our national – and indeed global – net-zero carbon targets in the future.
May 2021 19
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