REFRIGERANTS
What the future holds for refrigerants
John Poole of Refrigerant Solutions shares his view of how the future will unfold for refrigerant gases.
C
limate change is arguably one of the most talked about and high-profile issues which attracts much attention. Climate change and global warming, attributable to human activity, are mainly caused by CO2
emissions, and to a
lesser extent by methane from natural gas leakage and agriculture, which also contributes via N2
O generation.
Despite being a minor (<2%) direct contributor to global warming through fluorinated refrigerant losses, the acr Industry is facing the following conflicting, politically imposed burdens: ■ The need to service existing installations vital to our well-being against progressively reducing quotas of R410A and R404A.
■ The need to reduce the overall contribution of cooling technologies to global warming, direct and indirect. There is little point in sacrificing energy
efficiency and thus significantly increasing CO2 emissions merely to reduce direct global warming.
■ The need to ensure retrofit fluids meet the proper and exacting safety requirements of the industry, in particular non-flammability.
R404A and R507, while being excellent refrigerants in terms of energy efficiency, non-flammability, low toxicity and thermodynamic properties, nevertheless have GWPs which are at the high end of the commonly used HFCs. Although R22, which has been widely used in air conditioning systems, has a much lower ability to destroy ozone compared to CFCs, it is being phased out globally under the Montreal Protocol and already prohibited in the EU. Non-ozone depleting R410A has proved an excellent replacement for R22 in new air-conditioning equipment, including split systems, but it is also now being phased down because the comparatively high GWP (2088) means it is no longer environmentally acceptable.
The EU and other territories have imposed GWP quotas and/or taxes to progressively reduce the availability of R404A, R507 and R410A. These actions have two key consequences. First, there have been shortages of these refrigerants available to service existing equipment and charge new equipment, which disrupted the acr industry last year. Second, the price of remaining refrigerants
10 June 2019
increased substantially as supply was unable to meet demand. Without replacement refrigerants, critical equipment such as that used for preserving food in supermarkets, and air conditioning in hospitals, may stop functioning, with serious social repercussions. The recent ready availability of high GWP blends due to large quantities of illegal imports into the EU is a temporary situation which hopefully the authorities will crack down upon, and the take-up of lower GWP refrigerants will resume as the F-Gas quota system tightens over the coming years. CO2
is the largest contributor to global warming of approximately two thirds of the total due to the combustion of fossil fuels in motor vehicles, industrial processes, and power plants. Methane emissions are also a significant contributor to global warming, approaching 20%. Fluorinated gases hydrochlorofluorocarbons (HCFCs such as R22) and hydrofluorcarbons (HFCs such as R134a) contribute less than 2% to global warming, and of course HCFCs, being ozone depleting substances, are being phased out as above. In the EU, as already mentioned, HFCs are being restricted according to an aggressive phase-down schedule which is causing major problems of supply and high prices. The F-Gas regulation is too simplistic in controlling and restricting the use of HFCs solely by their GWP, and there are many other factors related to global warming, not the least of which is efficiency. The availability of so called ‘natural’ refrigerants, such as ammonia, hydrocarbons and CO2
itself is
well-known, but these alternatives have their own inherent problems of flammability and toxicity (both in the case of ammonia) and are therefore limited in their application and use. These compounds are demonstrably not natural, being manufactured on chemical plants. So, what does the future hold for the adoption of new refrigerant compounds by the acr industry?
Fluorochemical manufacturers have developed the new compounds hydrofluoro-olefins (HFOs) which have very low GWPs (less than 10), but they are flammable, for which ASHRAE has added a new safety classification of A2L. HFO R1234yf is now the product of choice for air conditioning in new motor vehicles, replacing R134a. However, HFOs can be combined with specific HFCs to provide refrigerant
blends which are non-flammable, have low GWPs (below GWP 400) and are energy efficient. The ability to produce blends which are non-flammable is dependent on the availability of HFCs so that, over the medium term (10 years), it is essential that HFCs are available in sufficient quantities to satisfy market demand.
The deployment of blends with a GWP less than ~400 which are non-flammable, energy efficient, low toxicity, with similar cooling capacities as the products they replace and requiring little or no changes to existing equipment, provides a practical and low cost solution to this whole problem for 10 years or even longer, providing certainty and clarity to users and OEMs alike. The key differentiating factor of these blends is the fact that they are non- flammable under all conditions of fractionation as required to obtain a safety classification of A1 from ASHRAE. Below a GWP of 400 would make such blends flammable and thereby limited in their application, together with increased costs such as leak detection controls, the need for a secondary loop, and an energy penalty.
Ever since the discovery of CFCs, HCFCs and HFCs, the world has been accustomed to using safe non- flammable and low toxicity refrigerants which have a well-known advantages over their precursors such as sulfur dioxide, methyl chloride, hydrocarbons, and ammonia. By using GWP as the sole determinate for restricting the use of refrigerants, F-Gas is in practice forcing the industry to adopt the use of flammable refrigerants. However, it must be emphasised that any blends with A2L safety classification are flammable, so a number of changes need to be made to new equipment to handle these refrigerants. Furthermore, A2L blends cannot be used to replace refrigerants in existing installations.
Reducing GWP tends to increase the risk of flammability. So far in formulating retrofit refrigerants it has proved possible to walk a fine line between flammability and GWP while delivering acceptable performance. Ultimately, however, there is a limit to this balancing act. Where is it likely to be? In our view, we consider that it lies around a GWP of ~400. Recognising that F-Gas does control refrigerants by their GWP alone, it is common sense to utilise blends with GWP of ~400 which continue to provide all the benefits of non-flammability without losing other important properties such as efficiency, low toxicity, and lower costs.
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