REFRIGERANTS
To retrofi t or not to retrofi t
Professor Dick Powell of Refrigerant Solutions looks at the challenges of retrofi tting in a time of transition.
In this article I address not the long-term OEM options for safe
refrigerants, but the problem presented by the vast amount of refrigeration and air-
conditioning equipment existing
globally that contain HFC refrigerants.
E
ach type of refrigeration and HVAC unit is designed around the specifi c properties of the refrigerant fl uid to be used. At inception of the industry these fl uids
were typically sulphur dioxide, hydrocarbons, methyl chloride and carbon dioxide, products which became available in signifi cant quantities from the burgeoning 19th century chemical industry. These hazardous compounds were replaced in the mid-20th century by the low toxicity and non-fl ammable CFCs and HCFCs highly esteemed by those OEMs conscious of their responsibilities to provide their customers with low hazard products. The exception was ammonia, which has continued in widespread use as a major industrial refrigerant to the present day although severe and fatal injuries from adventitious leaks are reported yearly.
Advances in basic scientifi c knowledge in the early 1970s, indicated that CFCs and HCFCs could deplete stratospheric ozone so have eff ectively been replaced by the non-ozone- depleting containing-HFCs. HFCs have since been included in a phasedown schedule under the Montreal Protocol due to their high Global Warming Potential (GWP), although their actual contribution to global warming is stilled dwarfed by that of CO2
from fossil fuels and methane from agriculture.
In previous articles I have commented at length about the distortion of the global warming debate by the focus of green activists and politicians, especially in Europe, on fl uorine containing refrigerants including HFOs introduced over the past 20 years which off er a desirable combination of low hazard at point use with very low GWPs. Some green politicians have resorted to political sophistry to have the HFOs phased out under PFAS regulations. Despite the misinformation spread by these environmental activists, as I have noted in previous articles, the HFO refrigerants off er a long-term safety and low environmental impact. Advocating the re-introduction of 19th
century refrigerants by attaching
the spurious descriptor ‘natural’ to them – in-accurately described as ‘natural’ in view of the fact that they are manufactured at scale in large chemical plants – might make them emotionally appealing to the voting public but does not ameliorate their intrinsic hazards. In this article I address not the long-term OEM options for
safe refrigerants, but the problem presented by the vast amount of refrigeration and air-conditioning equipment existing globally that contain HFC refrigerants. Retrofi t of
18 December 2023 •
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this equipment with non-fl ammable refrigerants with lower GWPs and similar performance is essential to the continued operating of a whole range of applications essential for maintaining our standard of living including operating theatres, food preservation, comfort cooling etc. Retrofi tting a fl uid into a system for which it has not been specifi cally designed is a technically challenging task. Even to those with just a limited appreciation of the economics and logistics of the refrigeration and HVAC industries, replacing equipment before the end of its working by new units should be seen as blatantly nonsensical even to those advocating a return to the hazardous ‘natural’ refrigerants. But by limiting availability of higher GWP refrigerants through stringent quotas and taxes runs the real risk of inadequate product being available for maintenance of existing equipment. This will result in undesirable consequences including increased costs to users and thus ultimately the consumer, and an increased incentive to smuggling scarce refrigerants, especially in the EU.
Existing equipment can be retrofi tted with a new lower
GWP alternative provided that the alternative has suffi ciently similar properties to the refrigerant being replaced, thereby minimising system modifi cations. Such refrigerant retrofi ts are attractive for reducing the environmental impact of systems with large refrigerant charge, such as centralized commercial refrigeration systems. Obviously, a retrofi t fl uid should have a signifi cantly lower GWP than the fl uid being replaced, the actual GWP value will be set by existing or anticipated in forthcoming legislation. The discharge pressure must not exceed the maximum pressure for which the equipment is rated. A fundamental point is that existing systems using HFC refrigerants are not specifi cally designed to use fl ammable refrigerants, retrofi t of existing systems is limited to using only A1 alternatives, namely non-fl ammable under ASHRAE testing under all conditions of fractionation. Retrofi tting with A2L or A3 refrigerants is not permitted. Regulators need to understand that as they reduce the GWP values the more diffi cult it becomes to fi nd technically viable retrofi t products to the point where it becomes impossible. Progressively reducing GWP targets by regulators in the hope that fl uid manufacturers can comply is fruitless. I note the concern already being voiced in the industry about dangerous practices induced by GWP restrictions. The
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