January is a good time for taking stock, looking back over what’s been achieved and looking forward to what is to come. 2020 has a particular significance because it is the year that the Montreal Protocol restriction on the use of HCFCs such as R-22 reaches 100%—a complete ban—for developed economies.
Looking back over the Montreal Protocol it is interesting to note that the original text was published in 1986, the year that I started work full time in the refrigeration industry, and was signed the following year and subsequently ratified by all the members of the United Nations as well as other entities such as the Holy See and the European Union. The original text only required a reduction to 50% of baseline consumption for CFCs but this quickly transformed into a complete phaseout and was followed by the phaseout of HCFCs.
Looking further back, the introduction of CFCs to the market took about 40 years, from the initial launch of R-12 in 1930 to the development of R-502 in the late 1960s. This period was somewhat extended because of the Second World War, when R-12 was reserved for military uses and the domestic systems of that time continued to use methyl chloride until the war was over. So it took 40 years to bring CFCs in but they only had 19 years of use before the eight-year phaseout started. HCFCs came in after the war and were included in the Montreal phaseout lists in the late 1980s.
The replacement for CFCs, the HFCs, fared less well. Introduced from about 1990 it took only 15 years for concerns to be raised about their global warming potential and within a further 10 years they had been added to the Montreal phasedown mechanism. Interest in their replacements, the HFOs, dates back almost to the introduction of the HFCs but they started to receive significant interest around 2005 and within 10 years became widespread in their use. So we had CFCs for 60 years and they disappeared in a further six, HCFCs for 40 years with a 20-year phasedown and HFCs for 25 years before their restriction started. On the face of it, this shortening of the time horizon does not bode well for the HFOs.It is true that their development has addressed each of the questions asked of previous generations of refrigerant so that they offer no threat to the ozone layer and have a global warming potential similar to that of CO2, but doubts remain about long-term reliability, effects on the environment and, perhaps most importantly, energy efficiency.
Looking forward, it seems likely that efficiency will be the dominant determinant in refrigerant choice over the next few years. It seems unlikely that the challenges presented in this respect can be resolved simply by putting new fluids into old system designs. When considered on a “source-to-sink” basis most “notin-kind” technologies fare less well than any of the systems using fluorinated gases so they also don’t seem to offer a complete solution.
We have come a long way in the last 30 years and have achieved a great deal, but there is a lot to be done. The questions facing us are getting harder, and the time available to answer them is less. I’ll leave you with this question to consider: Will HFOs have a longer application life than the CFCs that they are replacing?