www . refrigerationandaircon . co . za RACA Journal I February 2025 7
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important , with high costs of electricity occasionally raising the profile of efficiency initiatives . Safety and reliability were also being improved , partly through legislation such as the European Machinery ( Safety ) Directive and Pressure Equipment Directive , partly through national regulations and partly through the relentless increase in product liability litigation , particularly in the US but increasingly seen in other parts of the world .
4 . STATUS REPORT As we start 2025 it is helpful to take stock of the current position across the broad range of technologies that comprise the refrigeration world , including of course air-conditioning and heat pumps . We are 40 years on from the Vienna Convention for the Protection of the Ozone Layer , the forerunner of the Montreal Protocol and we are 33 years on from the Earth Summit in Rio de Janeiro , the kickstart to the Framework Convention on Climate Change that produced the Kyoto Protocol 28 years ago . This led to the European f-gas regulations 19 years ago , updated 11 years ago and again in early 2024 . It also , eventually , led in the US to the AIM Act , which entered into force four years ago .
The decisive action under the Montreal Protocol has reversed the trend of ozone depletion and levels in the Antarctic , where depletion was most severe , and over the whole globe are expected to return to 1980s levels by about 2060 , as shown in Figure 1 .
In contrast , NASA estimated in 2009 ( Carlowicz , 2009 ) that by 2065 the ozone shield at mid-latitude in the stratosphere would have reduced to about one third of its 1980 level if action had not been taken against chlorine compounds . This , it was said , would cause sunburn within five minutes and would have resulted in damage to DNA in plants , animals and humans causing a wide range of health problems . This bleak scenario appears to have been averted . Figure 1 : Ozone Forecasts ( from Salawitch et al , 2022 )
Moves to address the threat of global warming have been less successful so far and we seem to be in grave danger of missing the targets that were originally set as safe limits . It has been much harder to impress the dangers of climate change on the minds of the public and this has translated into a rather weak political response to the scientific evidence of the need for action . The issue is far more complex than the ozone depletion scenario and has been the subject of massive debate about the truth of the scientists ’ claims with misinformation on both sides of the argument leading to confusion and ultimately inaction in the political world .
The Paris Agreement , adopted at COP21 in 2015 , set targets to limit the effects of climate change , including a goal to “ hold the increase in the global average temperature to well below 2 ° C above pre-industrial levels ” and an objective “ to limit the temperature increase to 1.5 ° C above pre-industrial levels ”. This objective would have required greenhouse gas emissions to peak before 2025 and to decline by 43 % by 2030 .
Figure 2 : Greenhouse Gas Emission Forecasts ( from Fyson et al , 2023 )
The forecast shown in Figure 2 , from the Climate Analytics report , “ When will global greenhouse gas emissions peak ?’ ( 2023 ), presents three scenarios . Even the most optimistic of these , where fossil fuel CO2 emissions peak in 2024 , HFC emission targets are met and growth trends in wind and solar power and in electric vehicles continue at the present rate , only shows a reduction of 10 % in emissions from the peak value by 2030 . This is good , but not good enough to limit temperature rise to 1.5 ° C .
In the refrigeration world analysis of progress needs to be done on a sector-by-sector basis including consideration of environmental issues , efficiency issues and safety issues .
In the domestic refrigerator market , most production around the world is now based on R-600a , isobutane , and it is estimated that there are over 800 million of these units in operation , with an excellent safety record ( UNEP RTOC , 2022 ). There is no case for adoption of any alternative considering this good experience so the only change that might be foreseen would be a switch to R-600 , normal butane , which has a higher critical temperature and offers marginally better efficiency but at the expense of
www . refrigerationandaircon . co . za RACA Journal I February 2025 7