R12 is essentially the father of gases of this type - the majority of refrigerants. It was known even before World War II, and it was an absolutely groundbreaking discovery that enabled the development of energy extraction in a manner similar to today's heat pumps. A forgotten yet revolutionary invention. At one point, R12 was the absolute market dominator. Why did dichlorodifluoromethane - its full chemical name - disappear from heat pumps and refrigerators?
✅ R12 was invented in 1928 in the USA by Thomas Midgley Jr. and his colleagues at General Motors, in collaboration with DuPont. Midgley was a brilliant chemist and inventor, holding over 100 patents, but we won't focus on him here. Soon, DuPont (of French origin) patented R12 under the commercial name "Freon".
The discovery of Freon was part of a larger project aimed at finding a safer replacement for toxic and flammable substances such as ammonia (NH₃), sulfur dioxide (SO₂), and methyl ether. It's worth noting that the word "freon" in some languages has become synonymous with refrigerant gas - and is often (very often incorrectly) used to refer to all gases used in heat pumps.
R12 was characterized by:
✅ The problem was its high ODP (Ozone Depletion Potential) - in simpler terms, its significant impact on ozone layer depletion. However, before World War II (and until the 1970s), this was not understood.
From the 1930s, R12 gas was widely used in:
In the 1950s and 1960s, R12 became a global standard, revolutionizing refrigeration technology. The widespread adoption of refrigerators contributed significantly to this - it was used en masse as a standard in refrigerators in both the Western and Eastern blocs. It also became a standard in food refrigeration technologies, etc.
It seemed that R12 would become the foundation of the still-nascent heat pump technology - however...
In the 1970s - when the refrigerant R12 was at its peak - scientists discovered that freons, including R12, had a destructive impact on the ozone layer. Mario Molina and F. Sherwood Rowland published research in 1974 showing that CFCs - the group of gases to which R12 belonged - were depleting the ozone.
The 1980s saw further research into the so-called ozone hole.
✅ In 1987, the Montreal Protocol was adopted - an international agreement aimed at protecting the ozone layer. This meant the gradual phase-out of ozone-depleting substances, including chlorofluorocarbons (CFCs) such as R12 (dichlorodifluoromethane). This marked their slow market death and the need to chart new paths for technology development - such as heat pumps, refrigerators, and air conditioning.
The production of R12 was banned in most countries under international regulations. Of course, the process had its own pace, as different countries implemented the Montreal Protocol at different times. Today, the use of R12 refrigerant is allowed only in exceptional cases, such as servicing very old equipment (and even this is strictly regulated). Essentially, it can be said that R12 is commercially and technologically dead.
R12 played a key role in the development of modern refrigeration technologies - few people know that without the CFC revolution - R12, today's advanced heat pump technology would not exist. Heat pumps, in turn, represent a revolution in the heating industry and ecology - without a doubt, even their critics would agree.
Although R12 refrigerant had many technical advantages, its environmental impact and contribution to the ozone hole necessitated the development of alternatives. R134a, R410a, and R407c are much more environmentally friendly, but they bring challenges in system design, particularly related to higher pressure and global warming potential. The refrigeration industry is increasingly turning to even more environmentally friendly refrigerants, such as R1234yf or R290. Especially heat pumps operating on R290 seem to be a growing trend recently. However, none of this would have been possible without the invention in 1928 of the now forgotten - R12 refrigerant.
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