The history of refrigerant development

In 1928 Thomas Midgley Jr. created the first non-flammable, non-toxic chlorofluorocarbon gas, Freon (R-12). Following the discovery of better synthesis methods, CFCs such as R-11, R-12, R-123 and R-502 dominated the market.

Phasing out of CFCs

In the early 1980s, scientists discovered that CFCs were causing major damage to the ozone layer that protects the earth from ultra-violet radiation, and to the ozone holes over polar regions. This led to the signing of the Montreal Protocol in 1987 which aimed to phase-out CFCs and HCFC but did not address the contributions that HFCs made to climate change. The adoption of HCFCs such as R-22, and R-123 was accelerated and so were used in most U.S. homes in air conditioners and in chillers from the 1980s as they have a dramatically lower Ozone Depletion Potential (ODP) than CFCs, but their ODP was still not zero which led to their eventual phase-out.

Hydrofluorocarbons (HFCs) such as R-134a, R-143a, R-407a, R-407c, R-404a and R-410a (a 50/50 blend of R-125/R-32) were promoted as replacements for CFCs and HCFCs in the 1990s and 2000s. HFCs were not ozone depleting but did have global warming potentials (GWPs) thousands of times greater than CO2 with atmospheric lifetimes that can extend for decades. This in turn, starting from the 2010s, led to the adoption in new equipment of Hydrocarbon and HFO (hydrofluoroolefin) refrigerants R-32, R-290, R-600a, R-454b, R-1234yf, R-514A, R-744 (CO2), R-1234ze and R-1233zd, which have both an ODP of zero and a lower GWP. Hydrocarbons and CO2 are sometimes called natural refrigerants because they can be found in nature.

In 1996 Eurammon, a European non-profit initiative for natural refrigerants, was established and comprises European companies, institutions, and industry experts.

In 1997, FCs and HFCs were included in the Kyoto Protocol to the Framework Convention on Climate Change.

In 2000 in the UK, the Ozone Regulations came into force which banned the use of ozone-depleting HCFC refrigerants such as R22 in new systems. The Regulation banned the use of R22 as a "top-up" fluid for maintenance between 2010 for virgin fluid and from 2015 for recycled fluid.

Addressing greenhouse gases

With growing interest in natural refrigerants as alternatives to synthetic refrigerants such as CFCs, HCFCs and HFCs, in 2004, Greenpeace worked with multinational corporations like Coca-Cola and Unilever, and later Pepsico and others, to create a corporate coalition called Refrigerants Naturally! Four years later, Ben & Jerry's of Unilever and General Electric began to take steps to support production and use in the U.S. It is estimated that almost 75 percent of the refrigeration and air conditioning sector has the potential to be converted to natural refrigerants.

In 2006, the EU adopted a Regulation on fluorinated greenhouse gases (FCs and HFCs) to encourage to transition to natural refrigerants (such as hydrocarbons). It was reported in 2010 and some refrigerants are being used as recreational drugs, leading to an extremely dangerous phenomenon known as inhalant abuse.

From 2011 the European Union started to phase out refrigerants with a global warming potential (GWP) of more than 150 in automotive air conditioning (GWP = 100 year warming potential of one kilogram of a gas relative to one kilogram of CO2) such as the refrigerant HFC-134a (known as R-134a in North America) which has a GWP of 1526. In the same year the EPA decided in favor of the ozone- and climate-safe refrigerant for U.S. manufacture.

A 2018 study by the nonprofit organization "Drawdown" put proper refrigerant management and disposal at the very top of the list of climate impact solutions, with an impact equivalent to eliminating over 17 years of US carbon dioxide emissions.

In 2019 it was estimated that CFCs, HCFCs, and HFCs were responsible for about 10% of direct radiative forcing from all long-lived anthropogenic greenhouse gases, and in the same year the UNEP published new voluntary guidelines, however many countries have not yet ratified the Kigali Amendment.

With the begin of the 2020 HFCs (including R-404a, R-134a and R-410a) are being superseded: Residential air-conditioning systems and heat pumps are increasingly using R-32. This still has a GWP of more than 600. Progressive devices use refrigerants with a almost no climate impact: R-290 (propane), R-600 (isobutane) or R-1234yf (less flammable, in cars). In commercial refrigeration also CO2 (R-744) can be used.

Desirable properties

The ideal refrigerant would be: non-corrosive, non-toxic, non-flammable, with no ozone depletion and global warming potential. It should preferably be natural with well-studied and low environmental impact. It also needs to have: a boiling point that is somewhat below the target temperature (although boiling point can be adjusted by adjusting the pressure appropriately), a high heat of vaporization, a moderate density in liquid form, a relatively high density in gaseous form (which can also be adjusted by setting pressure appropriately), and a high critical temperature. Extremely high pressures should be avoided. Newer refrigerants address the issue of the damage that CFCs caused to the ozone layer and the contribution that HCFCs make to climate change, but some do raise issues relating to toxicity and / or flammability.

Shenyang Zhongda Huanxin Refrigeration Technology Co., Ltd.

AUG 11, 2022