Editing Refrigerant (section)

== History ==
[[Image: HCFC and HFC atmospheric trends.png|thumb|right|upright=1.5|The observed stabilization of HCFC concentrations (left graphs) and the growth of HFCs (right graphs) in earth's atmosphere.]]
The first air conditioners and [[refrigerator]]s employed toxic or flammable gases, such as [[ammonia]], [[sulfur dioxide]], [[methyl chloride]], or [[propane]], that could result in fatal accidents when they leaked.<ref name="r7">{{Cite web |last=Pearson |first=S. Forbes |title=Refrigerants Past, Present and Future |url=http://www.r744.com/files/pdf_597.pdf |url-status=dead |archive-url=https://web.archive.org/web/20180713171048/http://www.r744.com/files/pdf_597.pdf |archive-date=2018-07-13 |access-date=2021-03-30 |website=R744}}</ref>

In 1928 [[Thomas Midgley Jr.]] created the first non-flammable, non-toxic [[chlorofluorocarbon]] gas, ''[[Freon]]'' (R-12). The name is a [[trademark]] name owned by [[DuPont]] (now [[Chemours]]) for any [[chlorofluorocarbon]] (CFC), [[HCFC|hydrochlorofluorocarbon]] (HCFC), or [[hydrofluorocarbon]] (HFC) refrigerant. Following the discovery of better synthesis methods, CFCs such as [[Trichlorofluoromethane|R-11]],<ref name="cool">{{Cite web|url=https://www.coolingpost.com/world-news/finally-a-replacement-for-r123/|title=Finally, a replacement for R123?|date=17 October 2013|website=Cooling Post}}</ref> [[Dichlorodifluoromethane|R-12]],<ref>{{cite journal  |last1=Hmood |first1=K. S. |last2=Pop |first2=H. |last3=Apostol |first3=V. |last4=Ahmed |first4=A. Q. |date=2017 |title=Refrigerants Retrofit as Alternative for R12 and R134a in Household Refrigerators |url=https://asrjetsjournal.org/index.php/American_Scientific_Journal/article/view/3297 |journal=American Scientific Research Journal for Engineering, Technology, and Sciences |volume=35 |issue=1 |pages=251–265 |access-date=2025-05-28 }}</ref> R-123<ref name="cool"/> and R-502<ref name="achr"/> dominated the market.

=== Phasing out of CFCs ===
{{See also|Montreal Protocol}}
In the mid-1970s, scientists discovered that CFCs were causing major damage to the [[ozone layer]] that protects the earth from ultraviolet radiation, and to the [[ozone hole]]s over polar regions.<ref>{{cite journal |last1=Molina |first1=Mario J. |last2=Rowland |first2=F. S |title=Stratospheric sink for chlorofluoromethanes: chlorine catalysed destruction of ozone |journal=Nature |date=28 June 1974 |volume=249 |pages=810–812 |doi=10.1038/249810a0 |url=https://courses.seas.harvard.edu/climate/eli/Courses/EPS281r/Sources/Ozone-hole/2-Molina-Rowland-1974.pdf |access-date=October 6, 2024}}</ref><ref>{{cite book |last1=National Research Council |title=Halocarbons: Effects on Stratospheric Ozone |date=1976 |publisher=The National Academies Press |location=Washington, DC |doi=10.17226/19978 |isbn=978-0-309-02532-4 |url=https://nap.nationalacademies.org/catalog/19978/halocarbons-effects-on-stratospheric-ozone |access-date=October 6, 2024}}</ref> This led to the signing of the [[Montreal Protocol]] in 1987 which aimed to phase out CFCs and HCFC<ref>{{cite web |access-date=27 July 2023 |date=1 July 2011|title=Air Conditioners, Dehumidifiers, and R-410A Refrigerant |url=https://www.sylvane.com/blog/air-conditioners-dehumidifiers-r-410-a-refrigerant/|website=Sylvane}}</ref> but did not address the contributions that HFCs made to climate change. The adoption of HCFCs such as [[Chlorodifluoromethane|R-22]],<ref>{{Cite web|url=https://books.google.com/books?id=zMYRAAAAIAAJ&dq=r+22+replaced+r+12&pg=RA1-PA589|title=Clean Air Act Amendments of 1987: Hearings Before the Subcommittee on Environmental Protection of the Committee on Environment and Public Works, United States Senate, One Hundredth Congress, First Session, on S. 300, S. 321, S. 1351, and S. 1384 ...|first=United States Congress Senate Committee on Environment and Public Works Subcommittee on Environmental|last=Protection|date=May 14, 1987|publisher=U.S. Government Printing Office|via=Google Books}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=5AGjDf5QkfwC&pg=PA179 |page=179 |title=Fluorinated Hydrocarbons—Advances in Research and Application |edition=2013 |date=June 21, 2013 |publisher=ScholarlyEditions |isbn=9781481675703 |via=Google Books}}</ref><ref>{{Cite book|url=https://books.google.com/books?id=zeYGAAAAQBAJ&pg=PA171 |page=171 |title=Refrigeration and Air Conditioning Technology |first1=Bill |last1=Whitman |first2=Bill |last2=Johnson |first3=John |last3=Tomczyk |first4=Eugene |last4=Silberstein |date=February 25, 2008 |publisher=Cengage Learning |isbn=978-1111803223 |via=Google Books}}</ref> and R-123<ref name="cool" /> was accelerated and so were used in most U.S. homes in air conditioners and in [[chiller]]s<ref>{{Cite web |url=https://ec.europa.eu/clima/sites/clima/files/docs/0007/mcquay_hfc_scroll_chillers_paper_en.pdf |title=Scroll Chillers: Conversion from HCFC-22 to HFC-410A and HFC-407C |access-date=2021-03-29 |archive-date=2021-07-20 |archive-url=https://web.archive.org/web/20210720201831/https://ec.europa.eu/clima/sites/clima/files/docs/0007/mcquay_hfc_scroll_chillers_paper_en.pdf |url-status=dead }}</ref> from the 1980s as they have a dramatically lower [[Ozone depletion potential|Ozone Depletion Potential]] (ODP) than CFCs, but their ODP was still not zero which led to their eventual phase-out.

[[Hydrofluorocarbon]]s (HFCs) such as [[R-134a]],<ref>{{Cite web|url=https://www.achrnews.com/articles/135112-whats-happening-with-r-134a|title=What's Happening With R-134a? &#124; 2017-06-05 &#124; ACHRNEWS &#124; ACHR News|website=achrnews.com}}</ref><ref>{{cite web |url=https://www.techtips.ie/Hella-Ireland/aircon-conversion-r12r134a.pdf |date=1 October 2005 |access-date=27 July 2023 |title=Conversion R12/R134a |work=Behr Hella Service GmbH }}</ref> [[R-407A]],<ref>{{Cite press release |url=https://www.achrnews.com/articles/110226-r-407a-gains-snap-ok |date=22 June 2009 |title=R-407A Gains SNAP OK |website=achrnews.com }}</ref> [[R-407C]],<ref>{{Cite web|url=https://www.achrnews.com/articles/110377-june-26-2009-emerson-approves-r-407a-r-407c-for-copeland-discus-compressors?v=preview|title=June 26, 2009: Emerson Approves R-407A, R-407C for Copeland Discus Compressors|website=achrnews.com}}</ref> [[R-404A]],<ref name="achr">{{Cite web |date=1 May 2017 |first=John |last=Tomczyk |url=https://www.achrnews.com/articles/134928-whats-the-latest-with-r-404a|title=What's the Latest with R-404A?|website=achrnews.com}}</ref> [[R-410A]]<ref>{{Cite web|url=https://www.achrnews.com/articles/84438-taking-new-refrigerants-to-the-peak?v=preview|title=Taking New Refrigerants to the Peak|website=achrnews.com}}</ref> (a 50/50 blend of [[R-125]]/[[Difluoromethane|R-32]]) and R-507<ref>{{cite web | url=https://www.osti.gov/etdeweb/biblio/167601 | title=R502/R22 - replacement refrigerant R507 in commercial refrigeration; R502/R22 - Ersatzkaeltemittel R507 in der Gewerbekuehlung. Anwendungstechnik - Kaeltemittel | date=31 December 1995 | last1=Koenig | first1=H. }}</ref><ref>{{cite web | url=https://www.osti.gov/biblio/211821 | osti=211821 | title=System performance comparison of R-507 with R-502 | date=31 December 1995 | last1=Linton | first1=J. W. | last2=Snelson | first2=W. K. | last3=Triebe | first3=A. R. | last4=Hearty | first4=P. F. }}</ref> were promoted as replacements for CFCs and HCFCs in the 1990s and 2000s. HFCs were not ozone-depleting but did have [[global warming potential]]s (GWPs) thousands of times greater than CO<sub>2</sub> 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,<ref>{{Cite web|url=https://www.coolingpost.com/world-news/daikin-reveals-details-of-r32-vrv-air-conditioner/|title=Daikin reveals details of R32 VRV air conditioner|date=6 February 2020|website=Cooling Post}}</ref> R-290,<ref name="auto">{{Cite web|url=https://www.coolingpost.com/world-news/refrigerant-blends-to-challenge-hydrocarbon-efficiencies/|title=Refrigerant blends to challenge hydrocarbon efficiencies|date=22 December 2019|website=Cooling Post}}</ref> R-600a,<ref name="auto"/> [[R-454B]],<ref>{{Cite web|url=https://www.achrnews.com/articles/144613-an-hvac-technicians-guide-to-r-454b?v=preview|title=An HVAC Technician's Guide to R-454B|website=achrnews.com}}</ref> [[R-1234yf]],<ref>{{cite web |url=https://autoexpert.com.au/posts/the-truth-about-new-automotive-ac-refrigerant-r1234yf |title=The truth about new automotive A/C refrigerant R1234YF | date=25 July 2018 }}</ref><ref>{{cite journal |url=https://docs.lib.purdue.edu/cgi/viewcontent.cgi?article=2524&context=iracc |last=Kontomaris |first=Konstantinos |title=HFO-1336mzz-Z: High Temperature Chemical Stability and Use as A Working Fluid in Organic Rankine Cycles |year=2014 |journal=International Refrigeration and Air Conditioning Conference |quote=Paper 1525}}</ref> R-514A,<ref>{{Cite web|url=https://www.coolingpost.com/world-news/trane-adopts-new-low-gwp-refrigerant-r514a/|title=Trane adopts new low GWP refrigerant R514A|date=15 June 2016|website=Cooling Post}}</ref> R-744 ({{CO2}}),<ref>{{Cite web|url=https://www.coolingpost.com/features/r404a-the-alternatives/|title=R404A – the alternatives|date=26 February 2014|website=Cooling Post}}</ref> [[R-1234ze(E)]]<ref>{{Cite web|url=https://www.coolingpost.com/products/carrier-expands-r1234ze-chiller-range/|title=Carrier expands R1234ze chiller range|date=20 May 2020|website=Cooling Post}}</ref> and [[1-Chloro-3,3,3-trifluoropropene|R-1233zd(E)]],<ref>{{Cite web|url=https://www.coolingpost.com/world-news/carrier-confirms-an-hfo-refrigerant-future/|title=Carrier confirms an HFO refrigerant future|date=5 June 2019|website=Cooling Post}}</ref> 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.

The environmental organization [[Greenpeace]] provided funding to a former East German refrigerator company to research alternative ozone- and climate-safe refrigerants in 1992. The company developed a hydrocarbon mixture of [[propane]] and [[isobutane]], or pure isobutane,<ref>{{Cite web |title=Greenfreeze: A revolution in domestic refrigeration |url=https://www.ecomall.com/greenshopping/greenfreeze.htm |access-date=2022-07-04 |website=ecomall.com}}</ref> called "Greenfreeze", but as a condition of the contract with Greenpeace could not patent the technology, which led to widespread adoption by other firms.<ref name="greenpeace.org">{{cite web|title=Happy birthday, Greenfreeze! |date=25 March 2013 |url=http://p3-raw.greenpeace.org/international/en/news/Blogs/makingwaves/happy-birthday-greenfreeze/blog/44473/ |work=Greenpeace|archive-url=https://web.archive.org/web/20200408034609/http://p3-raw.greenpeace.org/international/en/news/Blogs/makingwaves/happy-birthday-greenfreeze/blog/44473/ |access-date=8 June 2015|archive-date=2020-04-08 }}</ref><ref name="ozone.unep.org">{{cite web|title=Ozone Secretariat |url= http://ozone.unep.org/Events/4C1_PublicInfo_Awards97.shtml|archive-url =http://webarchive.loc.gov/all/20150412225008/http://ozone.unep.org/Events/4C1_PublicInfo_Awards97.shtml |url-status=dead|archive-date=12 April 2015|publisher=United Nations Environment Programme}}</ref><ref name=Spiegel>{{cite news|last=Gunkel|first=Christoph|title=Öko-Coup aus Ostdeutschland|url= http://www.spiegel.de/einestages/oeko-revolution-aus-ostdeutschland-wie-foron-den-ersten-fckw-freien-kuehlschrank-der-welt-erfand-a-951064.html |date=13 September 2013|work=Der Spiegel |language=de|access-date=4 September 2015}}</ref> Policy and political influence by corporate executives resisted change however,<ref>{{cite journal |doi=10.1111/1467-9388.00275 |title=Making a Difference: A Case Study of the Greenpeace Ozone Campaign |year=2001 |last1=Maté |first1=John |journal=Review of European Community & International Environmental Law |volume=10 |issue=2 |pages=190–198 }}</ref><ref>Benedick, Richard Elliot Ozone Diplomacy Cambridge, MA: Harvard University 1991.</ref> citing the flammability and explosive properties of the refrigerants,<ref>{{Cite web |last=Honeywell International, Inc. |date=2010-07-09 |title=Comment on EPA Proposed Rule Office of Air and Radiation Proposed Significant New Alternatives Policy (SNAP) Protection of Stratospheric Ozone: Listing of Substitutes for Ozone-Depleting Substances – Hydrocarbon Refrigerants |url=https://downloads.regulations.gov/EPA-HQ-OAR-2009-0286-0170/attachment_1.pdf}}</ref> and [[DuPont]] together with other companies blocked them in the U.S. with the U.S. EPA.<ref name="ReferenceA">{{cite web|url=http://www.greenpeace.org/brasil/pt/Noticias/discurso-de-frank-guggenheim-n/|title=Discurso de Frank Guggenheim no lançamento do Greenfreeze &#124; Brasil|website=Greenpeace.org|access-date=10 June 2015|archive-date=24 September 2015|archive-url=https://web.archive.org/web/20150924024715/http://www.greenpeace.org/brasil/pt/Noticias/discurso-de-frank-guggenheim-n/|url-status=dead}}</ref><ref>{{cite web|url= https://www.greenpeace.de/themen/klimawandel/klimaschutz/der-greenfreeze-endlich-den-usa-angekommen|title=Der Greenfreeze - endlich in den USA angekommen|language=de |website=Greenpeace.de|date=28 December 2011|access-date=10 June 2015}}</ref>

Beginning on 14 November 1994, the [[Federal government of the United States|U.S.]] [[United States Environmental Protection Agency|Environmental Protection Agency]] restricted the sale, possession and use of refrigerants to only licensed technicians, per rules under sections 608 and 609 of the Clean Air Act.<ref>{{cite web|url= http://www.epa.gov/ozone/title6/608/608fact.html |title=Complying With The Section 608 Refrigerant Recycling Rule &#124; Ozone Layer Protection - Regulatory Programs |website=Epa.gov |date=21 April 2015|access-date=10 June 2015}}</ref> In 1995, Germany made CFC refrigerators illegal.<ref name="ecomall.com">{{cite web|title= Greenfreeze: a Revolution in Domestic Refrigeration|url= http://www.ecomall.com/greenshopping/greenfreeze.htm |website=ecomall.com |access-date=8 June 2015}}</ref>

In 1996 [[Eurammon]], a European non-profit initiative for [[natural refrigerant]]s, was established and comprises European companies, institutions, and industry experts.<ref name="about">{{Cite web|url=http://www.eurammon.com/about-eurammon|title=Company background|access-date=2021-03-15|archive-date=2020-02-20|archive-url=https://web.archive.org/web/20200220124551/http://www.eurammon.com/about-eurammon|url-status=dead}}</ref><ref>{{cite report |publisher=IPCC/TEAP |title=Safeguarding the ozone layer and the global climate System: issues related to Hydrofluorocarbons and Perfluorocarbons |year=2005 |url=https://www.ipcc.ch/report/safeguarding-the-ozone-layer-and-the-global-climate-system/ }}</ref><ref>{{cite journal |url=https://www.science.org/doi/10.1126/science.289.5477.270 |doi=10.1126/science.289.5477.270 |title=Causes of Climate Change over the Past 1000 Years |year=2000 |last1=Crowley |first1=Thomas J. |journal=Science |volume=289 |issue=5477 |pages=270–277 |pmid=10894770 |bibcode=2000Sci...289..270C |url-access=subscription }}</ref>

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<ref>{{cite web|url=https://www.gov.uk/government/policies/protecting-and-enhancing-our-urban-and-natural-environment-to-improve-public-health-and-wellbeing/supporting-pages/controlling-ozone-depleting-substances-and-fluorinated-greenhouse-gases |title=2010 to 2015 government policy: environmental quality |website=GOV.UK |date=8 May 2015|access-date=10 June 2015}}</ref> 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 from 2010 for virgin fluid and from 2015 for recycled fluid.{{citation needed|date=March 2021}}

=== Addressing greenhouse gases ===
With growing interest in [[natural refrigerant]]s 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|Pepsico]] and others, to create a corporate coalition called Refrigerants Naturally!.<ref name="ecomall.com" /><ref>{{cite web|title=PepsiCo Brings First Climate-Friendly Vending Machines to the U.S.|url=http://phx.corporate-ir.net/phoenix.zhtml?c=78265&p=irol-newsArticle&ID=1270984&highlight=|access-date=8 June 2015|website=phx.corporate-ir.net}}</ref> Four years later, Ben & Jerry's of Unilever and General Electric began to take steps to support production and use in the U.S.<ref>{{cite web|title=Climate-Friendly Greenfreezers Come to the United States|date=2 October 2008 |url=http://www.nbcnewyork.com/news/green/Climate-Friendly_Greenfreezers_Come_to_the_United_States.html|access-date=8 June 2015|publisher=WNBC}}</ref> It is estimated that almost 75 percent of the refrigeration and air conditioning sector has the potential to be converted to natural refrigerants.<ref name=":13">{{Cite press release|last=Data|first=Reports and|date=7 August 2020|title=Natural Refrigerants Market To Reach USD 2.88 Billion By 2027 {{!}} Reports and Data|url=http://www.globenewswire.com/news-release/2020/08/07/2074791/0/en/Natural-Refrigerants-Market-To-Reach-USD-2-88-Billion-By-2027-Reports-and-Data.html|access-date=17 December 2020|website=GlobeNewswire News Room}}</ref>

In 2006, the EU adopted a Regulation on [[fluorinated gases|fluorinated greenhouse gases]] (FCs and HFCs) to encourage to transition to natural refrigerants (such as hydrocarbons). It was reported in 2010 that some refrigerants are being used as [[Recreational drug use|recreational drugs]], leading to an extremely dangerous phenomenon known as [[inhalant abuse]].<ref>Harris, Catharine. "Anti-inhalant Abuse Campaign Targets Building Codes: 'Huffing’ of Air Conditioning Refrigerant a Dangerous Risk." The Nation's Health. American Public Health Association, 2010. Web. 5 December 2010. https://www.thenationshealth.org/content/39/4/20</ref>

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 CO<sub>2</sub>) such as the refrigerant [[HFC-134a]] (known as R-134a in North America) which has a GWP of 1526.<ref name="ar6">{{Harvnb|IPCC AR6 WG1 Ch7|2021|p=}}</ref> In the same year the EPA decided in favour of the ozone- and climate-safe refrigerant for U.S. manufacture.<ref name="greenpeace.org" /><ref>{{cite web|url= http://www.greenpeace.org/usa/en/campaigns/global-warming-and-energy/green-solutions/greenfreeze/ |title=GreenFreeze|work=Greenpeace}}</ref><ref name="epa.gov">{{cite web|url= https://www.epa.gov/snap/substitutes-household-refrigerators-and-freezers |title=Significant New Alternatives Program: Substitutes in Household Refrigerators and Freezers|website=Epa.gov|date=13 November 2014|access-date=4 June 2018}}</ref>

A 2018 study by the nonprofit organization "[[Drawdown (climate)|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.<ref>{{Cite web|url=https://www.nationalgeographic.com/environment/2019/04/disposing-old-cfcs-refrigerants-reduces-climate-change-greenhouse-gases-cheaply/|archive-url=https://web.archive.org/web/20190429113314/https://www.nationalgeographic.com/environment/2019/04/disposing-old-cfcs-refrigerants-reduces-climate-change-greenhouse-gases-cheaply/|url-status=dead|archive-date=April 29, 2019|title=One overlooked way to fight climate change? Dispose of old CFCs.|last=Berwald|first=Juli|date=29 April 2019|website=[[National Geographic]] - Environment|access-date=30 April 2019}}</ref>

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.<ref>{{Cite web |url=https://www.esrl.noaa.gov/gmd/aggi/aggi.html |title=The NOAA Annual Greenhouse Gas Index (AGGI) |publisher=[[NOAA]] Global Monitoring Laboratory/Earth System Research Laboratories |author=Butler J. and Montzka S. |year=2020 }}</ref> and in the same year the [[UNEP]] published new voluntary guidelines,<ref>{{cite web|url=http://www.unenvironment.org/news-and-stories/story/new-guidelines-air-conditioners-and-refrigerators-set-tackle-climate-change|title=New guidelines for air conditioners and refrigerators set to tackle climate change|last=Environment|first=U. N.|date=31 October 2019|website=UN Environment|language=en|access-date=30 March 2020}}</ref> however many countries have not yet ratified the [[Kigali Amendment]].

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