Progressing From CFCs To HFCs And HFOs

Fluorocarbons CFC-11 & CFC-12 were developed in the late 1920s, and commercialised in the 1930s, to resolve the major difficulties and the risks from using toxic or highly flammable refrigerants. Later, when CFCs and then HCFCs were implicated and regulated for their impact on the ozone layer, HFCs were introduced, with similar technical properties to the CFCs and HCFCs, to enable their replacement to occur as rapidly as practicable. Fluorocarbons producers funded cooperative international programmes called PAFT (Program for Alternative Fluorocarbon Testing) -for extensive toxicity testing and AFEAS (Alternative Fluorocarbon Environmental Acceptability Study) – for environmental impact research. These programmes enabled the candidate HFCs’ properties and impacts to be understood, taking into account short-term and long-term issues.

The currently most widely used HFCs were shown to be non-flammable and of low toxicity, like the CFCs and HCFCs. Their environmental impact was fully characterized. When HFC-134a was introduced, no other industrial product had been so extensively tested. HFCs are hydrocarbons containing fluorine atoms that give them their exceptional properties. Their common names consist of the abbreviation HFC (hydrofluorocarbon), a number and some letters which reveal the exact molecular structure. For more details, refer to EFCTC Learn about – Nomenclature Of (H)(C)FCs And HFOs.

The range of available HFCs, used pure or blended, allows the design of “tailor-made” systems for specific application sectors, delivering higher performances. Their wide field of application covers:

  • Preserving food and medicines in refrigeration appliances.
  • Providing comfortable and safe living via air-conditioning in offices, houses hospitals, and shops.
  • Saving energy as blowing agent for high performance thermal insulation foams.
  • Allowing production of semiconductors and electronics as precision cleaning solvents.
  • Saving lives and goods property as waterless fire extinguishers.
  • Treating asthma as propellants for medical aerosols inhalers (MDIs- metered dose inhalers).
  • Saving our written heritage from self-destruction thanks to a paper de-acidification process.

It was recognised when HFCs were introduced that they are greenhouse gases with high GWPs, however, on average (based on their commercial use) their GWPs are significantly lower than the CFCs they replaced (for more information about GWPs see EFCTC Learn about-Global warming potentials as revised in 2013. HFCs were only one of a range of technologies and alternatives used to replace CFCs, and with lower charge sizes and improved containment for refrigeration and air-conditioning systems the quantities of HFCs used are much lower. All these factors resulted in lower emissions to atmosphere, refer to EFCTC Learn about- Lessons from replacing CFCs in Europe. Globally, the CFC phase-out, and the substitution of CFCs and HCFCs, notably by HFCs, avoided an additional 0.3 W m2 of global radiative forcing. For more information see https://www.esrl.noaa.gov/gmd/aggi/aggi.html. This is equivalent to more than half of the increase in radiative forcing due to CO2 alone since 1990.

At present, HFCs contribute less than 1% to climate change, for more information, refer to EFCTC Learn about- The Role of HFCs in Long Term Climate Change and the US NOAA report on the HFC impact in 2016. It is widely recognised that emissions of HFCs will increase unless measures are taken to reduce their use. This is why EFCTC supports the F-Gas Regulation 517/2014 and the Kigali Amendment to the Montreal Protocol which will phase-down the use of HFCs, while enabling the introduction of lower GWP options, that for refrigeration and air-conditioning, maintain or improve the energy efficiency of the currently use systems.

HFCs continue to have a role to play, with lower GWP HFCs replacing higher GWP HFCs. R-404A is be replaced or retrofitted by other HFCs such as R-407A, R-407F, R-407H. R-32 is being adopted as an alternative to R-410A in some air-conditioning applications.

A new class of fluorocarbons, the HFOs (hydrofluoro-olefins), with their very low GWPs is enabling the introduction of a wider range of lower GWP solutions further reducing environmental impact (greenhouse gas emissions) and offering similar safety, performance and energy efficiency benefits. The use of these substances in the EU has required their REACH registration and the submission of toxicology and environmental data. HFOs, HFO/HFC blends and HFO blends with other substances are being used in or under development for a range of applications including:

  • HFO-1234yf has already been adopted for car air-conditioning as a replacement for HFC-134a.
  • HFO-1234zeE is being introduced as a alterative for HFC-134a in chillers, and is being used as a propellant, either alone or as a blend with HFCs, HCs.
  • HFO-1336mzz is being introduced as a non-flammable working fluid for Organic Rankine Cycle, foam blowing agent, and solvent.
  • HFO/HFC refrigerant blends have been formulated to minimise environmental impacts (low GWP) while meeting technical and safety requirements (flammability/non-flammability).

HFCs and HFC blends (with HFOs) will continue to be used under the phase-down in the EU and globally but their uses will become more focused on those applications where they continue to provide performance and safety benefits, and in which leakages can be minimised in equipment

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