CFC REFRIGERANTS
Chlorofluorocarbon refrigerant gases (CFCs) were developed in the 1928s by Thomas Midgley
They arose from the need to find safe, non-toxic and non-flammable substances for use in the refrigeration sector and other applications such as propellants in aerosol cans, solvents and foaming agents.
Earlier, between 1800 and 1929, toxic gases such as ammonia (NH3), methyl chloride (CH3Cl) and sulfur dioxide (SO2) were used for refrigeration, with which several fatal accidents occurred in the 1920s due to methyl chloride leaks. From this point on, a new stage in the search for solutions that are harmless to human beings began.
CFCs, such as R-11, R-12 or R-502 are considered the 1st generation of fluorinated refrigerant gases (F-gases).
Chlorofluorocarbons (CFCs) are a highly stable organic compound containing chlorine, fluorine and carbon, produced as a volatile derivative of methane and ethane.
During the 1970s, studies by Fatbian, Borders and Penkett found that CFCs represent a major environmental threat, because once released into the atmosphere they accumulate in the stratosphere, causing the destruction of the ozone layer.
Stratospheric ozone protects living organisms on Earth from the harmful effects of ultraviolet radiation from the Sun; even a relatively small decrease in the concentration of stratospheric ozone can result in an increased incidence of skin cancer in humans and genetic damage in many organisms. In the stratosphere, CFC molecules decompose under the action of solar ultraviolet radiation and release their constituent chlorine atoms. These then react with the ozone molecules, resulting in their elimination.
Due to their high chemical stability, CFCs have a lifetime in the atmosphere of approximately 20 to 100 years.
It was at the Vienna Convention in 1978 that the Montreal Protocol was adopted as a framework for international cooperation to eliminate the use of ozone-depleting substances (ODS).
Since its adoption, more than 98% of controlled ODS have been successfully phased out, helping to reverse damage to the ozone layer.
However, significant challenges remain. The ban on the market introduction of CFCs (high ozone depleting potential, or ODP) as well as HCFCs (with a lower ODP) in some markets, such as the EU, has been completed. Currently HFCs, with an ODP level of zero but high global warming potential (GWP), are the most widely used solutions worldwide. CFCs, HCFCs and HFCs are considered greenhouse gases (GHGs).
Each of the GEFs affects the atmosphere to a different degree and remains in the atmosphere for a different period of time. The extent to which a given GEF contributes to global warming is defined as its Global Warming Potential (GWP).
The challenge is to develop safe alternatives with good thermodynamic performance (cooling capacity and COP) for refrigeration and air conditioning that not only do not have an ODP equal to zero, but also have a low global warming potential (GWP).
