Refrigerant

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A DuPont R-134a refrigerant Can of DuPont R-134a refrigerant.jpg
A DuPont R-134a refrigerant

A refrigerant is a working fluid used in cooling, heating or reverse cooling and heating of air conditioning systems and heat pumps where they undergo a repeated phase transition from a liquid to a gas and back again. Refrigerants are heavily regulated because of their toxicity and flammability [1] and the contribution of CFC and HCFC refrigerants to ozone depletion [2] and that of HFC refrigerants to climate change. [3]

Contents

Refrigerants are used in a direct expansion (DX- Direct Expansion) system (circulating system)to transfer energy from one environment to another, typically from inside a building to outside (or vice versa) commonly known as an air conditioner cooling only or cooling & heating reverse DX system or heat pump a heating only DX cycle. Refrigerants can carry 10 times more energy per kg than water, and 50 times more than air.

Refrigerants are controlled substances and classified by International safety regulations ISO 817/5149, AHRAE 34/15 & BS EN 378 due to high pressures (700–1,000 kPa (100–150 psi)), extreme temperatures (−50 °C [−58 °F] to over 100 °C [212 °F]), flammability (A1 class non-flammable, A2/A2L class flammable and A3 class extremely flammable/explosive) and toxicity (B1-low, B2-medium & B3-high). The regulations relate to situations when these refrigerants are released into the atmosphere in the event of an accidental leak not while circulated.

Refrigerants (controlled substances) must only be handled by qualified/certified engineers for the relevant classes (in the UK, C&G 2079 for A1-class and C&G 6187-2 for A2/A2L & A3-class refrigerants).

Refrigerants (A1 class only) Due to their non-flammability, A1 class non-flammability, non-explosivity, and non-toxicity, non-explosivity they have been used in open systems (consumed when used) like fire extinguishers, inhalers, computer rooms fire extinguishing and insulation, etc.) since 1928.

History

The observed stabilization of HCFC concentrations (left graphs) and the growth of HFCs (right graphs) in earth's atmosphere. HCFC and HFC atmospheric trends.png
The observed stabilization of HCFC concentrations (left graphs) and the growth of HFCs (right graphs) in earth's atmosphere.

The first air conditioners and refrigerators employed toxic or flammable gases, such as ammonia, sulfur dioxide, methyl chloride, or propane, that could result in fatal accidents when they leaked. [4]

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), hydrochlorofluorocarbon (HCFC), or hydrofluorocarbon (HFC) refrigerant. Following the discovery of better synthesis methods, CFCs such as R-11, [5] R-12, [6] R-123 [5] and R-502 [7] dominated the market.

Phasing out of CFCs

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 holes over polar regions. [8] [9] This led to the signing of the Montreal Protocol in 1987 which aimed to phase out CFCs and HCFC [10] but did not address the contributions that HFCs made to climate change. The adoption of HCFCs such as R-22, [11] [12] [13] and R-123 [5] was accelerated and so were used in most U.S. homes in air conditioners and in chillers [14] 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, [15] [16] R-407A, [17] R-407C, [18] R-404A, [7] R-410A [19] (a 50/50 blend of R-125/R-32) and R-507 [20] [21] 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, [22] R-290, [23] R-600a, [23] R-454B, [24] R-1234yf, [25] [26] R-514A, [27] R-744 (CO2), [28] R-1234ze(E) [29] and R-1233zd(E), [30] 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, [31] called "Greenfreeze", but as a condition of the contract with Greenpeace could not patent the technology, which led to widespread adoption by other firms. [32] [33] [34] Policy and political influence by corporate executives resisted change however, [35] [36] citing the flammability and explosive properties of the refrigerants, [37] and DuPont together with other companies blocked them in the U.S. with the U.S. EPA. [38] [39]

Beginning on 14 November 1994, the U.S. 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. [40] In 1995, Germany made CFC refrigerators illegal. [41]

In 1996 Eurammon, a European non-profit initiative for natural refrigerants, was established and comprises European companies, institutions, and industry experts. [42] [43] [44]

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 [45] 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 ]

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!. [41] [46] Four years later, Ben & Jerry's of Unilever and General Electric began to take steps to support production and use in the U.S. [47] It is estimated that almost 75 percent of the refrigeration and air conditioning sector has the potential to be converted to natural refrigerants. [48]

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 that some refrigerants are being used as recreational drugs, leading to an extremely dangerous phenomenon known as inhalant abuse. [49]

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. [50] In the same year the EPA decided in favour of the ozone- and climate-safe refrigerant for U.S. manufacture. [32] [51] [52]

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. [53]

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. [54] and in the same year the UNEP published new voluntary guidelines, [55] 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 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.

Requirements and desirable properties

A refrigerant 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. Working pressures should ideally be containable by copper tubing, a commonly available material. Extremely high pressures should be avoided.[ citation needed ]

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. 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. [56]

Common refrigerants

Refrigerants with very low climate impact

With increasing regulations, refrigerants with a very low global warming potential are expected to play a dominant role in the 21st century, [57] in particular, R-290 and R-1234yf. Starting from almost no market share in 2018, [58] low GWPO devices are gaining market share in 2022.

CodeChemicalName GWP 20yr [59] GWP 100yr [59] StatusCommentary
R-290C3H8 Propane 3.3 [60] Increasing useLow cost, widely available and efficient. They also have zero ozone depletion potential. Despite their flammability, they are increasingly used in domestic refrigerators and heat pumps. In 2010, about one-third of all household refrigerators and freezers manufactured globally used isobutane or an isobutane/propane blend, and this was expected to increase to 75% by 2020. [61]
R-600a HC(CH3)3 Isobutane 3.3Widely usedSee R-290.
R-717 NH3 Ammonia 00 [62] Widely usedCommonly used before the popularisation of CFCs, it is again being considered but does suffer from the disadvantage of toxicity, and it requires corrosion-resistant components, which restricts its domestic and small-scale use. Anhydrous ammonia is widely used in industrial refrigeration applications and hockey rinks because of its high energy efficiency and low cost.
R-1234yf HFO-1234yf C3H2F4 2,3,3,3-Tetrafluoropropene <1Less performance but also less flammable than R-290. [57] GM announced that it would start using "hydro-fluoro olefin", HFO-1234yf, in all of its brands by 2013. [63]
R-744 CO2 Carbon dioxide 11In useWas used as a refrigerant prior to the discovery of CFCs (this was also the case for propane) [4] and now having a renaissance due to it being non-ozone depleting, non-toxic and non-flammable. It may become the working fluid of choice to replace current HFCs in cars, supermarkets, and heat pumps. Coca-Cola has fielded CO2-based beverage coolers and the U.S. Army is considering CO2 refrigeration. [64] [65] Due to the need to operate at pressures of up to 130 bars (1,900 psi; 13,000 kPa), CO2 systems require highly resistant components, however these have already been developed for mass production in many sectors.

Most used

CodeChemicalName Global warming potential 20yr [59] GWP 100yr [59] StatusCommentary
R-32 HFC-32CH2F2 Difluoromethane 2430677Widely usedPromoted as climate-friendly substitute for R-134a and R-410A, but still with high climate impact. Has excellent heat transfer and pressure drop performance, both in condensation and vaporisation. [66] It has an atmospheric lifetime of nearly 5 years. [67] Currently used in residential and commercial air-conditioners and heat pumps.
R-134a HFC-134aCH2FCF3 1,1,1,2-Tetrafluoroethane 37901550Widely usedMost used in 2020 for hydronic heat pumps in Europe and the United States in spite of high GWP. [58] Commonly used in automotive air conditioners prior to phase out which began in 2012.
R-410A 50% R-32 / 50% R-125 (pentafluoroethane)Between 2430 (R-32) and 6350 (R-125)> 677Widely UsedMost used in split heat pumps / AC by 2018. Almost 100% share in the USA. [58] Being phased out in the US starting in 2022. [68] [69]

Banned / Phased out

CodeChemicalName Global warming potential 20yr [59] GWP 100yr [59] StatusCommentary
R-11 CFC-11CCl3F Trichlorofluoromethane 69004660BannedProduction was banned in developed countries by Montreal Protocol in 1996
R-12 CFC-12CCl2F2 Dichlorodifluoromethane 1080010200BannedAlso known as Freon, a widely used chlorofluorocarbon halomethane (CFC). Production was banned in developed countries by Montreal Protocol in 1996, and in developing countries (article 5 countries) in 2010. [70]
R-22 HCFC-22CHClF2 Chlorodifluoromethane 52801760Being phased outA widely used hydrochlorofluorocarbon (HCFC) and powerful greenhouse gas with a GWP equal to 1810. Worldwide production of R-22 in 2008 was about 800 Gg per year, up from about 450 Gg per year in 1998. R-438A (MO-99) is a R-22 replacement. [71]
R-123 HCFC-123CHCl2CF3 2,2-Dichloro-1,1,1-trifluoroethane 29279US phase-outUsed in large tonnage centrifugal chiller applications. All U.S. production and import of virgin HCFCs will be phased out by 2030, with limited exceptions. [72] R-123 refrigerant was used to retrofit some chiller that used R-11 refrigerant Trichlorofluoromethane. The production of R-11 was banned in developed countries by Montreal Protocol in 1996. [73]

Other

CodeChemicalName Global warming potential 20yr [59] GWP 100yr [59] Commentary
R-152a HFC-152aCH3CHF2 1,1-Difluoroethane 506138As a compressed air duster
R-407C Mixture of difluoromethane and pentafluoroethane and 1,1,1,2-tetrafluoroethaneA mixture of R-32, R-125, and R-134a
R-454B Difluoromethane and 2,3,3,3-TetrafluoropropeneHFOs blend of refrigerants Difluoromethane (R-32) and 2,3,3,3-Tetrafluoropropene (R-1234yf). [74] [75] [76] [77]
R-513AAn HFO/HFC blend (56% R-1234yf/44%R-134a)May replace R-134a as an interim alternative [78]
R-514AHFO-1336mzz-Z/trans-1,2- dichloroethylene (t-DCE)An hydrofluoroolefin (HFO)-based refrigerant to replace R-123 in low pressure centrifugal chillers for commercial and industrial applications. [79] [80]

Refrigerant reclamation and disposal

Coolant and refrigerants are found throughout the industrialized world, in homes, offices, and factories, in devices such as refrigerators, air conditioners, central air conditioning systems (HVAC), freezers, and dehumidifiers. When these units are serviced, there is a risk that refrigerant gas will be vented into the atmosphere either accidentally or intentionally, hence the creation of technician training and certification programs in order to ensure that the material is conserved and managed safely. Mistreatment of these gases has been shown to deplete the ozone layer and is suspected to contribute to global warming. [81]

With the exception of isobutane and propane (R600a, R441A and R290), ammonia and CO2 under Section 608 of the United States' Clean Air Act it is illegal to knowingly release any refrigerants into the atmosphere. [82] [83]

Refrigerant reclamation is the act of processing used refrigerant gas which has previously been used in some type of refrigeration loop such that it meets specifications for new refrigerant gas. In the United States, the Clean Air Act of 1990 requires that used refrigerant be processed by a certified reclaimer, which must be licensed by the United States Environmental Protection Agency (EPA), and the material must be recovered and delivered to the reclaimer by EPA-certified technicians. [84]

Classification of refrigerants

R407C pressure-enthalpy diagram, isotherms between the two saturation lines R407C eng.PNG
R407C pressure-enthalpy diagram, isotherms between the two saturation lines

Refrigerants may be divided into three classes according to their manner of absorption or extraction of heat from the substances to be refrigerated:[ citation needed ]

R numbering system

The R- numbering system was developed by DuPont (which owned the Freon trademark), and systematically identifies the molecular structure of refrigerants made with a single halogenated hydrocarbon. ASHRAE has since set guidelines for the numbering system as follows: [85]

R-X1X2X3X4

Series

Ethane Derived Chains

  • Number Only Most symmetrical isomer
  • Lower Case Suffix (a, b, c, etc.) indicates increasingly unsymmetrical isomers

Propane Derived Chains

  • Number Only If only one isomer exists; otherwise:
  • First lower case suffix (a-f):
    • a Suffix Cl2 central carbon substitution
    • b Suffix Cl, F central carbon substitution
    • c Suffix F2 central carbon substitution
    • d Suffix Cl, H central carbon substitution
    • e Suffix F, H central carbon substitution
    • f Suffix H2 central carbon substitution
  • 2nd Lower Case Suffix (a, b, c, etc.) Indicates increasingly unsymmetrical isomers

Propene derivatives

  • First lower case suffix (x, y, z):
    • x Suffix Cl substitution on central atom
    • y Suffix F substitution on central atom
    • z Suffix H substitution on central atom
  • Second lower case suffix (a-f):
    • a Suffix =CCl2 methylene substitution
    • b Suffix =CClF methylene substitution
    • c Suffix =CF2 methylene substitution
    • d Suffix =CHCl methylene substitution
    • e Suffix =CHF methylene substitution
    • f Suffix =CH2 methylene substitution

Blends

  • Upper Case Suffix (A, B, C, etc.) Same blend with different compositions of refrigerants

Miscellaneous

  • R-Cxxx Cyclic compound
  • R-Exxx Ether group is present
  • R-CExxx Cyclic compound with an ether group
  • R-4xx/5xx + Upper Case Suffix (A, B, C, etc.) Same blend with different composition of refrigerants
  • R-6xx + Lower Case Letter Indicates increasingly unsymmetrical isomers
  • 7xx/7xxx + Upper Case Letter Same molar mass, different compound
  • R-xxxxB# Bromine is present with the number after B indicating how many bromine atoms
  • R-xxxxI# Iodine is present with the number after I indicating how many iodine atoms
  • R-xxx(E) Trans Molecule
  • R-xxx(Z) Cis Molecule

For example, R-134a has 2 carbon atoms, 2 hydrogen atoms, and 4 fluorine atoms, an empirical formula of tetrafluoroethane. The "a" suffix indicates that the isomer is unbalanced by one atom, giving 1,1,1,2-Tetrafluoroethane. R-134 (without the "a" suffix) would have a molecular structure of 1,1,2,2-Tetrafluoroethane.

The same numbers are used with an R- prefix for generic refrigerants, with a "Propellant" prefix (e.g., "Propellant 12") for the same chemical used as a propellant for an aerosol spray, and with trade names for the compounds, such as "Freon 12". Recently, a practice of using abbreviations HFC- for hydrofluorocarbons, CFC- for chlorofluorocarbons, and HCFC- for hydrochlorofluorocarbons has arisen, because of the regulatory differences among these groups.[ citation needed ]

Refrigerant safety

ASHRAE Standard 34, Designation and Safety Classification of Refrigerants, assigns safety classifications to refrigerants based upon toxicity and flammability.

Using safety information provided by producers, ASHRAE assigns a capital letter to indicate toxicity and a number to indicate flammability. The letter "A" is the least toxic and the number 1 is the least flammable. [86]

See also

Related Research Articles

<span class="mw-page-title-main">Chlorofluorocarbon</span> Class of organic compounds

Chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs) are fully or partly halogenated hydrocarbons that contain carbon (C), hydrogen (H), chlorine (Cl), and fluorine (F), produced as volatile derivatives of methane, ethane, and propane.

<span class="mw-page-title-main">Isobutane</span> Chemical compound

Isobutane, also known as i-butane, 2-methylpropane or methylpropane, is a chemical compound with molecular formula HC(CH3)3. It is an isomer of butane. Isobutane is a colorless, odorless gas. It is the simplest alkane with a tertiary carbon atom. Isobutane is used as a precursor molecule in the petrochemical industry, for example in the synthesis of isooctane.

<span class="mw-page-title-main">Difluoromethane</span> Chemical compound

Difluoromethane, also called difluoromethylene, HFC-32Methylene Fluoride or R-32, is an organic compound of the dihalogenoalkane variety. Invented in 1964 by Hoechst AG (not Daikin) it has the formula of CH2F2. It is a colorless gas in the ambient atmosphere and is slightly soluble in water, with a high thermal stability. Due to the low melting and boiling point, (−136.0 and −51.6 °C [−212.8 and −60.9 °F; 137.2 and 221.6 K] respectively) contact with this compound may result in frostbite. In the United States, the Clean Air Act Section 111 on Volatile Organic Compounds (VOC) has listed difluoromethane as an exception (since 1997) from the definition of VOC due to its low production of tropospheric ozone. Difluoromethane is commonly used in endothermic processes such as refrigeration or air conditioning.

Dichlorodifluoromethane (R-12) is a colorless gas popularly known by the genericized brand name Freon. It is a chlorofluorocarbon halomethane (CFC) used as a refrigerant and aerosol spray propellant. In compliance with the Montreal Protocol, its manufacture was banned in developed countries in 1996, and in developing countries in 2010 out of concerns about its damaging effect on the ozone layer. Its only allowed usage is as a fire retardant in submarines and aircraft. It is soluble in many organic solvents. R-12 cylinders are colored white.

1,1,1,2-Tetrafluoroethane (also known as norflurane (INN), R-134a, Klea 134a, Freon 134a, Forane 134a, Genetron 134a, Green Gas, Florasol 134a, Suva 134a, HFA-134a, or HFC-134a) is a hydrofluorocarbon (HFC) and haloalkane refrigerant with thermodynamic properties similar to R-12 (dichlorodifluoromethane) but with insignificant ozone depletion potential and a lower 100-year global warming potential (1,430, compared to R-12's GWP of 10,900). It has the formula CF3CH2F and a boiling point of −26.3 °C (−15.34 °F) at atmospheric pressure. R-134a cylinders are colored light blue. A phaseout and transition to HFO-1234yf and other refrigerants, with GWPs similar to CO2, began in 2012 within the automotive market.

<span class="mw-page-title-main">Chlorodifluoromethane</span> Chemical propellant and refrigerant

Chlorodifluoromethane or difluoromonochloromethane is a hydrochlorofluorocarbon (HCFC). This colorless gas is better known as HCFC-22, or R-22, or CHClF
2. It was commonly used as a propellant and refrigerant. These applications were phased out under the Montreal Protocol in developed countries in 2020 due to the compound's ozone depletion potential (ODP) and high global warming potential (GWP), and in developing countries this process will be completed by 2030. R-22 is a versatile intermediate in industrial organofluorine chemistry, e.g. as a precursor to tetrafluoroethylene.

R-410A is a refrigerant used in air conditioning and heat pump applications. It is a zeotropic but near-azeotropic mixture of difluoromethane (CH2F2, called R-32) and pentafluoroethane (CHF2CF3, called R-125). R-410A is sold under the trademarked names AZ-20, EcoFluor R410, Forane 410A, Genetron R410A, Puron, and Suva 410A.

<span class="mw-page-title-main">Vapor-compression refrigeration</span> Refrigeration process

Vapour-compression refrigeration or vapor-compression refrigeration system (VCRS), in which the refrigerant undergoes phase changes, is one of the many refrigeration cycles and is the most widely used method for air conditioning of buildings and automobiles. It is also used in domestic and commercial refrigerators, large-scale warehouses for chilled or frozen storage of foods and meats, refrigerated trucks and railroad cars, and a host of other commercial and industrial services. Oil refineries, petrochemical and chemical processing plants, and natural gas processing plants are among the many types of industrial plants that often utilize large vapor-compression refrigeration systems. Cascade refrigeration systems may also be implemented using two compressors.

Natural refrigerants are considered substances that serve as refrigerants in refrigeration systems. They are alternatives to synthetic refrigerants such as chlorofluorocarbon (CFC), hydrochlorofluorocarbon (HCFC), and hydrofluorocarbon (HFC) based refrigerants. Unlike other refrigerants, natural refrigerants can be found in nature and are commercially available thanks to physical industrial processes like fractional distillation, chemical reactions such as Haber process and spin-off gases. The most prominent of these include various natural hydrocarbons, carbon dioxide, ammonia, and water. Natural refrigerants are preferred actually in new equipment to their synthetic counterparts for their presumption of higher degrees of sustainability. With the current technologies available, almost 75 percent of the refrigeration and air conditioning sector has the potential to be converted to natural refrigerants.

<span class="mw-page-title-main">2,3,3,3-Tetrafluoropropene</span> Chemical compound

2,3,3,3-Tetrafluoropropene, HFO-1234yf, is a hydrofluoroolefin (HFO) with molecular formula CH2=CFCF3. Its primary application is as a refrigerant with low global warming potential (GWP).

<span class="mw-page-title-main">1,1-Dichloro-1-fluoroethane</span> Chemical compound

1,1-Dichloro-1-fluoroethane is a haloalkane with the formula C
2H
3Cl
2F. It is one of the three isomers of dichlorofluoroethane. It belongs to the hydrochlorofluorocarbon (HCFC) family of man-made compounds that contribute significantly to both ozone depletion and global warming when released into the environment.

<span class="mw-page-title-main">R-407C</span> Mixture used as a refrigerant

R-407C is a mixture of hydrofluorocarbons used as a refrigerant. It is a zeotropic blend of difluoromethane (R-32), pentafluoroethane (R-125), and 1,1,1,2-tetrafluoroethane (R-134a). Difluoromethane serves to provide the heat capacity, pentafluoroethane decreases flammability, tetrafluoroethane reduces pressure. R-407C cylinders are colored burnt orange.

<span class="mw-page-title-main">1-Chloro-1,1-difluoroethane</span> Chemical compound

1-Chloro-1,1-difluoroethane (HCFC-142b) is a haloalkane with the chemical formula CH3CClF2. It belongs to the hydrochlorofluorocarbon (HCFC) family of man-made compounds that contribute significantly to both ozone depletion and global warming when released into the environment. It is primarily used as a refrigerant where it is also known as R-142b and by trade names including Freon-142b.

<span class="mw-page-title-main">Automotive air conditioning</span> System to cool the air in a vehicle

Automotive air conditioning systems use air conditioning to cool the air in a vehicle.

<span class="mw-page-title-main">Hydrofluoroolefin</span> Class of chemical compounds

Hydrofluoroolefins (HFOs) are unsaturated organic compounds composed of hydrogen, fluorine and carbon. These organofluorine compounds are of interest as refrigerants. Unlike traditional hydrofluorocarbons (HFCs) and chlorofluorocarbons (CFCs), which are saturated, HFOs are olefins, otherwise known as alkenes.

<i>trans</i>-1,3,3,3-Tetrafluoropropene Chemical compound

trans-1,3,3,3-Tetrafluoropropene (HFO-1234ze(E), R-1234ze(E)) is a hydrofluoroolefin. It was developed as a "fourth generation" refrigerant to replace fluids such as R-134a, as a blowing agent for foam and aerosol applications, and in air horns and gas dusters. The use of R-134a is being phased out because of its high global warming potential (GWP). HFO-1234ze(E) itself has zero ozone-depletion potential (ODP=0), a very low global warming potential (GWP < 1 ), even lower than CO2, and it is classified by ANSI/ASHRAE as class A2L refrigerant (lower flammability (see below) and lower toxicity).

Fluorinated gases (F-gases) are a group of gases containing fluorine. They are divided into several types, the main of those are hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), sulphur hexafluoride (SF6). They are used in refrigeration, air conditioning, heat pumps, fire suppression, electronics, aerospace, magnesium industry, foam and high voltage switchgear. As they are greenhouse gases with a strong global warming potential, their use is regulated.

Life Cycle Climate Performance (LCCP) is an evolving method to evaluate the carbon footprint and global warming impact of heating, ventilation, air conditioning (AC), refrigeration systems, and potentially other applications such as thermal insulating foam. It is calculated as the sum of direct, indirect, and embodied greenhouse gas (GHG) emissions generated over the lifetime of the system “from cradle to grave,” i.e. from manufacture to disposal. Direct emissions include all climate forcing effects from the release of refrigerants into the atmosphere, including annual leakage and losses during service and disposal of the unit. Indirect emissions include the climate forcing effects of GHG emissions from the electricity powering the equipment. The embodied emissions include the climate forcing effects of the manufacturing processes, transport, and installation for the refrigerant, materials, and equipment, and for recycle or other disposal of the product at end of its useful life.

The Significant New Alternatives Policy is a program of the EPA to determine acceptable chemical substitutes, and establish which are prohibited or regulated by the EPA. It also establishes a program by which new alternatives may be accepted, and promulgates timelines to the industry regarding phase-outs of substitutes.

References

  1. ↑ United Nations Environment Programme (UNEP). "Update on New Refrigerants Designations and Safety Classifications" (PDF). ASHRAE. Retrieved 6 October 2024.
  2. ↑ "Phaseout of Class II Ozone-Depleting Substances". US Environmental Protection Agency. 22 July 2015. Retrieved October 6, 2024.
  3. ↑ "Protecting Our Climate by Reducing Use of HFCs". United States Environmental Protection Agency. 8 February 2021. Retrieved 6 October 2024.
  4. 1 2 Pearson, S. Forbes. "Refrigerants Past, Present and Future" (PDF). R744. Archived from the original (PDF) on 2018-07-13. Retrieved 2021-03-30.
  5. 1 2 3 "Finally, a replacement for R123?". Cooling Post. 17 October 2013.
  6. ↑ https://asrjetsjournal.org/index.php/American_Scientific_Journal/article/download/3297/1244/
  7. 1 2 Tomczyk, John (1 May 2017). "What's the Latest with R-404A?". achrnews.com.
  8. ↑ Molina, Mario J.; Rowland, F. S (28 June 1974). "Stratospheric sink for chlorofluoromethanes: chlorine catalysed destruction of ozone" (PDF). Nature. 249: 810–812. doi:10.1038/249810a0 . Retrieved October 6, 2024.
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