A refrigerant is a compound used in a heat cycle that undergoes a phase change from a gas to a liquid and back. The two main uses of refrigerants are refrigerators/freezers and air conditioners. Cf. coolant. A heat engine is a physical or theoretical device that converts thermal energy to mechanical output. ... In its most common usage, the term phase change indicates that a substance has changed among the three classical phases of matter: solid, liquid and gas. ... This article does not cite any references or sources. ... A liquid will usually assume the shape of its container A liquid is one of the main states of matter. ... “Freezer” redirects here. ... A freezer is a home appliance, usually found above the refrigerator that keeps foods frozen. ... Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ... A coolant, or heat transfer fluid, is a fluid which flows through a device in order to prevent its overheating, transferring the heat produced by the device to other devices that utilize or dissipate it. ...

Until concerns about depletion of the ozone layer arose in the 1980s, the most widely used refrigerants were the halomethanes R-12 and R-22, with R-12 being more common in automotive air conditioning and small refrigerators, and R-22 being used for residential and light commercial air conditioning, refrigerators, and freezers. Some very early systems used R-11 because its low boiling point allows low-pressure systems to be constructed, reducing the mechanical strength required for components. New production of R-12 ceased in the United States in 1995, and R-22 is to be phased out in 2010. R-134a and certain blends are now replacing chlorinated compounds. One popular 50/50 blend of R-32 and R-125 now being increasingly substituted for R-22 is R410a, often marketed under the trade name Puron®. While the R-22, R-12 and other ozone depleting refrigerants are being phased out, they still have value and can be easily sold. The ozone layer is the part of the Earths atmosphere which contains relatively high concentrations of ozone (O3). ... Halomethane compounds are molecules of methane (CH4) with one or more of the hydrogen atoms replaced with halogen atoms. ... Disclaimer and references Dichlorodifluoromethane (R-12), usually sold under the brand name Freon-12, is a chlorofluorocarbon halomethane used as a refrigerant and aerosol spray propellant until its manufacture was discontinued in 1995, due to concerns about damage to the ozone layer. ... The haloalkanes are a group of chemical compounds, consisting of alkanes, such as methane or ethane, with one or more halogens linked, such as chlorine or fluorine, making them a type of organic halide. ... R-11, or trichlorofluoromethane, was the first widely used refrigerant. ... 1,1,1,2-Tetrafluoroethane, also called simply tetrafluoroethane or R-134a, is a refrigerant that has zero ozone depletion potential and thermodynamic properties similar to R-12. ... This article does not cite any references or sources. ...

The ideal refrigerant has good thermodynamic properties, is noncorrosive, and safe. The desired thermodynamic properties are a boiling point somewhat below the target temperature, a high heat of vaporization, a moderate density in liquid form, and a relatively high density in gaseous form. Since boiling point and gas density are affected by pressure, refrigerants may be made more suitable for a particular application by choice of operating pressure. Thermodynamics (from the Greek θερμη, therme, meaning heat and δυναμις, dunamis, meaning power) is a branch of physics that studies the effects of changes in temperature, pressure, and volume on physical systems at the macroscopic scale by analyzing the collective motion of their particles using statistics. ... The boiling point of a substance is the temperature at which it can change its state from a liquid to a gas throughout the bulk of the liquid at a given pressure. ... The heat of vaporization is a physical property of substances. ... In physics, density is mass m per unit volume V. For the common case of a homogeneous substance, it is expressed as: where, in SI units: ρ (rho) is the density of the substance, measured in kg·m-3 m is the mass of the substance, measured in kg V is... The use of water pressure - the Captain Cook Memorial Jet in Lake Burley Griffin in Canberra, Australia. ...

Corrosion properties are a matter of materials compatibility with the components used for the compressor, piping, evaporator, and condenser. Safety considerations include toxicity and flammability. A gas compressor is a mechanical device that increases the pressure of a gas by reducing its volume. ... Piping is used to convey fluids (usually liquids and gases but sometimes loose solids) from one location to another. ... The introduction to this article provides insufficient context for those unfamiliar with the subject matter. ... Look up condenser in Wiktionary, the free dictionary. ... // Toxic and Intoxicated redirect here – toxic has other uses, which can be found at Toxicity (disambiguation); for the state of being intoxicated by alcohol see Drunkenness. ... Flammable or Flammability refers to the ease at which a substance will ignite, causing fire or combustion. ...

Early mechanical refrigeration systems employed sulfur dioxide gas or anhydrous ammonia, with small home refrigerators primarily using the former. Being toxic, sulfur dioxide rapidly disappeared from the market with the introduction of Freon. Ammonia is still used in some large commercial plants, well away from residential areas, where a leak will not cause widespread injuries. Sulfur dioxide (or Sulphur dioxide) has the chemical formula SO2. ... Ammonia is a compound with the formula NH3. ... Freon is a trade name for a group of chlorofluorocarbons used primarily as a refrigerant. ...

Use of highly purified liquified propane gas as a refrigerant is gaining favor, especially in systems designed for R-12, R-22 or R-134a. As such, it is designated as R-290 and is marketed under the trade name Duracool®. Although propane is flammable, in home and automotive systems it is present in quantities small enough to not pose an undue fire hazard if a system should develop a leak. Moreover, propane is nontoxic. An odorant, such as ethyl mercaptan, can be added in trace amounts to alert persons of system leaks. 45 kg LPG cylinders Spherical Gas Container typically found in Refineries. ... Ethanethiol, also known as ethyl mercaptan, is an organic compound used as an odorant in propane. ...

Emissions from automotive air-conditioning are a growing concern because of their impact on climate change. From 2011 on, the European Union will 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). This will ban potent greenhouse gases such as the refrigerant HFC-134a – which has a GWP of 1300 – to promote safe and energy-efficient refrigerants. One of the most promising alternatives is the natural refrigerant CO₂ (R-744). Carbon dioxide is non-flammable, non-ozone depleting, has a global warming potential of 1, but is toxic and potentially lethal in concentrations above 5% by volume. R-744 can be used as a working fluid in climate control systems for cars, residential air conditioning, hot water pumps, commercial refrigeration, and vending machines. Global warming potential (GWP) is a measure of how much a given mass of greenhouse gas is estimated to contribute to global warming. ... Carbon dioxide is a chemical compound composed of one carbon and two oxygen atoms, and is in a gaseous state in the atmosphere of the Earth. ...

Recycling refrigerants

CFC's or chlorofluorocarbons are used as refrigerants in some commercial air conditioning and refrigeration systems. CFC's are considered to be 100% ozone depleting and are very dangerous to the environment. In most residential air conditioners and many refrigeration systems it is R-22 or Freon which is a hydrochlorofluorocarbon or HCFC. HCFC's are considered to be 5% ozone depleting and are also a danger to the Earth's vital ozone layer.

As of July 1, 1992 it is illegal to release Freon or other refrigerants into the atmosphere because they can cause severe damage to the ozone layer. When CFCs are removed they should be recycled to clean out any contaminants and return it to a usable condition. Refrigerants should never be mixed together. Some CFCs must be managed as hazardous waste, even if recycled and special precautions are required for their transport.

Refrigerants by class

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

Class 1 - This class includes refrigerants that cool by the absorption or extraction of latent heat from the substances to be refrigerated. In thermochemistry, latent heat is the amount of energy in the form of heat released or absorbed by a substance during evaporation. ...

Class 2 - These refrigerants cool substances by absorbing their sensible heats. They are air, calcium chloride brine, sodium chloride (salt) brine, alcohol, and similar nonfreezing solutions. The purpose of Class 2 refrigerants is to receive a reduction of temperature from Class 1 refrigerants and convey this lower temperature to the area to be air-conditioned. Sensible heat is heat energy that is transported by a body that has a temperature higher than its surroundings via conduction, convection, or both. ...

Class 3 - This group consists of solutions that contain absorbed vapors of liquefiable agents or refrigerating media. These solutions function by nature of their ability to carry liquefiable vapors, which produce a cooling effect by the absorption of their latent heat.

Numbering

The R-# numbering system was developed by DuPont and systematically identifies the molecular structure of refrigerants made with a single halogenated hydrocarbon. The meaning of the codes is as follows: Dupont, DuPont, Du Pont, or du Pont may refer to: // E.I. du Pont de Nemours and Company, the worlds third largest chemical company Du Pont Motors Gilbert Dupont, a French stock brokerage part of retail banking network Crédit du Nord ST Dupont, a French manufacturer of fine...

• Rightmost digit — Number of fluorine atoms per molecule.
• Tens digit — One plus the number of hydrogen atoms per molecule.
• Hundreds digit — The number of carbon atoms minus one. Omitted for methyl halides, which have only one carbon atom.
• Thousands digit — Number of double bonds in the molecule. This is omitted when zero, and in practice is rarely used, since most candidate compounds are unstable.
• A suffix with a capital B and a number indicates the number of bromine atoms, when present. This is rarely used.
• Remaining bonds not accounted for are occupied by chlorine atoms.
• A suffix of a lower-case letter a, b, or c indicates increasingly unbalanced isomers.
• As a special case, the R-400 series is made up of zeotropic blends (those where the boiling point of constituent compounds differs enough to lead to changes in relative concentration due to fractional distillation) and the R-500 series is made up of so-called azeotropic blends. The rightmost digit is assigned arbitrarily by ASHRAE, an industry organization.

For example, R-134a has 4 fluorine atoms, 2 hydrogen atoms, 2 carbon atoms, with 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 — a compound not especially effective as a refrigerant. Properties In chemistry and physics, an atom (Greek ἄτομος or átomos meaning indivisible) is the smallest particle still characterizing a chemical element. ... In science, a molecule is a group of atoms in a definite arrangement held together by chemical bonds. ... General Name, Symbol, Number hydrogen, H, 1 Chemical series nonmetals Group, Period, Block 1, 1, s Appearance colorless Atomic mass 1. ... General Name, Symbol, Number carbon, C, 6 Chemical series nonmetals Group, Period, Block 14, 2, p Appearance black (graphite) colorless (diamond) Standard atomic weight 12. ... Covalent bonding is a form of chemical bonding characterized by the sharing of one or more pairs of electrons between atoms, in order to produce a mutual attraction, which holds the resultant molecule together. ... Instability in systems is generally characterized by some of the outputs or internal states growing without bounds. ... General Name, Symbol, Number bromine, Br, 35 Chemical series halogens Group, Period, Block 17, 4, p Appearance gas/liquid: red-brown solid: metallic luster Atomic mass 79. ... General Name, Symbol, Number chlorine, Cl, 17 Chemical series halogens Group, Period, Block 17, 3, p Appearance yellowish green Standard atomic weight 35. ... In chemistry, isomers are molecules with the same chemical formula and often with the same kinds of bonds between atoms, but in which the atoms are arranged differently. ... Fractional distillation is the separation of a mixture into its component parts, or fractions, such as in separating chemical compounds by their boiling point by heating them to a temperature at which several fractions of the compound will evaporate. ... This article needs more context around or a better explanation of technical details to make it more accessible to general readers and technical readers outside the specialty, without removing technical details. ... The American Society of Heating, Refrigerating and Air Conditioning Engineers (ASHRAE) is an international voluntary organization for people involved in heating, ventilation, air conditioning, or refrigeration (HVAC&R). ... 1,1,1,2-Tetrafluoroethane, also called simply tetrafluoroethane, R-134a or HFC-134a, is a refrigerant without an ozone depletion potential and thermodynamic properties similar to R-12 (dichlorodifluoromethane). ... 1,1,1,2-Tetrafluoroethane, also called simply tetrafluoroethane, R-134a or HFC-134a, is a refrigerant without an ozone depletion potential and thermodynamic properties similar to R-12 (dichlorodifluoromethane). ...

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 HFC- for hydrofluorocarbons, CFC- for chlorofluorocarbons, and HCFC- for hydrochlorofluorocarbons has arisen, due to the regulatory differences among these groups. Aerosol spray can Aerosol spray is a type of canister that sprays an aerosol when its button is pressed or held down. ... CFC molecules CFCs (chlorofluorocarbons) are a family of artificial chemical compounds containing chlorine, fluorine and carbon. ... For other uses, see CFC (disambiguation). ... This article should be merged with Freon, Halon, CFC, and Hydrochlorofluorocarbon and added to Alkyl halide Hydrochlorofluorocarbons (HCFCs) is one of a class of fluorocarbon compounds that are used primarily as chlorofluorocarbon (CFC) substitutes. ...

See also

• List of refrigerants

Chemical refrigerants are assigned an R number which is determined systematically according to molecular stucture. ...

External links

• The Natural Refrigerant CO₂ (R-744) - news, FAQs, legislation, suppliers, products
• Refripro - The European Portal for Refrigeration and A/C: refrigerant list, legislation, suppliers etc.
• - US Environmental Protection Agency page on the GWPs of various substances
• Gasco-group.com - some Molliers log(h)-p diagrams
• Recycling Refrigerants
• General Information on Air Conditioning, Heating, Ventilation, and Refrigeration.en:Refrigerante