Philip Trueman (
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A '''refrigerant''' is a substance used in a [[heat engine|heat cycle]] usually including, for enhanced efficiency, a reversible [[phase transition]] from a [[liquid]] to a [[gas]]. Traditionally, [[organofluorine chemistry|fluorocarbons]], especially [[chlorofluorocarbon]]s, were used as refrigerants, but they are being phased out because of their [[ozone depletion]] effects. Other common refrigerants used in various applications are [[ammonia]], [[sulfur dioxide]], and non-halogenated [[hydrocarbons]] such as [[propane]].<ref>Siegfried Haaf, Helmut Henrici "Refrigeration Technology" in Ullmann's Encyclopedia of Industrial Chemistry, 2002, Wiley-VCH, {{doi|10.1002/14356007.b03 19}}</ref> Many refrigerants are important [[ozone depletion|ozone depleting]] and [[global warming]] inducing compounds that are the focus of worldwide regulatory scrutiny. |
A '''refrigerant''' is a substance used in a [[heat engine|heat cycle]] usually including, for enhanced efficiency, a reversible [[phase transition]] from a [[liquid]] to a [[gas]]. Traditionally, [[organofluorine chemistry|fluorocarbons]], especially [[chlorofluorocarbon]]s, were used as refrigerants, but they are being phased out because of their [[ozone depletion]] effects. Other common refrigerants used in various applications are [[ammonia]], [[sulfur dioxide]], and non-halogenated [[hydrocarbons]] such as [[propane]].<ref>Siegfried Haaf, Helmut Henrici "Refrigeration Technology" in Ullmann's Encyclopedia of Industrial Chemistry, 2002, Wiley-VCH, {{doi|10.1002/14356007.b03 19}}</ref> Many refrigerants are important [[ozone depletion|ozone depleting]] and [[global warming]] inducing compounds that are the focus of worldwide regulatory scrutiny. |
||
== Physical properties == |
== Physical properties of my nan == |
||
{{unreferenced section|date=December 2013}} |
{{unreferenced section|date=December 2013}} |
||
The ideal refrigerant has favorable [[thermodynamic]] properties, is [[corrosive|noncorrosive]] to mechanical components, and is safe (including [[toxicity|nontoxic]], [[flammability|nonflammable]], and environmentally benign). The desired thermodynamic properties are a [[boiling point]] somewhat below the target temperature, a high [[heat of vaporization]], a moderate [[density]] in liquid form, a relatively high density in gaseous form, and a high [[Critical point (thermodynamics)|critical temperature]]. Since boiling point and gas density are affected by [[pressure]], refrigerants may be made more suitable for a particular application by choice of operating pressures. |
The ideal refrigerant has favorable [[thermodynamic]] properties, is [[corrosive|noncorrosive]] to mechanical components, and is safe (including [[toxicity|nontoxic]], [[flammability|nonflammable]], and environmentally benign). The desired thermodynamic properties are a [[boiling point]] somewhat below the target temperature, a high [[heat of vaporization]], a moderate [[density]] in liquid form, a relatively high density in gaseous form, and a high [[Critical point (thermodynamics)|critical temperature]]. Since boiling point and gas density are affected by [[pressure]], refrigerants may be made more suitable for a particular application by choice of operating pressures. |
||
== Refrigerant environmental issues== |
== Refrigerant environmental issues== |
![]() | This article has multiple issues. Please help
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![]() |
A refrigerant is a substance used in a heat cycle usually including, for enhanced efficiency, a reversible phase transition from a liquid to a gas. Traditionally, fluorocarbons, especially chlorofluorocarbons, were used as refrigerants, but they are being phased out because of their ozone depletion effects. Other common refrigerants used in various applications are ammonia, sulfur dioxide, and non-halogenated hydrocarbons such as propane. [1] Many refrigerants are important ozone depleting and global warming inducing compounds that are the focus of worldwide regulatory scrutiny.
The ideal refrigerant has favorable thermodynamic properties, is noncorrosive to mechanical components, and is safe (including nontoxic, nonflammable, and environmentally benign). The desired thermodynamic properties are a boiling point somewhat below the target temperature, a high heat of vaporization, a moderate density in liquid form, a relatively high density in gaseous form, and a high critical temperature. Since boiling point and gas density are affected by pressure, refrigerants may be made more suitable for a particular application by choice of operating pressures.
The inert nature of many Halons, Chlorofluorocarbons (CFC) and Hydrochlorofluorocarbons (HCFC), with the benefits of them being nonflammable and nontoxic, made them good choices as refrigerants, but their stability in the atmosphere and their corresponding global warming potential and ozone depletion potential raised concerns about their usage. In order from the highest to the lowest potential of ozone depletion are Bromochlorofluorocarbon, CFC then HCFC. Though HFC and PFC are non-ozone depleting, many have global warming potentials that are thousands of times greater than CO2. Other refrigerants such as propane and ammonia are not inert, and are flammable or toxic if released.
New refrigerants have been developed that are safe to humans and to the environment, but their application has been held up by regulatory hurdles. [2]
Early mechanical refrigeration systems employed sulfur dioxide, methyl chloride and ammonia. Being toxic, sulfur dioxide and methyl chloride rapidly disappeared from the market with the introduction of CFCs.
Occasionally, one may encounter older machines with methyl formate, chloromethane, or dichloromethane (called carrene in the trade).
Until concerns about depletion of the ozone layer arose in the 1980s, the most widely used refrigerants were the halomethane chlorofluorocarbons. [ citation needed]
Following legislative regulations on ozone depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), substances used as substitute refrigerants such as perfluorocarbons (FCs) and hydrofluorocarbons (HFCs) have also come under criticism. They are currently subject to prohibition discussions on account of their harmful effect on the climate. In 1997, FCs and HFCs were included in the Kyoto Protocol to the Framework Convention on Climate Change. In 2006, the EU adopted a Regulation on fluorinated greenhouse gases, which makes stipulations regarding the use of FCs and HFCs with the intention of reducing their emissions. The provisions do not affect climate-neutral refrigerants.
Ammonia (R717) has been used in industrial refrigeration plants for more than 130 years and is thought to be environment-friendly, economical, and energy-efficient. Carbon dioxide (R744) has a similarly long tradition in refrigeration technology.
Refrigerants such as ammonia, carbon dioxide and non-halogenated hydrocarbons preserve the ozone layer and have no (ammonia) or only a low (carbon dioxide, hydrocarbons) global warming potential.[ citation needed] They are used in air-conditioning systems for buildings, in sport and leisure facilities, in the chemical/pharmaceutical industry, in the automotive industry and above all in the food industry (production, storage, retailing). New applications are opening up for non-halogenated refrigerants; for example, in vehicle air-conditioning.[ citation needed]
Emissions from automotive air-conditioning are a growing concern because of their impact on climate change.[ citation needed] 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).[ citation needed] This will ban potent greenhouse gases such as the refrigerant HFC-134a—which has a GWP of 1410—to promote safe and energy-efficient refrigerants. One of the most promising alternatives is 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.[ citation needed] 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.[ citation needed] R12 is compatible with mineral oil, while R134a is compatible with synthetic oil that contains esters.[ citation needed] GM has announced that it will start using "hydrofluoroolefin", HFO-1234yf, in all of its brands by 2013. [3] Dimethyl ether (DME) is also gaining popularity as a refrigerant, [4] but like propane, it is also dangerously flammable.
Some refrigerants are seeing rising use as recreational drugs, leading to an extremely dangerous phenomenon known as inhalant abuse. [5]
Under Section 608 of the EPA Clean Air Act it is illegal in the United States to knowingly release HFC-134a refrigerants into the atmosphere. [EPA 1]
When refrigerants are removed they should be recycled to clean out any contaminants and return them to a usable condition. Refrigerants should never be mixed together outside of facilities licensed to do so for the purpose of producing blends. Some refrigerants must be managed as hazardous waste even if recycled, and special precautions are required for their transport, depending on the legislation of the country's government.
![]() | This section's factual accuracy is
disputed. (May 2013) |
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]
The R-# numbering system was developed by DuPont corporation (which owns the Freon trademark) and systematically identifies the molecular structure of refrigerants made with a single halogenated hydrocarbon. The meaning of the codes is as follows:[ citation needed]
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—a compound not especially effective as a refrigerant.[ citation needed]
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, because of the regulatory differences among these groups.[ citation needed]
Below are some notable blended HFC mixtures. There exist many more (see list of refrigerants). All R-400 (R-4xx) and R-500 (R-5xx) hydroflurocarbons are blends, as noted above.
"Air cycle is not a new technology. At the turn of the century air cycle or 'cold air machines' were available from companies such as J & E Hall... These were used on board ships and by food producers and retailers to provide cooling for their food stores." [17]
Air has been used for residential, [18] automobile, [17] and turbine-powered aircraft [19] [20] air-conditioning and/or cooling. The reason why air is not more widely used as a general-purpose refrigerant is the perception that because there is no change of phase, it is too inefficient to be practical. [18] Yet, with suitable compression and expansion technology, air can be a practical (albeit not the most efficient) refrigerant, free of the possibility of environmental contamination or damage, [18] and almost completely [21] harmless to plants and animals.
An explosion could result from refrigerant-type compressor lubricating oils being compressed together with the air.
The simplest refrigerant is water - non toxic, low cost, and widely available. The simplest cooling systems, known as swamp coolers in the south-west United States, do not even need power for a compressor, merely a blower fan - humidified air is simply vented to the living space. However, drawbacks are multiple and severe as well. The total cooling power of the unit is limited by the fact that neither coolant nor air is recirculated. A swamp-cooled home will have a constant supply of fresh, not too-dry air, but if the air outside is already humid, cooling power is severely limited. This is why such units are not found in areas of frequent and high humidity, such as the south-east United States. Furthermore, if the temperature outside is severely hot, such as over 110 degrees F or 43 °C, the unit will not cool the air sufficiently for comfort even if the dew point outside is very low.
{{
cite news}}
: Unknown parameter |coauthors=
ignored (|author=
suggested) (
help)
Philip Trueman (
talk |
contribs)
m
Reverted edits by
212.219.56.213 (
talk) to last version by ClueBot NG |
|||
Line 9: | Line 9: | ||
A '''refrigerant''' is a substance used in a [[heat engine|heat cycle]] usually including, for enhanced efficiency, a reversible [[phase transition]] from a [[liquid]] to a [[gas]]. Traditionally, [[organofluorine chemistry|fluorocarbons]], especially [[chlorofluorocarbon]]s, were used as refrigerants, but they are being phased out because of their [[ozone depletion]] effects. Other common refrigerants used in various applications are [[ammonia]], [[sulfur dioxide]], and non-halogenated [[hydrocarbons]] such as [[propane]].<ref>Siegfried Haaf, Helmut Henrici "Refrigeration Technology" in Ullmann's Encyclopedia of Industrial Chemistry, 2002, Wiley-VCH, {{doi|10.1002/14356007.b03 19}}</ref> Many refrigerants are important [[ozone depletion|ozone depleting]] and [[global warming]] inducing compounds that are the focus of worldwide regulatory scrutiny. |
A '''refrigerant''' is a substance used in a [[heat engine|heat cycle]] usually including, for enhanced efficiency, a reversible [[phase transition]] from a [[liquid]] to a [[gas]]. Traditionally, [[organofluorine chemistry|fluorocarbons]], especially [[chlorofluorocarbon]]s, were used as refrigerants, but they are being phased out because of their [[ozone depletion]] effects. Other common refrigerants used in various applications are [[ammonia]], [[sulfur dioxide]], and non-halogenated [[hydrocarbons]] such as [[propane]].<ref>Siegfried Haaf, Helmut Henrici "Refrigeration Technology" in Ullmann's Encyclopedia of Industrial Chemistry, 2002, Wiley-VCH, {{doi|10.1002/14356007.b03 19}}</ref> Many refrigerants are important [[ozone depletion|ozone depleting]] and [[global warming]] inducing compounds that are the focus of worldwide regulatory scrutiny. |
||
== Physical properties == |
== Physical properties of my nan == |
||
{{unreferenced section|date=December 2013}} |
{{unreferenced section|date=December 2013}} |
||
The ideal refrigerant has favorable [[thermodynamic]] properties, is [[corrosive|noncorrosive]] to mechanical components, and is safe (including [[toxicity|nontoxic]], [[flammability|nonflammable]], and environmentally benign). The desired thermodynamic properties are a [[boiling point]] somewhat below the target temperature, a high [[heat of vaporization]], a moderate [[density]] in liquid form, a relatively high density in gaseous form, and a high [[Critical point (thermodynamics)|critical temperature]]. Since boiling point and gas density are affected by [[pressure]], refrigerants may be made more suitable for a particular application by choice of operating pressures. |
The ideal refrigerant has favorable [[thermodynamic]] properties, is [[corrosive|noncorrosive]] to mechanical components, and is safe (including [[toxicity|nontoxic]], [[flammability|nonflammable]], and environmentally benign). The desired thermodynamic properties are a [[boiling point]] somewhat below the target temperature, a high [[heat of vaporization]], a moderate [[density]] in liquid form, a relatively high density in gaseous form, and a high [[Critical point (thermodynamics)|critical temperature]]. Since boiling point and gas density are affected by [[pressure]], refrigerants may be made more suitable for a particular application by choice of operating pressures. |
||
== Refrigerant environmental issues== |
== Refrigerant environmental issues== |
![]() | This article has multiple issues. Please help
improve it or discuss these issues on the
talk page. (
Learn how and when to remove these template messages)
|
![]() |
A refrigerant is a substance used in a heat cycle usually including, for enhanced efficiency, a reversible phase transition from a liquid to a gas. Traditionally, fluorocarbons, especially chlorofluorocarbons, were used as refrigerants, but they are being phased out because of their ozone depletion effects. Other common refrigerants used in various applications are ammonia, sulfur dioxide, and non-halogenated hydrocarbons such as propane. [1] Many refrigerants are important ozone depleting and global warming inducing compounds that are the focus of worldwide regulatory scrutiny.
The ideal refrigerant has favorable thermodynamic properties, is noncorrosive to mechanical components, and is safe (including nontoxic, nonflammable, and environmentally benign). The desired thermodynamic properties are a boiling point somewhat below the target temperature, a high heat of vaporization, a moderate density in liquid form, a relatively high density in gaseous form, and a high critical temperature. Since boiling point and gas density are affected by pressure, refrigerants may be made more suitable for a particular application by choice of operating pressures.
The inert nature of many Halons, Chlorofluorocarbons (CFC) and Hydrochlorofluorocarbons (HCFC), with the benefits of them being nonflammable and nontoxic, made them good choices as refrigerants, but their stability in the atmosphere and their corresponding global warming potential and ozone depletion potential raised concerns about their usage. In order from the highest to the lowest potential of ozone depletion are Bromochlorofluorocarbon, CFC then HCFC. Though HFC and PFC are non-ozone depleting, many have global warming potentials that are thousands of times greater than CO2. Other refrigerants such as propane and ammonia are not inert, and are flammable or toxic if released.
New refrigerants have been developed that are safe to humans and to the environment, but their application has been held up by regulatory hurdles. [2]
Early mechanical refrigeration systems employed sulfur dioxide, methyl chloride and ammonia. Being toxic, sulfur dioxide and methyl chloride rapidly disappeared from the market with the introduction of CFCs.
Occasionally, one may encounter older machines with methyl formate, chloromethane, or dichloromethane (called carrene in the trade).
Until concerns about depletion of the ozone layer arose in the 1980s, the most widely used refrigerants were the halomethane chlorofluorocarbons. [ citation needed]
Following legislative regulations on ozone depleting chlorofluorocarbons (CFCs) and hydrochlorofluorocarbons (HCFCs), substances used as substitute refrigerants such as perfluorocarbons (FCs) and hydrofluorocarbons (HFCs) have also come under criticism. They are currently subject to prohibition discussions on account of their harmful effect on the climate. In 1997, FCs and HFCs were included in the Kyoto Protocol to the Framework Convention on Climate Change. In 2006, the EU adopted a Regulation on fluorinated greenhouse gases, which makes stipulations regarding the use of FCs and HFCs with the intention of reducing their emissions. The provisions do not affect climate-neutral refrigerants.
Ammonia (R717) has been used in industrial refrigeration plants for more than 130 years and is thought to be environment-friendly, economical, and energy-efficient. Carbon dioxide (R744) has a similarly long tradition in refrigeration technology.
Refrigerants such as ammonia, carbon dioxide and non-halogenated hydrocarbons preserve the ozone layer and have no (ammonia) or only a low (carbon dioxide, hydrocarbons) global warming potential.[ citation needed] They are used in air-conditioning systems for buildings, in sport and leisure facilities, in the chemical/pharmaceutical industry, in the automotive industry and above all in the food industry (production, storage, retailing). New applications are opening up for non-halogenated refrigerants; for example, in vehicle air-conditioning.[ citation needed]
Emissions from automotive air-conditioning are a growing concern because of their impact on climate change.[ citation needed] 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).[ citation needed] This will ban potent greenhouse gases such as the refrigerant HFC-134a—which has a GWP of 1410—to promote safe and energy-efficient refrigerants. One of the most promising alternatives is 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.[ citation needed] 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.[ citation needed] R12 is compatible with mineral oil, while R134a is compatible with synthetic oil that contains esters.[ citation needed] GM has announced that it will start using "hydrofluoroolefin", HFO-1234yf, in all of its brands by 2013. [3] Dimethyl ether (DME) is also gaining popularity as a refrigerant, [4] but like propane, it is also dangerously flammable.
Some refrigerants are seeing rising use as recreational drugs, leading to an extremely dangerous phenomenon known as inhalant abuse. [5]
Under Section 608 of the EPA Clean Air Act it is illegal in the United States to knowingly release HFC-134a refrigerants into the atmosphere. [EPA 1]
When refrigerants are removed they should be recycled to clean out any contaminants and return them to a usable condition. Refrigerants should never be mixed together outside of facilities licensed to do so for the purpose of producing blends. Some refrigerants must be managed as hazardous waste even if recycled, and special precautions are required for their transport, depending on the legislation of the country's government.
![]() | This section's factual accuracy is
disputed. (May 2013) |
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]
The R-# numbering system was developed by DuPont corporation (which owns the Freon trademark) and systematically identifies the molecular structure of refrigerants made with a single halogenated hydrocarbon. The meaning of the codes is as follows:[ citation needed]
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—a compound not especially effective as a refrigerant.[ citation needed]
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, because of the regulatory differences among these groups.[ citation needed]
Below are some notable blended HFC mixtures. There exist many more (see list of refrigerants). All R-400 (R-4xx) and R-500 (R-5xx) hydroflurocarbons are blends, as noted above.
"Air cycle is not a new technology. At the turn of the century air cycle or 'cold air machines' were available from companies such as J & E Hall... These were used on board ships and by food producers and retailers to provide cooling for their food stores." [17]
Air has been used for residential, [18] automobile, [17] and turbine-powered aircraft [19] [20] air-conditioning and/or cooling. The reason why air is not more widely used as a general-purpose refrigerant is the perception that because there is no change of phase, it is too inefficient to be practical. [18] Yet, with suitable compression and expansion technology, air can be a practical (albeit not the most efficient) refrigerant, free of the possibility of environmental contamination or damage, [18] and almost completely [21] harmless to plants and animals.
An explosion could result from refrigerant-type compressor lubricating oils being compressed together with the air.
The simplest refrigerant is water - non toxic, low cost, and widely available. The simplest cooling systems, known as swamp coolers in the south-west United States, do not even need power for a compressor, merely a blower fan - humidified air is simply vented to the living space. However, drawbacks are multiple and severe as well. The total cooling power of the unit is limited by the fact that neither coolant nor air is recirculated. A swamp-cooled home will have a constant supply of fresh, not too-dry air, but if the air outside is already humid, cooling power is severely limited. This is why such units are not found in areas of frequent and high humidity, such as the south-east United States. Furthermore, if the temperature outside is severely hot, such as over 110 degrees F or 43 °C, the unit will not cool the air sufficiently for comfort even if the dew point outside is very low.
{{
cite news}}
: Unknown parameter |coauthors=
ignored (|author=
suggested) (
help)