Refrigerant

Refrigerants transport enthalpy (i.e. thermal energy) from the goods to be cooled to the environment. The difference to the coolant is that a refrigerant in a refrigeration circuit can do this along a temperature gradient , so that when energy is applied (mostly volume change work in the form of compression) the ambient temperature can even be higher than the temperature of the object to be cooled during a Coolant is only able to transport the enthalpy in a cooling circuit against the temperature gradient to a point of lower temperature.

According to DIN EN 378-1 Paragraph 3.7.1, the refrigerant is defined as "fluid that is used for heat transfer in a refrigeration system and that absorbs heat at low temperature and low pressure and gives off heat at higher temperature and higher pressure, whereby usually Changes in the state of the fluid take place. " Or according to DIN 8960 section 3.1 as " working medium that absorbs heat in a refrigeration machine process at low temperature and low pressure and emits heat at higher temperature and higher pressure. " The definitions according to DIN refer to compression Chillers. A change of state in the sense of the standard means a change in the physical state (see refrigeration machine ).

Refrigerants are used as a working medium in closed or open refrigeration systems. While with refrigerants in the narrower sense latent heat is absorbed by evaporation at low pressure and low temperature, this happens chemically in a cold mixture through a mixture or solution reaction. In the case of refrigerants, regeneration therefore takes place by liquefaction (in a compressor with a subsequent condenser), or in the case of pairs of refrigerants by segregation (in a "thermal compressor" of an absorption chiller).

In contrast to halogenated hydrocarbons , ammonia, carbon dioxide and water, but also hydrocarbons and air, are also called natural refrigerants. Halogenated hydrocarbons are substances that also occur in nature. They are released in not inconsiderable quantities both by microorganisms and plants and as a result of volcanic activity. Natural refrigerants do not contribute to the depletion of the ozone layer and either have no or only a very small direct influence on the greenhouse effect .

nomenclature

Historical development of the nomenclature

The development of the nomenclature of refrigerants is documented in Volume 3 of the book series Advances in Fluorine Chemistry . It was first proposed by Henne, Midgley, and McNary. The exact time of the introduction of the nomenclature of these three scientists, who were all employees of the DuPont company, is not mentioned. The reason for their introduction was the desire to simplify their studies with halogenated hydrocarbons. The nomenclature was also used by DuPont itself, which ultimately led to the well-known brand names with the same numbering for the refrigeration industry. Today's brand names are rarely related to this nomenclature in their numbering. For the first two decades after the introduction of synthetic refrigerants, DuPont held a virtual monopoly on synthetic refrigerants. Fluorine chemistry grew rapidly at that time due to the production of refrigerants but also due to the fluoropolymers discovered shortly after the refrigerants , especially PTFE , which was to play a central role as a sealing material in the uranium enrichment in the Manhattan project . During this time, the identification of the compounds with the corresponding code number became firmly anchored in the refrigeration industry. As a result, the later manufacturers of these established products saw it as advantageous to integrate the numbering system of the market leader DuPont with their approval into their own individual branding systems. Of course, consumer groups quickly recognized the advantage of this standardization, and through the intermediary of ASHRAE , they agreed to adopt the numbering system from June 1957. Until 1958, ASHRAE operated as ASRE. This decision was later approved by the ASA, now ANSI , under the title ASA / ASRE B79.1 - Numerical Designation of Refrigerants in September 1960. Manufacturers around the world had now accepted this standard. In October 1960, an ISO committee recommended the adoption of that part of the nomenclature that applies to halogenated hydrocarbons and hydrocarbons. The edition of Standard B79.1 was then renumbered by ASHRAE to Standard 34 in 1978. The first official ISO standard in the form of ISO 817 was published in 1974. The first German standard, DIN 8960, was introduced in 1977.

designation

The general designation of the refrigerants (DIN 8960 Paragraph 6) is made with the letter R and then three (special cases: two or four) digits z, i.e. in the form R-zzz, possibly also with the letter b attached in the form of a short code R-zzzbb.

The "R" stands for refrigerant, English for refrigerant.

The sequence of digits “zzz” allows conclusions to be drawn about the sum formula. The third digit from the left gives the group assignment.

The letter sequence “bb” denotes variations in the structural formula.

Another (shorter) algorithm that provides information on the chemical composition is given in the article halogenated hydrocarbons .

Designation of organic refrigerants

The organic refrigerants are named according to the scheme (DIN 8960 Paragraph 6.1)

R- | c - 1 | h + 1 | f ;

The first digit is 1 smaller than the number c of carbon atoms,

the second digit is 1 greater than the number h of hydrogen atoms, and

the third digit is equal to the number f of fluorine atoms per molecule;

the number of chlorine atoms is equal to the number of remaining bonds.

A molecule of the refrigerant R-123, for example, therefore consists of

c = 1 + 1 = 2 carbon atoms,

h = 2 - 1 = 1 hydrogen atoms and

f = 3 fluorine atoms;

the two remaining bonds are filled by two chlorine atoms. The empirical formula is therefore C ₂ HF ₃ Cl ₂ , so it is dichlorotrifluoroethane .

special cases

If the number c of carbon atoms is 1 , c − 1 = 0. In this case, the first digit is not written out, and the second and third digits immediately follow the letter R. The refrigerant R-22 (actually R-022) for example consists of

c = 0 + 1 = 1 carbon atoms,

h = 2 - 1 = 1 hydrogen atoms and

f = 2 fluorine atoms;

the remaining bond is filled by a chlorine atom. The empirical formula is therefore CHF ₂ Cl, i.e. it is chlorodifluoromethane .

If the compound contains bromine , the name is appended with the capital letter B, followed by the number of bromine atoms. The refrigerant R-13B1, for example, consists of

c = 0 + 1 = 1 carbon atoms,

h = 1 - 1 = 0 hydrogen atoms and

f = 3 fluorine atoms;

the remaining bond is filled by a bromine atom (the number of chlorine atoms that may be present is reduced by the number of bromine atoms). The empirical formula is therefore CF ₃ Br, so it is bromotrifluoromethane .

If it is an unsaturated organic compound, a 1 is added before the first digit. The refrigerant R-1150, for example, therefore consists of

c = 1 + 1 = 2 carbon atoms,

h = 5 - 1 = 4 hydrogen atoms and

f = 0 fluorine atoms;

the remaining bond is part of the double bond. The molecular formula is C ₂ H ₄ , so it is ethene .

If cyclic hydrocarbons are involved , a C is added in front of the code. For example, cyclooctafluorobutane, empirical formula C ₄ F ₈ , is referred to as R-C318.

Since only the numbers 0 to 9 are available, this scheme only works up to hydrocarbons with a maximum of 8 hydrogen atoms per molecule.

For butane , empirical formula C ₄ H ₁₀ , with its 10 hydrogen atoms, for example, a different scheme is required; it is therefore listed under group R-6xx (DIN 8960 Section 6.3.1).

Attached lower case letters are used for compounds with two or more carbon atoms in order to differentiate between isomers (DIN 8960 Paragraph 3.5 and 6.1). The alphabetically higher the letter or letters attached, the greater the asymmetry of the isomer. In the case of compounds with two carbon atoms, the most symmetrical isomer does not have an appended letter; so is for example

R-134 1,1,2,2-tetrafluoroethane,

R-134a on the other hand 1,1,1,2-tetrafluoroethane.

For compounds with three carbon atoms (propane derivatives) two lower case letters are required to denote the isomer. The first letter then refers to the central carbon atom and is assigned in the order of decreasing mass of the substituents (H, F and Cl):

a	b	c	d	e	f
-CCl 2 -	-CClF-	-CF 2 -	-CHCl-	-CHF-	-CH 2 -

Here too, the second letter denotes the asymmetry of the isomer, ie it is assigned according to the increasing mass difference between the substituents on the terminal carbon atoms; the most symmetrical isomer is given the letter a (in contrast to the notation used for ethane derivatives, where the most symmetrical isomer is not given a letter).

In the special case of hydrofluoroolefins , two lower case letters are also added, but the first of the two here designates the substituent on the central carbon atom according to the rule: x = Cl, y = F and z = H. The second lower case letter describes the substitution on the terminal methylene carbon atom according to the table above.

Zeotropic mixtures of hydrocarbons are summarized under R-4xx, azeotropic mixtures of hydrocarbons under R-5xx (DIN 8960 Section 6.2). The last two digits indicate the qualitative composition; Attached capital letters are used here to indicate different mixing ratios.

Designation of inorganic refrigerants

The inorganic compounds are named according to the scheme (DIN 8960 Section 6.3.2)

R-7zz

The first digit, 7, denotes the group of inorganic compounds; the following two digits indicate the molar mass . The refrigerant R-717, NH ₃ , for example, has a molar mass of 17 g.

Attached letters are used to distinguish substances of similar molecular weight. For example, carbon dioxide is R-744; for the new refrigerant nitrous oxide (nitrogen oxide) the designation R-744A is under discussion.

Historical development

Diethyl ether (R-610) was initially used as the first “professional” refrigerant , followed by ammonia (R-717). Ammonia has been used in industrial refrigeration systems for over 130 years and is considered environmentally friendly, economical and energy efficient.

However, a disadvantage of these refrigerants is their physiological hazard (lung damage; diethyl ether also has an anesthetic effect). However, ammonia has a strong, characteristic odor and can be perceived in the air from a concentration of 3 mg / m³. The warning effect therefore occurs long before a harmful concentration (> 1,750 mg / m³). Diethyl ether is very easily flammable and forms an explosive mixture with air.

In contrast, the synthetic refrigerants based on halogenated hydrocarbons brought onto the market in the 1930s had the advantage that they were not directly toxic or flammable, which is why they are also referred to as safety refrigerants . By varying the chemical composition, a wide range of properties of these substances could be changed, so that refrigerants could be developed for almost all relevant temperature ranges. Common commercial names for these halogenated hydrocarbons are the terms Freon (DuPont) and Frigen (Hoechst), followed by the abbreviations for the respective chemical compositions. So are z. B. the designations Freon 502 and Frigen 502 for the same refrigerant, for which the abbreviation R-502 (R for Refrigerant) is used today.

The refrigerants carbon dioxide (R-744), ammonia (R-717) and hydrocarbons such as propane (R-290) also have a long tradition in refrigeration technology.

However, the danger of the hydrocarbons ( CFCs and halons ) halogenated mainly with chlorine and bromine , which was proven in the 1980s , is that they are essentially responsible for ozone depletion and intensify the greenhouse effect. Their use in new devices has therefore been banned on the basis of the CFC-Halon Prohibition Ordinance .

The chlorinated hydrocarbons (CFC, HCFC) were replaced in the 1990s by a large number of fluorinated hydrocarbons ( PFC , HFC ). These hydrocarbons, halogenated only with fluorine, have no ozone depletion potential , but in some cases have a considerable global warming potential . The frequently used HFC R-404A contributes around 3,900 times more to the greenhouse effect than carbon dioxide.

Due to their flammability, non-halogenated flammable hydrocarbons such as butane (R-600 / R-600a) or propane (R-290) have mainly been used in device classes with low filling requirements. In Europe, almost exclusively non-halogenated hydrocarbons are used in refrigerators and freezers with typical refrigerant fill quantities of 50 to 150 g. Device classes from the field of air conditioning, refrigeration and heat pump technology with a larger power range have a higher fill quantity requirement and are less often filled with these refrigerants due to the explosion protection measures required for this. In the last ten years, however, asymmetrical plate heat exchangers , microchannel heat exchangers and round tube / lamellar heat exchangers with a small nominal diameter have been introduced, which significantly reduce the fill quantity required even for systems with higher capacities.

The non-flammable and hardly environmentally hazardous carbon dioxide (R-744) is also being used increasingly . It does not contribute to ozone depletion and has a much lower greenhouse potential than conventional refrigerants such as fluorocarbons. The refrigerant CO _{2 is} already used as a working medium in vehicle air conditioning systems, heat pumps, beverage machines and in supermarket and transport refrigeration . Due to the high system pressures compared to the hydrocarbon compounds and the low critical temperature, extensive new developments of the refrigeration components and the system technology have been necessary, which have already been completed in many areas of application.

As for all refrigeration, air conditioning and heat pump applications, the sensible use of CO _{2 is based} on aspects such as high system efficiency. For example, heat pumps with R744 only make sense from an energetic point of view if the temperature difference used between the flow and return is at least 50 K. However, this high temperature spread is only rarely applicable, since hot water preparation with heat pumps in Germany is usually operated with storage tanks in order to be able to use an economically more sensible heat pump heating system with the lowest possible heating output.

Carbon dioxide has a long tradition in refrigeration technology. It was used more than a hundred years ago before it was largely supplanted by synthetic refrigerants. Thanks to its environmental compatibility and the much lower refrigerant price, it is being used more and more again today. As a refrigerant, carbon dioxide was first suggested by Alexander Twinning in his British patent of 1850. The first CO ₂ compression refrigeration machine in Europe was designed by Carl von Linde in 1881 , manufactured by MAN and commissioned by Friedrich Krupp AG in Essen in 1882 .

After the ban on CFCs and HCFCs, substances used as replacement refrigerants such as PFCs and HFCs have come under fire. Because of their climate-damaging effect, they are exposed to a discussion of bans. In 1997, for example, PFCs and HFCs were included as greenhouse gases in the Kyoto Protocol . In 2006, the EU passed the F-Gas Regulation , which specifies the use of PFCs and HFCs and aims to reduce their emissions. The climate-neutral refrigerants are not affected by the regulations.

In March 2018, a split device from Midea was awarded the Blue Angel as the first split air conditioning device , as it works with the R-290 in a very environmentally friendly and at the same time energy-efficient and quiet.

properties

Refrigerants should ideally have the following properties:

• large specific enthalpy of vaporization
• high volumetric cooling capacity
• high thermal conductivity
• Boiling point below the target temperature
• high critical temperature
• no temperature glide
• low viscosity
• non-flammable or explosive
• no ozone depletion potential
• no greenhouse effect
• not poisonous
• noticeable through odor when released
• not corrosive
• Compatible with the lubricant (mostly about solubility)
• high purity both in single-substance and in multi-substance refrigerants

Security groups, L groups, installation areas

The refrigerants are classified according to flammability and toxicity (EN 378-1 appendix E) in the safety groups A1, A2, A3, B1, B2, B3. The letters stand for

A = lower toxicity

B = greater toxicity

the numbers for

1 = no flame spread

2 = lower flammability

3 = greater flammability.

For easier handling, the security groups A1, B1, A2 ... etc. are summarized in the so-called L groups L1, L2, L3 (EN 378-1 section 5.4.2):

L1 includes A1

L2 includes B1, A2, B2

L3 includes A3, B3

In addition, refrigeration systems can be divided into three installation areas A, B, C depending on the type of installation (EN 378-1 Appendix C):

A = All refrigerant-carrying parts in the occupied area

B = high pressure side of the refrigeration system in the machine room or outdoors

C = All refrigerant-carrying parts in the machine room or outdoors

Depending on the L group and the installation area, requirements apply to the permissible refrigerant fill quantities (EN 378-1 appendix C).

Commonly used refrigerants

A general distinction is made between natural and synthetic refrigerants. Natural refrigerants are substances that occur in nature, such as B. hydrocarbons, carbon dioxide, ammonia, water and air. Synthetic refrigerants are created artificially. These substances include chlorofluorocarbons (CFCs), partially halogenated chlorofluorocarbons (H-CFCs), as well as fluorocarbons and partially halogenated fluorocarbons (HFCs and HFCs)

Natural refrigerants

Ammonia (R-717)

Ammonia is a classic, climate-neutral refrigerant that is mainly used in large systems such as deep-freeze warehouses, slaughterhouses, breweries, central refrigeration in the chemical industry and in ice rinks. Compact cold water cooling systems are also offered, which have a relatively small amount of refrigerant in order to reduce the risk potential. However, compact ammonia refrigeration systems have only been able to replace application areas for hydrocarbon refrigerants to a limited extent.

Molecular formula	NH 3
Specific enthalpy of vaporization (−10 ° C)	approx. 1,300 kJ / kg
Volumetric cooling capacity (−10 ° C)	approx. 3,100 kJ / m³
Boiling pressure (−10 ° C)	2.91 bar
Boiling pressure (+20 ° C)	8.57 bar
Boiling temperature (1 bar)	−33 ° C
Critical point	+132.36 ° C / 113.61 bar

Ammonia has a very large specific enthalpy of vaporization and thus a high volumetric cooling capacity, which leads to a relatively high degree of compactness in systems. It also offers the advantages of extremely low flammability and does not contribute to the greenhouse effect or ozone depletion ( half-life in the atmosphere approx. 14 days). One disadvantage is its toxicity; Damage is caused mainly by corrosion of the lungs and the eyes , because ammonia is a basic reaction solution with water: . However, the pungent odor is already perceptible in very low concentrations (5 ppm), far below the maximum workplace concentration ( MAK value, 50 ppm - new designation TRGS 900 AGW (Technical Rules Hazardous Substance Workplace Limit Value) new values ​​20 (40) ppm 20 ppm within 8 hours of working time or within 8 hours of working time 4 times 15 minutes with 40 ppm). Due to this excellent warning effect, ammonia is assigned to safety group B2 (greater toxicity, lower flammability according to EN 378-1: 2008-06 appendix table E.1) and thus to L group L2b, despite its physiological hazard. Ammonia systems are usually designed in the nominal pressure class PN 25 (EN 378-2 section 5.1). The installation costs for ammonia refrigeration systems is greater because, in contrast to systems with hydrocarbons no -ferrous metals (such as copper pipes , brass - fittings ) can be used. ${\displaystyle {\ce {NH3 + H2O -> NH4+ + OH-}}}$

Carbon dioxide (R-744)

Molecular formula	CO 2
Specific enthalpy of vaporization (−10 ° C)	approx. 260 kJ / kg
Volumetric cooling capacity (−10 ° C)	approx. 18400 kJ / m³
Boiling pressure (−10 ° C)	26.49 bar
Boiling pressure (+20 ° C)	57.29 bar
Boiling temperature (1 bar)	not liquid below 5.2 bar
Critical point	+30.98 ° C / 73.77 bar

Similar to ammonia, carbon dioxide has a very large volumetric cooling capacity, which analogously leads to more compact and less material required cooling circuits. Carbon dioxide also has the advantage of being non-flammable and does not contribute to ozone depletion. Its greenhouse effect is negligible due to the comparatively marginal amounts (which are not even temporarily released into the atmosphere due to its use as a refrigerant ). Compared to ammonia, carbon dioxide is less toxic and odorless; however, it is heavier than air and can be fatal in concentrations of around 8% by obstructing breathing.

Carbon dioxide belongs to safety group A1 (lower toxicity, no flame spread) and thus to L group L1. The relatively high operating pressures are a disadvantage. A distinction is usually made between subcritical (subcritical) CO ₂ refrigeration systems, supercritical (supercritical) or transcritical (both subcritical and supercritical states occur) systems. Subcritical carbon dioxide systems are therefore usually designed with a nominal pressure rating of PN 40 or PN 64 (EN 378-2 Section 5.1). When the system is switched off and heated to the ambient temperature, however, much higher pressures occur, so that the refrigerant either has to be transferred to a high-pressure container or an emergency cooling system has to be installed.

Components for these systems are now available and carbon dioxide is increasingly used in commercial systems. It is sometimes used in two-stage refrigeration systems for the primary circuit (lowest evaporation temperature), whereby ammonia is used as the refrigerant for the secondary circuit (higher evaporation temperature). A major advantage of carbon dioxide is that, unlike ammonia, leaks in the direct evaporators do not contaminate the products to be cooled. This is e.g. B. a decisive advantage in the cooling of food and pharmaceutical products. Two-stage refrigeration systems, in which both pressure stages are operated with the refrigerant carbon dioxide with supercritical liquefaction, are now also used on an industrial scale. The attempts to use carbon dioxide in car air conditioning systems have almost been given up because of the relatively high cost and the shift of the vda away from R-744 to R-1234yf. Nowadays, mobile air conditioning systems based on R-744 are only found in a few high-priced models. In most cases, however, the introduction has been dispensed with on the grounds of wanting to create global standardization. Another reason to forego the changeover was certainly the economic efficiency. Completely new developments for cooling circuits in mobile air conditioning systems would have been necessary, as the pressure level of R-744 meant that it was not possible to fall back on existing assemblies of previous air conditioning systems based on R-134a. This behavior can ultimately also be found in car manufacturers. The exemption from the EU Commission to bring mobile air conditioning systems with refrigerants with a higher global warming potential onto the market is in danger of expiring - from a purely legal point of view, according to the MAC Directive 2006/40 / EC, a switch to refrigerants in mobile air conditioning systems with a GWP value of below 150 was necessary, which, however, was not done by any of the European manufacturers, as the refrigerant was not yet available and therefore it was not possible to switch from R-134a to R-1234yf for a long time. With a lot of media attention, the introduction of this refrigerant was questioned with reference to the flammability of this refrigerant. Ultimately, however, as described above, most of the models with air conditioning systems based on R-1234yf were also brought onto the market for this manufacturer .

water

Due to its freezing point, water (R-718) can only be used as a refrigerant above 0 ° C. It only has a relatively low volumetric cooling capacity, which leads to large-volume systems. However, it is used in special cases. The applicability below 0 ° C is the subject of current research projects. Because of its high specific heat capacity, water is always well suited as a coolant.

Hydrocarbons

Molecular formula	C 3 H 8
Specific enthalpy of vaporization (−10 ° C)	approx. 388 kJ / kg
Volumetric cooling capacity (−10 ° C)	approx. 2960 kJ / m³
Boiling pressure (−10 ° C)	3.45 bar
Boiling pressure (+20 ° C)	8.36 bar
Boiling temperature (1 bar)	−42.4 ° C

Properties using the example of propane (R-290); the properties of other hydrocarbons can vary significantly depending on their chemical composition.

Hydrocarbons typically have specific enthalpies of vaporization on the order of 200 kJ / kg. Typical refrigerants are ethane (R-170), propane (R-290), butane (R-600), isobutane (R-600a) and pentane (R-601). The listed hydrocarbons have a very low greenhouse gas and no ozone depletion potential. Typical hydrocarbons used as refrigerants in refrigeration technology are non-toxic according to DIN EN 378 and are therefore classified with A3, taking into account flammability. The volumetric cooling capacity is lower than with ammonia or CO ₂ or also R-32 and R-410A. However, due to the low viscosity, systems can still get by with very low filling quantities. The low pressure ratio, which is set depending on the driving temperature gradient and against which the compressor only has to apply a relatively small volume change work, usually has a very advantageous effect.

The hydrocarbons relevant on the market mostly belong to the L group L3. Since the mid-1990s, hydrocarbons such as isobutane and pentane have dominated the refrigerants used in refrigerators and freezers. However, due to the performance range and the filling quantity, this only accounts for a fraction of the refrigerants used in Germany. Systems in commercial refrigeration and as heat pumps based on propane as a refrigerant are also increasingly found.

Synthetic refrigerants

Molecular formula	C 2 H 2 F 4
Specific enthalpy of vaporization (−10 ° C)	approx. 206 kJ / kg
Volumetric cooling capacity (−10 ° C)	approx. 2070 kJ / m³
Boiling pressure (−10 ° C)	2.01 bar
Boiling pressure (+20 ° C)	5.72 bar
Boiling temperature (1 bar)	−26.3 ° C

Properties using the example of 1,1,1,2-tetrafluoroethane (R-134a); the properties of other halogenated hydrocarbons can also differ significantly depending on their chemical composition.

Synthetic refrigerants are based exclusively on the halogenated hydrocarbons group . However, the variety is great, which leads to significantly different properties. These refrigerants belong to the L groups L1 or L2. Some halogenated hydrocarbons have an anesthetic effect and are sometimes used as anesthetics (cf. Chloroform CCl ₃ H). The odor is weak to strong and solvent-like.

The abbreviations commonly used in German-speaking countries for halogenated and non-halogenated hydrocarbons are (EN 378-1 Section 3.7.9):

abbreviation	designation	Halogenation	Items included
HCFC	Hydrogen-fluorine-chlorine-carbon-hydrogen	Partly halogenated	H , F , Cl , C
HFC	Hydrogen-fluorine-carbon-hydrogen	Partly halogenated	H, F, C
CFC	Fluorine-chlorine-carbon-hydrogen	Fully halogenated	F, Cl, C
HFC	Fluorine-carbon-hydrogen	Fully halogenated	F, C
KW	Carbon-hydrogen	Not halogenated	H, C

Influence on the ozone layer and the greenhouse effect

While ammonia, carbon dioxide and the non-halogenated hydrocarbons are largely environmentally friendly, the halogenated hydrocarbons have two disadvantages in this regard:

On the one hand, the chlorine and bromine radicals released from the chlorinated and brominated hydrocarbons at great heights under UV radiation destroy the ozone layer:

${\displaystyle {\ce {O3 + Cl -> O2 + ClO}}}$

${\displaystyle {\ce {O3 + ClO -> 2 O2 + Cl}}}$

so overall

${\displaystyle {\ce {2 O3 -> 3 O2}}}$

This means that chlorine is not consumed in this reaction, but can always convert new ozone molecules (O ₃ ) into normal oxygen molecules (O ₂ ). This effect is more pronounced, the lower the stability and the higher the chlorine content of the compound. The more the ozone layer is damaged, the more of the short-wave UV components are let through to the earth's surface. The contribution of a refrigerant to the depletion of the ozone layer by means of the ozone depletion potential (ODP) can be quantified; by definition for trichlorofluoromethane (R-11) this is equal to 1.0. Particularly high ozone depletion potentials of up to 10 have brominated hydrocarbons such. B. Bromotrifluoromethane (R-13B1); Except for chlorodifluoromethane (R-22), the ODP values ​​of the refrigerants still permitted are close to zero. Refrigerants from the HFC and HFC groups do not contribute to the depletion of the stratospheric ozone layer (ODP = 0).

On the other hand, halogenated hydrocarbons contribute to the greenhouse effect in a similar way to CO ₂ . Short-wave radiation is converted into long-wave infrared radiation when it hits the earth's surface, which is then reflected back to earth by molecules with a high degree of absorption in the infrared range (carbon dioxide, CFC, halon). While CO ₂ and hydrocarbons from non-fossil sources are harmless because they are part of the biological cycle, this does not apply to artificially produced and hardly biodegradable halogenated hydrocarbons. This effect is more pronounced the higher the stability of the connection. The contribution of a refrigerant to the greenhouse effect through the global warming potential (GWP) can be measured in numbers (according to DIN 8960 Tab. 2); by definition, this is 1.0 for CO ₂ . Similarly, the HGWP value ( Halocarbon Global Warming Potential ) was introduced specifically for halogenated hydrocarbons ; In contrast to the GWP value, the HGWP value for trichlorofluoromethane (R-11) is 1.0. Chlorotrifluoromethane (R-13) and fluoroform (R-23) achieve a particularly high global warming potential of greater than 12,000 ; the global warming potential of the refrigerants still in use today is between 1500 and 4000.

	Ozone Depletion Potential (ODP)	Global Warming Potential (GWP)
Ammonia (NH 3 )	0	0
Carbon dioxide (CO 2 )	0	1
Hydrocarbons (propane C 3 H 8 , butane C 4 H 10 )	0	3
Water (H 2 O)	0	0
Fluorine-chlorine hydrocarbons (CFC)	1	4,680-10,720
Partially halogenated fluorine-chlorine hydrocarbons (HCFC)	0.02-0.06	76-2270
Per-fluorohydrocarbons (PFCs)	0	5,820-12,010
Partially halogenated fluorocarbons (HFCs)	0	122 - 14,310

Because of the ozone-depleting effect, in 1987, with the participation of around 70 nations, a decision was made to phase out the production and use of CFCs (“ Montreal Protocol ”) and incorporated into national regulations, for example, for Germany by a resolution of the Federal Cabinet of May 30, 1990 (“Ordinance on the prohibition of certain halogenated hydrocarbons that deplete the ozone layer "," CFC-Halon Prohibition Ordinance "; Halon = halogenated hydrocarbon that contains bromine in addition to fluorine or chlorine). The CFCs were subsequently replaced by other halogenated hydrocarbons, in which the chlorine atoms have been partially replaced, as in HCFCs, or completely, as in HFCs, PFCs and HCs, by fluorine or hydrogen atoms. For the chemical properties of the individual compositions, the general rule is that the compound becomes flammable due to a high hydrogen content, toxic due to a high chlorine content and stable due to a high fluorine content.

In order to be able to continue to operate the old CFC plants under the same conditions as possible, the HCFC, HFC, PFC and HC used as replacement refrigerants should have the same physical properties as possible, which in some cases can only be achieved with mixtures. These mixtures are divided into zeotropic and azeotropic mixtures according to their boiling behavior (DIN 8960 Section 3.6): Zeotropic mixtures have a boiling range (= temperature glide , difference between the boiling and dew point temperatures at constant pressure) and separate when they boil; Liquid and vapor have different compositions. Azeotropic mixtures have a boiling point and do not separate when they boil, so liquid and vapor have the same composition

Abbreviation

Abbreviations for the organic refrigerants

R-xx hydrocarbons with 1 carbon atom

ASHRAE number	formula	Surname	group
R-10	CCl 4	Carbon tetrachloride	CKW
R-11	CFCl 3	Trichlorofluoromethane	CFC
R-12	CF 2 Cl 2	Dichlorodifluoromethane	CFC
R-12B1	CF 2 ClBr	Bromochlorodifluoromethane	CFC
R-12B2	CF 2 Br 2	Dibromodifluoromethane	CFC
R-13	CF 3 Cl	Chlorotrifluoromethane	CFC
R-13B1	CF 3 Br	Bromotrifluoromethane	CFC
R-13I1	CF 3 I.	Trifluoroiodomethane	CFC
R-14	CF 4	Tetrafluoromethane	HFC
R-20	CHCl 3	chloroform
R-21	CHFCl 2	Dichlorofluoromethane	HCFC
R-22	CHF 2 cl	Chlorodifluoromethane	HCFC
R-22B1	CHF 2 Br	Bromodifluoromethane	HCFC
R-23	CHF 3	Fluoroform	HFC
R-30	CH 2 Cl 2	Dichloromethane
R-31	CH 2 FCl	Chlorofluoromethane	HCFC
R-32	CH 2 F 2	Difluoromethane	HFC
R-40	CH 3 Cl	Chloromethane
R-41	CH 3 F	Fluoromethane
R-50	CH 4	methane	KW

R-1xx hydrocarbons with 2 carbon atoms

ASHRAE number	formula	Surname	group
R-110	C 2 Cl 6	Hexachloroethane
R-111	C 2 FCl 5	Pentachlorofluoroethane	CFC
R-112	C 2 F 2 Cl 4	1,1,2,2-tetrachloro-1,2-difluoroethane	CFC
R-112a	C 2 F 2 Cl 4	1,1,1,2-tetrachloro-2,2-difluoroethane	CFC
R-113	C 2 F 3 Cl 3	1,1,2-trichloro-1,2,2-trifluoroethane	CFC
R-113a	C 2 F 3 Cl 3	1,1,1-trichloro-2,2,2-trifluoroethane	CFC
R-114	C 2 F 4 Cl 2	1,2-dichloro-1,1,2,2-tetrafluoroethane	CFC
R-114a	C 2 F 4 Cl 2	1,1-dichloro-1,2,2,2-tetrafluoroethane	CFC
R-115	C 2 F 5 Cl	Chloropentafluoroethane	CFC
R-116	C 2 F 6	Hexafluoroethane	HFC
R-120	C 2 HCl 5	Pentachloroethane
R-122	C 2 HF 2 Cl 3	Trichlorodifluoroethane	HCFC
R-123	C 2 HF 3 Cl 2	2,2-dichloro-1,1,1-trifluoroethane	HCFC
R-123a	C 2 HF 3 Cl 2	1,2-dichloro-1,1,2-trifluoroethane	HCFC
R-123b	C 2 HF 3 Cl 2	1,1-dichloro-1,2,2-trifluoroethane	HCFC
R-124	C 2 HF 4 Cl	1-chloro-1,2,2,2-tetrafluoroethane	HCFC
R-124a	C 2 HF 4 Cl	Chlorine-1,1,2,2-tetrafluoroethane	HCFC
R-125	C 2 HF 5	Pentafluoroethane	HFC
R-131	C 2 H 2 FCl 3	Trichlorofluoroethane	HCFC
R-132	C 2 H 2 F 2 Cl 2	Dichlorodifluoroethane	HCFC
R-133a	C 2 H 2 F 3 Cl	1-chloro-2,2,2-trifluoroethane	HCFC
R-134	C 2 H 2 F 4	1,1,2,2-tetrafluoroethane	HFC
R-134a	C 2 H 2 F 4	1,1,1,2-tetrafluoroethane	HFC
R-141	C 2 H 3 FCl 2	1,2-dichloro-1-fluoroethane	HCFC
R-141b	C 2 H 3 FCl 2	1,1-dichloro-1-fluoroethane	HCFC
R-142	C 2 H 3 F 2 Cl	Chloro-1,2-difluoroethane	HCFC
R-142b	C 2 H 3 F 2 Cl	1-chloro-1,1-difluoroethane	HCFC
R-143	C 2 H 3 F 3	1,1,2-trifluoroethane	HFC
R-143a	C 2 H 3 F 3	1,1,1-trifluoroethane	HFC
R-150	C 2 H 4 Cl 2	1,2-dichloroethane
R-150a	C 2 H 4 Cl 2	1,1-dichloroethane
R-151	C 2 H 4 FCl	Chlorofluoroethane	HCFC
R-152a	C 2 H 4 F 2	1,1-difluoroethane	HFC
R-160	C 2 H 5 Cl	Chloroethane
R-170	C 2 H 6	Ethane	KW

R-11xx hydrocarbons with 2 carbon atoms and C double bond

ASHRAE number	formula	Surname	group
R-1112a	C 2 Cl 2 F 2	1,1-dichloro-2,2-difluoroethene
R-1113	C 2 ClF 3	1-chloro-1,2,2-trifluoroethene
R-1114	C 2 F 4	Tetrafluoroethylene
R-1120	C 2 HCl 3	Trichlorethylene
R-1130	C 2 H 2 Cl 2	1,2-dichloroethene
R-1132a	C 2 H 2 F 2	1,1-difluoroethene
R-1140	C 2 H 3 Cl	Chlorethene (formerly: vinyl chloride)	HCKW
R-1141	C 2 H 3 F	Fluoroethene (formerly: vinyl fluoride)	HFC
R-1150	C 2 H 4	Ethene (formerly: ethylene)	KW

R-2xx hydrocarbons with 3 carbon atoms

In the last column, the respective CAS number of the substance in question is also noted.

ASHRAE number	formula	Surname	CAS number
R-211	C 3 Cl 7 F	Heptachlorofluoropropane	422-78-6
R-212	C 3 Cl 6 F 2	Hexachlorodifluoropropane	76546-99-3
R-213	C 3 Cl 5 F 3	Pentachlorotrifluoropropane	2354-06-5
R-214	C 3 Cl 4 F 4	Tetrachlorotetrafluoropropane	2268-46-4
R-215	C 3 Cl 3 F 5	Trichloropentafluoropropane	4259-43-2
R-216	C 3 Cl 2 F 6	1,2-dichloro-1,1,2,3,3,3-hexafluoropropane	661-97-2
R-216 approx	C 3 Cl 2 F 6	1,3-dichloro-1,1,2,2,3,3-hexafluoropropane	662-01-1
R-217	C 3 ClF 7	1-chloro-1,1,2,2,3,3,3-heptafluoropropane	422-86-6
R-217ba	C 3 ClF 7	2-chloro-1,1,1,2,3,3,3-heptafluoropropane	76-18-6
R-218	C 3 F 8	Octafluoropropane	76-19-7
R-221	C 3 HFCl 6	Hexachlorofluoropropane	422-26-4
R-222	C 3 HF 2 Cl 5	Pentachlorodifluoropropane	134237-36-8
R-222c	C 3 HF 2 Cl 5	1,1,1,3,3-pentachloro-2,2-difluoropropane	422-49-1
R-223	C 3 HF 3 Cl 4	Tetrachlorotrifluoropropane	134237-37-9
R-223 approx	C 3 HF 3 Cl 4	1,1,3,3-tetrachloro-1,2,2-trifluoropropane	422-52-6
R-223cb	C 3 HF 3 Cl 4	1,1,1,3-tetrachloro-2,2,3-trifluoropropane	422-50-4
R-224	C 3 HF 4 Cl 3	Trichlorotetrafluoropropane	134237-38-0
R-224 approx	C 3 HF 4 Cl 3	1,3,3-trichloro-1,1,2,2-tetrafluoropropane	422-54-8
R-224cb	C 3 HF 4 Cl 3	1,1,3-trichloro-1,2,2,3-tetrafluoropropane	422-53-7
R-224cc	C 3 HF 4 Cl 3	1,1,1-trichloro-2,2,3,3-tetrafluoropropane	422-51-5
R-225	C 3 HF 5 Cl 2	Dichloropentafluoropropane	127564-92-5
R-225aa	C 3 HF 5 Cl 2	2,2-dichloro-1,1,1,3,3-pentafluoropropane	128903-21-9
R-225ba	C 3 HF 5 Cl 2	2,3-dichloro-1,1,1,2,3-pentafluoropropane	422-48-0
R-225bb	C 3 HF 5 Cl 2	1,2-dichloro-1,1,2,3,3-pentafluoropropane	422-44-6
R-225 approx	C 3 HF 5 Cl 2	3,3-dichloro-1,1,1,2,2-pentafluoropropane	422-56-0
R-225cb	C 3 HF 5 Cl 2	1,3-dichloro-1,1,2,2,3-pentafluoropropane	507-55-1
R-225cc	C 3 HF 5 Cl 2	1,1-dichloro-1,2,2,3,3-pentafluoropropane	13474-88-9
R-225da	C 3 HF 5 Cl 2	1,2-dichloro-1,1,3,3,3-pentafluoropropane	431-86-7
R-225ea	C 3 HF 5 Cl 2	1,3-dichloro-1,1,2,3,3-pentafluoropropane	136013-79-1
R-225eb	C 3 HF 5 Cl 2	1,1-dichloro-1,2,3,3,3-pentafluoropropane	111512-56-2
R-226	C 3 HF 6 Cl	Chlorhexafluoropropane	134308-72-8
R-226ba	C 3 HF 6 Cl	2-chloro-1,1,1,2,3,3-hexafluoropropane	51346-64-6
R-226 approx	C 3 HF 6 Cl	3-chloro-1,1,1,2,2,3-hexafluoropropane	422-57-1
R-226cb	C 3 HF 6 Cl	1-chloro-1,1,2,2,3,3-hexafluoropropane	422-55-9
R-226da	C 3 HF 6 Cl	2-chloro-1,1,1,3,3,3-hexafluoropropane	431-87-8
R-226ea	C 3 HF 6 Cl	1-chloro-1,1,2,3,3,3-hexafluoropropane	359-58-0
R-227ea	C 3 HF 7	1,1,1,2,3,3,3-heptafluoropropane	431-89-0
R-236fa	C 3 H 2 F 6	1,1,1,3,3,3-hexafluoropropane	690-39-1
R-245cb	C 3 H 3 F 5	1,1,1,2,2-pentafluoropropane	1814-88-6
R-245fa	C 3 H 3 F 5	1,1,1,3,3-pentafluoropropane	460-73-1
R-261	C 3 H 5 FCl 2	Dichlorofluoropropane	134237-45-9
R-261ba	C 3 H 5 FCl 2	1,2-dichloro-2-fluoropropane	420-97-3
R-262	C 3 H 5 F 2 Cl	Chlorodifluoropropane	134190-53-7
R-262 approx	C 3 H 5 F 2 Cl	1-chloro-2,2-difluoropropane	420-99-5
R-262fa	C 3 H 5 F 2 Cl	3-chloro-1,1-difluoropropane
R-262fb	C 3 H 5 F 2 Cl	1-chloro-1,3-difluoropropane
R-263	C 3 H 5 F 3	Trifluoropropane
R-271	C 3 H 6 FCl	Chlorofluoropropane	134190-54-8
R-271b	C 3 H 6 FCl	2-chloro-2-fluoropropane	420-44-0
R-271d	C 3 H 6 FCl	2-chloro-1-fluoropropane
R-271fb	C 3 H 6 FCl	1-chloro-1-fluoropropane
R-272	C 3 H 6 F 2	Difluoropropane
R-281	C 3 H 7 F	Fluoropropane
R-290	C 3 H 8	propane	74-98-6

R-12xx hydrocarbons with 3 carbon atoms and C double bond

ASHRAE number	formula	Surname	CAS number
R-1216	C 3 F 6	Hexafluoropropene	116-15-4
R.	(C 3 F 6 ) 3	Hexafluoropropene trimer	6792-31-0
R-1224yd (Z)	C 3 HClF 4	(Z) -1-chloro-2,3,3,3-tetrafluoropropene
R-1225ye	C 3 HF 5	1,2,3,3,3-pentafluoropropene	5528-43-8
R-1225zc	C 3 HF 5	1,1,3,3,3-pentafluoropropene	690-27-7
R-1233zd (E)	C 3 ClF 3 H 2	1-chloro-3,3,3-trifluoropropene	102687-65-0
R-1234ye (E)	C 3 H 2 F 4	1,1,2,3-tetrafluoro-2-propene	115781-19-6
R-1234ye (Z)	C 3 H 2 F 4	1,1,2,3-tetrafluoro-2-propene	730993-62-1
R-1234yf	C 3 H 2 F 4	2,3,3,3-tetrafluoropropene	754-12-1
R-1234ze (E)	C 3 H 2 F 4	(E) -1,3,3,3-tetrafluoropropene	29118-24-9
R-1243zf	C 3 H 3 F 3	3,3,3-trifluoropropene	677-21-4
R-1270	C 3 H 6	Propene (formerly: propylene)	115-07-1

R-3xx Fluorinated hydrocarbons with 4 or more carbon atoms

ASHRAE number	formula	Surname	group
R-C316	C 4 Cl 2 F 6	1,2-dichloro-1,2,3,3,4,4-hexafluorocyclobutane	CFC
R-C317	C 4 F 7 Cl	Chlorheptafluorocyclobutane	CFC
R-C318	C 4 F 8	Octafluorocyclobutane	HFC

R-13xx hydrocarbons with 4 carbon atoms and C double bond

ASHRAE number	formula	Surname	CAS number
R-1336mzz (E)	C 4 H 2 F 6	(E) -1,1,1,4,4,4-hexafluoro-2-butene	66711-86-2
R-1336mzz (Z)	C 4 H 2 F 6	(Z) -1,1,1,4,4,4-hexafluoro-2-butene	692-49-9

R-6xx Chlorine- and fluorine-free hydrocarbons with 4 or more carbon atoms

R no.	Molecular formula	Surname	Structural formula	Art	Siedep. in ° C	Pressure (0 ° C) in bar	Pressure (20 ° C) in bar
R-600	C 4 H 10	n - butane	CH 3 -CH 2 -CH 2 -CH 3	KW	−0.50 ° C		2.080
R-600a	C 4 H 10	Isobutane		KW	−11.7 ° C		3.019
R-601	C 5 H 12	n -pentane	CH 3 -CH 2 -CH 2 -CH 2 -CH 3	KW	36 ° C		0.562
R-601a	C 5 H 12	Isopentane		KW	28 ° C		0.761
R-601b	C 5 H 12	Neopentane		KW	9.5 ° C		1,500
R-610	C 4 H 10 O	Diethyl ether	CH 3 -CH 2 -O-CH 2 -CH 3		35		0.590
R-611	C 2 H 4 O 2	Methyl formate	CH 3 -O-CO-H		32		0.640
R-630	CH 5 N	Methylamine	CH 3 (NH 2 )		−6.3		2,900
R-631	C 2 H 7 N	Ethylamine	CH 3 -CH 2 (NH 2 )		16.6		1,100

Abbreviations for the inorganic refrigerants

“Xx” or the last two digits denote the molar mass.

R-7xx elements and inorganic compounds

ASHRAE number	formula	Surname	annotation
R-702	H 2	hydrogen
R-704	Hey	helium
R-717	NH 3	ammonia
R-718	H 2 O	water
R-720	No	neon
R-723	-	Ammonia / dimethyl ether	Mixture, azeotropic (60:40 m / m)
R-728	N 2	nitrogen
R-729	-	air	mixture
R-732	O 2	oxygen
R-740	Ar	argon
R-744	CO 2	carbon dioxide
R-744A	N 2 O	Nitrous oxide	Synonyms: laughing gas, nitrogen oxide (outdated)
R-764	SO 2	Sulfur dioxide
R-846	SF 6	Sulfur hexafluoride	(700 + molecular weight 146 = 846)

Abbreviations for the organic refrigerant mixtures

R-4xx Zeotropic mixtures of hydrocarbons

ASHRAE number	Mass fractions	composition
R-400	50% or 60% 50% or 40%	R-12 R-114
R-401A	53.0% 13.0% 34.0%	R-22 R-152a R-124
R-401B	61.0% 11.0% 28.0%	R-22 R-152a R-124
R-401C	33.0% 15.0% 52.0%	R-22 R-152a R-124
R-402A	60.0% 2.0% 38.0%	R-125 R-290 R-22
R-402B	38.0% 2.0% 60.0%	R-125 R-290 R-22
R-403A	75.0% 20.0% 5.0%	R-22 R-218 R-290
R-403B	56.0% 39.0% 5.0%	R-22 R-218 R-290
R-404A	44.0% 4.0% 52.0%	R-125 R-134a R-143a
R-405A	45.0% 7.0% 5.5% 42.5%	R-22 R-152a R-142b R-C318
R-406A	55.0% 41.0% 4.0%	R-22 R-142b R-600a
R-407A	20.0% 40.0% 40.0%	R-32 R-125 R-134a
R-407B	10.0% 70.0% 20.0%	R-32 R-125 R-134a
R-407C	23.0% 25.0% 52.0%	R-32 R-125 R-134a
R-407D	15.0% 15.0% 70.0%	R-32 R-125 R-134a
R-407E	25.0% 15.0% 60.0%	R-32 R-125 R-134a
R-407F	30.0% 30.0% 40.0%	R-32 R-125 R-134a
R-407G	2.5% 2.5% 95.0%	R-32 R-125 R-134a
R-407H	32.5% 15.0% 52.5%	R-32 R-125 R-134a
R-407I	19.5% 8.5% 72.0%	R-32 R-125 R-134a
R-408A	7.0% 46.0% 47.0%	R-125 R-143a R-22
R-409A	60.0% 25.0% 15.0%	R-22 R-124 R-142b
R-409B	65.0% 25.0% 10.0%	R-22 R-124 R-142b
R-410A	50.0% 50.0%	R-32 R-125
R-410B	45.0% 55.0%	R-32 R-125
R-411A	1.5% 87.5% 11.0%	R-1270 R-22 R-152a
R-411B	3.0% 94.0% 3.0%	R-1270 R-22 R-152a
R-412A	70.0% 5.0% 25.0%	R-22 R-218 R-142b
R-413A	88.0% 9.0% 3.0%	R-134a R-218 R-600a
R-414A	51.0% 28.5% 4.0% 16.5%	R-22 R-124 R-600a R-142b
R-414B	50.0% 39.0% 9.5% 1.5%	R-22 R-124 R-600a R-142b
R-415A	82.0% 18.0%	R-22 R-152a
R-415B	25.0% 75.0%	R-22 R-152a
R-416A	59.0% 39.5% 1.5%	R-134a R-124 R-600a
R-417A	46.6% 50.0% 3.4%	R-125 R-134a R-600
R-417B	79.0% 18.3% 2.7%	R-125 R-134a R-600
R-417C	19.5% 78.8% 1.7%	R-125 R-134a R-600
R-418A	1.5% 96.0% 2.5%	R-290 R-22 R-152a
R-420A	88.0% 12.0%	R-134a R-142a
R-421A	58.0% 42.0%	R-125 R-134a
R-421B	85.0% 15.0%	R-125 R-134a
R-422A	85.1% 11.5% 3.4%	R-125 R-134a R-600a
R-422B	55% 42% 3%	R-125 R-134a R-600a
R-422C	82% 15% 3%	R-125 R-134a R-600a
R-422D	65.1% 31.5% 3.4%	R-125 R-134a R-600a
R-422E	58.0% 39.3% 2.7%	R-125 R-134a R-600a
R-423A	52.5% 47.5%	R-134a R-227ea
R-424A	50.5% 47.0% 0.9% 1.0% 0.6%	R-125 R-134a R-600a R-600 R-601a
R-425A	18.5% 69.5% 12.0%	R-32 R-134a R-227ea
R-426A	5.1% 93.0% 1.3% 0.6%	R-125 R-134a R-600 R-601a
R-427A	50% 25% 15% 10%	R-134a R-125 R-32 R-143a
R-428A	77.5% 20.0% 0.6% 1.9%	R-125 R-143a R-290 R-600a
R-429A	60.0% 10.0% 30.0%	R-E170 R-152a R-600a
R-430A	76.0% 24.0%	R-152a R-600a
R-431A	71.0% 29.0%	R-290 R-152a
R-432A	80.0% 20.0%	R-1270 R-E170
R-433A	30%, 0 70.0%	R-1270 R-290
R-433B	5.0% 95.0%	R-1270 R-290
R-433C	25.0% 75.0%	R-1270 R-290
R-434A	63.2% 18.0% 16.0% 2.8%	R-125 R-143a R-134a R-600a
R-435A	80.0% 20.0%	R-E170 R-152a
R-436A	56.0% 44.0%	R-290 R-600a
R-436B	52.0% 48.0%	R-290 R-600a
R-436C	95.0% 5.0%	R-290 R-600a
R-437A	78.5% 19.5% 1.4% 0.6%	R-134a R-124 R-600a R-601
R-438A	8.5% 45.0% 44.2% 1.7% 0.6%	R-32 R-125 R-134a R-600 R-601a
R-439A	50.0% 47.0% 3.0%	R-32 R-125 R-600a
R-440A	0.6% 1.6% 97.8%	R-290 R-134a R-152a
R-441A	3.1% 54.8% 6.0% 36.1%	R-170 R-290 R-600a R-600
R-442A	31.0% 31.0% 30.0% 3.0% 5.0%	R-32 R-125 R-134a R-152a R-227ea
R-443A	55.0% 40.0% 5.0%	R-1270 R-290 R-600a
R-444A	12.0% 5.0% 83.0%	R-32 R-152a R-1234ze (E)
R-444B	41.5% 10.0% 48.5%	R-32 R-152a R-1234ze (E)
R-445A	6.0% 9.0% 85.0%	R-744 R-134a R-1234ze (E)
R-446A	68.0% 29.0% 3.0%	R-32 R-1234ze (E) R-600
R-447A	68.0% 3.5% 28.5%	R-32 R-125 R-1234ze (E)
R-447B	68.0% 8.0% 24.0%	R-32 R-125 R-1234ze (E)
R-448A	26.0% 26.0% 20.0% 21.0% 7.0%	R-32 R-125 R-1234yf R-134a R-1234ze (E)
R-449A	26.1% 24.9% 25.1% 23.9%	R-134a R-1234yf R-125 R-32
R-450A	42% 58%	R-134a R-1234ze
R-451A	89.8% 10.2%	R-1234yf R-134a
R-451B	88.8% 11.2%	R-1234yf R-134a
R-452A	11.% 59.0% 30.0%	R-32 R-125 R-1234yf
R-452B	67.0% 7.0% 26.0%	R-32 R-125 R-1234yf
R-452C	12.5% 61.0% 26.5%	R-32 R-125 R-1234yf
R-453A	20.0% 20.0% 53.8% 5.0% 0.6% 0.6%	R-32 R-125 R-134a R-227ea R-600 R-601a
R-454A	35.0% 65.0%	R-32 R-1234yf
R-454B	68.9% 31.1%	R-32 R-1234yf
R-454C	21.5% 78.5%	R-32 R-1234yf
R-455A	3.0% 21.5% 75.5%	R-744 R-32 R-1234yf
R-456A	6.0% 45.0% 49.0%	R-32 R-134a R-1234ze (E)
R-457A	18.0% 70.0% 12.0%	R-32 R-1234yf R-152a
R-458A	20.5% 4.0% 61.4% 13.5% 0.6%	R-32 R-125 R-134a R-227ea R-236fa
R-459A	68.0% 26.0% 6.0%	R-32 R-1234yf R-1234ze (E)
R-459B	21.0% 69.0% 10.0%	R-32 R-1234yf R-1234ze (E)
R-460A	12.0% 52.0% 14.0% 22.0%	R-32 R-125 R-134a R-1234ze (E)
R-460B	28.0% 25.0% 20.0% 27.0%	R-32 R-125 R-134a R-1234ze (E)
R-460C	2.5% 2.5% 46.0% 49.0%	R-32 R-125 R-134a R-1234ze (E)
R-461A	55.0% 5.0% 32.0% 5.0% 3.0%	R-125 R-143a R-134a R-227ea R-600a
R-462A	9.0% 42.0% 2.0% 44.0% 3.0%	R-32 R-125 R-143a R-134a R-600
R-463A	6.0% 36.0% 30.0% 14.0% 14.0%	R-744 R-32 R-125 R-1234yf R-134a
R-464A	27.0% 27.0% 40.0% 6.0%	R-32 R-125 R-1234ze (E) R-227ea
R-465A	21.0% 7.9% 71.1%	R-32 R-290 R-1234yf
R-466A	49.0% 11.5% 39.5	R-32 R-125 R-13I1
R-467A	22.0% 5.0% 72.4% 0.6	R-32 R-125 R-134a R-600a
R-468A	3.5% 21.5% 75.0%	R-1132a R-32 R-1234yf
R-469A	35% 32.5% 32.5%	R-744 R-32 R-125

R-5xx Azeotropic mixtures of hydrocarbons

ASHRAE number	Mass fractions	composition
R-500	73.8% 26.2%	R-12 R-152a
R-501	25.0% 75.0%	R-12 R-22
R-502	48.8% 51.2%	R-22 R-115
R-503	59.9% 40.1%	R-13 R-23
R-504	48.2% 51.8%	R-32 R-115
R-505	78.0% 22.0%	R-12 R-31
R-506	55.1% 44.9%	R-31 R-114
R-507 [A]	50.0% 50.0%	R-125 R-143a
R-508 [A]	39.0% 61.0%	R-23 R-116
R-508B	46.0% 54.0%	R-23 R-116
R-509 [A]	44.0% 56.0%	R-22 R-218
R-510A	88.0% 12.0%	R-E170 R-600a
R-511A	95.0% 5.0%	R-290 R-E170
R-512A	5.0% 95.0%	R-134a R-152a
R-513A	44.0% 56.0%	R-134a R-1234yf
R-513B	58.5% 41.5%	R-1234yf R-134a
R-514A	74.7% 25.3%	R-1336mzz (Z) R-1130 (E)
R-515A	88.0% 12.0%	R-1234ze (E) R-227ea
R-515B	91.1% 8.9%	R-1234ze (E) R-227ea
R-516A	77.5% 8.5% 14.0%	R-1234yf R-134a R-152a

Line identification

The lines in a refrigeration system are generally identified by means of colored signs that are pointed on one side (DIN 2405). The tip indicates the direction of flow, the basic color the type of medium.

In the case of flammable refrigerants, the tip is red.

Refrigerants have one or more horizontal stripes behind the tip.

The horizontal stripe color indicates the condition of the refrigerant.

The number of horizontal stripes stands for the number of the respective stage of the refrigeration system. The starting point is the lowest temperature level: primary circuit = 1st level, secondary circuit = 2nd level, etc.

Assignment of basic colors and horizontal stripe colors to the type and condition of the medium:

Type of medium	Base color	Condition of the medium	Horizontal stripe color
Brine	violet RAL 4001	liquid
Liquid refrigerated goods	brown RAL 8001	liquid
air	blue RAL 5009	gaseous
vacuum	gray RAL 7002	(Vacuum)
water	green RAL 6010	liquid
Steam	red RAL 3003	gaseous
Refrigerant	yellow RAL 1012	cold, gaseous	blue RAL 5009
Refrigerant	yellow RAL 1012	hot, gaseous	red RAL 3003
Refrigerant	yellow RAL 1012	liquid	green RAL 6010

literature

• German Institute for Standardization (publisher): DIN 8960 - refrigerants - requirements and abbreviations . Berlin November 1st, 1998.
• Peter Stephan, Stephan Kabelac, Matthias Kind, Dieter Mewes, Karlheinz Schaber, Thomas Wetzel (eds.): VDI-Wärmeatlas . 12th edition. Springer-Verlag GmbH Germany, Berlin 2019, ISBN 978-3-662-52988-1 , Part D Thermophysical material properties.

See also

• thermodynamics
• Heat pump
• fridge
• List of refrigerants with details of many properties (English)
• Liquid cooling
• Montreal Protocol
• Kyoto protocol
• Research Council for Refrigeration Technology
• American Society of Heating, Refrigerating and Air-Conditioning Engineers

Web links

• The refrigerant report , 19th edition , overview of many refrigerants (PDF file; 2.3 MB)
• Which refrigerant for air conditioning? (PDF file; 1.2 MB)
• Concept of climate-friendly refrigeration technology ( Memento from June 1, 2010 in the Internet Archive ) Presentation slides Dessau - September 2008
• What does refrigeration have to do with climate protection? Presentation slides
• Natural refrigerants in "Greenfreeze" protect the ozone layer and the climate
• Natural refrigerants in the food industry
• Energy-efficient refrigeration technology
• Fact sheets on various refrigerants
• ASHRAE refrigerant designations

Individual evidence

1. ↑ Spectrum of Science. (PDF; 416 kB) June 2005, archived from the original on January 26, 2009 ; Retrieved October 11, 2009 . 
2. ↑ JM Hamilton Jr .: The organic fluorochemicals industry . In: Tatlow, John C. and Sharpe, Alan G. and Stacey, M. (Eds.): Advances in Fluorine Chemistry . tape 3 . Butterworth, London 1963, p. 117-181 .
3. ↑ DuPont: German translation of the article "Freon History - Seventy Years of Safety - Fluorocarbon Refrigerants - The History of an Era: 1929 to 1999" . In: ASHRAE Journal . ( vhkk.org [PDF]).
4. ↑ H. Gold White: The Manhattan Project . In: Journal of Fluorine Chemistry . tape 33 , no. 1-4 . Elsevier, 1986, p. 109-132 .
5. ↑ ^{a b} @misc {wiki: ###, title = “Celebrating 100 years of ASHRAE Standard 34”, author = “Reindl, Douglas T. et al.”, Journal = “ASHRAE Journal”, volume = “56”, number = “11”, pages = “36-43”, year = “2014”, publisher = “American Society of Heating, Refrigerating, and Air-Conditioning Engineers”}
6. ↑ https://www.iso.org/standard/5168.html
7. ↑ https://www.beuth.de/de/norm/din-8960/532079
8. ↑ (H) (C) FC and HFO Nomenclature - basic principles. European Fluorocarbons Technical Committee (EFCTC), January 2016, accessed June 26, 2019 . 
9. ↑ eurammon information publication No. 2. (PDF; 62 kB) Accessed on September 12, 2009 . 
10. ↑ eurammon information brochure No. 1. (PDF; 54 kB) Retrieved on September 12, 2009 . 
11. ^ SF Pearson: Refrigerants - Past, Present and Future . In: International Institute of Refrigeration (Ed.): Proceedings of the International Congress of Refrigeration . Paris 2003, p. 11 .
12. ↑ DuPont safety data sheet R-404A. (PDF; 138 kB) Archived from the original on August 17, 2013 ; Retrieved September 21, 2012 . 
13. ↑ blau-engel.de: press article ; exact device name ; accessed on August 8, 2018
14. ↑ https://www.zeit.de/auto/2011-11/auto-kaeltemittel-r1234yf/seite-2
15. ↑ Press release of the vda from May 28, 2009
16. ↑ Daimler boycotts agreement on R1234yf in Spiegel from September 25, 2012.
17. ↑ https://www.motor-talk.de/news/ab-2017-verwendet-mercedes-r1234yf-t5472874.html
18. ↑ https://www.eta.tu-berlin.de/menue/energie_forschung/projekte/subsie/