Refrigerant is also called refrigeration work substance, the development of refrigerant has gone through three stages, the first stage is from 1830 to 1930, mainly adopt NH3, HCS, CO2 air, etc. as refrigerant gas, some of them are toxic, some are flammable, some are very inefficient, this situation has continued until the occurs of new type refrigerants.
The second stage is from 1930 to 1990, mainly using refrigerant gas after updates, and then after 60 years of use.
Scientists have plenty of evidence that refrigerants are destroying the ozone layer, So environmental requirements emerged, In an effort to better protect our planet, new demands have to be made on refrigerant gas.
The third phase is from 1990 to the present, entering the period when HFCS refrigerant gas are mainly used.
But the GWP of HFCS refrigerants is mostly above 1000, so there is still need more research for refrigerant R&D.
Refrigerant Gas Working Principle
At present, almost all HVAC and refrigeration equipment in the world complete energy conversion through refrigerants, of course, the types of refrigerants are also very rich.
Refrigerants are substances that need to constantly change their form of existence in closed systems and realize cooling or heating by changing their own state, such as refrigeration units.
Refrigerant realizes working cycle inseparable from four basic accessories, that is an HVAC compressor, condenser, expansion valve, and evaporator.
According to the use requirements, the types of compressors are divided into rotary compressors, scroll compressors, piston compressors, screw compressors, etc.
No matter what type of refrigeration compressor, its role is to provide power to the HVAC&R system.
The main role of the evaporator unit and air-cooled condenser is to drop the entire circulation system temperature and blow the warm or cold air generated by fan coils or air outlets into the room to realize the circulation of refrigerant gas.
The types of condensers and evaporators include single air outlets, double air outlets, etc.
Nomenclature of Refrigerant Gas
After discussing the working method of refrigerants gas, We should understand the naming method of refrigerants so that we can better understand refrigerants.
We often see names such as R22, HCFC22, R290, HC29, and propane.
In fact, this is a unified refrigerant naming method that is followed internationally, including in China.
As with other products, the naming method is to make it easier for you to remember him, so refrigerants gas is numbered in a way that is linked to the chemical formula of the refrigerant.
Now explain the naming methods as follows:
Inorganic Compound Refrigerant Gas
Inorganic compound refrigerant is named by adding R700 to the relative molecular mass of the compound.
For example, NH3, H2O, and CO2 have molecular weights of 17, 18, and 44.
Thus, ammonia refrigerant is designated R717, water refrigerant is designated R718, and CO2 refrigerant is designated R744.
Freon Refrigerant Naming Rules
Freon refrigerant is a saturated hydrocarbon, and the naming method is more complex.
The chemical structure of saturated hydrocarbons is CmH2m+2. When the constituent elements of saturated hydrocarbons are converted to fluorine, the chemical structure of Freon is deduced, that is CmHnFxClyBrz.
Also, you can further deduce the nomenclature of Freon series refrigerants according to the formula n+x+ y+z = 2m+2.
For methane series refrigerants, because m = 1, so n+x+y+z = 4
For ethane series refrigerants, because m = 2, so n+x+y+z = 6
This is the naming method of Freon refrigerants.
Hydrocarbons Refrigerant Gas Naming Rules
The numbering rules for saturated hydrocarbon codes are the equivalent of those for Freon.
For example R50 for methane freon, R170 for ethane freon, R290 for propane freon.
In addition, if the elements are the same, but the constituents are different, the letter “a” is appended to the code, or a number is appended to the digit, such as R152a for Isodifluoroethane, R600a for isobutane, etc.
Cyclic Compounds Refrigerant Gas Naming Rules
Cyclic organic compounds are written with the letter “C” after R, and then according to the numbering rules of Freon.
For example, RC316 for Hexafluorocyclobutane, RC318 for octafluorocyclobutane, etc.
Unsaturated Hydrocarbons and Their halogenated Element Derivatives
This type of refrigerant is written with a “1” after R, and then according to the numbering rules of Freon.
For example R1150 for ethylene, R1270 for propylene, R1112a for Difluorodichloroethylene, etc.
Azeotropic Refrigerant Gas Naming Rules
Azeotropic refrigerants are made from a variety of mutually soluble single refrigerants, mixed in a strict ratio, so that azeotropic refrigerants have the same properties as single refrigerants.
Non-azeotropic Refrigerant Gas Naming Rules
Non-azeotropic refrigerants, like azeotropic refrigerants, are composed of different non-azeotropic refrigerants.
The naming method for non-azeotropic refrigerants is as follows: R followed by 400 for numbering.
For example: R400, R401, R402,…R411
The isomers are noted with lowercase letters, such as CHF2-CHF2 R134, CF3-CH2F R134a.
Montreal Agreed Nomenclature Refrigerant Gas Naming Rules
There is another method of naming refrigerants by the Montreal Protocol.
The main feature of this nomenclature is to express the category of the refrigerant according to its chemical composition.
It is also named to distinguish the degree of damage to the environment.
The nomenclature is as follows:
CFC refrigerant – chlorofluorocarbon, contains chlorine, does not contain hydrogen, public hazard, serious ozone layer destruction banned.
For example, R12 refrigerant, R11 refrigerant, etc.
HCFC refrigerant – hydrochlorofluorocarbons, chlorine, hydrogen, low public hazard substances are transitional substances.
For example, R22 refrigerant, R123 refrigerant, R141b refrigerant, R142b refrigerant, etc.
HFC refrigerants – hydrofluorocarbon, chlorine-free, non-polluting can be considered as alternatives.
For example, R134a refrigerant, R125 refrigerant, R32 refrigerant, R407C refrigerant, R410A refrigerant, R152 refrigerant, etc.
HC refrigerant – hydrocarbon, chlorine-free, fluorine-free, non-polluting, and can be considered as alternatives.
Classification of Refrigerant Gas
Almost all substances have a temperature, and of course, refrigerants are no exception.
We usually judge by the thermal energy at which the refrigerant evaporates under the standard ambient pressure.
Therefore refrigerants gas that evaporates at high temperatures is called high-temperature refrigerants gas, and those that evaporate at medium temperatures are called medium-temperature refrigerants gas, and those that evaporate at low temperatures are called low thermal energy refrigerants gas.
Refrigerant Gas Safety Classification
The safety of refrigerant gas mainly refers to the toxicity, combustibility, and explosiveness of refrigerants. The reliability class of refrigerant gas is expressed by A, B, C plus 1, 2, and 3, A stands for unsafe, C stands for unsafe.
The substances with safety level C (C1, C2, C3) cannot be used as refrigerants in general. Therefore, they are no longer presented in the picture.
Refrigerant Gas Safety classification list
Class A1: R11, R12, R13, R113, R114, R115, R116, R22, R23, R124, R125, R134a, R218, R410a, R410b, R401a, R401b, R402a, R402b, R403a, R403b,
R404a, R404b, R407a, R407b, R407c, R407d, R408a, R409a, R417a, R422d, R500, R501, R502, R507a, R718, R744 etc.
Class A2: R32, R142b, R143a, R152a.
Class A2L: R143a, R32, R1234yf, R1234ze.
Class A3: R290, R600, R600a, R601a, R1270, R510a/R511a.
Class B1: R123.
Class B2: R717.
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