In Refrigeration and air conditioning various types of refrigerants or gases are used to produce cooling or heating effects. Any substance that absorbs heat through expansion or vaporisation may be called refrigerant.
Requirements of a refrigerant :-
1. It should be non-toxic, non-poisonous, non corrosive,non-inflammable and non-explosive.
2. It should have very low boiling point at low pressure.
3. It should be a stable gas.
4. Leaks should be easily detectable and locatable.
5. It should have well balanced enthalpy of evaporation per unit mass.
6. Difference between vaporising pressure and condensing pressure should be minimum.
7. The standard comparison of refrigerant used in HVAC and refrigeration industry is based on an evaporating temperature of -15 deg cel and condensing temperature of +30 deg cel.
Types of refrigerants :-
Safest refrigerants Commonly used
Refrigerant name Chemical name Boiling point deg.cel
R11 - Trichloromonofluoromethane CCL3F +23.71
R12- Dichlorodifluoromethane CCL2F2 -29.8
R21- Dichloromonofluoromethane CHCL2F -26.8
R22- Monochlorodifluoromethane CHCLF2 -40.8
R30/40 - Methylene chloride CH2CL2 -22.8
R113- Trichlorotrifluoroethane CCL2FCCLF2 +47.56
R114- Dichlorotetrafluoromethane C2CL2F4 +3.55
R134a- Tetrafluoroethane CH2F-CF3 -26.3
R500- Azeotropic mixture -33.51
R502- Azeotropic mixture -33.51
R744- Carbon Dioxide CO2 -78
R-11 is a synthatic chemical product with low pressure refrigerant, espacially made for refrigeration. This refrigerant it widely used with centrifugal compressor systems of 300 TR capacity and above. This refrigerant is also used for flushing purposes of refrigeration system copper piping network.
CFC and HCFC ( Contains hydrogen, chlorine, fluorine and carbon atoms)
It was discovered in 1965 by scientinsts that the refrigerants which CFC and HCFC are causing a huge demage to ozone layer which protects our atmosphere and humans from ultraviolet rays from sun and increasing global warming. So an agreement was made to eliminate CFC (R12) and replacing them with R134a which has zero ozone depletion potential. The HCFC (R22) was foud non-toxic, non-inflammable and non corrosive but it was observed that because of hydrogen atoms presence it demages the ozone layer. R134a must be used very carefully because it reacts with moisture or humid air and can demage compressor. A spacial lubrication oil (polyolester oil) must be used with R134a which are prone to hydrolysis with moisture resulting in formation of acids.
Toxic refrigerants
R-717- Ammonia NH3
R-1130- Dichloroethylene C2H2CL2
R-160- Ethyl Chloride C2H5CL
R-611- Methyl Formate C2H4O2
R-764- Sulphur Dioxide SO2
R-600- Butane C4H10
R-170- Ethane C2H6
R-290- Propane C3H3
Why to use a refrigerant ?
If air or any other substance is expanded in a vaccum, it looses its temperature but air can't be used as a refrigerant as its boiling temperature is very low -194.35 and its a mixture of various gases so its not a stable gas. Refrigerants are used in air conditioning and refrigeration as they meat the standard requirements evaporating temperature of -15 deg cel and condensing temperature +30 deg cel.
Requirements of a refrigerant :-
1. It should be non-toxic, non-poisonous, non corrosive,non-inflammable and non-explosive.
2. It should have very low boiling point at low pressure.
3. It should be a stable gas.
4. Leaks should be easily detectable and locatable.
5. It should have well balanced enthalpy of evaporation per unit mass.
6. Difference between vaporising pressure and condensing pressure should be minimum.
7. The standard comparison of refrigerant used in HVAC and refrigeration industry is based on an evaporating temperature of -15 deg cel and condensing temperature of +30 deg cel.
Types of refrigerants :-
Safest refrigerants Commonly used
Refrigerant name Chemical name Boiling point deg.cel
R11 - Trichloromonofluoromethane CCL3F +23.71
R12- Dichlorodifluoromethane CCL2F2 -29.8
R21- Dichloromonofluoromethane CHCL2F -26.8
R22- Monochlorodifluoromethane CHCLF2 -40.8
R30/40 - Methylene chloride CH2CL2 -22.8
R113- Trichlorotrifluoroethane CCL2FCCLF2 +47.56
R114- Dichlorotetrafluoromethane C2CL2F4 +3.55
R134a- Tetrafluoroethane CH2F-CF3 -26.3
R500- Azeotropic mixture -33.51
R502- Azeotropic mixture -33.51
R744- Carbon Dioxide CO2 -78
R-11 is a synthatic chemical product with low pressure refrigerant, espacially made for refrigeration. This refrigerant it widely used with centrifugal compressor systems of 300 TR capacity and above. This refrigerant is also used for flushing purposes of refrigeration system copper piping network.
CFC and HCFC ( Contains hydrogen, chlorine, fluorine and carbon atoms)
It was discovered in 1965 by scientinsts that the refrigerants which CFC and HCFC are causing a huge demage to ozone layer which protects our atmosphere and humans from ultraviolet rays from sun and increasing global warming. So an agreement was made to eliminate CFC (R12) and replacing them with R134a which has zero ozone depletion potential. The HCFC (R22) was foud non-toxic, non-inflammable and non corrosive but it was observed that because of hydrogen atoms presence it demages the ozone layer. R134a must be used very carefully because it reacts with moisture or humid air and can demage compressor. A spacial lubrication oil (polyolester oil) must be used with R134a which are prone to hydrolysis with moisture resulting in formation of acids.
Toxic refrigerants
R-717- Ammonia NH3
R-1130- Dichloroethylene C2H2CL2
R-160- Ethyl Chloride C2H5CL
R-611- Methyl Formate C2H4O2
R-764- Sulphur Dioxide SO2
R-600- Butane C4H10
R-170- Ethane C2H6
R-290- Propane C3H3
Why to use a refrigerant ?
If air or any other substance is expanded in a vaccum, it looses its temperature but air can't be used as a refrigerant as its boiling temperature is very low -194.35 and its a mixture of various gases so its not a stable gas. Refrigerants are used in air conditioning and refrigeration as they meat the standard requirements evaporating temperature of -15 deg cel and condensing temperature +30 deg cel.