The three main types of refrigerants:
- Hydrocarbons, R-290 = C3H8 (Propane)
- Inorganic fluids, R-717 = NH3 (Ammonia)
Ionic liquids vapour pressure is less than hydrocarbon types and as suitable as a refrigerant that increases the efficiency of absorption refrigeration processes.
Further Classification of Halocarbons:
- Fully halogenated chlorofluorocarbons, (CClF3)
- Hydrochlorofluorocarbons, (CHClF2)
- Hydrofluorocarbons, (CHF3)
The numerical coding system of refrigerants:
Refrigerants were represented as R-ABCD, it is developed based their molecular structure.
- A: number of double bonds in the structure
- B: number of C atoms – 1
- C: number of H atoms + 1
- D: number of F atoms
For dichlorodifluoromethane, the code used is R-12, which is understood as
- R stands for the refrigerant
- ClCl-C-FF we observe that as similar to Methane molecule, Carbon atom as single bonds with each molecule of chlorine and fluorine and have no double bonds so A=0.
- The value of B is zero because of single carbon atom (i.e 1-1=0).
- The value of C is plus one on H atom where we do not have so its value is 0+1=1.
- Finally, the value of D is 2 due to two fluorine atoms.
Therefore, the code given for dichlorodifluoromethane is R-0012, commonly called as R-12.