Refrigerant Fluids: Classification, Properties and Standards

Cooling Fluids

Following the Montreal Protocol, an agreement was reached to suspend the use of chlorofluorocarbon (CFC) gases due to their high chlorine content, and to phase out the production of hydrochlorofluorocarbon (HCFC) gases by the year 2030.

CFC gases, given their high chemical stability, remain in the atmosphere for long periods, which adversely affects the ozone-oxygen equilibrium. HCFC gases have a very low ozone depletion potential (ODP) due to the presence of hydrogen atoms and lower chlorine content. This group includes R-22, which is used as a transition fluid from CFCs. In fact, R-22 and a series of pure products and ternary mixtures based on R-22 are used in the manufacture of alternatives to CFCs and to maintain existing equipment. This evolution of refrigerant fluids leads to hydrofluorocarbons (HFCs), which contain chlorine and hydrogen atoms, have no ODP, and possess a very low greenhouse effect.

Definitions

• COP: Coefficient of performance of a system. It is the relationship between the thermal energy released by the system and the absorbed energy of a conventional type.
• CHILLER: A term used in the field of refrigeration referring to cooling systems that primarily cool water, and to a lesser extent, other fluids.

Final Refrigerant Gases: HFC Gases

The charging of these mixtures should be performed in the liquid phase, unless the charge requires accurate dosing.

Coding of Refrigerants

Refrigerants are identified by their chemical formula rather than a trade name. A code is established for each refrigerant, denoted by a number preceded by the letter R (refrigerant). The number is determined as follows:

• Units: Number of fluorine atoms.
• Tens: Number of hydrogen atoms + 1.
• Hundreds: Number of carbon atoms - 1 (in the case of the methane series, as this figure is equal to zero, it is not mentioned in the nomenclature).

Chlorine atoms are not considered.

Azeotropic Mixtures

These are the result of mixing two substances of the same chemical nature with the condition that they do not react with one another, both at the time of the mixture and in the long term, so that the resulting product characteristics depend on the characteristics of its constituent elements. These are identified by a numbering system in the 500 series.

Inorganic Refrigerants

Included in the 700 series, the code number is set as follows: The units and tens are represented by the corresponding molecular weights, and the hundreds digit is always 7.