A refrigerant is a substance that takes part in a heat exchange in a refrigeration unit. It absorbs heat through evaporation at low temperature and low pressure. As the refrigerant condenses at the higher temperature and higher pressure, heat is released. Refrigerants can be single-component or mixtures. These can be substances of natural origin ( ammonia, water, carbon dioxide), flammable gases and their mixtures (propane, butane), and synthetic agents – hydrocarbons, in which hydrogen atoms have been replaced by chlorine, fluorine, or bromine, producing non-flammable, low-boiling substances commonly referred to as freons (CFC). Refrigerants are usually designated by a numerical symbol preceded by the letter “R”, e.g. R12, R22, R134a. Because of their adverse effect on the environment (ozone depletion), the use of CFC refrigerants is restricted and some are banned – in newly manufactured or refilled equipment (e.g. R12, R22, R502).
3R12 – formerly the most popular refrigeration working fluid, widely used in household refrigerators, replaced by R134a.
R22, R502 – have been used in larger refrigeration equipment, are being replaced by newly developed blends such as R402A, R404A, R407, R507.
R134a – the most popular refrigerant, standard refrigerant in automotive air-conditioning systems
R1234yf – the latest refrigerant used in automotive air conditioning, intended to replace R134a.
Refrigerants are usually called with the brand name of their manufacturer e.g., Suva HP62, Suva MP52, Forane134a, Reclin 404A, etc. In addition to the refrigerants, there are lubricating oils used in the systems. Their effect on hose material and seals should always be considered. These oils include mineral oils (MO) and synthetic oils such as polyalphaolefins (PAO), alkylbenzenes (AB), and polyalkylene glycols (PAG).