Is R744 a totally new refrigerant?
Not exactly. CO2 was already used as a refrigerant in the mid-nineteenth century and its use steadily increased, reaching a peak in the 1920s. After that, the natural refrigerant was displaced by chlorofluorocarbons (CFCs) that operated at much lower pressures. Due to the impact on the environment of CFCs, and later HFCs, CO2 was re-evaluated as an alternative refrigerant in the late 1980s. A new way to contain the high pressure was discovered by Professor Gustav Lorentzen and his group of researchers from Norway, giving way to the application of transcritical R744 to different heating and cooling systems.
