The R744 (CO2) system is intended to mostly operate in the gas region, and it is expected to yield the highest efficiencies for applications with large temperature glides.
R744 as refrigerant
R744 (CO2) is a natural refrigerant with a relatively low critical temperature. It is widely used in refrigeration applications such as supermarkets and other commercial installations. Depending on the temperature, it is operated in subcritical or transcritial operation modes. R744 is environmentally sound, and it typically yields low cost of ownership due to good operating performances and limited investment costs.
In the current project, it is intended to design a R744 system operating as a Reversed Brayton cycle. In this cycle, the refrigerant is in the gas phase at all conditions. The compressors will be modified piston compressors from Bock, while Fuchs focuses on the development of a suitable lubricant.
The R744 system is expected to show the highest performances in applications with large temperature glides, e.g. spray dryers.