Water as a Refrigerant in Centrifugal Compressor Cooling Systems for Industrial Applications

As a consequence of the F-gas regulation R404A is no longer a viable option for commercial refrigeration applications. Therefore, this paper focuses on natural refrigerants. There are a few alternatives like carbon dioxide, which has an efficiency loss with increasing environment temperatures. A promising option is the combination of a carbon dioxide process with a chiller using water as refrigerant. Two types of interconnection seem to make energy sense. On the one hand, the interconnection as a cascade, whereby the complete heat of condensation is given off to the water chiller, on the other hand the subcooling of transcritical CO2 after the gas cooler. Both types of interconnection result in optimized operating parameters for the CO2 process. These are examined more closely, and finally, the annual COP values are compared with the standard systems.