New Refrigerant Developments For Very Low Temperature Refrigeration

Very Low Temperature cascade refrigeration is of increasing importance in ensuring a suitable cold chain for high value materials such as vaccines or premium seafood. Koura is developing new refrigerant options for system designers including R-473A. This refrigerant was designed as a non-flammable "near drop-in" alternative to R-23 or R-508B, with Global Warming Potential (GWP) below 2000. It contains 60% of R-744 but can operate well below that refrigerant's triple point. This paper presents information on R-473A in use including: performance testing, oil and materials compatibility studies and analysis of its effective temperature range. Options will be discussed for further reduction in GWP to enable non-flammable refrigerants or weakly flammable refrigerants capable of operating at -90 degrees C evaporator conditions.