Refrigerants with low environmental impact for refrigeration systems

Refrigerants with high global warming potential (GWP), such as R404A, have been used in a wide range of refrigeration applications, but were subject to regulations and mandatory bans in several countries in the last few years. This paper presents several options to significantly reduce the environmental impact in both existing and new commercial refrigeration applications, while improving the energy efficiency. As the leading option for retrofitting R404A in existing systems R448A is presented in a supermarket refrigeration system retrofit case study. This field evaluation showed energy savings with R448A of 9-20% depending on the ambient temperature while maintaining the operational requirements. Compressor discharge temperatures remained within manufacturer specifications and no mitigation measures were needed. For new refrigeration systems a concept design is introduced using hermetic self-contained units to provide refrigeration at low temperature levels with R1234yf and medium temperature levels with the nonflammable blend R515A. The environmental impact of this new concept is compared with other system architectures. The R515A /R1234yf system shows up to 27% lower total emissions and up to 30% higher energy efficiency than a transcritical R744 system.