Hybrid Supermarket System Using GWP Refrigerants

Global pressure has intensified to reduce the use of R404a with high global warming potential and relatively high leak rates in supermarket systems. In Europe, several design modifications such as cascade systems and new refrigerant choices are being investigated. One of the new leading options is to utilize a hybrid cascade system using CO2 in low temperature refrigeration circuit and R134a in medium temperature. R134a has higher efficiency than R404a and about one third the direct global warming potential (GWP). To make even greater gains in GWP reduction, a new lower GWP refrigerant has been developed that is retrofittable in the medium temp R134a circuit with minimal system changes. This refrigerant has less than half the GWP of R134a and is also non-flammable. This paper will show results of experimental calorimeter and supermarket system performance. A TEWI analysis will also be presented to demonstrate the significant reduction in environmental impact if XP10 is used in a hybrid cascade system with CO2.