Crossing CO2 equator with the aid of multi-ejector concept: A comprehensive energy and environmental comparative study

The results of this theoretical study revealed that multi-ejector “CO2 only” systems can outperform R404A-, R290-, R1234ze(E)-, R134a-, R450A- and R513A-based solutions in an average-size supermarket located in various cities below the so-called “CO2 equator”. In fact, energy savings as well as reductions in environmental impact respectively up to 26.9% and 90.9% were estimated over conventional hydrofluorocarbon (HFC)-based solutions for the scenario including the AC demand. Also, the solution using multi-ejector block (in non-optimized operating conditions) enabled reducing the power input up to 50.3% over HFC-based units at outdoor temperatures from −10 °C to 5 °C. Finally, the study demonstrated that transcritical CO2 multi-ejector systems integrated with the AC unit allow potentially pushing the “CO2 equator” further South than Northern Africa.