Energetic and environmental performance evaluation of a R744 multi-ejector enhanced parallel compression system in high ambient temperature locations

Hydrofluorocarbons (HFCs) are widely used today in supermarket refrigeration and air conditioning applications, despite their environmentally deleterious nature. However, the EU F-Gas Regulation 517/2014 ambitiously aims at lessening the HFC consumption by 79% by 2030. A further drop in the intake and production of these man-made refrigerants on global perspectives is offered by the recent adoption of the Kigali Amendment to the Montreal Protocol. Efficient HFC-free technologies for supermarket heating, cooling and refrigeration, such as fully integrated R744 multi-ejector enhanced parallel compression systems, are already available for the European food retail industry. In this theoretical work the energy consumption and the carbon footprint of a multi-ejector R744 refrigeration solutionintegrated with the air conditioning (AC) equipment are contrasted with those of two separated HFC-based units. The investigation was based on an average-size supermarket located in various Southern Europe cities. The results revealed that reductions in the electricity intake as well as in the Total Equivalent Warming Impact (TEWI) up to respectively 24.9% and 74.8% can be achieved by adapting the refrigerating system layout to the peculiarities of R744.