Innovative fully integrated transcritical R744 refrigeration systems for a HFC-free future of supermarkets in warm and hot climates

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The regulatory pressures on environmentally deleterious refrigerants have been growing more intense, prompting CO2 to draw ever-widening attraction as the sole working fluid (R744) in supermarket applications. Direct space heating and cooling is considered as one of the most appealing techniques to promote the diffusion of “CO2 only”systems in warm and hot climates. However, to the best of the author’s knowledge, the energy and environmental benefits related to its adoption have not been estimated yet. The results of this work revealed that “CO2 only”units implementing direct space heating and cooling offer an annual energy saving by up to 33.3% as well as a reduction in carbon footprint by up to 89.5% compared to the systems using hydrofluorocarbons (HFCs) in high ambient temperature countries. It could be concluded that direct space heating and cooling is a very good prospect to lead to a HFC-free future of supermarkets, even in hot climates.
Original languageEnglish
JournalInternational Journal of Refrigeration
Pages (from-to)283-310
Publication statusPublished - 2019


  • CO2 refrigeration system
  • HFC refrigeration system
  • Direct space heating and cooling
  • Overfed evaporator
  • System integration
  • Two-phase ejector

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