IIR document

Field measurements and performance evaluation of CO2 supermarket refrigeration systems.

Number: pap. S3-P2



This paper studies field measurements and performance analysis of eight supermarkets in Sweden among which five supermarkets use CO2 and three use HFC as the refrigerant. The differences in system design are discussed and detailed performance evaluation of one of the systems is presented. The performances of all the supermarkets are compared and the reasons for higher or lower energy efficiency are discussed. Some key components of CO2 systems are evaluated, as well. According to the results, the older CO2 systems have lower COP than the reference systems. High vapour fraction in low temperature cabinets inlet, relatively high amount of internal and external superheating and 10-15% lower overall efficiency of low temperature compressors compared to the other systems are some of the main reasons for this lower COP. But, the newer CO2 systems proved to have higher efficiency, or at least, as energy-efficient as the conventional systems. This originates from the modification in the system design and more efficient components. System design modification includes two-stage expansion by receiver and flash gas by-pass. The newer CO2 components have higher efficiency; medium temperature level compressors have 5-10% higher overall efficiency compared to HFC and older CO2 compressors and the cabinets run with lower superheating so the system can be controlled to run at higher evaporation temperatures. This study shows that CO2 systems have comparable COP to advanced conventional systems applied in Sweden.

Available documents

Format PDF

Pages: 8 p.


  • Public price

    20 €

  • Member price*


* Best rate depending on membership category (see the detailed benefits of individual and corporate memberships).


  • Original title: Field measurements and performance evaluation of CO2 supermarket refrigeration systems.
  • Record ID : 30007197
  • Languages: English
  • Subject: HFCs alternatives
  • Source: 2nd IIR International Conference on Sustainability and the Cold Chain. Proceedings: Paris, France, April 2-4, 2013.
  • Publication date: 2013/04/02


See other articles from the proceedings (79)
See the conference proceedings