IIR document

R744 compared to R290 in small freezer applications.

Author(s) : BEEK M. van, JANSSEN M.

Summary

An experimental and analytical comparison between R744 (CO2) and R290 (propane) as refrigerant for small capacity freezer applications is described. A commercially available plug-in freezer cabinet for sales of frozen foods or ice cream, fitted with a R290 (8,1 cm3) hermetic compressor, was retrofitted to R744 using standard components and a state of the art R744 compressor. The results of energy consumption and storage temperature testing on both systems are presented as well as a discussion on the system modifications required for using R744. Both refrigerant loops are analysed and the deviations with the thermodynamically ideal loops are discussed. The analysis is further supported by calorimetric tests of the R744 compressor at low evaporation temperatures. Theoretical comparison of the ideal loops, using performance data from the compressors used in the experiments, shows that the R744 circuit is 31% less efficient than the R290 circuit, at normal operating conditions for frozen foods or ice cream. Comparison of the experimental results from the almost fully optimised R-744 freezer with a standard R290 freezer at an ambient of 30ºC, shows that the R744 freezer is 23% less efficient than the R290 freezer, based on the ISO 23953-2 methodology (warmest product temperature of -18ºC). The R744 is 13 % less efficient than the R290 freezer at an average product temperature of -23°C. Finally, costs of major components of both systems are evaluated. This shows that the difference in production costs between a R744 and a R290 freezer is mainly driven by the compressor.

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Pages: 2008-2

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Details

  • Original title: R744 compared to R290 in small freezer applications.
  • Record ID : 2010-1924
  • Languages: English
  • Source: 8th IIR-Gustav Lorentzen Conference on Natural Working Fluids (GL2008)
  • Publication date: 2008/09/07

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