Experimental investigation of NH3/CO2 cascade system and comparison with R404A system for supermarket refrigeration.

Una "cascata" di NH3/CO2.

Author(s) : SAWALHA S., PERALES CABREJAS C., LIKITTHAMMANIT M., et al.

Type of article: Periodical article

Summary

This article is the Italian translation of an article presented at the 22nd IIR international Congress in Beijing, China (see the Bulletin of the IIR, reference 2007-2661). This study investigates the performance of an NH3/CO2 cascade system for supermarket refrigeration application in a laboratory environment. The tested CO2 system is designed and scaled to fulfil the requirements of an average size supermarket in Sweden. Possibility for hot gas defrost in the freezers has been investigated and compared to the conventional electric heaters defrost method. Two cascade condenser arrangements have been evaluated. The cascade system has been compared to R404A system installed in the same laboratory. The results show that connecting the cascade condenser via thermosiphon or hot gas de-superheat arrangements yields good system stability and heat transfer performance. Hot gas defrost successfully defrosted the freezer evaporator but with long period and higher energy consumption compared to the conventional electric defrost method. The tested cascade system had up to 60% higher total COP compared to the R404A system installed in laboratory.

Details

  • Original title: Una "cascata" di NH3/CO2.
  • Record ID : 2009-1125
  • Languages: Italian
  • Source: Bull. IIF-IIR/Freddo - vol. 63 - n. 2
  • Publication date: 2009/04
  • Document available for consultation in the library of the IIR headquarters only.

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