IIR document

Study on transcritical R744 (CO2) Voorhees heat pump cycle.

Author(s) : ZHA S., HAFNER A., NEKSÅ P.

Summary

R744 has become an important working fluid for several applications. Using a Voorhees supercharge method in a R744 heat pump cycle is an effective way to improve the heating capacity of a heat pump in cold climates or to increase the cooling capacity of a refrigeration system at high ambient temperature conditions. An intermediate pressure receiver (flash tank) arrangement (Voorhees cycle) is studied in this paper, one out of several system design options for realising this concept. To improve the heating capacity of the R744 transcritical cycle at present, a new modified construction of a reciprocating compressor with supercharge ports is introduced. The new concept is compared with the traditional screw or scroll economizer cycles and the losses of the new concept are analyzed. In addition, the optimum discharge pressure, the pressure difference (between discharge pressure and intermediate pressure), mass flow ratio, heating capacity and COPh of the new Voorhees cycle are analyzed and calculated, comparing them to results for the conventional transcritical heat pump cycle. A Voorhees CO2 heat pump cycle is found to have the potential to increase both capacity and COP compared to a conventional CO2 transcritical cycle. (See also this Bulletin, reference 2006-0960.)

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Pages: 2005-3

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Details

  • Original title: Study on transcritical R744 (CO2) Voorhees heat pump cycle.
  • Record ID : 2006-0962
  • Languages: English
  • Source: Commercial Refrigeration. Thermophysical Properties and Transfer Processes of Refrigerants. Proceedings of the IIR International Conferences.
  • Publication date: 2005/08/30

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