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Performance evaluation of a 2-stage CO2 heat pump cycle heat generator.

Author(s) : KUWABARA O., KOBAYASHI M., MUKAIYAMA H., et al.

Summary

Because of its low critical temperature, carbon dioxide refrigerant is especially suitable for a heat pump cycle with high heat rejecting temperature, such as a water heater or a central heating boiler. The authors have been developing residential CO2 heat pump space heating system for cold regions. However, the water temperature returned from the panel radiators is not so low. So, a simple CO2 heat pump can't achieve enough heating capacity and high COP at low ambient temperature. In the 2-stage heat pump cycle (gas injection cycle using 2-stage compressor), both the heating capacity and the COP are much improved compared with simple cycle, with high water temperature and at low ambient temperature. The authors measured the heating capacity and the COP of the heat pump heat generator unit. Conclusions: the 2-stage heat pump cycle improves heating capacity by 50%, COP by 22%, at ambient temperature -20°C. And also it improves the annual average COP by 11%, considering the climate condition in cold region in Japan. It is possible that a compact and efficient CO2 heat pump heat generator replace conventional boiler and reduce residential energy consumption in cold region.

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Pages: ICR07-E2-1009

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Details

  • Original title: Performance evaluation of a 2-stage CO2 heat pump cycle heat generator.
  • Record ID : 2008-0859
  • Languages: English
  • Source: ICR 2007. Refrigeration Creates the Future. Proceedings of the 22nd IIR International Congress of Refrigeration.
  • Publication date: 2007/08/21

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