Transactions of the Korean Society of Mechanical Engineers B (대한기계학회논문집B)

The Korean Society of Mechanical Engineers (대한기계학회)
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Cooling and Heating Performances of a CO2 Heat Pump with the Variations of Operating Conditions

운전조건 변화에 따른 이산화탄소 열펌프의 냉난방 성능특성 비교

  • 조홍현 (미국국립표준연구원) ;
  • 백창현 (고려대학교 기계공학과 대학원) ;
  • 이응찬 (고려대학교 기계공학과 대학원) ;
  • 강훈 (고려대학교 기계공학과 대학원) ;
  • 김용찬 (고려대학교 기계공학과 대학원)
  • Published : 2008.06.01
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Abstract

Since operating conditions are significantly different for heating and cooling mode operations in a $CO_2$ heat pump system, it is difficult to optimize the performance of the $CO_2$ cycle. In addition, the performance of a $CO_2$ heat pump is very sensitive to outdoor temperature and gascooler pressure. In this study, the cooling and heating performances of a variable speed $CO_2$ heat pump with a twin-rotary compressor were measured and analyzed with the variations of EEV opening and compressor frequency. As a result, the cooling and heating COPs were 2.3 and 3.0, respectively, when the EEV opening was 22%. When the optimal EEV openings for heating and cooling were 28% and 16%, the cooling and heating COPs increased by 3.3% and 3.9%, respectively, over the COPs at the EEV opening of 22%. Beside, the heating performance was more sensitive to EEV opening than the cooling performance. As the compressor speed decreased by 5 Hz, the cooling COP increased by 2%, while the heating COP decreased by 8%.

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References

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