The performance comparison of a two-stage compression CO2 cycle using internal heat exchangers.

Number: pap. D2-110

Author(s) : BAE K., KWAK M., KANG B., et al.


In a CO2 system, an internal heat exchanger (IHX) with high effectiveness is an important factor to achieve high system performance. IHX can minimize the sensitivity of the system to the refrigerant quality at the evaporator inlet. In this study, the coefficients of performance of three different cycles with IHX were compared with operating condition by using simulation study. The IHX can be located at the low-stage compressor inlet, the high-stage compressor inlet, and both side to increase the system capacity and reliability. Beside, the optimal high&low-stage IHX length ratio at the two-stage compression system was investigated and the system characteristics were analyzed with operating condition. As a result, the cooling COP decreased with outdoor temperature, and that was shown the maximum value for the high-stage IHX system. Besides, the high-stage IHX system had the maximum performance with a variation of 2nd-stage EEV opening. As the 2nd-stage EEV opening increased, the COPs of the system with high-stage IHX and high- & low-stage IHX increased, whereas that of the system with low-stage IHX decreased until the 2nd-EEV opening of 46% and then increased again. When the length ratio of low- and high-stage IHX was 50%, the system performance decreased due to the increase of low-stage compressor work and decrease of high-stage evaporator capacity.

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  • Original title: The performance comparison of a two-stage compression CO2 cycle using internal heat exchangers.
  • Record ID : 30005396
  • Languages: English
  • Source: ACRA2010. Asian conference on refrigeration and air conditioning: Tokyo, Japan, June 7-9, 2010.
  • Publication date: 2010/06/07


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