Korean Journal of Air-Conditioning and Refrigeration Engineering (설비공학논문집)

The Society of Air-Conditioning and Refrigerating Engineers of Korea (대한설비공학회)
권호 표지
DOI QR코드

DOI QR Code

Comparison of Performance in CO2 Cooling System with an Ejector for Various Operating Conditions

다양한 운전조건에서 이젝터를 적용한 CO2 냉동기의 성능비교

  • Kang, Byun (Graduate School of Chosun University) ;
  • Cho, Hong-Hyun (Department of Mechanical Engineering, Chosun University)
  • 강변 (조선대학교 대학원) ;
  • 조홍현 (조선대학교 기계공학과)
  • Received : 2011.02.24
  • Accepted : 2011.06.14
  • Published : 2011.07.10
Download PDF
⟨ Previous Next ⟩

Abstract

Recently, many researchers have analyzed the performance of the transcritical $CO_2$ refrigeration cycle in order to identify opportunities to improve the system energy efficiency. The reduction of the expansion process losses is one of the key issues to improve the efficiency of the transcritical $CO_2$ refrigeration cycle. In this study, the analytical study on the performance characteristics of $CO_2$ cycle with an ejector carried out with a variation of outdoor temperature, gascooler inlet air velocity, evaporator inlet air velocity, and evaporator inlet air temperature. As a result, the system performance could be improved over 85% by using an ejector for various operating condition because of the reduction of compressor work. Moreover, the cooling capacity increased about 18% for variable outdoor condition. Therefore, the high performance of an ejector system could be maintained for wide operating conditions and system reliability could be improved compared to that of a basic system.

Keywords

References

  1. Sarkar, J., 2008, Optimization of ejector-expansion transcritical $CO_2$ heat pump cycle, Energy, Vol. 33, pp. 1399-1406. https://doi.org/10.1016/j.energy.2008.04.007
  2. Deng, J., Jiang, P., Lu, T., Lu, W., 2007, Particular characteristics of transcritical $CO_2$ refrigeration cycle with an ejector, Applied Thermal Engineering, Vol. 27, pp. 381-388. https://doi.org/10.1016/j.applthermaleng.2006.07.016
  3. Li, D., Groll, A., 2005, Transcritical $CO_2$ refrigeration cycle with ejector-expansion device, International Journal of Refrigeration, Vol. 28, pp. 766-773. https://doi.org/10.1016/j.ijrefrig.2004.10.008
  4. Ortiz, T. M., Li, D., Groll, A. E., 2003. Evaluation of the Performance Potential of CO2 as a Refrigerant in Air-to-Air Conditioner and Heat Pumps：System Modelling and Analysis, ARTI final report No. 21CR/610-10030.
  5. Gnielinski, V., 1976, New equations for heat and mass transfer in turbulent pipe and channel flow, International Chemical Engineering, Vol. 16, pp. 59-68.
  6. Churchill, S. W., 1977, Friction-factor equation span all fluid flow regimes, Chemical Engineering, Vol. 7, pp. 91-92.
  7. Yoon, S. H., 2002, Studies on the Characteristics of Evaporation and supercritical Gas Cooling Heat Transfer of Carbon Dioxide, Ph. D. thesis, Seoul University, Seoul, Korea.
  8. Wang, C. C., Lee., S. W., and Sheu, W. J., 2001, A Comparative Study of Compact Enhanced Fin-and-Tube Heat Exchanges, International Journal of Heat and Mass Transfer, Vol. 44, pp. 3565-3573. https://doi.org/10.1016/S0017-9310(01)00011-4
  9. ASHRAE 1983, Methods of testing for seasonal efficiency of unitaty air-conditioner and heat pumps, ASHRAE Standard, p. 116.
  10. Nakagawa, M., Marasigan, A. R., Matsukawa, T., Kurashina, A., 2010, Experimental investigate performance of two-phase ejector for $CO_2$ refrigeration cycle with and without heat exchanger, Proceedings of 9 th IIR Gustav Lorentzen Conference, Sydney.