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

The Society of Air-Conditioning and Refrigerating Engineers of Korea (대한설비공학회)
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Analysis of the Gravity Effect on the Distribution of Refrigerant Flow in a Multi-circuit Condenser

다분지 응축기의 냉매유량 분배에 미치는 중력의 영향을 고려한 해석방법

  • 이장호 (포항공과대학교 기계공학과) ;
  • 김무환 (포항공과대학교 기계공학과)
  • Published : 2004.12.01
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Abstract

The method to consider gravity effect on the performance of a condenser is developed, and a simple condenser having 'nU' type two circuits is analyzed. Each circuit has the same length and inlet air-side operational conditions. The only difference between two circuits is the direction of refrigerant flow, which is exactly opposite each other between the upper 'n' type circuit and the lower 'U' type circuit. It is shown that the gravity makes the distribution of refrigerant flow uneven in the two circuits at lower refrigerant flow rates; heat transfer rate also becomes uneven. Moreover, much of the refrigerant exists as liquid state in the circuit having low refrigerant flow rate, which will make the cycle balance unstable in the refrigeration cycle system like a heat pump.

Keywords

References

  1. Wang, C.-C., Jang, J.-Y., Lai, C.-C. and Chang, Y.-J., 1999, Effect of circuit arrangement on the performance of air-cooled condensers, International J. of refrigeration, Vol. 22, pp.275-282 https://doi.org/10.1016/S0140-7007(98)00065-6
  2. Domanski, P. A., 1989, An evaporator simulation model accounting for refrigerant and one-dimensional air distribution, NISTIR 89-4133
  3. Lee, J. H., Bae, S. W., Bang, K. H. and Kim, M. H., 2002, Experimental and numerical re-search on condenser performance for R-22 and R-407C refrigerants, International J. of Refrigeration, Vol. 25, pp.372-382 https://doi.org/10.1016/S0140-7007(01)00012-3
  4. Cavallini, A and Zecchin, R., 1974, A dimensionless correlation for heat transfer in forced convection condensation, Proc. 5th Int. Heat Transfer Conf., September 3-7, pp.309-313
  5. Shah, M. M., 1979, A general correlation for heat transfer during film condensation inside pipes, Int. J. of Heat and Mass Transfer, Vol. 22, pp.547-556 https://doi.org/10.1016/0017-9310(79)90058-9
  6. Traviss, D. P., Rohsenow, W. M. and Baron, A.B., 1973, Forced convection condensation inside tubes: A heat transfer equation for condenser design, ASHRAE Trans., Vol. 79, Part 1, pp, 157-165
  7. Dobson, M. K. and Chato, J. C., 1998, Condensation in smooth horizontal tubes, Journal of Heat Transfer, Vol. 120, pp.193-213 https://doi.org/10.1115/1.2830043
  8. Ould Didi, M. B., Kattan, N. and Thome, J.R., 2001, Prediction of two phase pressure gradient of refrigerants in horizontal tubes, International J. of refrigeration, Vol. 24, pp.935-947
  9. Pierre, B., 1964, Flow resistance with boiling refrigerants part II, ASHRAE Journal pp.73-77
  10. Lee, J. and Domanski, P. A, 1997, Impact of air and refrigerant mal-distributions on the performance of finned-tube evaporators with R-22 and R-407C, NIST, DOE/CE/23810-81
  11. Lee, J. H., 1994, A development of a computer simulation code for the analysis of multi-path evaporator used in air conditioners, Master Thesis, Pohang University of Science and Technology
  12. Incropera, F. P. and Dewitt, D. P., 1996, Introduction to heat transfer, John Willey & Sons, Inc
  13. Petukhov, B. S., 1970, Heat transfer and friction in turbulent pipe flow with variable physical properties, Advances in Heat Transfer, Vol. 6, pp. 503-564
  14. Ito, H., 1960, Pressure losses in smooth pipe bends, Basic Engineering Transaction of ASME, pp. 131-143
  15. Gray, D. and Webb, R., 1986, Heat transfer and friction correlations for plate finned-tube heat exchangers having plain fins, Proc. of Eighth Int. Heat Transfer Conference, San Francisco.
  16. Nakata, H., 1990, Finned tube heat exchanger, Japanese J. of Refrigeration, Vol.65, No. 758, pp.1-14