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

The Society of Air-Conditioning and Refrigerating Engineers of Korea (대한설비공학회)
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A Study of External Condensation Heat Transfer of Flammable Refrigerants

가연성 냉매의 외부 응축 열전달에 관한 연구

  • Published : 2004.06.01
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Abstract

In this study, external condensation heat transfer coefficients (HTCs) of flammable refrigerants of propylene, propane, isobutane, butane, DME, and HFC32 were measured on a horizontal plain tube, 26 fpi low fin tube, and Turbo-C tube. All data were taken at the temperature of 39$^{\circ}C$ with a wall subcooling of 3∼8$^{\circ}C$. Test results showed a typical trend that condensation HTCs of flammable refrigerants decrease with increasing wall subcooling. HFC32 had the highest HTCs among the tested refrigerants showing 44% higher HTCs than those of HCFC22 while DME showed 28% higher HTCs than those of HCFC22. HTCs of propylene and butane were similar to those of HCFC22 while those of propane and isobutane were similar to those of HFC134a. Based upon the tested data, Nusselt's equation is modified to predict the plain tube data within a deviation of 3%. For 26 fpi low fin tube, Beatty and Katz equation predicted the data within a deviation of 7.3% for all flammable refrigerants tested. The heat transfer enhancement factors for the 26 fpi low fin and Turbo-C tubes were 4.6∼5.7 and 4.7∼6.9 respectively for the refrigerants tested indicating that the performance of Turbo-C tube is the best among the tubes tested.

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References

  1. Molina, M. J. and Rowland, F. S., 1974, Stratospheric sink for chlorofluoromethanes: chlorine atom catalyzed destruction of ozones, Nature, Vol. 249, pp. 810-812 https://doi.org/10.1038/249810a0
  2. Zhu R. and Wu Y., 2002, Application of nature working fluids in refrigeration in china, natural working fluid 2002: 5th IIR-Gustav Lorentzen Conference, pp. 401-407
  3. Nusselt, W., 1916, Die Oberflachenkondensation des Wasserdampfes, Z. Ver. Deut. Ing., 60, p. 541
  4. Nguyen, T.-N. and Orozco, J. A., 1994, Condensation of R-113 on enhanced surfaces, ASHRAE Trans. 100. Part 1. pp. 736-743
  5. Cheng, B. and Tao, W. Q., 1994, Experimental study of R-152a film condensation on single horizontal smooth tube and enhanced tubes, J. of Heat Transfer 116, pp. 266-270
  6. Yilbas, B. S. and Altuntop, N., 1990, Condensing heat transfer of freon-21 on plain horizontal tubes, Indian Journal of Technology 28, pp. 100-106
  7. Jung, D. S., Kim, C. B., Cho, S. J. and Song, K. H., 1999, Condensation heattransfer coefficients of enhanced tubes with alternative refrigerants for CFC11 and CFC12, Int. J. Refrigeration, Vol. 22, pp. 548-557 https://doi.org/10.1016/S0140-7007(99)00020-1
  8. Hwang, S. M., Kim, K. K., Jung, D. S. and Kim, C. B., 1999, Condensation heat transfer coefficients of R22 alternative refrigerants on enhanced tubes, Transactions of the Korean Society of Mechanical Engineers B, Vol. 23, No. 4, pp. 459-469
  9. Beatty, K. O. and Katz, D. L., 1948, Condensation of vapors on outside of finned tubes, Chemical Engineering Progress, Vol. 44, No. 1, pp. 55-70
  10. Rudy, T. M. and Webb, R. L., 1985, An analytical model to predict condensate retention on horizontal integral-fin tubes, J. of Heat Transfer, Vol. 107, pp. 361-368 https://doi.org/10.1115/1.3247423
  11. Kim, N. H., Jung, I. K. and Kim, K. H., 1995, An experimental study on condensation heat transfer of low finned tubes, Korean Journal of Air-Conditioning and Refrigeration Engineering, Vol. 7, No. 2, pp. 298-309
  12. Joo, J. K., Cho, S. J., Jung, D. S. and Kim, C. B., 1997, Condensation heat transfer coefficients of CFC-11 and its alternative refrigerants, Transactions of the Korean Society of Mechanical Engineers B, Vol. 21, No. 6, pp. 830-840
  13. Hwang, S. M., Kim, K. K., Jung, D. S. and Kim, C. B., 1999, Condensation heat transfer coefficients of R22 alternative refrigerants on enhanced tubes, Transactions of the Korean Society of Mechanical Engineers B, Vol. 23, No. 4, pp. 459-469
  14. Webb, R. L. and Murawski, C. G., 1990, Row effect for R-11 condensation on enhance enhanced tubes, Transactions of the ASME, Vol. 112, pp. 768-776 https://doi.org/10.1115/1.2910452
  15. McLinden, M. O., Klein, S. A., Lemmon, E. W. and Peskin, A. P., 1998, NIST thermodynamics and Transport Properties of Refrigerants and Refrigerant Mixtures-REFPROP Version 6.0.
  16. Kline, S. J. and McClintock, F. A., 1953, Describing uncertainties in single-sample experiments, Mechanical Engineer, Vol. 75, pp.3-9