Comparison of Condenser Characteristics using R134a and R22 under the Same Inlet Temperature Condition

동일한 유입온도조건에서 R134a와 R22 적용 응축기의 특성비교

  • Kang, Shin-Hyung (Department of Mechanical Engineering, Kenyang University) ;
  • Byun, Ju-Suk (Yonsei Center for Clean Technology, Yonsei University) ;
  • Kim, Chang-Duk (Industry Academia Coop. Korea Industrial Complex Corp.)
  • 강신헝 (건양대학교 기계공학과) ;
  • 변주석 (연세 CT 연구단) ;
  • 김창덕 (한국산업단지공단 중부지역본부)
  • Published : 2006.09.30

Abstract

R134a is considered as an alternative refrigerant to R22 for air conditioners. An experimental investigation was made to study the characteristics of the heat transfer and pressure drop for R134a flowing in a fin-and-tube heat exchanger used for commercial air-conditioning units. Experiments were carried out under the conditions of inlet refrigerant temperature of $60^{\circ}C$ and refrigerant mass fluxes of $150,\;200,\;and\;250\;kg/m^{2}s$. The inlet air has dry bulb temperature or $35^{\circ}C$, relative humidity of 40% and air velocity varying from 0.68 to 1.6 m/s. Experiments show that air velocity decreased by 5.9% is needed for R134a than that of R22 while pressure drop for R134a was $18.1{\sim}20.4%$ higher than that of R22 for the degree of subcooling $5^{\circ}C$. The results are useful in designing more compact and effective condensers for various refrigeration and air conditioning systems using refrigerant R134a.

본 연구에서는 상용 냉동 공조기기에서 사용하고 있는 휜-관 열교환기에서 R22와 이의 대체냉매로 채용하고 있는 R134a 압력강하와 열전달 특성에 대해 실험적으로 연구하였다. 실험은 입구온도 $60^{\circ}C$, 질량유량 $150,\;200,\;250\;kg/m^{2}s$의 범위에 대해 수행하였다. 이때 공기의 유입조건은 전구온도 $35^{\circ}C$, 상대습도 40%, 공기유속은 $0.68{\sim}1.6m/s$이다. 실험 결과 응축기 출구의 과냉도를 $5^{\circ}C$로 유지한 경우 Rl34a의 필요공기유속은 R22보다 5.9%작게 나타났으며, R134a의 압력강하는 R22보다 $18.1{\sim}20.4%$의 범위 내에서 크게 나타났다.

Keywords

References

  1. Shin, J.K.; Kim, K.H.; Nam, L.W. 'The performance test of centrifugal compressor for HFC-R134a', Proceedings of the SAREK '00 Summer Annual Conference, 2000, 429-434
  2. Lee, H.; Yoon, P.H.; Kim, C.D.; Lee, Y.D.; Jeong, J. 'Performance test of a R134a centrifugal water chiller', Korean J. Air-Conditioning and Refrigeration Engineering, 2001, 13(5), 333-340
  3. McLinden, M.O.; Klein, S.A.; Lemmon, E.W.; Peskin, A.P. 'Thermodynamic and transport properties of refrigerants and refrigerant mixtures database (REFPROP)', Ver. 6.01, NIST, 1998
  4. Liu, X. 'Condensing and evaporating heat transfer and pressure drop characteristics of HFC-134a and HCFC-22', Int. J. Heat Transfer, 1997, 119, 158- 163 https://doi.org/10.1115/1.2824081
  5. Torikoshi, K.; Ebisu T. 'Evaporation and condensation heat transfer characteristics of R-134a, R-32, and a mixture of R-32/R-134a inside a tube', ASHRAE Transactions, 1993, 99, 90-96
  6. Eckels, S.J.; Tesene B.A. 'A comparison of R-22, R-134a, R410A, and R407C condensation performance in smooth and enhanced tubes', part 1, heat transfer. ASHRAE Transactions, 2002, 105, 428-441
  7. Kim, C.D.; Jeon, C.D.; Lee, J. 'Evaluation of airside heat transfer and friction characteristics on design conditions of condenser', Korean J. Air- Conditioning and Refrigeration Engineering, 2003, 15(3), 220-229
  8. Kim, C.D.; Lee, J. 'Comparison of condenser characteristics using R410A and R22 on the same inlet temperature condition', Korean J. Air-Conditioning and Refrigerating Engineering, 2003, 15(12), 1049-1059
  9. ASHRAE. Fundamental Handbook (SI), 1993
  10. Kline, S.J.; McClintock, F.A. 'Describing uncertainties in single sample experiments', Mechanical Engineering, 1953, 75, 3-8
  11. Cavallini, A.; Censi, D.; Del Col, L.; Doretti, L.; Longo, G.A.; Rossetto, L. 'Experimental investigation on condensation heat transfer and pressure drop of new HFC refrigerants', Int. J. Refrigeration, 2001, 24, 73-87 https://doi.org/10.1016/S0140-7007(00)00070-0