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Vol.3 , No. 1, Publication Date: Jan. 7, 2016, Page: 1-11
 ton of refrigeration air conditioning unit was used to build a tube by tube model to investigate the evaporator performance. The refrigerants selected for this object were R22 and the zeotropic blends R407C and R407A refrigerants. The validation of the present model for pure and mixtures showed good agreement between experimental and those predicted values. The predicted duty when circulating R22 and R407C refrigerants exhibited under prediction behavior scatter by (-5%) and (-4%) respectively. On the contrary, R407A simulation results revealed over prediction by a maximum of (+1.7%). The simulation showed that when circulating R22 in the unit, maximum discrepancy between predicted and measured air temperature at entry to the condenser ranges between (+21.3% and – 7.8%). When R407C refrigerant was circulated, the maximum discrepancy in air temperature simulation was in the range (-11% and 11.6%). R407A revealed over predicted results, the maximum discrepancy was within (24.3%).&picture=http://www.aascit.org/aascit/decorators/img/journal/902.jpg)
| [1] | Ali Hussain Tarrad, Private Consultant Engineer/Mechanical Engineering, Copenhagen, Denmark. |
| [2] | Ayad Khudhair Al-Nadawi, Department of Machinery and Equipment, Technical Institute/Al-Anbar, Middle Technical University, Iraq. |
The present research represents a mathematical rating model applied for an air cooled louvered finned tube condenser. The energy and continuity equations at the steady state conditions together with available correlations in the open literature were implemented in the present model. The steady state experimental data of a window type (2) ton of refrigeration air conditioning unit was used to build a tube by tube model to investigate the evaporator performance. The refrigerants selected for this object were R22 and the zeotropic blends R407C and R407A refrigerants. The validation of the present model for pure and mixtures showed good agreement between experimental and those predicted values. The predicted duty when circulating R22 and R407C refrigerants exhibited under prediction behavior scatter by (-5%) and (-4%) respectively. On the contrary, R407A simulation results revealed over prediction by a maximum of (+1.7%). The simulation showed that when circulating R22 in the unit, maximum discrepancy between predicted and measured air temperature at entry to the condenser ranges between (+21.3% and – 7.8%). When R407C refrigerant was circulated, the maximum discrepancy in air temperature simulation was in the range (-11% and 11.6%). R407A revealed over predicted results, the maximum discrepancy was within (24.3%).
Keywords
Air Cooled, Heat Exchanger, Modeling, Refrigerant Alternatives, Zeotropic Blends
Reference
| [01] | Ellison, R. D., Creswick, F. A., Fisher, S. K., and Jackson, W. L.,” A Computer Model for Air-Cooled Refrigerant Condensers with Specified Refrigerant Circuiting”, ASHRAE Transaction, Vol. 87, Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee, 1981. |
| [02] | Domanski, P. A., and Didion, D. A., ” Computer Modeling of the Vapour Compression Cycle with Constant Flow Area Expansion Device”, Center of Building Technology, National Bureau of Standards, Washington, USA, May, 1983. |
| [03] | Kempiak, M. J. and Crawford, F. R.,” Three-Zone Modeling of a Mobile Air Conditioning Condenser”, Air Conditioning and Refrigerating Center (ACRC), University of Illinois, Mechanical Industrial Engineering Department, Urbane, April, 1991. |
| [04] | Bensafi, A. and Borg, S., ”Design and Simulation of finned-Tube Heat Exchanger Using Pure and Mixed Refrigerants”, Belgium, Proceedings of Clima 2000 conference, held in Burssels, August 30th to September 2nd 1997. |
| [05] | Sadler, E. M., ”Design Analysis of a Finned-Tube Condenser for a Residential Air Conditioner using R22”, M. sc thesis, The Academic Faculty, Georgia Institute of Technology, April 2000. |
| [06] | Wright, M. F., “Plate-Fin-and Tube Condenser Performance and Design for Refrigerant R410A Air-Conditioner”, M. sc thesis, The Academic Faculty, Georgia Institute of Technology, May 2000. |
| [07] | Tarrad, A. H. and Khudor, D. S., “A Correlation for the Air Side Heat Transfer Coefficient Assessment in Continuous Flat Plate Finned Heat Exchangers”, Transactions of the ASME, Journal of Thermal Science and Application, Vol. (7), No. 2, Paper No. TSEA-14-1194, DOI: 10.11151/1.4029459, 2015. |
| [08] | Tarrad, A. H. and Altameemi, A. F., “Experimental and Numerical Model for Thermal Design of Air Cooled Condenser”, Global Journal of Researches in Engineering (GJRE-A), Mechanical and Mechanics Engineering, Volume 15, Issue 3, Version 1.0, pp. 11-26, 2015. |
| [09] | Al-Nadawi, A. K., “Experimental and Theoretical Study of R407C and R407A as Alternatives of R22 Refrigerant in a Window Type Air Conditioner”, MSc. Thesis, Mechanical Engineering Department, College of Engineering, Al-Mustansiriya University, 2010. |
| [10] | Stewart, S. W., “Enhanced Finned - Tube Condenser Design and Optimization”, PhD thesis, The Academic Faculty, Georgia Institute of Technology, November, 2003. |
| [11] | Thome, J. R., “Engineering Data Book III”, Faculty of Engineering Science and Technology, Swiss Federal Institute of Technology Laussanne (EPEL), Switzerland, Wolverine Tube, INC, 2008. |
| [12] | Perrotin, T. and Clodic, D.," Fin Efficiency Calculation in Enhanced Fin-And-Tube Heat Exchangers in Dry Conditions", International Congress of Refrigeration, Washington, USA, pp. 1-8, 2003. |
| [13] | Tarrad, A. H. and Shehhab, U. S.,” The Prediction of Environment Effect on the Performance of a Vapour Compression Refrigeration System in Air Conditioning Application”, Journal of Engineering and Development. Vol. 11, No. 1, pp. 169-189, March 2007. |
| [14] | Tarrad, A. H., Khudor D. S., and Abdul Wahed M., “A simplified Model for the Prediction of the Thermal Performance for Cross Flow Air Cooled Heat Exchangers with a New Air Side Thermal Correlation”, Engineering and Development Journal, Vol. 12, No. 3, September 2008. |
| [15] | Subbarao, P. M., “Fin- Tube Condenser and Evaporator with Delta Winglet Window A/C”, Mechanical Engineering Department, Indian Institute of Technology, Delhi, iitd. ac. in., 2008. |
| [16] | Sweeney, K. A. and Chato, J. C., “The Heat Transfer and Pressure Drop Behavior of a Zeotropic Refrigerant Mixture in a Micro-Finned Tube”, Air Conditioning and Refrigerating Center (ACRC), University of Illinois, Mechanical Industrial Engineering Department, Urbane, May, 1996. |
| [17] | Quiben, J. M., “Experimental and Analytical Study of Two-Phase Pressure Drops during Evaporation in Horizontal Tubes”, PhD thesis, DEA-Dynamique des Fluides et des Transferts, Universite, Pierre et Mari Carie, Paris, France, Laussanne, 2005. |
| [18] | Choi, J. Y., Kedzierski, M. A., and Domanski, P. A., “A Generalized Pressure Drop Correlation for Evaporation and Condensation of Alternative Refrigerants in Smooth and Micro-Fin Tubes”, National Institute of Standards and Technology (NIST), Gaithersburg, USA, October 1999. |
| [19] | Incropera F. P. and DeWitt D. P., 1985. “Fundamentals of Heat and Mass Transfer”, 2nd edition, John Wiley & Sons Inc., USA. |
| [20] | Janna W. S., 2000. Engineering Heat Transfer, 2nd edition, CRC press LLc, USA. |
