Rating Charts of R-22 Alternatives Flow through Adiabatic Capillary Tubes

Authors: E. Elgendy, J. Schmidt

Abstract:

Drop-in of R-22 alternatives in refrigeration and air conditioning systems requires a redesign of system components to improve system performance and reliability with the alternative refrigerants. The present paper aims at design adiabatic capillary tubes for R-22 alternatives such as R-417A, R-422D and R-438A. A theoretical model has been developed and validated with the available experimental data from literature for R-22 over a wide range of both operating and geometrical parameters. Predicted lengths of adiabatic capillary tube are compared with the lengths of the capillary tube needed under similar experimental conditions and majority of predictions are found to be within 4.4% of the experimental data. Hence, the model has been applied for R-417A, R- 422D and R-438A and capillary tube selection charts and correlations have been computed. Finally a comparison between the selected refrigerants and R-22 has been introduced and the results showed that R-438A is the closest one to R-22.

Keywords: Adiabatic flow, Capillary tube, R-22 alternatives, Rating charts, Modelling.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1086627

References:

[1] J. M. Calm, P. A. Domanski. "R-22 Replacement status”, ASHRAE Journal 2004, 46 (8), pp. 29-39.
[2] United Nations Environment Program. "Decisions of the Fourth Meeting of the Parties to the Montreal Protocol on substances that deplete the ozone layer”, 1992, Copenhagen, Denmark.
[3] V. La Rocca, , G. Panno. "Experimental performance evaluation of a vapour compression refrigerating plant when replacing R22 with alternative refrigerants”. Applied Energy 2011, 88 (8), pp.2809-2815.
[4] C. C. Allgood, C. C. Lawson. "Performance of R-438A in R-22 Refrigeration and Air Conditioning Systems”. In: International Refrigeration and Air Conditioning Conference, 2010, Purdue.
[5] D. L. Da Silva, C. J. L. Hermes, C. Melo, J.M. Gonçalves, G.C. Weber. "A study of carbon dioxide flow through adiabatic capillary tubes”. Int. J. Refrigeration. 2009, 32 (5),pp. 978–987.
[6] D. Jung, C. Park, B. Park. "Capillary tube selection for HCFC22 alternatives”. Int. J. Refrigeration. 1999, 22 (8), pp. 604-614.
[7] T. N. Wong, K. T. Ooi. "Refrigerant flow in capillary tube: An assessment of the two phase viscosity correlations on model prediction. Int. Commun. Heat Mass Transf. 1995, 22 (4), pp. 595–604.
[8] Wong, T. N., Ooi, K. T., 1996. "Evaluation of capillary tube performance for CFC-12 and HFC-134a”, Int. Commun. Heat Mass Transf. 23 (7), 993–1001.
[9] S. Wongwises, T. Songnetichaovalit, N. Lokathada, P. Kritsadathikaran, M. Suchatawat, W. Pirompak. "A comparison of the flow characteristics of refrigerants flowing through adiabatic capillary tubes”. Int. Comm. Heat Mass Transf. 2000a, 27 (5), pp. 611–621.
[10] S. Wongwises, P. Chan, N. Luesuwanatat, T. Purattanarak. "Two-phase separated flow model of refrigerants flowing through capillary tubes. Int. Comm. Heat Mass Transf. 2000b, 27(3), pp. 343–356.
[11] S.M. Sami, T. Duong. "An improved model for predicting refrigerant flow characteristics in capillary tubes”. ASHRAE Trans. 1987, 93 (2), pp. 682–700.
[12] J. Wang, F. Cao, Z. Wang, Y. Zhao, L. Li. "Numerical simulation of coiled adiabatic capillary tubes in CO2 transcritical systems with separated flow model including metastable flow”. Int. J. Refrigeration 2012, 35 (8), pp.2188–2198.
[13] ASHRAE, ASHRAE Handbook – Refrigeration. American Society of Heating, Refrigerating and Air-Conditioning Engineers, Atlanta, 2012, (Chapter 44).
[14] M. O. McLinden, S. A. Klein, E. W. Lemmon, A. P. Peskin. NIST Thermodynamic and Transport Properties of Refrigerant and Refrigerant mixtures (REFPROP) Version 8, NIST, 2007, Gaithersburg, MD.
[15] S. G. Kim, M. S Kim, S. T. Ro. "Experimental investigation of the performance of R22, R407C and R410A in several capillary tubes for air-conditioners”. Int. J. Refrigeration 2002, 25 (5), pp. 521-531.