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Horizontal Convective Condensation of Alternative Refrigerants Within a Micro-Fin Tube



Mark A. Kedzierski, J Goncalves


This paper presents Local convective condensation Measurements for four refrigerants: R134, R410A (R32/R125, 50/50 % mass), R125, and R32 in a micro-fin tube. Both heat transfer and pressure drop measurements are provided. The heat transfer degradation associated with R410A was shown to be relatively small and believed to be mostly due to nonlinear property effects. The measured convective condensation Nusselt numbers for all of the test refrigerants where correlated to a single expression consisting of a product of dimension less properties. The correlation was shown to predict some existing data from the literature well. The correlation poorly predicted the heat transfer performance of cross-grooved, micro-fin tubes. The pressure drop measurements for the micro-fin tube were satisfactorily predicted by an existing correlation for flow boiling pressure drop in a smooth tube.
NIST Interagency/Internal Report (NISTIR) - 6095
Report Number


building technology, condensation, enhanced heat transfer, fluid heating, micro-fin, pressure drop, refrigerant mixtures


Kedzierski, M. and Goncalves, J. (1997), Horizontal Convective Condensation of Alternative Refrigerants Within a Micro-Fin Tube, NIST Interagency/Internal Report (NISTIR), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed July 20, 2024)


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Created December 1, 1997, Updated February 19, 2017