This study experimentally investigates the effect of circuitry on the refrigerant-side pressure drops of plate finned tube evaporators. Experiments were performed with countercross, parallel-cross, and z-shape arrangements. The results showed that the parallel-cross-flow circuit gives a lower pressure drop than other arrangements. Generally, the refrigerant-side pressure drops increase with air frontal velocities. However, for and parallel flow, the pressure drops decrease with increase of air frontal velocity. This unusual characteristic is most likely related to the flow pattern transition when subjected to heat addition.
Issue Section:
Technical Brief
1.
Ebisu, T., Yoshida, K., and Torikoshi, K., 1996, “Air-Cooled Heat Exchanger Performance for R-410A,” Proc., 1996 International Refrigerant Conf., Purdue, IN, pp. 139–144.
2.
Wang
, C. C.
, Jang
, J. Y.
, Lai
, C. C.
, and Chang
, Y. J.
, 1999
, “Effect of Circuit Arrangement on the Performance of Air-Cooled Condensers
,” Int. J. Refrig.
, 22
, pp. 275
–282
.3.
ANSI/ASHRAE Standard 37, 1988, “Methods of Testing for Rating Unitary Air-conditioning and Heat Pump Equipment.”
4.
ASHRAE Standard 41-2, 1987, “Standard Methods for Laboratory Air-flow Measurement.”
5.
Wang
, C. C.
, Chiang
, C. S.
, and Lu
, D. C.
, 1997
, “Visual Observation of Flow Pattern of R-22, R-134a, and R-407C in a 6.5 mm Smooth Tube
,” Exp. Therm. Fluid Sci.
, 15
, pp. 395
–405
.6.
Dukler, A. E., and Taitel, Y., 1991, “Flow Patterns Transitions in Gas-Liquid Systems,” Chap. 3, Two-Phase Gas-Liquid Flow: A Short Course on Principles of Modeling Gas-Liquid Flow and on Modern Measuring Methods, University of Houston, Houston, TX: this paper is quoted from Chap. 3, Tong and Tang, Boiling Heat Transfer and Two-Phase Flow, 1997, Taylor & Francis.
7.
Taitel
, Y.
, and Dukler
, A. E.
, 1976
, “A Model for Prediction of Flow Regime Transitions in Horizontal and Near Horizontal Gas-Liquid Flow
,” AIChE J.
, 22
, pp. 47
–55
.Copyright © 2001
by ASME
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