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ACRC Technical Report 26PDF


Title:Condensation of Refrigerants 12 and 134a in Horizontal Tubes With and Without Oil
Author(s):Hinde, D.K.
Contributor(s):Dobson, M.K.; Chato, J.C.; Mainland, M.E.; Rhines, N.
Subject(s):refrigerant-side evaporation condensation studies
Abstract:This study investigated local condensation heat transfer and pressure drop for pure R- 12, pure R-134a and R-134a/oil mixtures and examined the results based on two-phase flow patterns. Condensing conditions simulated those found in domestic refrigerator/freezers. Experiments were performed to measure internal heat transfer coefficients and pressure drops inside a 0.25 in. (6.35 mm) 00, 0.180 in. (4.57 mm) ID smooth, horizontal copper tube. Direct measurements of the temperature difference between the tube wall and the condensing fluid were made. The heat transfer coefficients and pressure drops were compared with existing prediction techniques and differences were found due primarily to differing flow patterns from those used in models and the presence of liquid entrainment in the flow. Tests with a mixture of R-134a and ester lubricant showed a slight increase in heat transfer coefficient at 1.2% concentration and a decrease at 5% concentration. Pressure drop increased with oil concentration. Heat transfer coefficients for R-134a were found to be 10% to 20% higher than for R-12 at equivalent mass flux and saturation temperature, while the difference in pressure drop was within the range of experimental error.
Issue Date:1992-10
Publisher:Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign.
Series/Report:Air Conditioning and Refrigeration Center TR-26
Genre:Technical Report
Sponsor:Air Conditioning and Refrigeration Center Project 01
Date Available in IDEALS:2009-03-13
Identifier in Online Catalog:3694518

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