Condensation of Refrigerants 12 and 134a in Horizontal Tubes With and Without Oil

Hinde, D.K.

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https://hdl.handle.net/2142/9727 Copy

Description

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.

Issue Date

1992-10

Keyword(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.

Publisher

Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign.

Series/Report Name or Number

Air Conditioning and Refrigeration Center TR-26

Type of Resource

text

Language

en

Permalink

http://hdl.handle.net/2142/9727

Sponsor(s)/Grant Number(s)

Air Conditioning and Refrigeration Center Project 01

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