A comparison of the heat transfer and pressure drop performance of R-134a-lubricant mixtures in different diameter smooth tubes and micro-fin tubes
Abstract
The average heat transfer coefficients and pressure drops during evaporation and condensation are reported for mixtures of R-134a and an ester lubricant in tubes of 12.7 mm (1/2 in.) outer diameter. The objective of this paper is to evaluate the performance of the R-134a-lubricant mixtures in these tubes and determine the performance benefits of the micro-fin tube. The performance benefits of the tubes with 12.7 mm (1/2 in.) outer diameter are compared to those of smaller tubes with 9.52 mm (3/8 in.) outer diameter. The lubricant used was a 169 SUS penta erythritol ester mixed-acid lubricant. The lubricant concentration was varied from 0--5.1% in the mixture. The average heat transfer coefficients in the 12.7 mm (1/2 in.) micro-fin tube were 50--150% higher than those for the 12.7 mm (1/2 in.) smooth tube, while pressure drops in the micro-fin tube were 5% to 50% higher than in the smooth tube. The addition of lubricant degraded the average heat transfer coefficients in all cases except during evaporation at low lubricant concentrations. Pressure drops were always increased with the addition of lubricant. The experimental results also indicate that tube diameter has some effect on the performance benefits of the micro-fin tube over thatmore »
- Authors:
-
- Kansas State Univ., Manhattan, KS (United States). Dept. of Mechanical Engineering
- Iowa State Univ., Ames, IA (United States). Mechanical Engineering Dept.
- Publication Date:
- Sponsoring Org.:
- American Society of Heating, Refrigerating and Air-Conditioning Engineers, Inc., Atlanta, GA (United States)
- OSTI Identifier:
- 653207
- Report Number(s):
- CONF-980123-
Journal ID: ISSN 0001-2505; TRN: IM9827%%100
- Resource Type:
- Book
- Resource Relation:
- Conference: 1998 ASHRAE winter meeting, San Francisco, CA (United States), 17-21 Jan 1998; Other Information: PBD: 1998; Related Information: Is Part Of ASHRAE transactions 1998. Volume 104, Part 1A: Technical papers; PB: 834 p.
- Country of Publication:
- United States
- Language:
- English
- Subject:
- 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; HEAT TRANSFER; PRESSURE DROP; REFRIGERANTS; LUBRICANTS; MIXTURES; TUBES; PERFORMANCE; REFRIGERATING MACHINERY; EXPERIMENTAL DATA
Citation Formats
Eckels, S J, Doerr, T M, and Pate, M B. A comparison of the heat transfer and pressure drop performance of R-134a-lubricant mixtures in different diameter smooth tubes and micro-fin tubes. United States: N. p., 1998.
Web.
Eckels, S J, Doerr, T M, & Pate, M B. A comparison of the heat transfer and pressure drop performance of R-134a-lubricant mixtures in different diameter smooth tubes and micro-fin tubes. United States.
Eckels, S J, Doerr, T M, and Pate, M B. 1998.
"A comparison of the heat transfer and pressure drop performance of R-134a-lubricant mixtures in different diameter smooth tubes and micro-fin tubes". United States.
@article{osti_653207,
title = {A comparison of the heat transfer and pressure drop performance of R-134a-lubricant mixtures in different diameter smooth tubes and micro-fin tubes},
author = {Eckels, S J and Doerr, T M and Pate, M B},
abstractNote = {The average heat transfer coefficients and pressure drops during evaporation and condensation are reported for mixtures of R-134a and an ester lubricant in tubes of 12.7 mm (1/2 in.) outer diameter. The objective of this paper is to evaluate the performance of the R-134a-lubricant mixtures in these tubes and determine the performance benefits of the micro-fin tube. The performance benefits of the tubes with 12.7 mm (1/2 in.) outer diameter are compared to those of smaller tubes with 9.52 mm (3/8 in.) outer diameter. The lubricant used was a 169 SUS penta erythritol ester mixed-acid lubricant. The lubricant concentration was varied from 0--5.1% in the mixture. The average heat transfer coefficients in the 12.7 mm (1/2 in.) micro-fin tube were 50--150% higher than those for the 12.7 mm (1/2 in.) smooth tube, while pressure drops in the micro-fin tube were 5% to 50% higher than in the smooth tube. The addition of lubricant degraded the average heat transfer coefficients in all cases except during evaporation at low lubricant concentrations. Pressure drops were always increased with the addition of lubricant. The experimental results also indicate that tube diameter has some effect on the performance benefits of the micro-fin tube over that of the smooth tube.},
doi = {},
url = {https://www.osti.gov/biblio/653207},
journal = {},
issn = {0001-2505},
number = ,
volume = ,
place = {United States},
year = {Thu Oct 01 00:00:00 EDT 1998},
month = {Thu Oct 01 00:00:00 EDT 1998}
}