Average boiling and condensation heat transfer coefficients of the zeotropic refrigerant mixture R22/R142b in a coaxial tube-in-tube heat exchanger

Citation
Jp. Meyer et al., Average boiling and condensation heat transfer coefficients of the zeotropic refrigerant mixture R22/R142b in a coaxial tube-in-tube heat exchanger, J HEAT TRAN, 122(1), 2000, pp. 186-188
Citations number
17
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Mechanical Engineering
Journal title
JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME
ISSN journal
0022-1481 → ACNP
Volume
122
Issue
1
Year of publication
2000
Pages
186 - 188
Database
ISI
SICI code
0022-1481(200002)122:1<186:ABACHT>2.0.ZU;2-F
Abstract
Average boiling and condensation heat transfer coefficients were determined experimentally for a coaxial tube-in-tube heat exchanger used in hot water heat pumps. During manufacturing, the heat exchanger geometry used for the experiments changed from round tubes to elliptical tubes as no spacers wer e used to keep the inner tube from touching the outer tube. The refrigerant used was two different mixtures of R22 with R142b in mass ratios of 80 per cent/20 percent and 60 percent/40 percent. The results were compared to the oretical results for straight tubes. It was concluded that the theoretical modes do not predict the heat transfer coefficients very well in coaxial tu be-in-tube heat exchangers where the annulus touches the inside of the oute r tube.