Average boiling and condensation heat transfer coefficients of the zeotropic refrigerant mixture R22/R142b in a coaxial tube-in-tube heat exchanger
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 were 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%/20% and 60%/40%. The results were compared to theoretical results for straight tubes. It was concluded that the theoretical modes do not predict the heat transfer coefficients very well in coaxial tube-in-tube heat exchangers where the annulus touches the inside of the outer tube.
- Research Organization:
- Rand Afrikaans Univ., Johannesburg (ZA)
- OSTI ID:
- 20067722
- Journal Information:
- Journal of Heat Transfer, Journal Name: Journal of Heat Transfer Journal Issue: 1 Vol. 122; ISSN 0022-1481; ISSN JHTRAO
- Country of Publication:
- United States
- Language:
- English
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