Pool boiling heat transfer characteristics of low-GWP refrigerants in a horizontal tube bundle configuration
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
Heat transfer enhancement techniques have been adapted on the shell side to improve the overall performance of the flooded evaporators, such as finned tubes. In recent years, it has been demonstrated that the metal foam structure can offer enhanced heat transfer performance under pool boiling conditions. However, there are not much research in the open literature that examine the feasibility of metal foam embedded tubes in horizontal tube bundle configurations. Therefore, this paper proposed a novel metal foam embedded tube (i.e., foam embedded outside the tube) to improve the heat transfer behavior of flooded evaporators. Further, the experiments were performed on a horizontal tube bundle with a staggered arrangement. Moreover, the performance of low global warming potential (GWP) refrigerants (R-1234yf and R-1234ze(E)) is compared against R-134a for both plain tubes and metal foam tubes with porosities of 81%, 75%, and 62%. The results showed that a metal foam tube with a porosity of 62% showed a maximum heat transfer coefficient (HTC) enhancement of 291% compared to the plain tube. As compared with R-134a, the HTCs of R-1234yf and R-1234ze(E) are nearly 10% higher and 5% lower, respectively.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Building Technologies Office
- Grant/Contract Number:
- AC05-00OR22725
- OSTI ID:
- 2345334
- Alternate ID(s):
- OSTI ID: 2369873
- Journal Information:
- Applied Thermal Engineering, Journal Name: Applied Thermal Engineering Journal Issue: Part A Vol. 248; ISSN 1359-4311
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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