Enhanced heat transfer tubes for film absorbers of absorption chiller/heater

Book · Sun Dec 31 04:00:00 EST 1995

OSTI ID:438870

Sasaki, Naoe; Nosetani, Tadashi ^[1]; Furukawa, Masahiro; Kaneko, Toshiyuki ^[2]

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1. Sumitomo Light Metal Industry, Ltd., Nagoya, Aichi (Japan)
2. Sanyo Electric Co., Ltd., Ora, Gunma (Japan). Commercial Air-Conditioning Div.

Absorption chiller/heaters using non-CFC refrigerants are attracting attention as environmentally friendly energy systems. As the refrigerant/absorbent pair, the water/lithium bromide aqueous solution pair is preferably used for most absorption chiller/heaters in Japan. Absorption chiller/heaters, mainly used as water chillers and air-conditioners, are commercially available at least for unit cooling capacities above 60 kW. In absorption chiller/heaters, the absorber must be made compact, because the absorber has the largest heat transfer area of the four primary heat exchangers in the system: the evaporator, absorber, regenerator and condenser. Although a great amount of information is available on the evaporator and condenser, the same type of information concerning the absorber is lacking. This paper introduces two kinds of double fluted tubes called Arm tubs and Floral tubes for film absorbers. Arm tubes are manufactured using a two-pass drawbench process, while Floral tubes are made using a single pass drawbench process. The experiments using a lithium bromide aqueous solution with the addition of 250 ppm n-octyl alcohol as the surfactant showed that Arm tubes and Floral tubes had about 40% higher heat transfer performance than plain tubes. Therefore, Floral tubes are expected to realize a high performance at low cost. Furthermore, the optimization of the number of grooves on the outside of the tubes is also described here.

• OSTI ID: 438870
• Report Number(s): CONF-950828--; ISBN 0-7918-1715-6
• Country of Publication: United States
• Language: English

Related Subjects

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION
ABSORPTION REFRIGERATION CYCLE
AIR CONDITIONERS
DESIGN
EXPERIMENTAL DATA
HEAT EXCHANGERS
HEAT TRANSFER
PERFORMANCE
TUBES