Water vapor absorption enhancement in LiBr/H sub 2 O films falling on horizontal tubes

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Experimental Heat Transfer; (United States)

DOI:https://doi.org/10.1080/08916159108946425· OSTI ID:5648686

Lee, S K; Nagasaki, T ^[1]

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1. Dept. of Mechanical Engineering Science, Tokyo Inst. of Technology, 2-12-1 Ookayama, Meguro-Ku, Tokyo 152 (JP)

This paper reports that the enhancement or control of heat and mass transfer in an absorber, which is an essential component of an absorption system, is necessary so that low-grade energy, such as solar energy or exhaust cooling water, can be utilized more effectively. So far, several theoretical approaches for analyzing simple systems such as a vertical plane or a bare tube have been published. Additionally, the effects of extending the heat transfer surface and introducing a surfactant additive to improve a absorption efficiency were investigated. However, since the absorption process in the absorber is a simultaneous heat and mass transfer problem, there are still several aspects that are not well understood, such as the detailed heat and mass transfer mechanisms and other factors that dominate the performance of this system. An experimental investigation was conducted into the enhancement of water vapor absorption in aqueous lithium bromide solution films falling on horizontal tubes. The variable parameters included the solution flow rate, the inlet temperature of the cooling media, the solution inlet temperature, and the effective extended surface. The experimental results, which were correlated with the film Reynolds number, showed that the cooling effect of the tube was the governing factor in the absorption process for small solution flow rates, but the inlet solution subcooling dominated the absorption performance for large flow rates. Also, the R tube, which has unique ridged fin shape, exhibited the best absorption performance among the tested tubes.

• OSTI ID: 5648686
• Journal Information: Experimental Heat Transfer; (United States), Journal Name: Experimental Heat Transfer; (United States) Vol. 4:4; ISSN 0891-6152; ISSN EXHTE
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
420400* -- Engineering-- Heat Transfer & Fluid Flow
ABSORPTION
ALKALI METAL COMPOUNDS
AQUEOUS SOLUTIONS
BROMIDES
BROMINE COMPOUNDS
CONTROL
COOLING
DISPERSIONS
ENERGY TRANSFER
EQUIPMENT
FILMS
FLUIDS
GASES
HALIDES
HALOGEN COMPOUNDS
HEAT TRANSFER
HYDROGEN COMPOUNDS
LITHIUM BROMIDES
LITHIUM COMPOUNDS
LITHIUM HALIDES
MASS TRANSFER
MIXTURES
OXYGEN COMPOUNDS
PERFORMANCE
REYNOLDS NUMBER
SOLAR ABSORBERS
SOLAR EQUIPMENT
SOLUTIONS
SUBCOOLING
TUBES
VAPORS
WALLS
WATER
WATER VAPOR