Steam absorption into aqueous lithium bromide solution films falling inside vertical pipes

Abstract

AbstractThe realization of a compact and efficient air‐cooled absorber is the key technology for the small‐capacity absorption refrigerator for domestic use. A vertical pipe with absorbent flowing inside and air flowing outside is the best choice for the air‐cooled absorber due to the easy addition of fins to enhance heat transfer on the air side. In this paper, first, the modeling of the absorption process in the vertical pipe for a constant heat transfer coefficient on the outer surface is described. Then, experimental results are presented for pipes of inner diameters 8 to 26 mm, pressure 5 and 6 mm Hg, and outer surface heat transfer coefficient 2000 and 3300W/(m2·K). It was found that for pipes of diameter 13 mm or more, the absorption process is well estimated by the proposed model. The absorption with addition of surfactant is estimated by the pseudo‐turbulent method. The necessary heat transfer area for the air‐cooled condition is about three times that for the water‐cooled condition. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(8): 740–752, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10128