Absorption of Water Vapor into Lithium Bromide-water Solution Film Falling along a Vertical Plate

Abstract

Recently, the lithium-bromide/water absorption refrigerating machine has begun to be used for the air-conditioning of large buildings. However, more improvement of the absorber, one of its main components, is needed to achieve a better coefficient of performance and also to reduce the whole size and the installation space, In this paper, an analysis of the absorption process is made for the simplified cooling surface geometry of a vertical flat plate instead of the horizontal tubes used in real machines. An analytical model is formulated by assuming that the flow is laminar and that the absorbent is thermodynamically in equilibrium at the surface. The governing equations are solved by the finite difference method and the profile method. Calculation examples of both methods are given for a standard condition. Near the entrance region, the calculated temperature profiles differ slightly, but becomes equal rapidly as flow length increases. The average concentrations agree well.