Studies on bubble pump for a water–lithium bromide vapour absorption refrigerator: Etudes sur une pompe à bulles pour réfrigérateur à absorption eau–bromure de lithium

The hydrostatic principle and bubble pump technique are used in the two-fluid pumpless continuous vapour absorption refrigerator to create the circulations of the solution and refrigerant. In this paper, the bubble pump, which is the ‘heart' of this natural circulation type of refrigerator, has been investigated both analytically and experimentally. The bubble pump is modelled for intermittent slug flow of solution and vapour mixture. A test rig is built in glass to evaluate the performance of the bubble pump, to visualize the flow behavior and to validate the analytical model. Bubble pump tube diameter, pump lift, driving head and heat input are varied to analyze the pump performance. Results indicate that pumping ratio is nearly independent of the heat input, but increases with decrease in pump tube diameter, decrease in pump lift and increase in driving head.