Second law analysis and multi-objective optimization of a falling film absorber

A falling film absorber is studied in order to understand the phenomena that occur during its operation and find a way to improve its performance. The present work is divided in two parts using a developed model from previous article. The first part is focused on the study of the impact of design and operating parameters on different sources of entropy generation but also on the absorbed mass flow rate and recovered heat. In the second part, a multi-objective optimization is used in order to screen the falling film absorber performance by plotting Pareto-optimal fronts. The objective functions considered are the recovered heat, the absorbed mass flow rate and the entropy generation. The film and HTF Reynolds numbers as well as the HTF inlet temperature are found to be the most interesting variables to control to obtain high absorbed mass flow rate and recovered heat while controlling the entropy generation. The existence of an optimal film Reynolds number is also underlined in this study.