Ongoing and planned research work in the absorption field at Chalmers University of Technology can be divided into four areas:- System studies and optimization;A computer program has been developed with which a heat transformer can be simulated and its parts can be technically and/or economically optimized. Technical optimizations include optimal area distribution between the five heat exchangers to achieve a certain COP or a certain temperature lift and minimum total area needed for a certain heat output. Economic optimizations include optimal size of the heat transformer and its components at various conditions.- Desorption heat transfer; An experimental plant for studies of heat transfer coefficients of LiBr-H20 in a falling-film type desorber has been constructed. No results are yet available. -An activity-coefficient model for electrolyte systems; An activity-coefficient has been proposed to represent the properties over a wide electrolyte concentration range, i.e. high dilution to the solubility limit. It is well suited both for single-electrolyte and multi-electrolyte solutions.-Transport properties for electrolyte systems;The aim with this project is to develop methods and equations for correlation and prediction of transport properties, mainly viscosity, for single- and multicomponent electrolyte systems. An equation for correlation of viscosity data has been proposed and an equation for prediction of the viscosity based on activity coefficients is under development