Gives an overview of the research activities on absorption systems in the refrigeration and air conditioning laboratory at the Delft University of Technology. The research projects are - an absorption heat pump for domestic heating, fundamental research on heat and mass transfer in absorbers, a solar-driven absorption refrigeration machine, an absorption heat transformer for upgrading industrial waste heat and a hybrid heat pump system. A test plant has been built for each of these projects and the experimental results used to validate the simulation programs in order to carry out optimisation.KEYWORDS: Heat pumps, research, Netherlands, absorption heat pumps, domestic, heating, solar energy, absorption refrigeration, heat recovery, industrial.