Previous works on simulation of air conditioning systems with absorption chillers in conjunction with detailed experimental analysis have shown a need for a more detailed and generalized modelling and simulation of heat and mass transfer processes in absorption chillers. An existing model for absorption is adapted to be applicable for subcooled or superheated liquids and for the desorption process. New classes compatible with the Modelica_Fluid library (beta 2) for these sub-processes are developed. A media model for evaporating aqueous salt solutions based on Modelica.Media is developed and implemented accordingly. Subsequently, simulations of a complete absorption chiller are conducted and compared with experimental data. The comparison of simulations under stationary conditions show a good agreement with experimental data while the transient behaviour of the plant is not