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.

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A new correlation for some transport properties of aqueous solutions, based on the data published by Sawada et al. [1], is proposed. The main objective of the new fit is to give a smooth transition to the properties of pure water to allow the use of the fit in the region of very dilute solutions. Additionally, the quality of the fit to the experimental data is improved compared to the original correlation. An extrapolation of the new correlation in the other direction, i.e., to higher mass fractions and temperatures, is smooth but does not fully capture the trend described by other experimental datasets. To this end, the correlation has to be refined further.

A correlation for dynamic viscosity of aqueous lithium bromide solution is proposed. The correlation is based on an empirical approach accounting for physical limitations. The data are compiled from 11 sources over a temperature range from − 20 $$^{\circ }$$ ∘ C to 110 $$^{\circ }$$ ∘ C and from pure water to salt mass fractions of 65 %. The correlation succeeds in predicting the solution’s viscosity over the chosen range of measured data. In most parts of its validity range the accuracy is significantly improved compared to previous equations.