For the modern object-oriented software Dymola Modelica a new library with thermodynamic modules of components of ice slurry systems has been created. The theoretical models for the modules of heat exchangers, storage tanks, pumps and tubes were chosen from former work performed by the Working Party on Ice Slurries of the International Institute of Refrigeration. The first test system is a new super market in Switzerland (Migros Uzwil) with 34 display cabinets, at present operated with commercially available brine. Numerical simulations of the system with a two-component, mono-phase (water glycol mixture) and a two-component, two-phase fluid, namely an ice slurry (water ethylene mixture), were performed and the results of four different operation cases are compared. An aim was to work out, on one hand, an accurate comparison of the energy demands and the related costs and, on the other hand, of the installation investment costs of the two systems with different fluids. Finally the intention is to make these two economical key parameters of concurrence systems available to decision makers, who are involved in the design of new similar plants.