Paper presented to the 3rd Southern African Solar Energy Conference, South Africa, 11-13 May, 2015.
The aim of this paper is to predict the location of azeotropes for binary mixtures using two methods: firstly from the experimental data and secondly with a thermodynamic model. The model is composed of the Peng–Robinson equation of state, the Mathias–Copeman alpha function and the Wong–Sandler mixing rules involving the NRTL model. The binary systems of refrigerants considered in this paper are: Pentafluoroethane (R125) + Propane (R290) , 1,1,1-Trifluoroéthane (R143a) + Propane (R290)  and Carbon Dioxide (R744) + Propane (R290) . The mixtures mentioned above have been chosen because they are environment friendly with a null ODP and a low GWP.
The results proved that there is a good agreement between the predicted values and the experimental data. The presented methods are able of predicting the azeotropic positions.