It is known that when studying the fusion of phase change materials (PCM) in differential scanning calorimetry (DSC) experiments, the geometry of the samples is not well known. Yet, some studies show that a numerical model, needing obviously to clearly define the shape of the sample, may reproduce the experimental DSC curve. In particular, such methods are currently applied to identification process based on inversion methods applied to the thermodynamical parameters governing the numerical model. Consequently, it means that if several numerical models are able to reproduce the thermal behavior of a PCM undergoing phase transition, the best one is the simplest one, that is to say the one which is the fastest to solve. Recently, we have thus shown that for pure substances PCM, a reduced model based on a spherical assumption for the shape of the sample leads to similar DSC curves that a more general model based on cylindrical shape. Clearly, if this result may be extended to other kinds of PCM, this will promote the capability of this method to be used in inversion process involved by identification process. The aim of the present paper is therefore to further study this method by considering non-pure materials, i.e. binary solution in the present case.