Determination of the enthalpy of phase change materials by inverse method from calorimetric experiments. Applications to pure substances or binary solutions

Abstract : The aim of this paper is to present an inverse identification method to determine specific enthalpy of PCM from calorimetry experiments. We will focus on the cases of pure substances and ideal binary solutions including the eutectic equilibrium. The corresponding direct model, based on energy balance, is first presented. A classical enthalpy method is then used, which presents the advantage of easily decoupling the thermal transfers from the specific energetic behavior of the material (i.e. thermodynamical phenomenon). In the second part of the paper, we will present the used inverse method (genetic algorithms). The sensibilities of the different parameters for the identification are analyzed. Finally, we will present the identification from DSC experiments (1) at different rates of heating for pure substances and (2) at different concentrations of aqueous solutions of N H 4 Cl. In each case, we identify the thermodynamical parameters of the model and compare the corresponding thermograms with the experimental ones. A good agreement is obtained for both cases