A phenomenological approach of solidification of polymeric phase change materials

Une approche phénoménologique du processus de solidification dans une matériau à changement de phase stabilisé par un polymère

S. Amir Bahrani (1) , Laurent Royon (2) , Bérangère Abou (1) , Rémy Osipian (1) , Kamel Azzouz (3) , André Bontemps (2)

1 MSC - Matière et Systèmes Complexes
2 LIED (UMR_8236) - Laboratoire Interdisciplinaire des Energies de Demain
3 VALEO

Phase Change Materials (PCMs) are widely used in thermal energy storage and thermal management systems due to their small volume for a given stored energy and their capability for maintaining nearly constant temperatures. However, their performance is limited by their low thermal conductivity and possible leaks while in the liquid phase. One solution is to imprison the PCM inside a polymer mesh to create a Polymeric Phase Change Material (PPCM). In this work, we have studied the cooling and solidification of five PPCMs with different PCMs and polymer fractions. To understand the heat transfer mechanisms involved, we have carried out micro-and macrorheological measurements in which Brownian motion of tracers embedded in PPCMs has been depicted and viscoelastic moduli have been measured, respectively. Beyond a given polymer concentration, it was shown that the Brownian motion of the tracers is limited by the polymeric chains and that the material exhibits an elastic behavior. This would suggest that heat transfer essentially occurs by conduction, instead of convection. Experiments were conducted to measure temperature variation during cooling of the five samples, and a semi-empirical model based on a phenomenological approach was proposed as a practical tool to choose and size PPCMs

Mots clés: micro-rheology; solidification; phase change duration; stefan number; model; phase change material (PCM)

Domaines: Génie des procédés; Science des matériaux [cond-mat.mtrl-sci]; Matériaux

S. Amir Bahrani, Laurent Royon, Bérangère Abou, Rémy Osipian, Kamel Azzouz, et al.. A phenomenological approach of solidification of polymeric phase change materials. Journal of Applied Physics, 2017, 121 (3), pp.035103. ⟨10.1063/1.4974287⟩. ⟨hal-01473545⟩