Experimental analysis of the influence of microcapsule mass fraction on the thermal and rheological behavior of a PCM slurry

A microencapsulated PCM (Phase Change Material) slurry with three different PCM mass fractions (14, 20 and 30%) has been analyzed. The present study investigates the influence of the PCM microcapsule mass fraction on the thermal and rheological characterization. Specifically, the Enthalpy–Temperature curves, the Thermal Conductivity–Temperature curves and the Viscosity–Shear rate curves have been determined. In addition, the physical stability under thermo-mechanical cycles has also been studied, as well as the heat transfer phenomenon and the fluid mechanics. The results have shown an enhancement in the heat transfer phenomenon, the slurry with 20% PCM microcapsules being the best option for use as a heat transfer fluid. Rupture of the PCM microcapsules was only observed for the slurry with 30% PCM microcapsules, after being pumped during three weeks and having experienced 10,000 solidification–melting cycles.