Optimization of the formulation of a phase change slurry.

Based on a formulation for a Phase Change Slurry (PCS) with 30 wt.% n-octadecane, 7 wt.% emulsifier with an Hydrophilic-Lypophilic-Balance (HLB) of 12 and a nucleating agent an optimization of the composition of the PCS was done. The HLB and the emulsifier concentration as well as the phase change material (PCM)-fraction were modified. An improvement was checked on the basis of the particle size distribution, the viscosity and the phase change behaviour in the differential scanning calorimeter (DSC). To proof thermal-mechanical stability of the emulsion it is cycled in the rheometer over its phase change at a shear stress of 100 1·s-1. By changing the emulsifier concentration and the HLB of the emulsifiers it was possible to formulate PCSs showing low viscosities when cycling it over the phase change region. With the optimized formulation PCM-fractions of up to 45 wt.% of PCM were emulsified resulting in thermally-mechanically stable PCSs.