Due to the increasing share of regenerative energy, research into thermal storage systems is becoming increasingly important. Phase change slurries (PCS) can be used as a thermal storage system and consist of a phase change material (PCM) within a carrier fluid. This enables the pumping of the PCS in a hydraulic system independently of the state of matter of the PCM. In this contribution a PCS with 35 wt.% Parafol 18-97 (Sasol Germany, n-octadecane, Tm = 27.3 °C) as a PCM was characterized under realistic thermomechanical stress in a storage tank test facility at a scale of 0.5 m3. At a temperature difference of 7 K (20 °C â 27 °C) it was possible to store 2.57 times more heat in the PCS in comparison to water. Furthermore, the influence of PCS on the energy demand of a pump was investigated