In this project the concept of Phase Change Slurries (PCS) is investigated which is produced via a partial crystallization of a Phase Change Material (PCM). PCS systems promise higher energy densities both as heat transfer fluids and as storage media in comparison to sensible systems. At the same time they remain pumpable and therefore can achieve much better heat transfer characteristics than conventional latent heat storage technologies. This technology is expected to deliver high thermal power and high temperature stability in a compact design while operating with conventional components. The main objective of this project is the development of a proof-of-concept test rig to demonstrate the feasibility of a continuous and controllable crystallization of a PCS at temperatures between 50 and 90°C. The chosen PCM is aluminium ammonium sulfate dodecahydrate (NH4Al(SO4)2·12H2O).