Energy supply is facing a series of new challenges, one of which is to avoid further climate change and environmental pollution, which is why new energy sources are being sought and developed today. These new developments include renewable and clean energy sources. Within this area it is also the energy storage, in wich there are many new developments and research activities. Recent energy storage research is focused on finding new reaction systems that could provide good heat storage. As part of this research, this work has been aligned. This thesis deals with the theoretical and experimental investigations of selected TCS materials for heat storage. Therefore, several experiments with magnesium oxide as a test material were carried out, with which one wanted to investigate the potential of the direct water injection in the fluidized bed. On the other hand, a fluidized bed reactor was set up, with which further fluidization experiments were carried out. Calcium oxalate monohydrate was used as the main test material.