In order to investigate thermochemical energy storage in larger scale, a test bench as well as a reactor containing around 20kg of reaction material has been built and brought into operation. This investigation is based on the reversible decomposition reaction of calcium hydroxide, due to its wide availability, high reaction enthalpy and promising temperature range for CSP plants. Additionally, a developed simulation tool was used to analyze the experimental results. The comparison of the discharging processes showed a good agreement but also revealed thermal losses due to the experimental setup and the operation mode of the thermochemical storage. Therefore, first operation strategies of thermal energy storages based on chemical reactions can be derived

Thermochemical energy storage, for instance with Ca(OH)2, offers high energy densities at low material costs and could therefore be a promising storage alternative for CSP-plants. Yet, due to the low thermal conductivity of the Ca(OH)2 material large storage capacities operated in an indirectly heated fixed bed also require large heat exchangers. In other words the fixed bed concept somehow opposes one of the main advantages of Ca(OH)2, its low material costs. One approach to overcome this issue is to detach the costly reactor with the heat exchanger (power) from the storage material (capacity). This can be accomplished by a moving bed concept where the material moves through the reactor. Therefore a novel moving bed pilot plant was developed within the consortium of the European project TCS Power. The pilot plant was set into operation and revealed important information about the material flow through the reactor and the operation strategy of a moving bed concept.