The basic technical objective of the current project is to develop a modular second generation prototype of an advanced thermal storage system with high energy density based on sorption technology. To achieve this main objective, the existing first generation sorption heat storage unit was monitored and evaluated in the present installation. In order to meet the targets of straight forward installation and a reduction of costs, the main improvement is the integration of key components (evaporator/condenser and the reactor) into one single container as illustrated n figure 8. Then a vacuum connection between the different units is no longer needed, which makes the installation of the modules much easier. Due to the target of having a modular design and reducing the size and weight of the modules, the sorption units are designed much smaller than the first generation prototypes.

The heat exchanger design and production of the adsorbers play a dominant role for the system. In the new system the adsorber/desorber heat exchanger will be completely redesigned. For better a heat exchange, U-shaped finned tubes will be used. The silica gel area is surrounded by the evaporation/condensation area. In doing so, the ratio area to volume is greater than it was in the first generation prototype. Since more water vapour per time is able to come in contact with the silica gel, the physico-chemical reaction is faster. The compartments (silica gel area, evaporation/condensation area) are separated from each other by a water vapour permeable membrane and a metal inner surface. The whole weight of the silica gel is supported by a perforated slab.

One goal of this project is to monitor the system under real operation conditions. For this reason, the second generation thermal sorption storage system will be installed in a single-family house with a solar heating system and low temperature heat distribution. The energetic characteristics of the system and the relevant temperatures will be measured for at least one year. The monitoring will give information about the optimum control strategy of the different energy sources, the energy distribution and the general reliability of the system. After the monitoring, the data and information of the field test will be analysed, compared with the simulation and reported.