Tecnica di formatura gelcasting per la produzione di sistemi di accumulo termico

Solar energy is the most available and deeply used renewable energy. Three different technologies can be used to convert the sun energy into useful power: photovoltaic cells, thermal systems, and concentrated solar power systems. The latter is particularly interesting as can be used to produce electricity also when the sun is not present (during the night or in a cloudy day). The sun rays are in fact concentrated by parabolic mirrors on a defined area. The generated heat warms up a fluid or a reservoir and can be used to generate steam and therefore electricity. The heat produced can however be stored into specific devices that can release it during all the night. The process efficiency takes great advantages by a intimate contact between the collecting tubes and the storage system. For this reason the latter must be of a rather complex shape. Among the possible forming methods for inorganic powder, gel casting was considered the most suitable one. The thermal storage system in fact, besides the shape must have dimensions over 1 meter. Aim of this work was the study and optimization of the gel casting process for the shaping of thermal storage devices. The process wad deeply analyzed from the raw materials (nature and morphology of the inorganic powders, gelling and other organic additives), through the shaping parameters (gelling time and temperature, suspension viscosity etc.) up to the final sintering step. Particular attention was paid on the realization of an experimental set up and standard operation procedures suitable for an industrial scale-up. The optimization of the entire ceramic process leaded to obtain products with density and microstructural properties suitable for thermal storage systems