A sustainable and economically reasonable energy supply on the basis of renewable sources as well as an efficient usage of energy are part of the current research politics with regard to the European Grean Deal. In the frame of its core competence energy systems Fraunhofer ICT is studying energy storage for mobile and stationary systems, fuel cell technology and thermal energy storage and recovery as well as material energy storage.
Energy storage and energy conversion research and development activities in order to improve the energy efficiency play a crucial role at Fraunhofer ICT. The research work is emphasised on the development and manufacturing of bio-based thermal barrier materials and on the development of thermal energy storage, both on the basis of phase change materials (PCM) as well as sorptive thermal strorage devices. The use of PCMs enables an active and passive thermal management. In the case of sorptive thermal storage devices, the release of energy from adsorption and desorption processes is exploited. One of such systems studied at Fraunhofer ICT is zeolite and water. The components are held separately during the storage process and are brought together for the sorptive reaction. Thermochemical storage systems enable a temporally decoupled provision of heat and cold.
Adsorption heat pumps are realized on the basis of reversible adsorption reactions. Gas molecules are adsorbed in an exothermal process on the surface of a porous solid material. The equilibrium of the reaction depends on temperature and pressure. Additionaly to the adsorption equilibrium, the adsorption kinetics is a crucial factor for the power of the heat pump. By combining foamed polymers with PCM the insulation properties of the foam are combined with the thermal properties of the PCM. The PCM have a high storage capacity in defined temperature ranges and balance temperature fluctuations by absorbing and releasing heat depending on the ambient temperature.
For recovering heat at high temperatures as it arises in steel and non-ferrous metallurgical plants, molten salt cycles are a promising technology. Fraunhofer ICT has many years of experience in investigating and developing cost efficient coatings to protect materials in the highly corrosive environment of molten salts. Aluminide diffusion coatings deposited as Al powder slurry and subjected to a heat treatment are the approach.
The main application areas targeted by the reseach activities are buildings, electronics, optical systems, energy converters and industrial processes. The research activities comprise in detail:
Thermochemical reaction storage on the basis of sorptive thermal storage materials
- physical-chemical basical characterization of sorptive thermal storage materials
- design of modified and functionalized systems
- characterization and simulation of adsorption and desorption phenomena by means of
- kinetic evaluation of charging and decharging processes
- layout, design and test of demonstrators for selected applications
Thermal energy storage on the basis of PCM
- physical-chemical basical characterization of PCM
- design of application of modified materials
- characterization and simulation of melting and crystallisation phenomena
- kinetic simulation and thermal management
- degradation and safety issues
- layout, construction and test of thermal storage demonstrators
Foamed polymers with PCM
- integration of the PCM into polymers by steam chest molding
- system and thermodynamic analysis
- modification and functionalization of PCMs and particle foams
- compatibility of the PCMs with the matrix system
- manufacturing parts for demonstrator components and economic evaluation
Aluminide diffusion coatings to protect materials against harsh environments at high temperatures
- slurry formula development
- external burn-in heat treatment
- investigation of the protection potential against corrosion