Heat Storage in Future Zero-Energy Buildings
Institute of Materials & Machine Mechanics of Slovak Academy of Sciences (IMSAS) possesses the unique experience in the field of production of heating/cooling wall and ceiling panels based on aluminium foams for future energy autonomous houses and buildings. These novel heating/cooling panels have been developed and successfully tested in pilot application in 260 m2 open space office room. The low heat capacity of aluminium foam allows changing the temperature very quickly, whereas the temperature of the entire foam volume is always very uniform due to excellent thermal conductivity of aluminium cell walls. The heat is dissipated by foam using foamed-in tubes, which are completely embedded in the foam, keeping excellent contact to cell wall aluminium. Good thermal conductivity of the foam resulted in short length of embedded tubes, what is beneficial for low flow resistance and necessary pumping systems. The foamed panels can be partially impregnated at facing side by appropriate plaster, which improves the appearance and also serves as an absorber of potentially condensed air humidity. The developed panels provide an excellent alternative for large built-in ceiling radiators for efficient heating or cooling of rooms using low potential energy resources. The most appropriate ways of using these panels, which are able to increase extremely energy-efficiency in buildings have been outlined in this contribution. Moreover, technological solutions based on ability to store solar thermal energy effectively within the energy efficient buildings are introduced to scientific community in this contribution. The local thermal energy storage must provide the required flexibility to match the heat demand and supply because thermal energy cannot be transported over long distances without significant losses. Solar heat supply fluctuates not only between day and night, but extremely high fluctuations are problematically solvable mainly between summer and winter. In order to use the energy from sun to its maximum, the storage should be capable not only for short periods (hours and days) but also for long-term, e.g. seasonal heat storage. The advanced technologies for short-term storage as well as seasonal storage of solar heat obtained by thermo-solar collectors which allow to reduce energy consumption significantly during winter by interior heating and hot water generation in energyefficient buildings are discussed in this study.