A new insulating material for building walls stores 24 times more heat than concrete or plaster. It was developed by researchers at the Martin Luther University Halle-Wittenberg (MLU). It is a phase change material. When the sun shines, it absorbs heat so that it does not get into the wall and eventually into the interior. It becomes liquid. If it is cold the next night, the material crystallizes and gives off the heat again, usually on the walls, which act as a heater in this way.
Crystallization Triggers Heating
“Many people know the principle of hand warmers,” says Professor Thomas Hahn of MLU’s Institute of Chemistry. The phase change material is contained in a plastic pad. It is charged in hot water and the material becomes liquid. This so-called latent heat storage can then cool down without losing the stored energy. If necessary, a crystallization point is usually acoustically activated, causing the entire material to harden and release heat.
Insulating material in a silicate framework
Hahn and his team don’t just stick plastic bags to the walls. They developed a more subtle form of packaging. “In our development, the actually liquid heat accumulator is enclosed in a solid silicate frame and cannot escape,” says Hahn. The production mainly uses environmentally friendly substances: harmless fatty acids such as those found in soaps and creams. The additives used, which give the material its strength and increased thermal conductivity, can be obtained from rice husks.
Air conditioning and heating costs fall
The team was supported by a team led by Kirsten Bacia, professor of biophysical chemistry at MLU, who visualized the mechanism using fluorescence microscopy. “Knowing this is important for further optimization and also for industrial-scale production,” says Felix Marske, who led the development as part of his PhD at Hahn.
The scaffolding is formed into panels that are glued to the walls of houses as thermal insulation material. In winter, they prevent too much cold from entering the walls. You save on air conditioning in the summer and heating costs in the winter.
via Uni Halle