A new heat storage material could significantly improve building energy efficiency. It was created by researchers at Martin Luther University Halle-Wittenberg (MLU) and the University of Leipzig to store excess heat and release it back into the environment when needed.
In comparison to existing materials, the new one can absorb significantly more heat, is more stable, and is made of non-harmful substances. The team describes the material's formation mechanism in the Journal of Energy Storage.
The material in question is a shape-stabilized phase change material. It can absorb a large amount of heat by converting from a solid to a liquid state. When the material hardens, the stored heat is released.
"Many people are familiar with this principle from hand warmers," says MLU Institute of Chemistry Professor Thomas Hahn. However, Halle's invention will not be used in coat pockets. Instead, the construction industry could use it as large panels that could be integrated into walls.
These would then absorb heat during the day's sunny hours and release it later when the temperature drops. This could save a lot of energy: the researchers calculated that when the new material heats up, it can store up to 24 times more heat per 10 degrees Celsius than conventional concrete or wallboard under the right conditions.
The panels made of this material mixture, unlike hand warmers, do not melt when exposed to heat. "The heat storage material in our invention is enclosed in a framework of solid silicate and cannot escape due to high capillary forces," explains Hahn.
Most importantly, the ingredients used in its production are non-harmful fatty acids similar to those found in soaps and creams. Rice husks can also be used to obtain the additives that give the material its strength and increased thermal conductivity.
The current study describes the steps involved in creating the material's structure as well as how the various chemicals interact with one another. The team was helped by a group of MLU researchers led by Professor Kirsten Bacia, who used fluorescence microscopy to visualize the mechanism.
"The knowledge we're gaining can be used to further optimize the material and potentially produce it on an industrial scale," says Felix Marske, who spearheaded the development as part of his doctorate with Thomas Hahn.
Until now, the material has only been manufactured in small quantities in the laboratory. It can be combined with other steps in the future to help make buildings significantly more energy efficient or to passively cool photovoltaic systems and batteries, thereby increasing their efficiency.
(Source: Phys Org)
