The material that could save industries heat – ScienceDaily
Japanese scientists have discovered a common substance that can reversibly and quickly store and release relatively large amounts of low-grade heat without breaking down. The research could lead to more efficient reuse of industrial waste heat. The results were published in the journal Nature Communication and were a collaboration between scientists at Tohoku University’s Materials Research Institute and Rigaku Corporation, a company that designs and manufactures X-ray-based thermal measurement and analysis tools.
In their research, the researchers used a layered manganese oxide mineral containing potassium ions and crystal clear water. This mineral is quite similar in composition to birnessite, which is commonly found on the Earth’s surface. The team fabricated their compound as an insoluble black powder and then examined its crystal structure using an X-ray diffractometer and a transmission electron microscope. They then looked at how the structure of the compound changed when heated or cooled, and how much and how quickly thermal energy was stored and released.
Heating the material up to 200 degrees Celsius dehydrates it by giving its stored water molecules the energy they need to be released into the surrounding atmosphere. When the dehydrated material was then cooled below 120°C in a dry container and then exposed to moist air, it absorbed water molecules and released its stored heat.
“This ‘intercalation’ mechanism, where water molecules are reversibly inserted into a layered material, is very advantageous for heat storage,” says Tetsu Ichitsubo, materials scientist at Tohoku University. . “It’s very fast, reversible and the structure of the material is well preserved. In addition, oxygen in the atmosphere does not degrade the layered manganese oxide crystal and water does not dissolve it. This makes it an excellent candidate for reusing waste heat in industrial settings.
This “birnessite-like layered manganese dioxide with crystal water” compound demonstrated better overall performance compared to other compounds currently being studied for heat storage purposes. “Our material has a long lifespan, can reversibly store and release large amounts of heat per unit volume, and charges and discharges quickly,” says Ichitsubo.
The researchers validated the results of their experiments by theoretical calculations.
Next, they plan to work on increasing the amount of water molecules that can be accommodated by the material in order to increase the amount of thermal energy it can store.
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Material provided by Tohoku University. Note: Content may be edited for style and length.