Energy saving and thermal insulation
With rising temperatures and rising energy prices, home air conditioning is becoming an almost unsustainable option. For this reason, it is necessary to invest in materials capable of guaranteeing correct thermal insulation to save on the bill. The best solution, in this sense, is wood foam. Let's find out more.
Scientists from the University of Göttingen and Nanjing Forest University have designed a lightweight foam based on wood-based cellulose nanocrystals that reflects sunlight, expels absorbed heat and acts as a thermal insulator. The team behind this project suggests that this innovative material could reduce the energy needs for cooling buildings by more than a third.
Although there are already insulating materials on the market, some passively release absorbed heat and allow a large amount of heat to pass through buildings under the direct midday sun in the summer months.
On the other hand, other insulation that reflects sunlight does not work well in hot, humid, or cloudy weather. Therefore, the scientists wanted to develop a robust material that could reflect light, passively release heat and prevent the passage of heat in different atmospheric conditions, regardless of the type of climate.
To generate this cooling material, the researchers linked cellulose nanocrystals with a silane bridge, before freezing and lyophilizing (a chemical dehydration process) the material under vacuum. This process aligned the nanocrystals vertically, creating a light white foam that reflected 96% of the visible light and emitted 92% of the absorbed infrared radiation.
To test its performance, it was placed on a box lined with aluminum foil in the open air at noon. The material managed to keep the inside of the box 9.2 degrees cooler than the air outside. Even in rainy weather it kept the interior 7.4 degrees cooler. Researchers estimate that, when applied to coat the roof and walls of a building, it could reduce cooling energy needs by an average of 35%.
Scientists found it curious that the cooling power of the foam would decrease if it were compressed. It might seem like a disadvantage at first, but the team of scientists suggested that foam compression could be a useful way to adjust the amount of cooling based on the weather or the environment.
Scientists say the new cooling foam could pave the way for thermal regulation materials that are not only environmentally friendly, but also reduce the cost of energy used for cooling.
from idealista.it
Condividi l'articolo
