Energy efficient air conditioning to termite mounds Energy efficient air conditioning to termite mounds

Provide fresh air while maintaining temperature and humidity in the room. This is a challenge for air conditioning systems. Certain structures in termite mounds could be a model.

The special way in which termite mounds are ventilated can provide energy-efficient air conditioning in buildings. This is the conclusion that David Andréen of Lund University in Lund (S) and Rupert Soar of Nottingham Trent University in Nottingham (GB) draw from experiments with the initial complex of a termite mound.

The construction of the tunnels creates turbulence in the air, which is blown into the openings by a light wind. The study was published in the journal Frontiers in Materials.

“When you’re ventilating a building, you want to maintain the delicate balance of temperature and humidity inside without impeding the movement of stale air out and fresh air in — which most air conditioners struggle with,” explains Soar. In the termite species Macrotermes michaelseni in Namibia, the researchers found an exit complex on the steep top of the hill, which mainly invades the north side of the hill during the rainy season (November to April).

Constructions of the tunnels cause turbulence

It has already been suggested that the starting complex serves, among other things, to drain excess moisture from the mound. However, it was unclear exactly how this works. Using a 3D printer, the scientists reproduced part of a first complex recovered from a termite mound in Namibia in 2005. Andréen and Soar have learned from their experiments that the net-like structures of the tunnels create turbulence, allowing air (or water) to enter the interior fairly quickly.

The turbulence not only ensures that the air penetrates deeply when it is blown only a few millimeters into the openings. The turbulent air repeatedly comes into contact with the tunnel wall, where pollen and other suspended solids in the air are partially separated. A filter function is also created. The turbulent air also prevents a moisture film from adhering to the tunnel walls, which could lead to mold growth.

“We envision that in the future, building walls made with new technologies such as powder bed printers will feature networks similar to the original complex,” Andréen said. The networks could make it possible to move air through embedded sensors and actuators that require only small amounts of energy. For example, in the future the building envelope itself or even the entire interior of a building can be air-conditioned in an energy-saving manner. (saw/sda/dpa)