Researchers have uncovered a methodology for reducing energy consumption in buildings by studying the structure of termite mounds. Led by Lund University’s Dr. David Andréen and Nottingham Trent University’s Dr. Rupert Soar, the research suggests that the properties of lattice networks in termite mounds, known as an ‘egress complex,’ can be copied to optimize the interior climate of buildings.

“Here we show that the ‘egress complex’, an intricate network of interconnected tunnels found in termite mounds, can be used to promote flows of air, heat, and moisture in novel ways in human architecture,” said Andréen about the study, which was recently published in Frontiers in Materials.

The team grounded their research in the egress complex of Macrotermes michaelseni termites in Namibia, which they observed appeared to promote moisture regulation and ventilation. The mounds are regarded as some of the world’s largest biological structures, capable of reaching over 26 feet in height and holding more than a million individual termites. At the heart of the mounds lie symbiotic fungus gardens, which are farmed by termites for food.

Within the tunnels, the egress complex consisted of a dense, lattice-like network of tunnels measuring between 3mm and 5mm in width, which connects wider chambers in the mound with the exterior. During the rainy season, the tunnels emerge on the north-facing surface of the tunnel, directly exposed to the sun. Outside of this season, the tunnels are blocked.

The researchers observed that the network allowed for the evaporation of excess moisture while maintaining adequate ventilation, all by enabling oscillating or pulse-like flows of wind. To understand how such oscillations supported climate control, the researchers simulated wind conditions on a 3D-printed copy of an egress complex, through which they drove a CO2-air mixture at varying oscillation frequencies. They found that airflow was greatest at oscillation frequencies between 30Hz and 40 Hz; moderate at frequencies between 10Hz and 20 Hz; and least at frequencies between 50Hz and 120 Hz.

The researchers concluded that wind oscillation at certain frequencies generates turbulence inside the mound, which carries respiratory gases and excess moisture away from the heart of the mound. The authors conducted further studies on a series of 2D models of the lattice, through which they discovered that even weak wind oscillations enabled turbulence to penetrate the entire complex, but only if the layout was “sufficiently lattice-like.”

“When ventilating a building, you want to preserve the delicate balance of temperature and humidity created inside, without impeding the movement of stale air outwards and fresh air inwards,” Soar explained. “Most HVAC systems struggle with this. Here we have a structured interface that allows the exchange of respiratory gasses, simply driven by differences in concentration between one side and the other. Conditions inside are thus maintained.”

The team is confident that the properties observed in termite mounds can inform more energy-efficient building design. The researchers specifically highlight the potential for construction-scale 3D printing informed by their research which could keep homes cool, and regulate the flow of gases and moisture.

“We imagine that building walls in the future, made with emerging technologies like powder bed printers, will contain networks similar to the egress complex,” Andréen explained. “These will make it possible to move air around, through embedded sensors and actuators that require only tiny amounts of energy.”

News of the research comes weeks after a team of MIT researchers found that baking soda may help concrete absorb carbon. In March, meanwhile, researchers at the University of Michigan merged 3D printing with computational design to create an “ultra-lightweight, waste-free concrete.”