Termites: Destroyers or Green Builders?
They bore through your flooring, damage wooden studs and furniture, but scientists are studying how termites build their mounds for tips on how to build better green buildings. Researchers held a recent three-day conference in Italy, “From Insect Nest to Human Architecture: Workshop on engineering principles of innovation in swarm-made architectures.”
In a review of the conference, The New Scientist explained the structures in the following way: “In the heart of Africa’s savannah lies a city that is a model of sustainable development. Its buttressed towers are built entirely from natural, biodegradable materials.”
Most impressively, these insects build incredibly efficient HVAC (heating, venting, air conditioning) systems in their mounds that are capable of regulating humidity and temperature to keep their temperamental fungal food source thriving (Termites can not digest the cellulose—woody—materials they take the materials and use fungi they colonize to break the materials into nutrient-rich food.). The mounds discussed at the recent conference were capable of exchanging roughly 1,000 liters of air a day with no fans.
We rely primarily on forced-air systems that use significant amounts of electricity and other fuels to provide our heating and cooling and walls that provide a further barrier to external temperatures. But the walls of the termite mounds themselves are being studied for their ability to allow certain frequencies of wind currents to pass through.
Termite expert Scott Turner of the State University of New York in Syracuse, and Rupert Soar of Freeform Engineering in Nottingham, UK, researched how Macrotermes termites built their mounds in Namibia. Their research determined that the walls of the mounds are warmer than the heart of the nest. They theorized that the structures used turbulence and frequency changes in wind gusts to help regulate temperature.
They found that the outer walls of the mounds only allow with low frequencies to penetrate. The frequency changes in the wind gusts that penetrate the walls of the mound walls move within the mound and vibrating the stale air that is within the structure, allowing the bodies of air to be exchanged. “In essence, the mound functions as a giant lung,” according to the New Scientist.
Based on the research, Turner said we should rethink how walls could function. Rather than serving as barriers to the outside, we could design them as porous, adaptive surfaces that regulate heat and air exchange.
At the recent conference, termites’ ability to regulate humidity in dry climates by depositing a slurry of chewed wood and grass at the base of their mounds was also discussed. This spongy material can contain up to about 80 liters of water and can either perspire or expunge additional water into the air to help regulate the climate in mound.
Architects and engineers could mimic this by building water holding tanks into their structures that absorb and emit water to regulate humidity within a structure. Turner says such techniques could open up “new bio-inspired design principles” for human-made structures.