The scientists focused on the egress complex: a dense, lattice-like network of tunnels, between 3mm and 5mm broad, which connects wider conduits inside with the exterior. Andréen and Soar explored how the layout of the egress complex makes it possible for oscillating or pulse-like flows. They based their experiments on the scanned and 3D-printed copy of an egress complex fragment gathered in February 2005 from the wild. The authors then simulated the egress complex with a series of 2D designs, which increased in complexity from straight tunnels to a lattice. They found, to their surprise, that the motor needed to move air back and forth just a few millimeters (corresponding to weak wind oscillations) for the ebb and flow to penetrate the entire complex.
Part of the egress complex of a mound of Macrotermes michaelseni termites from Namibia. Credit: D. Andréen
The qualities of the “egress complex” discovered in termite mounds can be reproduced to improve the optimize interior climate of structures.
Of the roughly 2,000 acknowledged termite types, some play an important role as community engineers. The colossal mounds, approximately 8 meters high, constructed by a number of termite genera like Amitermes, Macrotermes, Nasutitermes, and Odontotermes, represent some of the most considerable biological developments worldwide. These structures have been developed and perfected by natural selection over tens of countless years. How might human architects and engineers gain from studying these industrious bugs?
An innovative research study released in Frontiers in Materials demonstrates the important lessons we can gain from termite mounds to develop comfy interior environments in our structures. The interesting part is, these methods might potentially reduce the carbon footprint normally connected with air conditioning.
” Here we show that the egress complex, an intricate network of interconnected tunnels found in termite mounds, can be utilized to promote flows of air, heat, and wetness in unique methods human architecture,” said Dr. David Andréen, a senior speaker at the bioDigital Matter research study group of Lund University, and the studys very first author.
Termite mound in Bangalore, India. Credit: D. Andréen
Termites from Namibia
Andréen and co-author Dr. Rupert Soar, an associate professor at the School of Architecture, Design and the Built Environment at Nottingham Trent University, studied mounds of Macrotermes michaelseni termites from Namibia. Nests of this species can consist of more than a million people. At the heart of the mounds lie the symbiotic fungi gardens, farmed by the termites for food.
The scientists focused on the egress complex: a dense, lattice-like network of tunnels, between 3mm and 5mm large, which links larger conduits inside with the outside. The complex is believed to permit evaporation of excess moisture, while preserving adequate ventilation.
Termite mound in Waterberg, Namibia. Credit: D. Andréen
Andréen and Soar explored how the design of the egress complex makes it possible for oscillating or pulse-like circulations. They based their experiments on the scanned and 3D-printed copy of an egress complex fragment gathered in February 2005 from the wild. This piece was 4cm close a volume of 1.4 liters, 16% of which were tunnels.
They simulated wind with a speaker that drove oscillations of a CO2-air mix through the fragment while tracking the mass transfer with a sensing unit. They found that air flow 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.
Turbulence helps ventilation
The researchers concluded that tunnels in the complex interact with wind blowing on the mound in ways that improve mass transfer of air for ventilation. Wind oscillations at particular frequencies produce turbulence inside, whose result is to bring breathing gases and excess moisture far from the mounds heart.
” When ventilating a building, you want to maintain the delicate balance of temperature level and humidity created within, without hindering the movement of stale air outwards and fresh air inwards. Conditions within are thus maintained,” described Soar
3D scan of a piece of the egress complex of Macrotermes michaelseni termites. Credit: D. Andréen and R. Soar.
The authors then simulated the egress complex with a series of 2D models, which increased in complexity from straight tunnels to a lattice. They found, to their surprise, that the motor needed to move air back and forth only a couple of millimeters (corresponding to weak wind oscillations) for the ebb and circulation to penetrate the whole complex.
Living and breathing buildings
The authors conclude that the egress complex can enable wind-powered ventilation of termite mounds at weak winds.
” We envision that building walls in the future, made with emerging technologies like powder bed printers, will include networks similar to the egress complex. These will make it possible to move air around, through embedded sensors and actuators that need only small quantities of energy,” said Andréen.
Skyrocket concluded: “Construction-scale 3D printing will only be possible when we can create structures as complex as in nature. The egress complex is an example of a complicated structure that could resolve numerous issues at the same time: keeping comfort inside our homes while managing the flow of respiratory gasses and moisture through the structure envelope.”
” We are on the brink of the shift towards nature-like building: for the very first time, it may be possible to develop a real living, breathing structure.”
The research study was funded by the Engineering and Physical Sciences Research Council, the Swedish Research Council, and the Human Frontier Science Program.
