Image credit: D. Andréen
Scientists have discovered that the unique features of termite mounds can provide valuable insights for creating buildings with optimized interior climates. Certain termite species, known as ecosystem engineers, construct massive mounds reaching up to eight meters in height. These remarkable structures, crafted by termites like Amitermes, Macrotermes, Nasutitermes, and Odontotermes over millions of years, have caught the attention of architects and engineers. By studying these industrious insects, researchers have unveiled groundbreaking techniques that could significantly reduce the energy consumption typically associated with air conditioning.
Dr. David Andréen, the first author of the study and a senior lecturer at Lund University’s bioDigital Matter research group, explained, “We have discovered that the ‘egress complex,’ an intricate network of interconnected tunnels found in termite mounds, can be harnessed to promote the flow of air, heat, and moisture in innovative ways within human architecture.”
For their research, Dr. Andréen and co-author Dr. Rupert Soar from Nottingham Trent University focused on mounds built by Macrotermes michaelseni termites in Namibia. These colonies can comprise over a million individuals and feature symbiotic fungus gardens at their core, cultivated by the termites as a food source.
The egress complex, a dense lattice of tunnels measuring between 3mm and 5mm in width, became the primary focus of the study. During the rainy season, the complex extends over the north-facing surface of the mound, directly exposed to the midday sun. However, outside this season, termite workers seal the egress tunnels. The purpose of this complex is believed to facilitate the evaporation of excess moisture while ensuring adequate ventilation. But how does it work?
To unravel the mysteries of the egress complex, Andréen and Soar examined how its layout enables oscillating flows. They conducted experiments using a scanned and 3D-printed replica of a fragment of the egress complex collected from the wild. By employing a speaker to generate oscillations of a CO2-air mixture through the replica and tracking the mass transfer with a sensor, the researchers found that the airflow was strongest within specific oscillation frequencies.
According to the team’s findings, the tunnels in the complex interact with wind blowing on the mound, enhancing the exchange of air for ventilation. Turbulence generated within the complex carries away respiratory gases and excess moisture from the mound’s core.
Soar explained, “When ventilating a building, it is crucial to maintain the delicate balance of temperature and humidity without impeding the movement of stale air outwards and fresh air inwards. Many HVAC systems struggle with this challenge. However, the structured interface provided by the egress complex allows the exchange of respiratory gases through a simple concentration gradient, thus maintaining ideal conditions inside.”
Using a series of 2D models, the researchers further simulated the egress complex, gradually increasing its complexity from straight tunnels to a lattice structure. They observed mass flow by driving an oscillating body of water, dyed for visibility, through the tunnels using an electromotor. Surprisingly, they found that minimal back-and-forth movement of air (corresponding to weak wind oscillations) was sufficient to propagate the ebb and flow throughout the entire complex. Importantly, the necessary turbulence only occurred when the layout resembled a lattice structure.
Andréen envisions a future where building walls, created with advanced technologies like powder bed printers, incorporate networks similar to the egress complex. These networks, equipped with embedded sensors and actuators that consume minimal energy, would facilitate the movement of air within the buildings.
Soar concluded, “For the first time, we may be able to design truly living and breathing buildings as we approach the transition towards nature-inspired construction. The egress complex exemplifies a complex structure that can simultaneously address multiple challenges—keeping our homes comfortable while regulating the flow of respiratory gases and moisture through the building envelope.”
The Engineering and Physical Sciences Research Council, the Swedish Research Council, and the Human Frontier Science Program provided funding for this study.
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Frequently Asked Questions (FAQs) about energy-efficient buildings
What is the main concept behind the study on termite mounds and buildings?
The main concept behind the study is to explore how the unique features of termite mounds, particularly the egress complex, can inspire the creation of energy-efficient buildings with optimized interior climates.
How do termite mounds contribute to energy efficiency in buildings?
Termite mounds provide valuable insights into natural ventilation and airflow systems. The egress complex, a network of interconnected tunnels within termite mounds, allows for the exchange of air, heat, and moisture. By studying and replicating these features, buildings can achieve better ventilation and reduce the need for excessive air conditioning, leading to energy savings.
What is the potential impact of this research on building design?
This research opens up possibilities for designing buildings that mimic the efficient airflow and ventilation systems found in termite mounds. By incorporating similar structures and principles into building design, it may be possible to create living and breathing structures that maintain comfortable interior climates while minimizing the carbon footprint associated with traditional air conditioning systems.
How could this study affect sustainable architecture in the future?
The study on termite mounds provides inspiration for sustainable architecture practices. By adopting nature-inspired designs, such as incorporating networks similar to the egress complex into building walls, it becomes feasible to move air effectively through embedded sensors and actuators requiring minimal energy. This approach has the potential to revolutionize sustainable building design by enhancing energy efficiency and creating more environmentally friendly structures.
What funding supported this study?
This study was funded by the Engineering and Physical Sciences Research Council, the Swedish Research Council, and the Human Frontier Science Program. Their support enabled researchers to explore the connections between termite mound structures and energy-efficient building design.
More about energy-efficient buildings
- Frontiers in Materials: Link
- Lund University: Link
- Nottingham Trent University: Link
- Engineering and Physical Sciences Research Council: Link
- Swedish Research Council: Link
- Human Frontier Science Program: Link
