Ventilated nests remove heat and gas: mound-building termites

1 of 1 Termite mounds in Moremi Game Reserve / Phil Zrim / License

Mounds of macrotermitine termites maintain homeostasis through tunnels, chimneys, and use of wind creating pressure fields.

Biomimicry Taxonomy

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Biomimetic Application Ideas

Use for low-cost ventilation of buildings.

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[Collapse all sections] Summary

Macrotermitine termites construct mounds that maintain a constant internal temperature due to their structure and interaction with the local environment, rather than use of expensive, external energy sources. Several factors allow mounds to stay 87° F inside--the optimum temperature for the fungi these termites cultivate--while the temperature ranges from 35° - 104° outside. For instance, the mounds' thermal mass has sufficient heat capacity to buffer the internal environment from heat gain during the day with cold accumulated over the night; narrowing shafts rising through the mound channel and accelerate the release of warm internal air out vents at the mounds’ top; and openings at the base of the mound allow cooler, denser air to flow in replacing warmer air as it rises. These principles informed the design of the Eastgate Center, built in Harare, Zimbabwe, in 1995, which uses about 35% of the energy required for temperature regulation as similar conventional office buildings and saved building owners USD 3.5 million up-front, because they did not need to buy an air conditioning system for the building.

Excerpt

"The macrotermitine termites build some of the most spectacular animal-built structures on the planet. Some, like the mound of Macrotermes michaelseni...are dominant landscape features over much of southern Africa. These termites control a significant portion of the flows of carbon and water through arid savanna ecosystems. These remarkable structures are not the residence for the colony--very few termites actually are found in them. Rather, they are accessory organs of gas exchange, which serve the respiratory needs of the subterranean colony, located about a meter or two below the mound…Functionally, these mounds are devices for capturing wind energy to power active ventilation of the nest. They are adaptive structures, continually molded by the termites to maintain the nest atmosphere. This ability confers on the colony emergent homeostasis, the regulation of the nest environment by the collective activities of the inhabitants." (Turner no date)

"Heat generated by the termites and their gardens in the core of the nest flows into the collecting pipes and rises in the chimneys at a rate of about five inches per minute. As this humid CO2-rich air flows up the chimneys it draws cooler air in through the cellar area under the nest, where it begins to flow up into the various chambers…The buttresses are riddled with tiny holes too small even for the termites but large enough for the warm stale air to diffuse out while cooler fresh air percolates in." (Gould and Gould 2007:139)

About the inspiring organism

Mound-building termites
Macrotermes michaelsei

IUCN Red List Status: Unknown
Habitat(s): Grassland, Savanna

Organism/taxonomy data provided by:
Species 2000 & ITIS Catalogue of Life: 2008 Annual Checklist

Bioinspired products and application ideas

Application Ideas: Use for low-cost ventilation of buildings.

Industrial Sector(s) interested in this strategy: Construction

Eastgate Centre building -

Upper Riccarton Community and School Library - Passive ventilation

Experts

Dept of Biology
Scott Turner
SUNY-ESF

Rapid Manufacturing Research Group
Rupert Soar
Wolfson School of Engineering at Loughborough University

References

Gould, James L; Gould, Carol Grant. 2007. Animal architects: building and the evolution of intelligence. New York: Basic Books. 324 p.

Turner JS. 2000. Architecture and morphogenesis in the mound of Macrotermes michaelseni (Sjöstedt) (Isoptera: Termitidae, Macrotermitinae) in northern Namibia. Cimbebasia. 16: 143-175.

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Also a great example of Life's Principle "Integrating cyclic processes through feedback lo...

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