Biomimicry in Action: African Termites Inspire a Green Building
This is a different kind of story about green building in Africa. Instead of the usual treatise on the need for more sustainable forms of development, this is a tale of technological innovation, biomimetic philosophy, and green building principles put successfully into action â read on to find out how the African termite guided architects towards a new method for thermal regulation.
What is Biomimetic Architecture?
According to the Biomimicry Institute, âBiomimicry is the science and art of emulating Nature's best biologicalÂ ideas to solve human problems.â Why? You ask. Well, because (as the argument goes) humans are relative newcomers to this planet, and not particularly successful ones at that. Presumably there are other species in nature that have derived better ways of doing things, and from which we humans can learn, if we are willing to pay attention. A statement on the home page of the Biomimicry Institute website reads: âHumans haveÂ a long way to goÂ towards living sustainably on this planet, but 10-30 million species with time-tested genius to help us get there.â Biomimetic Architecture is an extension of this logic â an approach that advocates looking to nature for inspirational ideas and solutions to architectural problems, a way of mining the biosphere to learn more about green building
Termites Inspire a Green Building
The Eastgate Center in Harare, Zimbabwe is, perhaps, the canonical example of biomimetic principles applied to the design of a green building. For this project, architect Mick Pearce worked with Arup Associates to design a building with a thermal regulation system inspired by that which is used to cool African termite mounds.
African termites build huge mounds that serve doubly as their communal colony home, as well as an incubator for the fungus they farm for sustenance. These mounds are, apparently, the largest non-human-made structures in the world. Termites build them with orally-transported soil particles (sand, silt, clay and organic carbon), cemented with saliva to form walls. This building material is so strong (and water resistant) that local humans often use it in the construction of their homes.
The fungus is grown in internal chambers, and must be maintained at a constant diurnal temperature (one source consulted said precisely 87 degrees F, another said between 88 and 89 degrees). Since external temperatures can fluctuate a great deal (between the low 30s at night and over 100 during the day), African termites have developed an ingenious thermal regulation system in which a series of vents are opened and closed throughout the day and night. At night, when the external temperature is cold, openings are blockaded to reduce heat loss and during the day, cooling vents are opened fully to maximize ventilation during times of increased solar gain. The termites constantly open and close various openings in order to create a series of convection currents that ventilate the mound and regulate the interior temperature.
The Eastgate Center has a ventilation system that operates in a very similar way, allowing the building to maintain a relatively constant temperature without the use of supplemental air conditioning. As a result, this often-touted green building has a greatly reduced energy footprint in addition to an interesting design story.