Sunday, November 16, 2008

Termite Mounds as Models for Building Ventulation

Nature has been designing things for a lot longer than humans have. Because of this, natural selection has already figured out effective ways of dealing with things. We can learn a lot by looking at the way natural things in our world work.

The water bear as an inspiration to store vaccines for long term resistance against hearse conditions is one example of this. What I’m going to look at today is termite mounds and how they inspired a building with a heating and cooling system that uses only 10% of the energy that a similarly sized building with a conventional system would.



Termites have a symbiotic relationship with a certain type of fungus that they grow in their mounds. In order for this fungus to grow, it needs a constant temperature of 87 degrees. Outside temperatures can fluctuate between 35 degrees during the night and 104 degrees during the day.

Despite this, termites are able to keep the temperature within their mound within a few degrees of 87 using vents. Cool air comes in through holes in the bottom of the mound, which forces hot, stale air out of vents in the top. Cool air also comes up from vents within the ground. By opening and closing the vents constantly, the termites are able to precisely control the temperature without fancy tricks or expensive systems, like humans need.
















When the Eastgate Shopping Centre in Harare, Zimbabwe was designed, they based the ventilation system off of the design of termite mounds. The way the system works is at the beginning of the day the building is cool. As the day goes on and the building heats up from all the machines and people with in it, the fabric of the building absorbs most of the heat. The building itself heats up a bit as the day goes on, but not by much.

Later on, when the temperature outside starts to cool, warm air inside the building is vented out the top, drawing cool air into the bottom of the building. Fans are used to help move the air more efficiently. During the night, cool air flows through the building, and cavities in the floor slabs, cooling the fabric of the building. When morning comes, the building is completely cooled for the start of the next day.






This is a simplistic version of how the building works. There are many other factors that the building had to be designed around. To learn more, check out this more in-depth Wikipedia article.

http://en.wikipedia.org/wiki/Eastgate_Centre,_Harare

http://www.inhabitat.com/2007/12/10/building-modelled-on-termites-eastgate-centre-in-zimbabwe/

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