When I first started reading about Biomimicry Principles and heard of an example of this method mimicking nature by regulating temperature control in a Zimbabwean shopping centre, using termites, I was excited! I had visions of termites crawling up and down double walls of the centre, somehow regulating the temperature. I can’t lie and say that I wasn’t disappointed when a little later into my research it appeared that no actual termites were used – simply the design methods they employ to regulated the temperature in their mounds. So much for my vivid imagination….but interesting nonetheless.
The Eastgate Centre in Harare was the brainchild of architect Mick Pearce in conjunction with Arup Associates. The centre has no air-conditioning or heating but manages to stay regulated; temperature wise; all year round, thanks to borrowing a simple design idea from mother nature. In this case from African termite;
Termites build gigantic mounds in which they farm fungus – their staple diet. For the fungus to grow and thrive, temperature in the mound, needs to be kept at a steady 30.56 degrees Celsius. The termites achieve this by constantly opening and closing a series of heating and cooling vents throughout the mound all day long! Air is sucked in at the lower point of the mound, down into muddy walled enclosures and the up through a channel to the top of the mound. The industrious termites constantly dig new vents and plug up old ones in order to regulate the temperature.
Eastgate Centre is Zimbabwe’s largest office and shopping complex and fully embraces the best of green architecture and ecological sensitivity. Largely constructed from concrete, its ventilation works much the same as the mounds of the termites. Air drawn from outside is either warmed or cooled by the building mass, dependant on which is hotter – the building concrete or the air. It is the vented into the buildings floors before exited via dramatic chimneys on the building’s roof. The complex consists of two side by side buildings, separated by an open glass covered space and subject to local breezes. Fans located on the first floor of the building continuously draw in air from this open space, which is then pushed up vertical supply sections of ducts that are located in the central spine of each of the two buildings. Fresh air replaces the stale air that rises and exits through exhaust ports in the ceilings of each floor. Ultimately it enters the exhaust section of the vertical ducts before it is flushed out of the building through chimneys.
This architectural and engineering marvel uses less than 10% of the energy of a conventional building its size. The energy efficiency of the building translates into huge cost savings for the owners, in terms of energy consumption for the centre and in turn the tenants who enjoy rentals some 20% less than those in conventional surrounding buildings.
A modern architecture lesson learnt from the humble creatures we sometime inadvertently squash underfoot.