Nature and tradition teach us to exploit natural resources with the construction of buildings capable of reacting to the evolution of external climatic conditions.
If once this happened only through the use of specific shapes and materials, now technologies allow achieving increasingly optimized results, thanks to models and systems that start from the idea of a dynamic envelope that allows perfecting the contribution of light and heat, reducing the energy consumption of buildings.
Eastgate Complex: a bionic building inspired by the termite mounds
One of the earliest and most cited cases representing a fundamental example in the field of biomimetics principles is the Eastgate Complex. This bionic building was built in Harare, Zimbabwe and was designed by Mick Pearce, in collaboration with Arup Engineers.
The complex was opened in 1996, built on a project inspired by the termite mounds in rural areas of Africa, more precisely paying attention to their ventilation system. These fascinating structures maintain the ventilation of termite nests that are naturally subterranean.
The top of the mound consists of a central chimney surrounded by an intricate grid of tunnels and passages. Air passes through the porous walls into a series of small tunnels until it reaches the central chimney and, finally, rises up.
When fresh air mixes with this warm air, the air cools and sinks down into the nest. This ventilation system constantly circulates the air and ensures that oxygen reaches the lower areas of the mound and keeps the nest from overheating.
Eastgate Complex is great example of bionic building because it uses passive air-conditioning that best characterize the meaning of green architecture and ecologically sensitive adaptation.
Thanks to passive cooling, during the day, the heat is stored and released at night as the temperature falls. We have outlined the functioning of the cooling system.
At the beginning of the day, in the morning, the building is cool. During the day, machines, cars and people cause heat and the sun heats the exterior surface of the building.
The heat is absorbed by the building envelope, which has a high thermal capacity. In this way the internal temperature increases, but not by much. In the evening, the outdoor temperature falls again.
The warm indoor air is released through the chimneys, aided by the fans, but the phenomenon occurs naturally because the hot air is less dense, so it tends to rise, leaves a gap and allows fresh air more dense to access from the bottom of the construction.
At night this process continues, the cold air flows through the cavities in the floors until the building has reached the ideal temperature to restart the process the next day.
The complex also consists of two buildings side by side that are separated by an open space that is covered by glass and open to the local natural ventilation.
The cooling system costs one-tenth of the conventional ones and uses 35% less energy than other buildings similar to Harare.
This bionic building, replication of designs created by termites, not only provide for a sound climate control solution but also is the most cost-effective way for humans to function in an otherwise challenging context.
