When architecture mimics nature

Perforated walls at the Catholic University of Eastern Africa’s Learning Resource Centre, Karen.

NAIROBI, KENYA: For millenniums, man has always sought ways of mimicking what is found in nature in order to improve the lives of mankind. The concept, known as biomimicry continues to inspire designers, engineers and architects the world over as they observe how nature solves complex design challenges.

Around the country, you no doubt have come across those earth-coloured termite hills. Many of us hardly give much thought to the mounds that stick out of the surface like a sore thumb.

However, as clumsy as they may appear, these termite hills are feats of engineering that continue to inspire architects in designing similar structures.

Termites abound in the tropics where temperatures can reach 42 degrees, yet they are able to keep the inner chamber temperatures at a constant 31 degrees. How do they do it and what can professionals learn from this? The termite mound contains numerous vents that are opened and closed at intervals throughout the day.

Air is sucked through the bottom of the mound and into the chamber. As the air gets hot, it is naturally pushed out of the chamber through the high chimney.

Additionally, wind blowing on top of the termite hill also helps suck air into the chamber through a system known as the “stack effect.”

“The walls of a termite hill are thick to absorb the heat from outside while the high chimney makes the living chamber cool. Likewise, we can build structures with thick walls that can absorb heat since we live in the tropics where it is generally hot all year round,” states Kimeu Musau, an architect and environmental design expert.

African examples

On the African continent, this system was put to good use in constructing the Eastgate Centre in Zimbabwe built in the 1990s and designed by Mick Pearce in conjunction with engineers at Arup Associates.

Another example of this is the Learning Resource Centre (LRC) at the Catholic University of East Africa in Karen, Nairobi.

The Eastgate Centre has no mechanical air-conditioning or heating system, yet stays regulated all year round with less energy consumption.

The LRC has been designed to make good use of natural lighting and a cooling system that is assisted by thermal chimneys.

At the LRC elaborate details that set the building apart from all others in the region are evident. Like the compass or magnetic termites of Australia that always orient their nest facing north – away from direct sunlight - the LRC’s orientation is also dictated by the sun’s movements.

Orientation

Thus, the building’s façade is oriented along the East-West axis. The part of the building with the most activity was oriented along the North-South axis. Any glass-clad openings are sun shaded using precast concrete fins.

And like the termites that rely on a non-mechanical air intake, the LRC has been designed in a manner that allows air to come in through louvre openings in the walls, past a granite rockbed where it is naturally cooled before entering the seating chamber through another set of vents under the seats.

Since hot air rises, foul air is eliminated through thermal chimneys aided by wind driven ventilation cowls.

Other buildings in Kenya that have incorporated some of the designs found in nature include: Cocacola East and Central Africa Business unit in Upper Hill, phase three of Strathmore University, the Maasai hut shaped Oleleshwa Primary School in Ewaso Ng’iro and the UNEP building in Nairobi.

Is there any feat of engineering that comes to mind as you observe a honeycomb? Nothing, you may say, apart from the honey stored therein.

According to the Biomimicry Manual however, ancient Greeks understood that the hexagonal honeycomb could make for the best storage space while using the least amount of building material.

“Architects and designers are tapping into this for all sorts of applications. Panelite in New York offers hexagonal, clear shade insulating glass that passively regulates heat, while still letting in lots of light. The Sinosteel skyscraper in Tianjin, China uses honeycomb windows the same way,” states the manual.

Remember your primary school lesson on photosynthesis, or the way a leaf uses light to create energy? The photovoltaic solar system you see on some roofs is the first step in imitating the leaf’s way of harnessing solar energy.

According to the Scientific American, energy harvesting experts are designing a silicon-based artificial “leaf” that will mimic the way a natural leaf gathers energy for the entire plant system.

The futuristic Habitat 2020 Building in China uses skin as its inspiration. Like a leaf, skin acts as a thermal regulator that wards off extra heat from the body and allows air, water and light to filter into the building.

While many developers think that incorporating such nature inspired designs will cost them an arm and a leg, the contrary is true.

They are more cost effective than the mechanical systems of heating and cooling. Eastgate Building, for example, uses 90 per cent less energy than other conventional buildings of the same size.

“Eastgate’s owners have saved $3.5 million (Ksh311 million) because of an air-conditioning system that did not have to be implemented. Outside of being eco-efficient and better for the environment, these savings also trickle down to the tenants whose rents are 20 percent lower than those of occupants in the surrounding buildings,” states inhabitat.com.

Ignoring

Sadly, Musau says many of the professionals in the local construction industry and in the East African region as a whole, continue to ignore such natural inspiration but continue to import “glass-clad designs” that work in the temperate climates of the western world, but are hardly practical in our hot climates.

Rather than building high thermal walls, Musau says our cities have resorted to the thin glass covering that turns buildings into furnaces, creating the need for expensive mechanical cooling systems.

“It is true that majority of today’s architects are busy designing climate non-responsive buildings. These include the fashionable greenhouse-emitting, glass façade edifices and sleek-looking energy intensive buildings that are in vogue today. Even the older buildings that were suitably designed for our local climate are being glass-clad whenever they are renovated,” he says.

According to the architect, our ancestors had it right when they built their homes to serve practical purposes and not only for aesthetic beauty, citing the case of grass thatch that kept homes cool.

“We have been cultured to believe that Western concepts are the best since our education system is also Western based. Must we copy our former colonial master or the West to attain the psychological threshold that says we have come of age? To change the trend, we must decolonise the mind and learn from our ancestors,” he says.

By copying nature, he adds, we are only using systems that have been tried and tested and proven since the dawn of creation.