What termites can teach architects

What termites can teach architects

By Carolyn Fry

Termite mounds are proving to be an innovative source of inspiration to architects – could we benefit from using biomimicry to solve complex human challenges?

If there’s one thing Mother Nature’s good at, it’s being efficient. Take a termite mound, for example.

These conical mud towers that punctuate the parched red landscapes of the tropics are built by termites harvesting mud from below the ground, mixing it with saliva and extruding it. Each mound is the result of hundreds of insects making individual decisions on when and where to place these gobbets of ‘cement’, guided by climatic, environmental and social conditions. The constant war fought between competing termites for precious mud resources and desirable locations, and the repeated recycling of materials by weathering, results in an efficient and sustainable building. This finished termite ‘tower block’ is far larger a construction than an individual insect could build, and can house a vast colony of termites.

If we are to truly take a leaf out of Mother Nature’s book, we must mimic nature’s processes.

Inspired by insects

When it comes to the process of building homes for people, we have had it easy by comparison. With a bountiful supply of natural resources at our fingertips and the intelligence to use them innovatively, we have not been driven by such a need for efficiency in construction, where all a building’s uses (from heating to circulating air and harvesting energy from nature) are integrated seamlessly into the construction process from the outset. However, with the Earth’s population soon to exceed 10 billion, and the competition for dwindling natural resources becoming fiercer, we need to adopt an approach that is closer to that of termites. So how do we do that, without physically fighting our neighbours to build houses, and living in vast communities?

The term ‘biomimicry’ is given to human efforts to design and produce structures and systems modelled on nature. Architects and engineers have long sought to emulate nature when designing buildings but they have tended to focus on what a construction will look like and what it will be used for. Traditionally, this is how we have viewed nature, too. However, if we are to be motivated by efficiency when designing things, this is the wrong approach, says Rupert Soar, reader in sustainable technologies at Nottingham Trent University. He believes that if we are to truly take a leaf out of Mother Nature’s book, we must do so by mimicking nature’s processes; after all, it is the process by which termites build their mounds that results in the integrated nature of their form and function. We may be able to achieve this, thanks to a union of science, computing and engineering.

’In order to write computer programmes, you have to describe or code a process by which something happens so, as computing technology has advanced, we have begun producing people who understand processes,’ explains Soar. ’And, armed with new laboratory technologies, biologists have begun looking beyond an organism’s shapes and what it does, and have got down to the nitty-gritty of examining how it does it. They are examining how organisms build structures to regulate and control the world around them. So, thanks to technological advances, humanity is now examining and understanding the processes by which nature works in a way we’ve never been able to do before.’

Intelligent creations

A termite mound creates the conditions that a colony of millions of termites needs to thrive. It must protect the termites from the harsh environment, safeguard them against attacks by ants, and supply fresh air deep underground. Some mounds capture the heat of the sun during the day and the cooling effects of the night, to drive a complex circulation of air that flips direction twice a day, to provide fresh air to the colony. One human building inspired by these principles is the Eastgate Centre in Harare, Zimbabwe. It has a porous surface that helps to store and release heat during the day-to-night cycle, much like a termite mound. This has helped to slash the energy costs of running the building. However, the widespread adoption of natural processes within construction has not generally been possible because of financial constraints.

One further technological advance may be about to change that: the ability to undertake 3D printing on a large scale at a relatively low cost. The construction company Laing O’Rourke has just launched what it claims is the world’s biggest 3D printer assembly, which will make wax moulds for concrete construction components. Whereas engineers have historically mostly been limited to building in straight lines, this advance will facilitate the use of curves and will enable designers to incorporate aesthetic, structural, acoustic and thermal elements into one design, an approach more in tune with natural processes.

This advance has the potential to take biomimicry in a new direction. Architects will be able to physically replicate the processes by which organisms build habitats or biological membranes, to control the flow of heat, moisture or any other component of ‘comfort’. ’Understanding the processes of construction in nature demands knowing how organisms add and subtract material simultaneously, as they fight over limited resources, which produces efficiency,’ says Soar. ‘We’re now working on the next generation of 3D printers, which will sense the environment they’re printing into; some heads will add material while others subtract it simultaneously. It will take years to reach that point but that’s where we’re headed. It’s about recreating, within the digital sphere, the process of the bloody and fierce negotiation by which nature operates.’

www.bbcearth.com

Termites Are Teaching Architects to Design Super-Efficient Skyscrapers

Termites Are Teaching Architects to Design Super-Efficient Skyscrapers

When a green architect does a particularly good job, you’ll know it by the bling: the silver, gold, and platinum LEED certifications that emblazon buildings’ exteriors. But the best eco-conscious constructions don’t need a seal of approval—and their builders probably wouldn’t appreciate it anyway. Mound termites, native to Africa, South Asia, and Australia, are pros at building self-regulating structures that maintain oxygen levels, temperature, and humidity. And now human architects and engineers want to adapt that ingenuity for their own designs.

From the outside, a termite structure just looks like a pile of dirt. But if you slice one in half—difficult considering some can be more than 30 feet tall—things get a bit more complicated. The above-ground mound has an outer wall riddled with holes, which lead to a labyrinth of tunnels that themselves lead to a series of chimneys. And below the mound is a large, oval nest, where the queen resides.

That queen needs to breathe somehow. “If we buried ourselves a meter underground we wouldn’t last very long if we didn’t have some way of getting oxygen from the atmosphere down to us,” says Scott Turner, a biologist at the State University of New York, Syracuse. “It’s the same logic in the termite mounds.”

How does the mound dissipate air through its network of holes? As the sun moves through the sky during the day, the air in the thinner chimneys on the outer edges of the mound heat up quickly, while the air in the mound’s big, central chimney stays relatively cool. Hot air rises up through the outer chimneys and cool air in the central chimney sinks, circulating air continuously—injecting oxygen and flushing out carbon dioxide. At night, the flow reverses as the outer chimney air cools down quicker than the inner chimney air.

Mimicking termites’ strategies, architects and engineers can drastically improve energy efficiency in buildings. Take Mick Pearce, a Zimbabwean architect who designed the award-winning Eastgate Center in Harare, Zimbabwe. Similar to termite mounds, the concrete outer walls of Eastgate are porous. As wind blows through the tunnels on a hot day, the concrete sucks up the heat, cooling the wind before it whooshes into the shopping center. Fans flush the heat out of the concrete at night so it will be ready to store more heat the next day. Following termites’ lead, Pearce cut energy use down to about 10 percent of a normal building that size.

“Ultimately, we want to bring termite ventilation to buildings because it would allow the buildings to breathe freely,” says Rupert Soar, a biomimetic expert at Nottingham Trent University. The next step: mimicking the *process *of termite construction. Scientists have already programmed computer termites to design complex structures based on real behavior—things like complicated porous walls with intersecting tunnels and ducts.

Actually building those structures will be more difficult than designing them. But Soar says the bottleneck is 3-D printing. Once large-scale 3-D printing technology catches on in construction, you may be living in your own termite mound.

www.wired.com

What termites can teach us about staying cool

How do you cool a building without air conditioning?

In nature, termites build skyscraper-like mounds that are ventilated by a complex system of tunnels. By emulating the ingenuity of termites, Zimbabwean architect Mick Pearce used an approach called biomimicry to design a natural cooling system that harnessed nature. The result is an architectural marvel that achieves 90 percent passive climate control by taking cool air into the building at night and expelling heat throughout the day.

In this first installation of the Decoder series, see how the Eastgate Centre in Harare, Zimbabwe utilizes a termite-inspired climate control system. To learn more, read “Termite Climate Control” from the May 2018 issue of National Geographic magazine.

See how termites inspired a building that can cool itself

How do you cool a building without air conditioning?

In nature, termites build skyscraper-like mounds that are ventilated by a complex system of tunnels. By emulating the ingenuity of termites, Zimbabwean architect Mick Pearce used an approach called biomimicry to design a natural cooling system that harnessed nature. The result is an architectural marvel that achieves 90 percent passive climate control by taking cool air into the building at night and expelling heat throughout the day.

In this first installation of the Decoder series, see how the Eastgate Centre in Harare, Zimbabwe utilizes a termite-inspired climate control system. To learn more, read “Termite Climate Control” from the May 2018 issue of National Geographic magazine.

video.nationalgeographic.com

What termites can teach us about natural ventilation in small buildings

By Fiona McWilliam Fiona McWilliam 2009-08-23T00:00:00+01:00

Termites of the species Macrotermes michaelseni, which Dr Rupert Soar studied in detail.

One of the individual contributors to the study.

Source: Isaac Eastgate

The research team in Namibia created an “endocast” of a mound by filling it with gypsum, then lifted it out for analysis.

The research team in Namibia created an “endocast” of a mound by filling it with gypsum, then lifted it out for analysis.

Termite mound construction offers a lesson in natural ventilation for small buildings

There is a certain logic in looking to termite mounds for a way to inform the design of comfortable and sustainable buildings with little or no need for mechanical heating or cooling. These intricate structures preserve a steady level of atmosphere, humidity and temperature in the termite nests beneath them while enabling the exchange of oxygen and carbon dioxide between the inside and outside of the mound.

Exactly how termite mounds function is a lot more complex than scientists initially thought, however, and potentially a great deal more useful in the design of sustainable, self-regulating buildings.

Dr Rupert Soar, the freeform construction pioneer, and the physiologist J Scott Turner have studied this topic since 2004 with engineers and scientists at Loughborough and Cambridge universities and the National Museum of Namibia. As part of the research, funded by the Engineering and Physical Sciences Research Council, they have digitally scanned a termite mound to understand how they “breathe” without ventilation by bulk air flow.

The heat-driven convective flows that drive natural ventilation in tall buildings cannot be applied to small structures such as termite mounds or, indeed, our homes, Soar says. Even tall, naturally ventilated buildings, with atriums or chimney systems, often have to be retrofitted with fans and other ventilation devices because occupants break the natural air flow by opening windows and doors, he points out.

Mechanical HVAC consumes an increasing proportion of energy in homes, and creating effective natural ventilation in small buildings can be tricky, Soar says. “If anything, governments and certification systems now tend to encourage the sealing of buildings, necessitating forced or mechanical ventilation systems

to allow gas exchange without removing heat (or vice versa in hot climates), requiring fans and a heat exchanger, which consume more electricity in an effort to conserve energy.”

Gas exchange in buildings is hitched to bulk air flow between the inside and outside. The process of constantly moving air out of the building, in order to replenish oxygen and expel carbon dioxide, inevitably takes with it heat and moisture in that air.

It is a problem, Soar says, “that all air-breathing animals and termite mounds solve automatically”. He likens the delicate balance or stasis of temperature, acidity and moisture inside our lungs to being comfortable in modern housing: “Inside the lung there cannot be bulk air flows and complete air exchanges [as there is in a chimney] as our lung membrane would dry out and cease to function. We are still like our fish ancestors, with our gills [lungs] in a nice wet place where oxygen and carbon dioxide can move across the lung membrane.”

To prevent the lung drying out we breathe in and out, which allows gas exchange but preserves the stasis of temperature, moisture and acidity.

While the idea of strapping muscles to the outside of our homes to make them breathe is absurd, Soar admits, what is needed is a way to make them breathe without using muscle. It is something Soar and Turner suspected was happening in termite mounds.

Much is known about resonance and standing waves in tubes, which have been studied for generations. Soar explains: “However, when tubes are humming at their natural resonant frequency, there appears to be a subtle twist to this knowledge, in that gases and molecules can speed up or down a tube if there is a different concentration of the gases between one end or the other.”

The skin of termite mounds is peppered with branching and convoluted tube networks as complex as our own capillaries. As light, gusty air moves over the surface of a mound, the energy in the wind is split into a range of frequencies or pulses that can even be heard with a microphone inside the mound. The high-frequency components of the wind’s energy work within the mound skin to create a gradient of oxygen and carbon dioxide.

The key to the system is that resonant oscillation is set up when gusts of wind travel over the mound surface, Soar explains. “We think it’s a form of the phenomenon of high-frequency oscillatory ventilation, and it’s all do with how the termites tune the structure they build.”

In addition, the low-frequency pulses travel deep into the mound, where they set the air sloshing – an effect known as pendelluft.

“All this can only happen in complex tubular networks known as impedance structures,” says Soar. “Our lungs are impedance devices which generate the gradients required, partly by breathing and partly because of their structure. With new computer and fabrication techniques, we can now copy and reproduce these complex channels and ducts in the walls, floors and ceilings of our homes. Houses will literally breathe rather than ventilate. They will not need electricity to do this, they will not affect the delicate balance of moisture and heat inside the building and they are not affected by scale.”

For years scientists have believed that termites regulated the temperature in their mounds, Soar says. “We can now show categorically that they don’t; if anything, what they regulate is water potential by constantly building and moving mortar through the system.

“Yes, it does retain a constancy of temperature and moisture, but they are not regulating it, as many biologists or architects would tell you. Ventilation is a misnomer as it uses bulk air flows or exchanges. This is respiration, and breathing is a good enough term for it.”

Soar believes that all termite species and other nest builders such as ants use a similar approach.

The research team’s findings challenge architects’ perception of walls as impermeable barriers, Soar says. “What we see in nature are permeable membranes which set up energy differentials between one side and the other. Recreating this membrane in buildings opens up a world of possibilities.”

Architects such as Achim Menges in Germany and Michael Hensel in Australia are already experimenting with the concept of permeable walls. Soar says: “Architects are naturally in tune with the solution, but without necessarily knowing how it works, which is the role of the engineer.”

He is now studying how membranes work – “how they can drive energy, and how air moves in an oscillating system”. This is where Soar’s main area of expertise – rapid manufacturing or, as he prefers to call it, freeform construction – comes to the fore.

Through his recently established company Freeform Engineering, he is working with colleagues in Namibia and America to pioneer construction technology whereby entire buildings and building components are “printed” using a range of materials, including gypsums, concretes, polymers and, ultimately, metals.

Soar works with architects worldwide: “In the face of the need for sustainable buildings and a green ethos, architects have had to rely on existing designs with green materials and retrofit technologies such as photovoltaics and wind turbines. With modern computer programs and agent-based modelling, we can design buildings from scratch that capture or harvest energy directly from the environment.”

Pestival

A walk-in termite pavilion is to be constructed at Pestival, a celebration of insects to be held in London on September 4-6. Dr Rupert Soar and his colleagues will reveal their discoveries in the 9m3 model of part of a Namibian termite mound chimney, located outside the Royal Festival Hall on the South Bank. The sounds of millions of termites at work and communicating with each other will be played inside.

About 150,000 people are expected to visit Pestival, which will illustrate the critical role insects play in life on Earth. The termite pavilion (model below) is an art and science collaboration between Softroom Architects, Freeform Engineering, Atelier One and Pestival.

www.building.co.uk

BIOMIMETIC ARCHITECTURE: Green Building in Zimbabwe Modeled After Termite Mounds

Architecture

Biomimicry’s Cool Alternative: Eastgate Centre in Zimbabwe
The Eastgate Centre in Harare, Zimbabwe, typifies the best of green architecture and ecologically sensitive adaptation. The country’s largest office and shopping complex is an architectural marvel in its use of biomimicry principles. The mid-rise building, designed by architect Mick Pearce in collaboration with Arup engineers, has no conventional air-conditioning or heating, yet stays regulated year round with dramatically less energy consumption using design methods inspired by indigenous Zimbabwean masonry and the self-cooling mounds of African termites!

Termites in Zimbabwe build gigantic mounds inside of which they farm a fungus that is their primary food source. The fungus must be kept at exactly 87 degrees F, while the temperatures outside range from 35 degrees F at night to 104 degrees F during the day. The termites achieve this remarkable feat by constantly opening and closing a series of heating and cooling vents throughout the mound over the course of the day. With a system of carefully adjusted convection currents, air is sucked in at the lower part of the mound, down into enclosures with muddy walls, and up through a channel to the peak of the termite mound. The industrious termites constantly dig new vents and plug up old ones in order to regulate the temperature.

The Eastgate Centre, largely made of concrete, has a ventilation system which operates in a similar way. Outside air that is drawn in is either warmed or cooled by the building mass depending on which is hotter, the building concrete or the air. It is then vented into the building’s floors and offices before exiting via chimneys at the top. 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 breezes.

Air is continuously drawn from this open space by fans on the first floor. It is then pushed up vertical supply sections of ducts that are located in the central spine of each of the two buildings. The fresh air replaces 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.

The Eastgate Centre uses less than 10% of the energy of a conventional building its size. These efficiencies translate directly to the bottom line: Eastgate’s owners have saved $3.5 million alone 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.

Who would have guessed that the replication of designs created by termites would not only provide for a sound climate control solution but also be the most cost-effective way for humans to function in an otherwise challenging context?

inhabitat.com

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