Nature's Lesson: How Termites inspire Sustainable Buildings

 

Nature’s Lesson: How Termites Inspire Sustainable

Buildings

As temperatures climb, we are faced with the increasingly challenging task of cooling our

cities - and the solution might be right beneath our feet.

In the soil, reside mound-building termites. Termites are the engineers of their ecosystem,

crafting what appear to be simple nests on the surface, but conceal complex systems

designed to meticulously regulate temperature, humidity and gas exchange. Let’s explore

how these miniscule designers inspire modern engineering and architecture; how we can

harness their natural adaptability to address our own challenges.

Structure of Termite Mounds

These ‘super-organisms’ construct towering mounds from a type of ‘cement’ that hardens

into a durable material. It is made from a mixture of the termite’s saliva, faeces and soil. The

interior houses the main living area in an organised network of chambers and tunnels which

serve various purposes. Lower chambers are used for cultivating fungi, a primary food

source, while the upper chambers protect the queen and her eggs. Worker termites

continuously expand the mound, adding layers and repairing damage— processes that can

take up to several years. Mounds vary in shape and size but are often conical, with a wider

base that narrows towards the top; sometimes scaling a height of thirty feet. If termites were

human-sized, their mounds would stand as tall as four Burj Khalifas!

The Genius of Termite Ventilation

The ventilation system in termite mounds exhibits nature’s ingenuity. Designed to regulate

temperature and humidity, it also functions as the mound’s lungs. Key to this system is the

central chimney, a vertical shaft that maintains internal conditions. Heat from the sun and

termite’s metabolic activities generates warm air, causing air inside to become less dense

and thus rise through the central chimney. A pressure difference is created by the movement

of warm air, drawing in cooler and denser air through the vents situated at the base of the

mound. The fresh air absorbs the interior heat as it travels through the tunnels, before rising

to the top and escaping through the chimney, introducing a natural convection cycle within

the mound. This cycle also facilitates gas exchange, essential for the colony‘s survival, as

carbon dioxide(CO2) is expelled with the warm air. The mound’s external surface further

enhances this process. Its textured exterior, dotted with minute protrusions, increases the

surface area exposed to cool air - therefore increasing the rate of heat transfer.

This natural engineering marvel has influenced various human innovations, with one notable

example being the Eastgate Centre in Harare, Zimbabwe.

The Eastgate Centre - Taking a leaf out of nature’s book

In 1991, Mick Pearce was faced with a challenge to design a retail building that needed to

maintain low energy consumption and avoid costly air conditioning systems. With Harare’s

extreme temperatures, achieving this seemed almost impossible—until Pearce found an

interest in the Zimbabwean termites.

The main challenge was to convert the building into a heat exchanger, absorbing heat during

the day and expelling it during the cooler night. Mimicking the mound’s ability to absorb heat,

Pearce used concrete slabs and bricks with a high thermal mass. This allows the building to

store significant heat during the day without much change in internal temperature. In the

evening, low-powered fans draw in cooler air into the first floor and disperse it throughout the

building, flushing out the accumulated warm air through the chimneys. As night falls and

temperatures drop, cooler air is drawn in, cooling the structure down even more. This cooling

cycle prepares the building to absorb heat the next day. The building’s ‘prickly’ exterior,

mirrors the mound’s texture and increases surface area, increasing heat dissipation at night.

The small bumps also create micro-shadows on the surface, reducing the amount of sunlight

that hits the building.

In this way, temperatures inside Eastgate Centre remain at a comfortable 27°C during the

day and 13°C at night, all while using only 10% of the energy required to cool conventional

commercial buildings.

This considerable achievement of biomimicry and sustainable cooling raises an important

question: What other innovations could nature inspire if we paid closer attention?

Sustainability

In buildings around the world, using air conditioners(ACs) for cooling accounts for nearly

20% of the total energy used by the building. As populations grow, the use of ACs is set to

surge, with around two-thirds of the world’s households expected to have an AC by 2050.

“Growing demand for air conditioners is one of the most critical blind spots in today’s energy

debate. Setting higher efficiency standards for cooling is one of the easiest steps

governments can take to reduce the need for new power plants, cut emissions and reduce

costs at the same time”, said the Executive Director of the IEA. The main problem isn’t just

the increase in demand for cooling but the use of inefficient ACs, as consumers often opt for

cheaper, less efficient models. According to the IEA, investing in more efficient ACs could

significantly reduce the cooling demand and can also reduce the need for new power plants

to meet peak demand.

For a sustainable future, we must rethink and remodel how we cool our buildings. The

Eastgate Centre shows how we can balance comfort and energy consumption through

nature-inspired models. By incorporating such innovations into new buildings and investing

in efficient air conditioning for existing buildings and homes, we can establish a sustainable

way of living. The choices we make about our comfort today will shape the comfort of our

future.

Resources:

1) Report:

International Energy Agency(IEA) ‘The Future of Cooling’. Available at:

https://www.iea.org/reports/the-future-of-cooling (Accessed: 29 August 2024)

2) Website Article:

Terminix ‘How and why Termites build mounds’. Available at:

https://www.terminix.com/termites/colonies/mounds/#:~:text=The%20mound%20is%20divide

d%20into,mound%20to%20maintain%20an%20optimal (Accessed: 29 August 2024)

3) Research Presentation:

Megan Greenfield ‘Project: EastGate’. Available at:

https://cpb-us-

e1.wpmucdn.com/blogs.uoregon.edu/dist/9/10058/files/2017/11/greenfieldmegan_69

766_4440791_Biomimicry-presentation_reduced-1-1qf73rd.pdf (Accessed: 29

August 2024)

4) Youtube Video:

National Geographic(2018)’See how Termites Inspired a building that cools itself’.

Available at: https://www.youtube.com/watch?v=620omdSZzBs (Accessed: 29

August 2024)

5) Youtube Video:

Frankenscience(2022)’How Termites evolved to build massive mounds’. Available at:

https://www.youtube.com/watch?v=HGiDwN33WJo (Accessed: 29 August 2024)

6) Research Article:

IRENA ‘Power to heat and cooling:Status’. Available

at:https://www.irena.org/Innovation-landscape-for-smart-electrification/Power-to-heat-

and-

cooling/Status#:~:text=Heating%20and%20cooling%20accounts%20for,energy%2Dr

elated%20carbon%20dioxide%20emissions. (Accessed: 29 August 2024)