Using termites ‘technology’ to cool buildings

NAIROBI: Termite mounds are common features in most African countries. However, few of us give a second glance at these “monuments” that may rise up to 12 feet.

But to environmental design experts, there is a lot to learn from the way two million termites can regulate the temperature in a chamber located within the tropics.

Ordinarily, the mound would get warmer and warmer as it gets exposed to the sun. However, the tiny creatures have engineered a complex system of cooling the chamber whereby a system of ducts brings in cool air and oxygen to the bottom of the mound.

Interestingly, termites know when to open and close the ducts during the day so that the temperature inside is kept constant with a variation of only a degree.

Architects have since tried to adapt their designs to imitate what nature has perfected to some degree.

In Africa, several buildings have successfully used this method to reduce the costs of either heating or cooling the structures.

Eastgate Centre in Zimbabwe is one such building where horizontal and vertical ducts expel foul air while others bring in fresh air from the outside. The structural design is assisted by fans that draw air from the outside via grills placed under the windows and into the offices.

Warm, foul air is automatically taken out through the vertical ducts and into the thermal chimneys on the rooftop. The cycle is repeated throughout the day.

By bypassing a conventional air conditioning system, the building was able to save $3.5 million (Sh339.5 million)

Locally, the Learning Resource Centre building at the Catholic University in Karen is a leading example of imitating the termites cooling system.

Here, the method consists of a well-arranged granite rock-bed underneath the seating area. Louvre openings on the walls allow air onto the rock-bed where it is cooled by the ice-cold rocks before entering the hall through vents beneath the seats.

During the cold season, the process is reversed somewhat with cool exterior air passing through the warmer rocks and into the building. Foul air is expelled through a “stack effect” where being hot, it naturally rises through thermal chimneys with the aid of wind driven ventilation cowls.

Well, the next time you drive past a termite mound, think of how you can borrow an idea or two to make your dwelling place more pleasant.