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Air-conditioning inspired by… termite mounds?

July 12, 2023 – New research from Lund University in Sweden suggests the climate control used by termites in their mounds could inspire tomorrow’s “climate-smart” buildings.

“The digitalization of design and construction processes creates enormous opportunities for how we shape architecture, and natural and biological systems provide an important model for how we can best utilize these possibilities,” said David Andréen, senior lecturer at Lund, and co-author of the research paper.

The ventilation system in termite mounds enables air circulation throughout the structure, helping maintain and regulate temperature and humidity. It is believed that future buildings inspired by these mounds could achieve the same effect as traditional climate control, but with greater energy efficiency and without a CO2 footprint.

Research results suggest a structure for buildings based on termite mounds that facilitates indoor climate control.

“The study focuses on the interior of termite mounds, which consist of thousands of interconnected channels, tunnels and air chambers, and how these capture wind energy in order to ‘breathe’,” Andréen explained. “We have explored how these systems work and how similar structures could be integrated in the walls of buildings to drive the flow of air, heat and moisture in a new way.”

The idea is to create new ways to control the airflow in buildings that will be significantly more energy-efficient and climate-smart than traditional air-conditioning; that is, develop systems “that are turbulent, dynamic and variable”.

“These can be controlled by very small equipment and require minor energy provision,” said Andréen.

In the study, the researchers demonstrated how airflows interact with geometry—the parameters in the structure that cause the flows to arise and how they can be selectively regulated. These can be driven without using mechanical components such as fans, valves and similar, as only electronic control is required.

In one experiment, researchers used transparent acrylic plastic to create 2-D models in which it was possible to see how airflow behaves. To track the airflow in the outflow, they used an electric motor to drive oscillating water laced with a fluorescent dye through the tunnels.

The results show that the tunnel networks in the outer walls of the termite mound can capture wind and create interior turbulence, which leads to increased air exchange with the surroundings and helps to control the indoor climate.

“This a precondition for a distributed system in which many small sensors and regulating devices are placed in the climate-adaptive building envelope through miniaturization, durability/sustainability, and cost reduction,” Andréen continued.

This enables regulation of the building’s indoor climate and the control of factors such as temperature and humidity without relying on large fans or HVAC systems.

The mechanisms are dependent on being able to create complex internal geometries (on the millimetre to centimetre scale), which is only possible using 3-D printing.

“It’s fascinating how the termites’ building process manages to create extremely complex well-functioning engineering masterpieces, without having the centralized control or drawings to refer to that we would need,” Andréen said.