Air Conditioning System Inspired by Termites Provides Climate-Friendly Approach for Smart Buildings With Less Carbon Footprint

In most homes and buildings, windows and other structural elements play a crucial role in ensuring good airflow. To provide a supply of good-quality air, some homes and industrial facilities install additional mechanical systems. However, traditional climate control systems achieve less energy efficiency and leaves carbon dioxide footprint.

Inspiration from Earthen Structure

Scientists from Lund University in Sweden got inspiration from termite mounds in developing an indoor climate control system. Led by senior lecturer David Andréen at the Department of Architecture and Built Environment, they made digital design and construction processes that can help in improving architecture and biological systems.

Termite mounds are known for having a complex ventilation system which allows air to circulate throughout the structure. Such system plays an important role in maintaining and regulating the indoor temperature and humidity.

In this study, the team focuses on the internal part of termite mounds made up of thousands of interconnected passages, tunnels, and air compartments. They investigate how these pathways capture wind to let the insects breathe or allow the exchange of oxygen and carbon dioxide in the environment. They also explored the possibility of integrating these structures in the walls of buildings as a new approach of driving the flow of air, moisture, and heat.

Traditional air conditioning system uses the principle of bulk flow where airflow is normally driven by fans. Andréen and his colleagues believe that the flow of air in buildings can be controlled in an energy-efficient and climate-smart way. To make this possible, the systems should be dynamic, turbulent, and variable.

The research team demonstrated the interaction between airflows and geometry being the elements that allow the flows to arise. They only needed electronic control so there is no need to use mechanical components like valves and fans. The distributed system also works using small sensors and regulating devices that apply miniaturization and sustainability. What makes it different from the traditional ventilation system is its dependence on the creation of complex internal geometries which can only be possible with 3D printing.

Engineering Secrets of Termite Mounds

Most insects are known for being good architects and engineers, and termites are no exception to this. There are termite mounds that reaches as high as 26 feet while there are also those that take up to five years to build. Using different materials, the earthen mounds created by termites can be comparable to man-made castles. The intricacy of these structures has baffled scientists and engineers and even inspire the robotics industry.

Since termites live in large colonies, they need to maintain an ideal level of temperature, moisture, and gases to ensure their survival. Some termite colonies also live in symbiotic relationship with fungi so a temperature of around 86 degrees Fahrenheit needs to be maintained to secure optimal growth and survival. The interior part of their mounds also contains channels which help in promoting ventilation and circulation.

Termite mounds are made of the insect's saliva and feces in addition to water and clay. At the initial phase of creating the nest, the mound is subterranean with a small part lying above the ground. As the colony continues building up the structure, some elements such as microstructure and wall porosity also changes with height.