Innovative cooling material inspired by saharan ant combats climate change

Inspired by Sahara ants, a group of students created (Sub)Ambient, an ecological material for the passive cooling of buildings, reducing the need for air conditioning and limiting environmental impact

According to data published by the European Commission, the decade from 2011 to 2020 was the warmest on record, with a temperature increase in 2019 of 1.1°C (about 2°F) above pre-industrial levels. To combat increasingly frequent heatwaves and cool indoor spaces during the summer, many people are turning to air conditioners.

However, these devices have a significant environmental impact and contribute to climate change. In response to this challenge, a group of students has developed (Sub)Ambient, an innovative passive radiative cooling material that effectively lowers indoor temperatures without harming the environment.

Inspired by the Silver Ant of the Sahara

In creating (Sub)Ambient, the students drew inspiration from the silver ant of the Sahara. This insect survives in the desert through a passive radiative cooling mechanism that reflects sunlight and disperses heat. Using the same principle, the team carefully selected components to create a material that functions like a mirror, nearly fully reflecting solar rays and maintaining a temperature about 9°F (5°C) lower than the surrounding environment.

Composition and benefits of (Sub)Ambient

(Sub)Ambient is made from easily accessible materials, including calcium carbonate, abundant in eggshells, and nanocellulose, a biodegradable substance derived from food waste. These materials were chosen not only for their abundance but also for their reflective properties and environmental compatibility. After numerous tests, the team refined the composition and shape of the material to optimize its cooling capabilities.

Unlike other radiative cooling materials on the market, (Sub)Ambient is removable, allowing it to be taken down during winter to prevent excessive cooling of indoor spaces, thus reducing the need for heating. This feature distinguishes it from permanent coatings and multilayer photonic films, which, while also removable, require costly and energy-intensive production processes.

Completely biodegradable, (Sub)Ambient is easy to produce: it is made by mixing calcium carbonate with nanocellulose, adding an additive, removing water from the compound, and hot-pressing the material.

Source: The James Dyson Award