A paint that cools buildings whilst simultaneously harvesting water from the air has been unveiled by scientists at the University of Sydney, Australia. The nano-engineered polymer was created in conjunction with startup Dewpoint Innovations, and reflects sunlight, cooling buildings by up to 6°C inside.
Not only does it reduce the need for energy-hungry air-conditioning systems, but the porous structure of the coating creates ideal conditions for atmospheric water vapour to condense into droplets on the cooler surface, the way steam condenses on a bathroom mirror. The fresh water dew is then harvested and can be used as water for animals, for horticulture of high-value plants, for use in cooling by misting, or even for use in hydrogen production.
“This technology not only advances the science of cool roof coatings but also opens the door to sustainable, low-cost and decentralised sources of fresh water – a critical need in the face of climate change and growing water scarcity,” said the university’s Prof Chiara Neto. “While humid conditions are ideal [for the paint], dew can form even in arid and semi-arid regions where night-time humidity rises. It’s not about replacing rainfall but supplementing it – providing water where and when other sources become limited.
Main image: Ian Talmacs
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