Water from air: What will they think of next?

Plastic square shaped 'flattish' dew collecting cones with lettuce at centre

Dew collectors in the desert

With news today that Australian scientist Edward Linacre has one the Dyson award for innovation,  we embark on another short journey in our series on bio-mimicry.

Edward’s invention is unlike most previous ‘plant mimicking’ water collection efforts, in that his inspiration was a desert beetle that collects dew off its back with a unique cellular structure. Plant mimicking devices typically feature a large fan type funnel structure, such as illustrated in the picture on the left.

His inspiration, the Namib Desert Beetle lives in one of the driest places on earth – just 40mm of rain per year. When late evening due or early morning fog offers a hint of moisture, the beetle is in for a drink – thanks to the amazing surface on its back.

The concept of this surface is simple: when mist or fog is blown across the desert beetle’s surface, miniature water droplets just 15-20 microns in diameter begin to condense on the tiny lumps on its back. Surrounding the tiny lumps are waxy water-repelling ridges (this type of coating is known as a hydrophobic coating – solar panels have this too!). When there is enough water to form droplet, it rolls down a ridge… right into the beetle’s thirsty mouth.

With Edward’s device, the Airdrop, water molecules are sucked from dry air, and then pumped through a network of underground pipes, subsequently chilling them in the process so the moisture condenses into water. From there, it settles at the roots of the plants above. 

Whilst Edward’s product is unique, he shares this source of inspiration with MIT scientists Robert Cohen and Michael Rubner, who were also were inspired the Namib Desert Beetle after reading a 2001 article in the journal Nature.  They have created a special material that can capture and control minuscule quantities of water. Their newly designed product combines a superhydrophilic (water-attracting) region with a surrounding superhydrophobic (water-repelling) surface (to allow the water to run-off, once condensed). 

Several other water saving devices are around, which use dew collecting ideas idea mentioned as long ago as 1965 in the classic Sci Fi Dune. Illustrated above is one such device used in Israel to collect moisture in the desert, and to concentrate that moisture locally around the plant.

See our related Greenforce Knowledge Base article answering the question why does dew form?


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