Now for my next trick, water from air

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Now for my next trick, water from air



This upturned pyramid is designed to extract at least 48 litres of fresh water from the air a day (Image: Arup)
WatAir can be built locally but is durable enough to be dropped by parachute from a plane.


Tracy Staedter
Discovery News
Monday, 25 June 2007



Dew settling on a spider's web has inspired a device that catches enough water to drink (Image: iStockphoto)


Leaves and spiders' webs beaded with dew have inspired a low-tech solution for collecting fresh water.

WatAir, an inverted pyramid made from elastic canvas, recycled polycarbonate, metal or glass, can reap dozens of litres of water a day from the air.

The inexpensive solution could help bring clean drinking water to people in remote or polluted areas, its developers say.

"The design has minimal special demands. It is low-tech and low-cost, and in fact can be even produced with local means," says Joseph Cory, a PhD candidate at the Technion-Israel Institute of Technology and an architect at Haifa's Geotectura Studio.

Cory and colleague Eyal Malka of Malka Architects recently won first place for the invention in a competition sponsored by WaterAid, an international nonprofit organisation dedicated to providing safe domestic water to poor nations, and Arup, a UK-based firm specialising in sustainable designs.

Cory and Malka were inspired by the passive way dew gathers on leaves, spiders' webs, even on sleeping bags and tents.

They designed a four-sided structure shaped like an inverted pyramid, with each panel about 3 metres tall.

At night, dew drops bead up on both the tops and undersides of the panels. Because the dew collecting on top may contain dust, dirt or insects, that water could be used for irrigation. But dew from the underside is drinkable.

Gravity draws the drops downward into tanks, wells or bottles at the bottom.

A 96 square metre structure can extract a minimum of 48 litres of fresh water daily. But the dimensions can vary, says Cory, from a small personal unit that fills a water glass to several large-scale units that provide water for a community.

The low-tech approach requires only low-cost materials and is quick and easy to deploy, says Cory.



The cost could be offset by printing sponsor logos or advertisements onto the canvas sheets.

"It is simple, practical, adaptable, sustainable, flexible and draws inspiration from nature resulting in a minimal intervention with potentially a big impact," says Frank Lawson, a senior engineer at Arup.

Cory and Malka are also looking into modifications to WatAir that could help produce energy.

They are investigating embedding photovoltaic cells into the canvas to convert sunlight into electricity.

The energy could be used to power electrical appliances or charge batteries. Or it could be used to cool the surface of the dew panels, which would allow the structure to produce water all day long.