A researcher is trying to improvefog harvesting by improving the mesh used. This is a good idea.
Taking it a bit farther, I suspectthat one liter production per meter is quite attainable. That then suggests that a simple sail rigcarrying a ten by ten meter mesh will be able to produce 100 liters ofwater. A little experimentation couldgive us something more compact and even easier to manage. In the meantime I am quite happy to rig asimple sail operating edge on to any wind and draining into the root mass of anadjacent tree.
In that way we can walk a forestup a coastal zone quite easily since an established forest will produce its ownhumidity and capture much of its own water taking much of the burden away fromthe sails.
On top of that it is bound to bevery cheap and need little maintenance.
We can now envisage going to aruined coast where we establish a break of mangroves at the water’s edge andplant trees inland as far as the fog takes you with these fog sails. In time the newly established forest will stabilizeand permit further expansion inland producing wealth for the growers.
Namib Beetle inspires new 'fog harvesting' research
By BenCoxworth
21:55 April 26, 2011
Mesh being tested for use on fog-harvesting devices by ShreerangChhatre and colleagues at MIT (Photo: Patrick Gillooly)
For years, people living in high-altitude or coastal arid countrieshave been collecting drinking water by harvesting fog. More specifically,they've mounted pieces of fine netting over top of containers, left the setupovernight, then collected the fog droplets that got caught in the net androlled down its fibers into the container. While it might sound like a ratherinsubstantial way of acquiring water, under the right conditions it can yield asurprisingly large amount of liquid. Now, a chemical engineering graduatestudent from the Massachusetts Institute of Technology (MIT) is looking toimprove on the technique.
Shreerang Chhatre was inspired by the Namib Beetle, an insect thatcollects water droplets on bumps on its back, then drinks them when they rolldown to its mouth. His "fog harvesters," like those created byother scientists, use a mesh panel in place of a net. Even solid materials suchas plastic sheeting will work, although they can create wind currents thatcarry some of the moisture away.
In tests of existing fog harvesters, some have been able to collectone liter (about a quart) of water per meter of mesh, per day.
Chhatre is trying to boost that output by refining the materials thatthe mesh is made from, attempting to strike a balance between hydrophilicmaterials that attract water droplets, and hydrophobic materials that then sendthem on their way down into the collection container. The Namib Beetle employsa similar strategy, with hydrophilic bumps that droplets stick to, andhydrophobic channels that allow those droplets to slide down to its mouthwithout being absorbed along the way.
Much as improving the amount of water obtainable from fog harvesters isa technical problem, it's also a social one – most of the potential userslikely couldn't afford such a device. To that end, Shreerang is hoping thatpeople in developed nations might also start using them, simply to offset theirconsumption of fresh water from traditional sources.
The more units that are sold to such First World consumers, the lowerthe prices could be for Third World recipients,and the more accessible the technology would become.
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