How to harvest drinking water from fog without using electricity

Natural Cures Not Medicine

Image: inhabitat.com

Coming up with ways to find water when the grid is down has become one of the hottest topics in the off thecondensing air into water have proved promising, but have drawbacks such as using a large amount of electricity. They are also too expensive to purchase or build for anyone who isn't rich. I was researching these types of water collection systems when I ran into some information on turning fog into drinking water.
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I've compiled as much information about how one would go about building a DIY fog into water collector here in this article. Technical data and know how on this subject is fairly scarce so if you plan on building one at home, some improvisation and experimentation will be needed. We have compiled all the basic steps you will need to take to build one of these water harvesting 'fog traps' for less than a few hundred dollars. An efficient fog collector could produce more than 3 liters of water per square yard of surface area per day in an area with a lot of fog and decent wind!

You will need some screen: usually fine-mesh nylon or polypropylene netting shade cloth. According to research the best cloth to use would be nylon shade cloth or polypropylene netting that provides 30-40% coverage similar to this commonly available greenhouse shade cloth, double layered.

From oas.org

"After testing the efficiency of various mesh densities, the fog collectors used at El Tofo were equipped with netting providing 35% coverage, mounted in double layers. This proportion of polypropylene-surface-to-opening extracts about 30% of the water from the fog passing through the nets."

Next you will have to build posts or a tent like structure to suspend the screen over. Remember that you want the screen to be fairly taut for highest efficiency.  You can use a simple technique that would be similar to making a fence post, then suspend the screen between the posts. You can also make a hoop style structure out of piping or plastic PVC, similar to what you see in the picture posted here:

From oas.org

"Full-scale fog collectors are simple, flat, rectangular nets of nylon supported by a post at either end and arranged perpendicular to the direction of the prevailing wind." 

Finally, you will have to build some kind of trough or gutter at the bottom of the netting to collect the water that has been captured from the fog and then drains into a storage container. The trough will have to be shaped as too take advantage of gravity to collect the water into the storage tank.

From oas.org

Here is an example of a trough or gutter design that can be used 

"As water collects on the net, the droplets join to form larger drops that fall under the influence of gravity into a trough or gutter at the bottom of the panel, from which it is conveyed to a storage tank or cistern. The collector itself is completely passive, and the water is conveyed to the storage system by gravity. If site topography permits, the stored water can also be conveyed by gravity to the point of use. The storage and distribution system usually consists of a plastic channel or PVC pipe approximately 110 mm in diameter which can be connected to a 20 nun to 25 nun diameter water hose for conveyance to the storage site/point of use."

Make sure to secure your fog collector down if needed. If you used the fence post style structure further support may not be needed, but with the PVC style you will need to.

Here is a time-lapse video showing the fog condensing and turning into water:

Example of a simple water storage setup

Once you have to water collected it is ready to use. If you plan on drinking the water you should check the quality of it to make sure it's potable. You can treat or filter the water if needed before you drink it, or perhaps you can use this DIY water distiller that we wrote about that requires no electricity.

This 'fog trapping' is being implemented in many third world countries where water is scarce, but could be used by anyone seeking to have a backup water supply in case of emergencies or to get off the water grid.