Tuesday, June 28, 2011

How To Build A Solar Still

When water sources become scarce or you find yourself in a survival situation without the normal channels of water present like rivers, lakes, ponds, etc… then advanced water retrieval methods may become necessary. In most climates, water is actually abundant but is inaccessible through standard water collecting methods. So today we are going to discuss one of the most common advanced water collecting techniques called the Solar Still:

Solar Still – The concept of a solar still is relatively simple. The suns heat raises the temperature of the air contained within the solar still as well as the soil itself and produces water vapor that tries to escape by means of evaporation. When the water rises and meets the surface of the solar still, then it collects on the underside and runs down towards an impression and finally drips into a collection container. The first step involved in building a solar still is locating a spot that receives lots of sunlight and is preferably in a low spot within the land where the soil may contain more water from prior rain runoff. Then you’ll need to dig a hole that is approximately 3 feet wide and 2 feet deep. Once the hole is dug, place a can, bottle, pan, canteen, or any other device that can be used to collect the water in the middle of the hole. Be sure to press it down firmly so that it will not tip over and use a small amount of soil to press up against the sides to help hold it into place. Now, cover the hole with a sheet of plastic or any other material that will seal the hole off but allow sunlight to pass through it. Place the material in a manner that slopes down towards the middle and creates a depression right above the water collector. Then place a small round stone in the middle of the sheet to create a water droplet point for your solar still. Now, use soil and/or rocks to anchor the side of the plastic sheet and seal off the interior. Try to keep the material tight so that it provides a flat smooth surface for the water to run down. Also, if any materials are available to construct a straw then it is extremely helpful to design a setup that allows you to drink from the collection container without disturbing the solar stills construction. But be sure to use grass or some other material to block the end of the straw to ensure that the solar still is kept airtight while the straw is not being used. Solar stills are especially effective within climates that see excessive heat during the days but experience cold temperatures during the night. Most solar stills of this size can produce approximately 20 ounces of water each day depending on climate. Solar stills can be used to turn all sorts of undrinkable water sources into clean drinkable water. Urine, salt water, stagnant water, contaminated water, etc… can all be poured within a reservoir created at the bottom of the solar still and turned into a viable water source. You can even cut up poisonous vegetation that contains significant amounts of water like several families of cactus and place them at the bottom of the still. The hazardous water contained within the poisonous vegetation will be forced out of the plant and then collected as safe drinkable water. To increase the availability and production of water, it may be necessary to build several solar stills.


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