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Survival Solar Still
Water procurement during a survival situation could possibly be your number
one concern. The length of time you body will survive without proper
hydration varies under different conditions. Increase in ambient temperature
and activity will lessen your chances of survival. Under arid conditions the human body can succumb to dehydration within a few days. Beginning symptoms of dehydration can be muscle cramps, headaches, and fatigue. As symptoms increase your chances to find water diminish.
In desert like regions or coastal survival, the solar still can be one of the
methods used to find desperately needed water. We will experiment with
several solar still methods on this article (adding information as we continue
to test).
So what is a solar still ? A still or distiller, equipment used to purify liquids. Usually a heat source is used to create vapor. The vapor the condenses as it cools turning into liquid form again. This process can be used to remove impurities from water that can be harmful. What we want to do is make water safe to drink. The same process can help to lower salinity levels in water if you care caught in a survival situation.
Solar stills are being used in countries where potable water is not readily available.
There are different types of survival solar stills or vapor stills. Usually the pit solar still is used in survival. There are box type and cone shaped stills. They all basically use the same principle, but have different shapes and ways of catching the liquid.
Note: Take a look at your surroundings. If the ground is very dry, a solar still will produce less water. Taking the time to find a dried creek or adding vegetation to the solar still will help yield a higher output of water. **
Carrying a sheet of clear plastic as part of your survival kit could save your
life. It can be used in so many different ways.
* Shelter (lean-to, poncho, insulation)
* Water (water catcher, solar still, canteen)
* Food (help to preserve food)
For this article we will use the clear plastic to catch the condensed water from our solar
still . We will use the sun's radiation to help us to distill water. Keep in mind that soil contains a certain level of moisture. Vegetation can be added to increase water output. For instance if in the desert a cactus can be crushed and added to the bottom of the still. Water from an unclean water source can be poured into the pit.
The shape of the pit can either be "v" shaped or box 'square' shaped. We will be testing several survival solar stills later. This pit was box shaped without any vegetation added to the pit.
We simply placed the small bowl in the center of the pit covering the pit with clear plastic. Sand was used as an anchor for the plastic. Sometimes stones can be used. A stone can also be placed in the middle right above the bowl. Here we used a small amount of sand. This will make the plastic sheet take a "v" shape. As the water evaporates and condenses on the plastic sheet. The water will drip into the cup.
If we look closely, we can see the water slowly dripping into the cup.
We did not have a measuring cup readily available. The picture below shows how much water this small still was able to produce in a twenty-four hour period. If we build a larger still and add vegetation the output would increase.
Tips:
We can increase the amount water evaporated by adding the following to the pit:
* add fluid (unclean water, urine)
* add vegetation
Surgical tubing can be used to draw the water out of the still without the need to remove the plastic sheet.
** Note: In areas where a solar still or a transpiration bag would be needed such as arid desert regions, the water produced is not sufficient for long term survival. In my opinion the current solar still designs are not a viable option for water procurement. A transpiration bag is another option that would help supplement a water supply. Experimentation with adding vegetation such as cactus etc, would be wise so that each person can draw from their own experience. Knowledge of plant life is crucial since the water can take the taste of the particular plant and in worse case, can be poisonous. **
Please see related articles:
Transpiration / Vegetation Bags
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