How to Make a Solar Still


Under the stress of Survival, a person who may be in a life and death decision needs to think and react quickly. Water for survival is normally a factor in that thinking. People who are in survival mode on land or sea can use the Sun, Evaporation & Condensation which is the Water Cycle, for a simple water distillation method that can save lives. How to make a solar still?

On Land:

  • Dig a hole
  • fill it with green vegetation
  • put a container in the middle of the hole
  • Cover hole with plastic
  • Collect condensation from the inside of plastic in container

On Sea:

  • Use a Bowl
  • Fill it with Seawater
  • put a cup in the middle of the bowl
  • Cover bowl with plastic
  • Collect condensation into a cup

Most people lost in a desert, on the ocean, or trapped in the wilderness from a plane crash or avalanche, have no water treatment equipment and may even be injured. Using ingenuity and what’s available and some limited supplies you are carrying can make the difference between life and death.

 

How to Make Water In the Desert

Everyone knows pretty much how important water is and the fact that in a survival situation, Exposure and Hypothermia can kill you the first night. After that, the clock is ticking.

You have no chance if you don’t have water in 3 days. It could be less depending on the environment. The saying used to be if you fell out of an airplane and survived in the wilderness then you would need:

  1. Shelter
  2. Fire
  3. Water

In that order. Water is the catalyst for everything in your body. Your body needs hydration for digestion. If you are eating food, your body won’t be able to break down the necessary sugars and proteins to keep it moving. This is why most survivalists like Bear Grylls say that the first thing he’s looking for in wilderness survival situation is signs of moisture and water.

In a desert or wilderness plains or jungles around the world where the temperatures are extreme, you would need twice as much water to replace the amount your constantly losing from the physical demands that the experience is putting on you. Even anxiety and stress will make your body lose more fluids than normal exercise would.

These experience, all combined, will give you even less time if you are not hydrating. The Importance of Hydration and Fluid Replacement is a critical component of Nutrition. It’s necessary for the health of a human body to recover, repair, regulate temperature and restore important minerals lost by sweating. The more the situation becomes more intense, physical and emotional, the more trouble you’ll be in if you are not drinking fluids.

Your mind will become irrational and just like what happens to athletes, your blood vessel begins to detract and your muscles will start to cramp. You’ll experience fatigue and nausea. Everything will snowball because your body is not replacing the fluids that it’s losing.

 

The Situation is;

You are lost in the desert after being separated by a group exploring the area for artifacts. Now it’s been 24 hours or more since you have seen them the day before. You are out of water and have minimal equipment. That includes a small shovel used on archeological digs along with a plastic sheet you use for a rain poncho.

You are lost and are suffering from headaches that you fear is Dehydration that may be setting in. Your pee was turning darker and a little cloudy. You can’t focus and are fatigued.

You need to find a water source. In the desert, there won’t be one. You need to make your own. You need to make it fast. You can do this by creating a simple Solar Water Distiller that uses The natural process of the Water Cycle.

  • Scoop a hole in the dirt or sand slowly so you don’t exert yourself and lose more fluid
  • Look for any kind of green vegetation around the area and fill the hole with it
  • Place a cup or container in the middle of the vegetation in the hole
  • Lay a piece of plastic over the top of the hole. (use a rain poncho or garbage bag)
  • Cover the corners of the plastic with dirt to hold the plastic down
  • Place a rock on the center of the plastic so it dips down in the middle over the cup.
  • You can pee on the vegetation to kickstart the Still. Keep a hollow stem and use it as a straw so everything stays in place. Just lift one end and use the straw to get a drink then drop the plastic cover and wait again. Any kind moisture in the air filling the hole will be drawn out as condensation and end up on the bottom of the plastic draining into the cup. There should be some plants and vegetation that will have some moisture that you can add to the hole every day to fuel it still.

Solar Still Desalination

Again in Survival just like in the previous post on how to make a Water Still in The Desert, this example uses the science of Distillation and the Sun but this time we are on the ocean.

In this situation; you are lost at sea and need water to survive. You can’t dig a hole in the boat of course so you will need to do something else. There is plenty of water source but it’s saltwater and you can’t drink it.

You can Desalinize it by using the same Natural Water Cycle and a Still to get fresh water to drink. But not the same process as we used in the desert.

A good example of desalinization in desert regions and how they deal with it every day is in Israel. Water is considered a natural resource in Israel. They have come up with technologies for Water Reclamation and Desalinization projects that are leading the world and helping others in the same regions who have the same problems.

In the last decade, they have come up leading the world in the area of Desalinization and how to take advantage of using the oceans that surround them for drinking water and agricultural development.

They use Reverse Osmosis but being in a survival situation we don’t have any luxuries like a teapot over a kitchen range or RO Portable Water Filters or Distillers dispensers that eliminate salt from drinking water.

Since we are in a Survival situation and on the Ocean, without the luxury of fire to distill the ocean water, we’ll use a Still similar to the way we used it in the Desert.

The Sun will heat the sea water-evaporate and separate the salt from the sea water-The condensation will be collected and drank-hydrating you until help arrives and saving your life.

 

The Situation is;

You were out fishing on the Bay and got pulled out to the Ocean by the tide in the inlet. Your small boat is adrift with no radio to call. You were carrying a few supplies for fishing and some odds & ends including some bait containers and plastic wrap that you used to wrap your sandwiches. It’s really hot on the water so you decided to build a Distiller until any help comes your way.

 It’s basically the same concept of the hole in the sand or dirt you used in the desert

  • Use a bowl and put a cup or smaller container on the inside
  • Pee or use Sea Water or both in the Bowl as your source water. Don’t get any in the cup!
  • Cover the bowl with plastic wrap, a rainwater poncho, a large sandwich bag, or some kind of plastic.
  • Secure the Plastic around the Bowl with a Fishing line or tape, string from a crab line.
  • Take a few coins, a sinker, or a heavy Jig and lay it down on the center of the plastic covering the Bowl.
  • Sit It out in the sun and let it Distill-it won’t take long

A person needs around 2 liters of water a day under normal situations. This is not a normal situation. You are in  Survival mode so you will sacrifice a few things that you normally wouldn’t do. These are unique situations that any outdoorsman can find themselves in.

You can’t prepare for everything, but try and carry a piece of plastic, waterproof matches or a lighter and a small bottle of iodine for (water treatment) in a tackle box or somewhere in a knapsack. It won’t take up any room and you’ll forget you have it. That is until you need it. 

If you ever saw someone dying of thirst they wouldn’t question if the bait containers were dirty or whether drinking your pee is the best overall thing to do in this situation.

Short-term situations like these are emergency situations that arise unexpectant. You live an hour to an hour to make it through to the next day.

 

 Katadyn Desalinator

You can find a Portable Desalinator right here on MyWaterEarth&Sky through Amazon well worth the price this unit can run on Solar Power if you have no power. It’s a great tool for Survival!

Water Treatment device like this one that should be on every water vessel like a Sail Boat that spends time on the water like this quality  Katadyn Power Survivor 40 E Watermaker Desalinator- This product saves lives.

  • Produces 1.5 gallons of freshwater per hour–enough for 2 to 3 crew members
  • Katadyn’s patented Energy Recovery system produces water at a fraction of the energy used by conventional watermakers
  • Draws only 4 amps from a 12-volt system

 Katadyn Power Survivor 40 E Watermaker Desalinator

Contaminants That Are Removed By Solar Distillation

The normal Distillation Process can remove nearly all impurities from water. Compounds removed include sodium, hardness compounds such as calcium and magnesium, other dissolved solids (including iron and manganese), fluoride, and nitrate. Operated properly, it will inactivate microorganisms such as bacteria, viruses, and protozoan cysts or any microbe that is living in it the source water Freshwater, Saltwater, and Brine that you are hydrating from. 

According to the EPA, only Distillation and Reverse Osmosis Water Filters can be called water purifiers, all other types of filters are called water treatments. For every gallon of purified drinking water produced, the process consumes 2 to 4 gallons of water.

In contrast, Solar Distillation wastes no water and is powered by the sun. instead of removing specific contaminants, as filtration systems are designed to do, Solar Distillation purifies water by removing only one thing: water.

Distillation takes advantage of the principle that chemicals vaporize at different temperatures. Most potential chemical contaminants in drinking water have vaporization points higher than water. When untreated water is heated in a solar distiller, pure water vaporizes first, separating and leaving contaminants behind.

Solar distillers work by mimicking the natural water cycle: The sun provides energy to warm the water, the water evaporates (forms clouds) and condenses (makes rain) when it meets a cooler surface. Unlike electric distillation, boiling is not required for solar distillation. Some people believe water from a solar distiller is purer than boiled water. Florida Solar Energy Center principle research scientist W.R. McCluney, Ph.D., says vigorous boiling “can force unwanted residue into the distillate (distilled water), defeating purification.

Bigger Solar Distillers

Heating water by solar energy can be harnessed by the use of a system of mirrors following the path of the sun to focus the sunlight on sheets of water in a solar still.

In solar stills, saltwater is filled in basins with a covered tilted glass pane that is tightly sealed to the holding frame. Upon heating, by solar heat, the water molecules are converted into steam leaving behind the salts at the basin.

The steam is condensed at the bottom of the glass roof of the still and water slides along the slopes of the glass panel and collected in the collecting troughs. See the pictures below.

The collecting troughs at the foot of the glass pane cover of the Still must be constructed in such a way that water will drain freely to the pipe which carries the distillate to the freshwater tank.

These simple, low-tech homemade solar water distillers, use the evaporation cycle to purify undesirable water. They are just boxes constructed from miscellaneous materials with a glass or plexiglass face, a trough to collect the water, and tubes to drain the clean water into a container.

Dirty water is placed into the distiller box and left in the sun. When the sun heats up the box, pure water evaporates and collects on the glass as condensation, leaving the contaminants behind. The water drips down off the glass into the trough, where it flows through the tube into a collection jar.

These Solar Distillation units that are 6 ft. by 4 ft. can provide enough water for a family of 4 for cooking and cleaning. Their crude low-tech examples of what can be done using the sun and the water cycle, which is a natural process here on earth.

The water that is undesirable can be evaporated, separating the water (condensation) from whatever contaminants that are involved with it. The plastic lid holds the condensation back from entering the atmosphere and collects it skipping the 

In our examples we used plastic but glass or plexiglass will work better. In the Water Cycle, water that is evaporated is condensed and separated held in the clouds and returns as rain. These crude small units can separate salt from seawater that holds 30,000 ppm and reduces it down to an acceptable 1 ppm. Normal treated drinking water has 50 mg/l or ppm.

These Solar Distillers are good tools for off-the Grid living when drinking water is questionable and there is no access to carbon filtration. In the matter of life and Death Survival, the simple solar methods might just save your life.

 

 

 

 

Related Questions:

 

 How much water can a solar still produce?

Properly operating a still requires about three times as much make-up water as the distillate produced each day. If the still produced 3 gallons of water, 9 gallons of make-up water should be added, of which 6 gallons leaves the still as excess.

 Does boiling water remove sodium?

No, through boiling the only water has been vaporized, sodium has a much higher boiling point than water, due to this reason the salt content will be increased if you boil water. Through distillation, you can definitely reduce the salt content catching the steam from the boiled water

Does a water softener remove sodium?

No, During the regeneration process, the resin beads that remove the calcium and magnesium in your water are flushed with a brine solution (made from the salt you add to your tank). The exact amount of sodium present in soft water will vary based on how much hardness is being removed by the softener.

 

 References: EPA-National Primary Drinking Water Regulations

Jim has over 30 years in the Water/Wastewater & Water Filtration Buisness. He has written over 200 articles on the World-Wide Water Situation

JimGalloway

Author/Editor, MyWaterEarth&Sky

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