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Solar Distillation Projects

Water distillation is a necessary part of life in many different areas of the world. Particularly in those places where there isn't abundant fresh water, drinking water may need to be distilled from salt water, swamp water or other sources that simply aren't potable. There may not be resources for traditional distilling (such as fuel to burn). Solar distillation processes solve this problem, and there are a variety of different methods and projects that are still exploring this natural power source.

  1. Pit Distillation

    • One of the simplest types of solar stills is called a pit still. This project is easy to undertake if a person is out in the wilderness or simply wants to see the solar distilling process in action. All you need is a small pit, a tarp to put over it, a bucket and a water or moisture source. Dig the pit deep enough that the bucket or cup fits inside, and then pour in brackish water, salt water or urine. Then put the tarp over the pit and secure the corners. The heat of the sun will cause condensation to rise up to the tarp (plastic works best by the way), and the condensation then drips from the center of the tarp into the cup or bucket. Lots of the water is lost in the earth via this method, and it doesn't provide a great deal of water... but some is better than nothing. To make this project more scientific, measure the water that's lost compared with what's transferred to the cup, the temperature, and how long the process took.

    Survival Stills

    • There are also solar "stills" that can be easily erected in the wilderness that don't require any water at all ... you simply need a plastic bag and a tree. If you wrap a plastic bag around a leafy branch, the sunlight will heat the branch even more. As the sun goes down, the temperature change will cause more dew to "bleed" out of the branches and leaves and collect in the plastic bag. This provides very little water practically, but it is a method that works without any water source, and it has been featured on the TV show "Survivorman." Once again, experiments could easily be done with different types of trees, different sizes of bags and different temperatures to see how the most water is distilled.

    Large-Scale Stills

    • While not practical as a build-it-yourself project, large-scale solar stills are a good topic for research projects. Water pyramids, for instance, are huge, inflatable domes that are used to distill water using solar energy in rural, tropical climates. These solar stills produce much more water than smaller solar stills that can be put together by hand in the wilderness, but they still don't produce much water compared with their size. Finding out what regions can use these large stills, how much water they produce, and what mechanism they use to produce it are all important parts of a research project. It may help your explanation to put together large, visual diagrams of how the process works, or to build a small-scale version of one of the larger stills to show the process.

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