In my research of green energy technology, I stumbled across something interesting called the solar water distiller, or solar still. Solar energy is having an explosion of new technology projects, but the solar water distiller isn't one of the advances. The main reason is probably because the solar water distiller isn't really a solar energy system. It uses the energy of the sun and hence “solar” is applied to the title, but it doesn't use solar cells or anything like it to distill water. The solar water distiller is more applicably titled the solar water still. The solar water distiller basically uses sunlight to heat water, which then evaporates and condenses on the wide glass pane, and then drops down into a large glass bottle. In the process, solar water purification happens, and the water that comes out the spout is relatively clean. Solar water purification isn't complete purification however, because the water in the distiller is never boiled.
Solar Water Distillation
The solar water distiller, or solar still, basically does nothing more than trap and heat water, causing faster evaporation of the liquid and also condensation on the glass pane. The water is then collected in a specific way that keeps the water mostly pure and stored generally in a five gallon glass jug. In technical terms, the solar water distiller isn't really a solar water distillation device. It's more an evaporation device. The solar still's dimensions are generally around 5 feet long and two feet wide, and can be made of wood and glass, with jugs and silicone tubbing – generally simple household items that have very little cost. But this is just a general dimension. There are many different sizes, even different solar water distiller designs. Some are more complex than others, but they all use the same essential factor -- sunlight.
Solar Water Distiller Plans and Designs
To make your own solar water distiller, you need a few things, most of which can be bought at your local Home Depo. The first thing you'll need is the box frame, which usually is made from wood. But ABS plastic is also a great thing because it won't rot from being constantly exposed to water. Whenever I build something for use with water, I always use ABS plastic. In the picture above, you can see all of the different components.
The whole apparatus can be made easily from black ABS plastic, and being a darker color, will cause the water to heat quickly. Once the frame is created, a trough of some kind needs to be placed at the bottom to collect the clean water that drips down from the glass pane. A mirror should also be used to focus light down on the the apparatus to cause the water to heat faster. Once both of those are in place, a glass pane needs to be fitted on top and sealed to completely enclose the apparatus. After that, all you need to do is drill 2 holes into either end of the still, one for water intake and one for a clean water spout.
A Modern Solar Water Distiller
http://www.thesietch.org/projects/distiller/index.htm
Their distiller is top of the line but you really have to be serious about building the distiller because the plans they've drawn up aren't easy. There's a little bit of machining involved, and some pretty complex setup. But you've gotta say, their distiller looks pretty amazing.
Solar Water Distiller -- Pros and Cons
Though the USA is going very quickly in the direction of green alternatives, in my opinion, the solar water distiller isn't really an applicable device for use here in America. It has a few drawbacks that generally cause a large concern. For one thing, the solar water distiller never actually brings the water it traps to a boil, and thus the water still might retain some of its bacteria and other hazards. Also, the solar water distiller has a difficult time retaining a good seal. Because of the large moist area it creates, the solar water distiller is often the target of insects and bacteria looking to exploit any weakness or opening in the seal.
That being said, however, the solar water distiller has great application for many third world countries. Having lived in a third world country myself (Cambodia) I know that fresh water can often be difficult to come by. During my stay in Southeast Asia, I would often drink the juice of unripe coconuts instead of the local water. The coconut provided a natural purification to the water, and the hard shell of the fruit kept the water preserved and pure. I like the idea of solar water distillers for countries like Cambodia, because the materials are cheap to produce and easy to assemble. Not only that, but there are no moving parts to worry about, which makes it a handy little device.
I'd love to see the solar water distiller employed in any number of third world countries around the globe. A compelling statistic lists a lack of fresh and clean water as one of the top causes of death worldwide, and literally millions of people every year die from lack of pure, clean water. Plans to build solar water distillers are available all over the internet, and generally, one can find plans that only use common household items for the construction. If you're wanting to build your own solar water distiller for home use, I encourage you to check out some of the cautions associated with the solar still. Speaking of clean water, our you sure your water is clean? Most people go years without changing their refrigerator water filter.
