02-02-2013, 04:45 PM
Home Made Solar Water Distiller
Home Made Solar.docx (Size: 622.73 KB / Downloads: 53)
ABSTRACT
A few years ago a storm flooded the local water treatment facility leaving me and all my neighbors without water for several weeks. Partially motivated by this I designed a portable solar powered water distiller. The idea is that a person adds water from any source (assumed to be dirty, salty or otherwise unfit for drinking) in one side and over the course of the day gets clean safe drinking water out the other side.
At the heart of this design is an innovative method for forming a medium size parabolic mirror using a flexible aluminized mylar sheet (the shiny metallic foil commonly used to make potato chip bags/decorative balloons). I built an aluminum frame, using 1 inch wide by 1/8 inch thick strips, that runs around the edge of the mirror and use a pair of wires at either end to draw the frame up into a parabola. The mirror is actually sandwiched between an upper frame and a lower frame. This mylar sheet, frame and wire construction makes a good parabola, is inexpensive, lightweight, and can be easily assembled/disassembled
The aluminum frame is much stronger than necessary (& more expensive) and could easily be made out of a cheap local material like wood or plastic. The function of the frame is to 1) hold/capture the mylar sheet, and 2) provide some stiffness so the wire stays taught. The wire length determines how steep or shallow the parabola is, which in turn determines how close/far the focus of the mirror is from the mirror surface. The mirror is cheap (a few dollars) and ideally the frame should only cost a few more, altogether I’d guess it should cost under $10 to make the mirrors in any serious volume (maybe $10-$15 in moderate volume). I say should, because I’m still working with a prototype, and a custom job costs at least 10 times what I think the cost should be… Still I imagine a big cheap mirror can be useful in any number of solar applications besides water purification.