BajaNomad

Solar Desalinator

bajachris - 1-25-2011 at 07:57 PM

Does anyone have some clever ways to build a solar desalinator? We've decided to combine my 5th grader's science fair project and something that could be useful at our Baja house. I would love to see some pictures and ideas of things that have worked well for people. Thanks!

BajaGringo - 1-25-2011 at 08:53 PM

I am in the design phase of an RO system for our place. It can be done with some planning and programming the unit to run during the sun peak times. We will be adding probably another kW of panels to the roof just to make sure we can keep our battery bank up to charge...

Diver - 1-25-2011 at 09:25 PM

You can make a simple solar desalinator with heavy plastic or glass for panels.
We made one with 4 triangilar sides (pyramid shape).
I made a 4' x 4' frame of 2x2 and then added 4 - 2x2 ridge boards to form the pyramid. We cut clear mylar sheets and sealed them to the frame with clear silicone caulk and some screen molding. The frame was made so the angle was about 25-30 degrees down each sheet.
This set-up was placed over a square basin we had that was just under 4' x 4' and 6" deep. Around the edges of the basin, we attached sections of plastic roof gutter and drilled holes in the bottoms to drain the water into a jug.
On sunny, warm days this will distill 3-4 liters per day from saline or drity water. The pyramid shape works well as the drops flow straight down - a simple tented set-up will also work as long as you seal the sides but will not produce as much in most situations. I have also seem them made with plastic stretched over pvc pipes bent to a half circle; also not usually as productive as a pyramid.

I'm sure you can imagine many more ways to make a solar still. The important thing is to set the angle so the water will run to the bottom and fall into your catch basin; too shallow and it will drip back into the source, the same for too steep. Make sure you have good light and heat; a black bottom to your basin will help. Also make sure that your glass (mylar, plastic, clear corrugated roofing or whatever) is smooth on the underside and lets in all of the sun's light. Another help is to place a mirror or foil reflectors (make one yourself) to direct even more sunlight into the pyramid. Or just put it in front of a south-facing, white wall.
Have fun !!

Hey, maybe put a big one over your swimming pool !?!?!
Or float one near-shore ?!?!?
Or a collapsible version teathered to your boat when at anchor ?!?!?
.

Bob and Susan - 1-26-2011 at 06:40 AM

for the money...nothing works yet
too expensive

remember too...when filtering salt water there is ALOT of waste water
maybe 9 to one

where do you put that stuff?

gnukid - 1-26-2011 at 08:42 AM

There has been a great deal of work at solar desal in the middleeast-if you search you'll find many designs from simple to complicated.

durrelllrobert - 1-26-2011 at 11:35 AM

Quote:
Originally posted by Bob and Susan
for the money...nothing works yet
too expensive

remember too...when filtering salt water there is ALOT of waste water
maybe 9 to one

where do you put that stuff?


and how do you get the sea water to the device? more solar panels to run a pump?

bajachris - 1-26-2011 at 02:41 PM

Thanks Diver for the detailed description. Maybe as part of the science project we will measure the water produced with different variations; black bottom, etc. Great information!!!