Saturday, May 21, 2005

next step in solar water purification

This is another experiment for cheap solar water purification. Previous post here.

In this attempt, our hero put the cup on a stand, to get the mouth closer to the top of the bottle, and also taped a small aluminum foil reflector around the back half of the bottle. I adjusted the reflector to re-point it at the sun periodically throughout the day. Weather conditions: severe clear and 80-85F.

  • The bottle with the reflector and the cup on the stand distilled 2-3/4 tsp of water.
  • The control bottle with just a plain black cup distilled... 2-3/4 tsp of water.
Doesn't look like the reflector or stand did a whole lot.

Still to try:
  1. a larger, external reflector made of aluminum foil taped over cardboard
  2. adding a wick to the cup to try to increase the surface area and speed the evaporation rate (thanks to John Galt for the suggestion)
  3. possibly sealing the gap where the top of the bottle fits into the bottom in case we're losing water vapor through there
I'm not so sure about #3: I haven't noticed that the level of liquid in the cup has dropped all that much, so I think it's more a problem of low evaporation rate than losing water vapor.

The next post in this series is here.

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