Re: Water and watering etc.

Patrick Cox (
Tue, 27 Jun 1995 15:46:20 AST

Ben Levin wrote:
=> How about a solar distiller? I remember seeing one in an old copy of CPN
=>from the days before it was printed on glossy paper. It was made by
=>putting a black plastic tray (I believe it was a photographer's
=>developing tray, or some such thing) into an aquarium which was covered

How about taking a toilet tank with the float and valve still in it. 1.
Remove any styrofoam insulation. 2. Paint the outside flat black. 3.
Hook up a water supply to the inlet at the bottom of the tank. 4.
Construct an air tight box around it (to prevent loss to the atmosphere)
with a sloping top made of glass or plexiglass. Something smooth and
clean. 5. Paint the outer surface of the glass with white or silver
paint. (To reflect heat from the outside) 6. Have a reservoir at the
bottom of the sloping top to collect condensed water.

The float will maintin a maximun volume of water in the tank. The flat
black surface will absorb solar energy and transfer it to the water. The
water evaporates and condenses on the glass roof. As water evaporates the
level in the tank will drop and this will open the valve to allow it to be
refilled. The slope of the roof should be such that the sun doesn't shine
on its surface. You could insulate it with the styrofoam from the inside
of the tank. Or if your supply water is cold, run some plastic tubing
back and forth over the surface of the glass to keep it cool. (This will
heat up the supply water as the condensing water gives up energy to the
supply water tubing.) The reservoir should be emptied and cleaned
regularly to prevent algae growth. (as should any water container)

Chintzy diagram:

| \
| \ <- Glass roof
| \
| | \
Toilet-> | | |
Tank | | | | <- Reservoir
| | | |
+--+ +--+

Probably expensive to build if you can't get used parts from somewhere.

TTYL, ''' Plant Science Computer Technician
Patrick Cox (o o) Nova Scotia Agricultural College
Sin has many tools, but a lie is the handle which fits them all.