Comments on: I Have To Heat Two Liters Of Water For A School Prodject By Using Solar Power?

By: Logan A

Logan A — Sun, 23 Aug 2009 03:18:36 +0000

Dear I avenge,
It is so simple that even I can do it. Put the water
in a black plastic bag. Other containers will work,
but thin plastic will not adsorb as much of the heat
as thicker materials. If you can arrange to mount the
bag so that it is flat it will work better. You might mount
the bag in a cardboard box and hold it in place with
strings. The more square the surface is to the sunlight
the better it will work.
For temperature, a small hole in one corner of the bag for
a thermometer, then wrap it with a rubber band. That ought
to about do it. Put it together at home and try it first, and
have lots of towls on hand.
Some “colors” may work better than black. What is
“black” to our eyes may be different in other frequencies
of light. You might try a dark green, the trees seem to
like it. Good Skill!
Logan A {:-) (-:[>

By: Elisa

Elisa — Sun, 23 Aug 2009 02:57:37 +0000

Go get a car radiator, paint it black if it isn’t already, cap one end, put 2 liters of water in it, cap the other end, and set it in the sun where there’s no wind. If you want to be able to measure the temperature inside without taking the water out, then punch a small hole in one of the cap and put a thermocouple through it so it dips in the water when you close the cap.

By: Mark G

Mark G — Sun, 23 Aug 2009 02:04:25 +0000

Use a large heavy duty black plastic trash bag and put the 2 liters of water in it and loosely close the bag. Lay the bag out flat in the sun on the blacktop at school and you will find that it will heat the water quite hot. Do not seal the bag tightly because you do not want pressure to build up inside the bag.
A couple of thinks to keep in mind…. dark objects absorb solar radiation and heat up. Surface area is key to efficiency, spreading the water in a thin layer inside a large bag is better than completley filling a small bag with a smaller surface area.
edit:
This concept is used in a Solar Shower produce used for camping