In researching and studying I decided it was time I tinkered with some simple solar water heating. I wanted it cheap and easy so gathered up some boxes, other materials, bought some containers of water, and a can of flat black paint for plastics. I kinda used the solar oven concept to help try and capture the sun to hold in the heat. Of course one gallon or 2 ½ gallons isn’t a lot of water but enough for some dishes or a quick wash off shower and a lot better than no hot water.
My testing was done July 28th 2012 in central
. I put them out full of about 80 degree tap water at 11 am with the ambient temp at 88. I checked them at 1 pm testing the water temp with a digital thermometer. The 1 gallon and the 2 ½ gallon were at 118 with air at 91. At 3 pm the 1 gallon was 137 and the 2 ½ was 122 air temp 99. At 5 pm the 1 gallon was still 137 and the 2 ½ gallon was 134 with air temp at 99. Throughout this time I rotated them to keep them in the peak sun and adjust the tilt a little. Texas
The paint stuck a lot better to the clear stiffer 1 gallon jug than the 2 ½ gallon which is more like a plastic milk jug plastic. Having the containers black allows for the absorption of the heat.
I'll get back to Ya with the true test which would be in the winter with a lot cooler air temps. This is fairly simple with minimal cost. I also plan on testing the 1 gallon in a collapsible reflector solar oven. If the hot water is put into a small cooler the water will stay warm for many hours.