solar heater

I like this:

Interesting, I happened to build something like this as an experiment.

I took a 4′x4′ piece of scrap plywood, spray painted it black. I screwed scrap 2×4’s around the perimeter to make a box about 3″ thick. I bought a $2.99 pack of window film and stapled it on the box. I put a 3 inch hole at the bottom and the top.

I laid the box up against a stone wall angling it towards the sun. Then I went to go get a thermometer (I had a digital one). So not to get direct sunlight on the thermometer probe, I put a piece of insulation over the probe. This was I was sure to read the true temperature of the air coming out of the top vent hole.

Well within a minute, the temperature of the air coming out had pegged the thermometer at it’s max of 130 degrees. So then I got my meat thermometer that I use for grilling, and the temperature read 160 degrees. There was a bit of an air flow coming out of the hole, so I know I was getting the hot air to rise, being replaced by cool air at the bottom.

So, the concept works. I haven’t done anything with it though.