I would like to suggest that the opening at the top and bottom be a bit on the small side.
you mean they're too small right now or too big? and how do ya figger that, teach?
the picture isn't very good, but the openings are about 2" x 24" right now. I could cut them larger and I could block part of them to make them smaller. I'll have to make little doors for the openings anyway, to close the heater at night.
what I like about the design is that the air is relatively unrestricted and can move through the heater quickly. should mean more air moving through and being heated, albeit to a lower temperature than if it were forced into a convoluted path. if I make the openings too small, that advantage will be lost. I also like that it's got such a low profile compared to the soda can heaters. the heater itself only extends 1.5" beyond the plane of the door.
anyhow, let me know what your thinking is about the size of the openings. probably be easier to change them now than after I hang the thing.
I've still got to caulk things to seal it up better, but it's pretty much done. except for the door knob and lock bits. I'll have to take those off the current door, so I won't do it until it's ready to hang.
weather's warming up and we haven't really needed any sort of heater for the last couple of weeks, and the sun is high enough in the sky now that it will only hit the lower third of the solar collector, so I kind of dropped the ball.
haven't put it in the sun yet, but I may get out to work on it today, in which case I'll give it a test run. apologies to all for being such a slowpoke on this.
well, it's still not done. it's far enough along that my mom gave it a brief test run today, though. she stood in the sun with the heater standing vertical for a couple minutes and put a meat thermometer at the outlet. ambient air temperature was 58 Fahrenheit. temperature coming out the top was just over 90 Fahrenheit when she got bored after about five minutes.
still needs to be sealed up a lot better, but at least I know it will work. too bad it was too late for this year.
There's a thread on the Soda Can Solar Heater in the Alternative Energy section. They were mentioning there can be a smell from the paint used to darken the interior. I am thinking something like high temp barbecue paint or engine paint might be the way to go. You might still need to cure it in the heat but I can't see something made for a barbecue would have a lot of fumes once cured.
That high temp paint wont cure at 140 degrees. I would not go that route. Needs a higher temp to cure. Use regular paint. There is a lady with a youtube video that has one of these heaters the length of her house and at least 8 ft tall. She had used the high temp paint and could not get rid of the fumes. She took it all apart and repainted it with regular paint, not high temp, and now she is fume free. Just a gold nugget for all of you to think about.
Rocketstoves, cob, ferrocement, strawbale, all make the world go round.
I used a 99¢ rattle can from the local hardware store and I'm not having any trouble with fumes. it'll probably run outside all summer before I install the heater, so any residual solvents should be gone by next Fall. I wore a respirator while I painted, though.
it works. I haven't installed it because the sun's too high now to hit the front door and it's plenty warm in the apartment without it. I'll probably hang it around the end of September. steps left are sealing it better and installing the lock and handle.