http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=353x2033This, from the "Frugal Living" forum on Skins's island.
There's a couple of photographs of this alleged "new thing," home-made solar ovens, and it's well worth getting out the boat and rowing over to Skins's island to look at them.
The primitives can be so entertaining, always re-inventing things decent and civilized people knew about a long time ago. One suspects the primitives would be enthralled by the wheel, thinking it something new.
IDemo Donating Member (1000+ posts) Sun Jul-13-08 10:26 AM
Original message
Solar ovens
I built a Fun Panel solar oven Thursday (pictured below) and have since cooked a pot of split pea soup and some roasted chicken and veggies. Both were delicious. The cost to build the cardboard and aluminum foil oven was about $7.00, most of that from having to buy a box from a shipping store. It took a couple of hours to build.
The energy savings from using one of these may not be enormous, but can add up over a year. I figure I saved about 10 kWh of electricity* for the two meals versus the electric oven. I was surprised to see the oven thermometer showing a temp of just under 300°. The thermometer was placed inside the oven roasting bag that surrounds the cooking pot to hold in heat.
You can pay nearly $300 for a Sun Oven, but I just don't see the value. There are also a myriad of plans available online for building your own.
Warpy Donating Member (1000+ posts) Sun Jul-13-08 12:37 PM
Response to Original message
1. I finally sprang for a sun oven because an arrangement like that one I'd used for dyepots finally fell apart and I wanted something that would get to a reliable temperature for summer baking. The Sun Oven comes with a thermometer so that you know the temperature of the interior and can gauge baking times more accurately. The arrangement you have loses heat by convection and is inadequate for things like baking bread. You need a closed, insulated box for that, although a thoroughly blackened cast iron Dutch oven will help.
However, the arrangement above, even poorly done (my version) worked just fine for heating pots of water, wool and dye to simmering and keeping it there until the dye bath was exhausted.
IDemo Donating Member (1000+ posts) Sun Jul-13-08 01:32 PM
Response to Reply #1
2. It does appear the Sun Oven and other enclosed box designs get hotter
They claim to be capable of 375 to 400°. But I'm betting I can bake a loaf of bread, even if it takes longer. Designs like the 'fun panel' need to use a black pot and either a glass bowl or turkey roasting bag to trap air around the pot, but they will still lose more heat than an insulated box design. I may ultimately build another oven, either a box-type or parabolic (which get very hot, but need to be adjusted frequently to follow the sun).
Warpy Donating Member (1000+ posts) Sun Jul-13-08 02:13 PM
Response to Reply #2
3. The open designs are certainly adequate for soups stews and boiling water for coffee. I'm a baker, though, and needed something closed.
I really, really hate store bread.
You know, it's too bad the primitives disparage the Boy Scouts so much.
I myself was never a Boy Scout, although all the brothers were.
One time, in pursuit of some old magazines, I came across a Boy Scout handbook from 1926.
There's nothing new about homemade solar ovens.
