Solar oven Wagon

[wiredwrong]

About a year ago I was given a bunch of insulation board with a shiny foil surface on one side, this was supposed to go into the wash room to help insulate better, but was later decided that it wasnt really needed there, this was our first year in this house and it was better insulated than I had expected, so this board has layed out back under a tarp for about a year. When the gas bill came in last month and was 3 times higher than the month before, I was looking for a way out... Solar oven-I have the perfect foil/insulation,I also had a couple of clear heavy shower doors I got from the curb on "large junk day" as we call it here. All I needed was the right size box for the job, I wanted to make it small enough that I could track the sun through out the day easily, but sturdy enough to last, not finding anything that was ready made I was about to give up when I spotted my daughters big green wagon, It was even a little bigger than I had originally planed but would be very simple and  on wheels so it could be moved with the food in it with ease. So this is what I came up with...





(this is a pic with the beans)Ill post a better pic later

 I havent taped anything together, no glue no screws nothing, didnt need anything but a razor bladed to slap this together it was used to cook beans the first day, it took more than 9 hours for me to call them done, it was partly cloudy all day and very hazzy outside from about 3 O'clock on, today I tried chicken and rice, and measured the temps of the oven and food all day, I decided at noon to try chicken and figured that if it didn't get all the way done I could move it to the stove or the BBQ grill, the chicken was frozen solid, I was sure it would not be done by 5:30pm and we had to be somewhere at 6, but I tried anyway, I tossed everything in to a nice large pot, covered it with a glass lid and put it in the sun. I seen the temp inside reach nearly 250F in about an hour, the chicked had thawed enough by then to poked a meat thermometer into it. I moven the wagon a couple of inches and went inside. About once every hour Id go outside and "track the sun?" and check the temp, by 3:30 I knew that the chicken would be done in time for dinner, I left the food out there till 5:30, when I pulled it out of the sun the temp of the chicken had reached 198F and had been there for more than an hour, when I tried to pick it up it fell from the bone. It was juicy, and tasted great, the best part is I didnt have to use gas or wood or electric or propane to cook, also the air conditioning did not have to work over time to cool the house back off, so I saved energy in more ways than one. Very fun, cant wait to try ribs, but the wife done said I have to do burgers next. Im thinking of a parabolic stove type for things like that so she may have to wait, the next step is puting the things in the wagon into a boxso my daughter can still play with the wagon when she wants, but I think that I will make it fit in the wagon still the same for the ease of moving and tracking it provided.

[ghurd]

I don't know much about those things. OK. Nothing really.

But wouldn't it work better if the bottom was flat black?

Seems like the foil would reflect energy right back out.

Maybe just cover the bottom with a black towel for a test.

G-

[xymox]

Thats pretty cool man. I bet those ribs are going to be falling right off the bone!

I bet it would get even hotter if you used a low e (northern stype) glass that would trap the heat better. And also while you are at it, place a rubber gasket around the perimeter of the wagon, how big is it anyways?

[wooferhound]

 It would work better if you painted the pan Flat Black

  Like Bar-B-Que grill paint . . .

[wildbill hickup]

Another suggestion would be to place a sheet of steel, aluminum, or copper on the bottom with spacers to just lift it off the insulation an inch or so. Paint the surface with high temp flat black paint. Also if you wanted more heat build a cover that hinges and cover the down side with aluminum foil or milar (potato chip bags turned inside out) so you can adjust the reflection of the sun into the cooker.

Just my 2 1/2 cents

Wildbill

[Ungrounded Lightning Rod]

Another suggestion would be to place a sheet of steel, aluminum, or copper on the bottom with spacers to just lift it off the insulation an inch or so. Paint the surface with high temp flat black paint.

But then you have to conduct the heat to the pot.  As is the heat reflects at the pot.

Instead I'd put the pot up a few inches on a grid.  That way the bottom would get the light that reflected off the lower shiny surface from near the pot while the side got what reflected from farther back.  (As is the bottom gets nothing, the side gets what reflects from near, while what reflects from far is largely lost.)

I'd also put a sheet of glass across the open top, under the slanted reflector, closing the box area, so that the incident light goes through the glass once (perhaps directly from the sun, perhaps after bouncing from the upper board), assuming it happens to hit the pot.  This way you get greenhouse effect AND block air conduction, both of which greatly reduce the energy that gets back out.  If a photon happens to hit the pot most of its energy stays in the box.  Should make a BIG difference.  (You can also do this with a glass box or cylinder around the pot.  But an old window pane across the top should be easier.)

DON'T use window glass with a thermal coating.  B-)

A caution:  Chicken tends to contain salmonella bacteria.  (It's a natural intestinal flora for chickens, so it tends to be present in the raw meat.)  Its toxin is VERY strong and doesn't break down at cooking temperature.  So you want to bring chicken up to cooking temperature pretty quickly, so the bugs spend little time between the "wake up" and "die" temperatures and don't make much toxin.  I'd hold off on doing chicken again until I got the oven tweaked so it brings the chicken's surface from thawed to hot over an hour or less, rather than ramping up over several hours.  (It's fine to let the chickie stew for a while once the surface is hotted up.)

Use beef for your early experiments:  Most of the unavoidable bugs on beef are so benign that meat processors deliberately let them grow for a while (like a day or two) under controlled conditions while the meat's own enzymes work on itself, to make the meat more tender and tasty.  (REALLY fresh beef is tough and pretty bland.)

[georgeodjungle]

it's a great start :

there's a lot of little things wrong for the greatest efficiency "most heat"and at night the most cold.

but hay, it will work.

any lil thing we do is better that nothing.

and free heat and cold works for me.

i'd raise the pot up like an inch or so and bounce a lil light underneath.

wrap the pot up in a cooking bag or two for a greenhouse effect.

i'd change all the angles of the shiny stuff to derect the light to about the center but not to pinpiont to one lil spot,spread the light all over the cooking vessel.

a little pin light laser works good.

here's a great site to check out:

 solorcooking.org

by the way great idea about the wagon, i just might steal it.

i have a wheel barrel cooker that works great it all ready has the angles pretty close.and easy tracking.

if your daughter didn't need it any more it would be a good canidate for a hybrid cooker.

p.s.

bugers and cube steak don't solar cook to good.

but meat loaf does.

it fun any ways.

[wiredwrong]

Thanks for all the complimenst and sugestions, the night I cooked the beans I had originaly set the beans on the bottom of the oven but later moved them on top of a burner grate from the kitchen stove, no one got sick from the chicken, it was delicious. I was thinking of cutting the size of the oven too 2'x2' because i have a peice of glass that size and also because I think the oven would heat up better being a little smaller.

"I'd also put a sheet of glass across the open top"

There is a peice of glass up there. the air temp of the oven reached 285F the other day when the sky was clear and the outside temp was in the low 90's this was about 1:00pm when i measured that temp, I was pre-heating for brownies , also by cutting down to 2x2 id have room for the ice chest at the back of this thing, I was thinking of constructing a Crosley Icy ball, that could be heated in the oven while I was cooking and making ice at the same time. For anyone that has not seen a crosley icy ball, have a look here http://www.ggw.org/~cac/IcyBall/crosley_icyball.html

updates soon,

Smell something burning???

Must be Wiredwrong