DIY Solar Oven

Thanks Jason...will look into it

Kostas

Hi Kostas,
What great research you are doing. I appled the first post in the thread, but in my mind it stands for the whole project and the thorough way you are testing and recording.  Thanks so much.

I had an idea about those round pans early on, the ones that did not cook as fast.  I wonder if, as you go about your tests, if you have considered surface to volume ratio.  Those flat round pans are going to lose heat faster than the compact loaf pans.

And if you have not tried your bread baking yet, I have a suggestion for a bread recipe that is made to be baked in a closed pan to keep the steam in for the first half hour.

It is the no knead bread that many people are using.  I know that the mother earth news published it a few years ago.  I'll gladly pass it along if you are interested.  One thing it requires is a hot oven AND pan.  The pan is a heavy cast iron or crock with lid of some kind.  The oven and pan are preheated to 475 F, then the dough is added.

I have a solar cooker, but it was a fancy thing I got off kickstarter, which is OK not fabulous, one of the things they recommend is preheating the oven,but they warn against getting the oven too hot before adding cold food.  They keep the heat in with a vacuum tube of borosilicate glass.

I wonder if you have tried lining the satellite dish with the mirrored roof insulation material to generate more heat than when it just stands up.  I think to bake the bread you need to maintain a hot temperature.

Anyway, good job and keep on, you'll get a good understanding of the variables and be able to advise others how to work with what they have.

Thank You Thekla...bread baking is going to be challenge...but I am sure we will find a way...any help will be appreciated.

Kostas

I don't know why it took so long to figure this out, but...as usual, simplicity rules !!! (and it hides well)

Assemble a solar oven with items found around the house or easily bought nearby. See the included video...its self explanatory...any comments or questions please let me know...

Simply set the oven outside in the morning 7, 8 or 9 am ...do not move it....return at 2 or 3 PM and the food will be cooked...needs further trials, but it looks good...

AND you can make Bread !!!

glass does not need to be tempered (make sure edges are sanded to prevent cuts)...make sure mirrors are tied down in case of windy weather...

The key is the well insulated outer box, using old clothes or old bathroom towels...this with a low cost brings the temperatures up tp 130 to 150+ degrees Celsius

Cooking in sunny weather becomes really simple and economical



Kostas

The following videos are in Greek...they are self explanatory..but here are some comments in English


All you needs is a tub like the ones shown and some old clothes, towels blankets etc for insulation, at the bottom of the tub and sides





We put our food in a dark pan or pot, cover it with glass (5 or 6 mil thick), and close it tightly with paper clips...we place our food container in a larger pot or pan, and cover this also with glass...glass does not need to be tempered...





we placed our pot in the larger black pan, covered it and sealed it with the clips..then put everything in the insulated tub...here we used cotton balls, but just old clothes will do





press the clothing next to the pot and insulate as well as you can to prevent heat loss





We place the tub facing east west (long side).
The east facing mirror is placed vertical (up and down...90 degrees with the horizontal)
The south facing mirror is slightly sloped (85 +/- degrees with the ground)
We placed the solar oven out at 10 AM, and will leave it until 2PM, without ever moving it !!!
This is a large oven roaster and does not heat up as easily as the flat pans.





In this arraignment,  we put the bread in the pan, and placed the ends of toothpicks at the top and bottom of the pan, to allow steam and moisture to escape the pan.
The oven is slightly sloped east to west to facilitate the escape of moisture and prevent the bread from getting wet





we place the bread pan inside the large pan, and the whole assembly is placed in the insulated box...in this case a wooden box...here we used clothes and cotton for insulation





Its 10:15 Am...the placement of the oven and mirrors is the same...we placed a piece of wood under the eastern end of the oven to give it a slight slope.
Its important to tie down the mirror, and be careful with the glass...Safety is a must and everyone is responsible for their actions !!!





For the 3rd oven, we are cooking rice...rice and water is placed in a bread baking form, and then placed inside a smaller oven roaster





Here we used a small plastic tub...its light and it worked just fine..obviously the rice does not need 3 hours to cook !!!





Its 11:20 AM..this is the 4th and last oven for today...its black eyed beans...we placed the oven facing the sun...so its not truly east west...place the oven facing the sun.
The rice is at 75C, the meat at 80C, and the bread also at 80C...note the thermometer is in the outside contained...so in the inside container where the food is, the temperature maybe 20 to 40 degrees more.





At 12:10 PM the rice has absorbed all the water...the temperature is at 120C...the rice should be done..the temperature at the beans is at 130C, the flat pan is better at raising the temperature, even though its not black...
the temperature at the large oven roaster is at 80C
the bread is at 100C...the water is sliding at the top glass, and the bread is getting a tan color





The rice is out and it looks and tastes good...please with the results...after an hour and 20 minutes the water has been absorbed the the rice is fluffy...rice made easy...place it in the sun and leave it !!!





at 12:30 PM the beans oven is at at 140C and the water is boiling...the meat oven is at 80C, but more important, the liquid inside the pot is staring to boil, so the meat and potatoes are cooking...the bread is changing color,  and the temperature is at 100C





At 1:00PM,  the beans are at 130C and the beans are boiling very well, the meat is at 100C, and the pot is boiling...the bread is at 100C and the bread has a nice color...with time we will gain experience on how to use these ovens, with the least amount of work...





at 1:30PM the beans are cooking well (temperature is not visible-and not really important...the food is cooking)
the meat is at 110C, and the food is cooking well all around
the bread is at 100C and the bread has a good color





At 2:00PM the beans are cooking slowly now
the meat has been cooking now for 4 hours
the bread looks done...its been in for 3.5 hours





The potatoes and meat have cooked well...the meat is a bit dry at the top side, but cooked well..





The bread smells good and is well cooked...its dry at the top and bottom, so the toothpicks worked well....we will need to try this again and again to verify the results





At 2:25PM  the beans have been cooking for 3 hours, the water has been absorbed, the outside temperature has dropped to 100C...black eyed beans take longer to cook...the bread came out good





The beans are done, they are a bit crunchy, but ok
all this cooking with only the sun....I am in owe at how simple it is !!!

Here is a brief write up for Solar Cooking Wiki

Solar Cooking Wiki

Kostas

Been using a solar oven for many years now. Our DIY plywood wedge served us for years until weather got to it. (picture #1) I made a cardboard one (picture #2) that functioned fine until I could replace it with a weather proof one that has been cooking for us ever since (picture #3)

I learned early on that trying to get high temperatures complicated construction and that 'medium' temperatures work fine, like a slow cooker does.

I like your can do spirit Jain...

I still wonder why so few people use solar energy to cook.

In any case I hope the idea of using old clothes, and the "no skills required - inexpensive" set up will help.


Kostas

Konstantinos Karoubas wrote:I like your can do spirit Jain...

I still wonder why so few people use solar energy to cook.

In any case I hope the idea of using old clothes, and the "no skills required - inexpensive" set up will help.


Kostas

Few people use solar for cooking because it requires some thought and effort to set up and make use of. Yes, the device can be made of so many 'at hand' materials and WORK! too. My first oven was inspired by a 1940s or 50s book on solar use. I made the first picture attached below out of cardboard and kitchen foil. I made a hot (focal) spot that would heat a cast iron skillet and fry meat! But it required near constant readjusting which meant I must be with the cooker to use it. The plywood oven first pictured in my previous post allowed me to put food in early in the day and leave it to slow cook until we were ready to eat hours later. It required a turn or two to keep it facing the sun which I could easily do during that time. But again, I needed to work with it, it wasn't automatic and 'fast' like a stove.

Solar cooking is also seasonal. I need to get back into the habit of preparing ahead of time so the food can be ready when we want to eat. And while my current cooker (pictured 3rd in previous post) is weather proof, it really doesn't get enough solar input during late fall thru early spring so gets tucked away those seasons.

If this hasn't already been referenced, here's a link to a site that has  MANY different type and plans for using solar to cook with - http://solarcooking.org/plans/   and another that inspired many to simply DO it - https://solarcooking.fandom.com/wiki/Heaven%27s_Flame

I do enjoy cooking and eating a home made meal each day. My solar cooker helped us to have that - while we built! - so that I didn't have to stop construction efforts to cook. I kept on using a solar cooker after we finished building because I enjoy its quiet, clean and efficient/energy saving cooking. Yes cooking (dry) beans takes 2 days - first for the beans, 2nd for additions/flavorings, but the hot dish is ready to eat when we want a meal.

One of the excellent examples of small cooker that one can use anywhere was a 'box' that lid covered glass top and could be sat in the sun to heat a person's lunch. It could be taken to work, school or construction site.

Until a person chooses to take the time to obtain (aka MAKE or buy) a solar cooker, they will never choose to USE one. Guess being online or playing a game is more fun?!? The irony is that I can do BOTH and still have a hot meal without standing over a stove

Hello solar cooking enthusiasts!!!

I am attaching a small video from 2 years ago...I will try to improve on this design in the next few weeks.



Kostas

Here is one version of the latest design...a 2nd version with a larger pan is coming up soon.



Kostas