Solar cooking

[Shalmanese]

Cooks Illustrated reviewed Solar Cookers in 2007 and rated the Sun Oven as "Not recommended" and the SOS Sport Oven Solar Cooker as "Recommended with reservations".

[dcarch]

Keeping in mind that a gas stove gives you 18,000 BTUs output.

 

A very good solar collector gives you about 200 BTUs per square foot of collecting surface. Therefore, a 2' x 2' solar oven will give you 800 BTUs.

 

Extreme insulation is key to a solar oven construction.

 

 

dcarch

[Spike L]

This popped up in a few news sources when it was being Kickstarted: 

 

https://www.kickstarter.com/projects/scotfrank/solsource-cook-anything-under-the-sun

 

Not sure what the equivalent BTU would be. But seems to take a different approach from the SunOven

[Smithy]

This popped up in a few news sources when it was being Kickstarted: 

 

https://www.kickstarter.com/projects/scotfrank/solsource-cook-anything-under-the-sun

 

Not sure what the equivalent BTU would be. But seems to take a different approach from the SunOven

That kickstarter campaign is over and done, but I see it's commercially available now: SolSource Parabolic Solar Cooker

[dcarch]

the problem with this item, in addition to the high price, is that you have to use special pots and pans which have totally black coated bottoms to help the absorption of solar energy.

 

dcarch

 

This popped up in a few news sources when it was being Kickstarted: 

 

https://www.kickstarter.com/projects/scotfrank/solsource-cook-anything-under-the-sun

 

Not sure what the equivalent BTU would be. But seems to take a different approach from the SunOven

[andiesenji]

Cooks Illustrated reviewed Solar Cookers in 2007 and rated the Sun Oven as "Not recommended" and the SOS Sport Oven Solar Cooker as "Recommended with reservations".

I believe the Sun Oven has been redesigned and made sturdier.   Australia is increasing their marketing of solar cooking units.

[ChefPip]

I've been gathering materials to assemble a solar oven of my own.  At this point I know I don't want it sitting on the ground and it will probably be more of a novelty at first until I can determine how well it will perform.  Then what types of baked goods it could best be suited to with consideration to temperatures and baking times.

 

This is the site I am considering.

 

http://www.williamgbecker.com/MakeSolarOven.html. 

[dcarch]

I've been gathering materials to assemble a solar oven of my own.  At this point I know I don't want it sitting on the ground and it will probably be more of a novelty at first until I can determine how well it will perform.  Then what types of baked goods it could best be suited to with consideration to temperatures and baking times.

 

This is the site I am considering.

 

http://www.williamgbecker.com/MakeSolarOven.html. 

 

I think the best approach is using Fresnel lens. Check out youtube "Fresnal cookers" "Fresnel BBQ" etc.

 

dcarch

[ChefPip]

Yes Dcarch,  I see what you mean.  I watched an evaluation of several  Fresnel Lenses.  I didn't know where people were getting them or the differences in the focal lengths..  I could see using this with Cast Iron ware for a number of things as the food would be covered.  One of the lenses that was evaluated by the show's host was thought to be a possibility for an otherwise solar oven.

 

I'm guessing the Fresnel would be mounted at the outer edge of the "funnel" instead of at the bottom where the glass window would be mounted.  I'm sure the Fresnel would significantly amplify the solar energy better than just a plate of glass.

 

It's an interesting idea.

 

Here's the Youtube video.

 

 

 

 

 

 

 

Source:  https://www.youtube.com/watch?v=xExXjXm0YV0

Edited October 3, 2014 by ChefPip (log)

[Smithy]

*bump* Has anyone here been experimenting with solar cookery lately? I assembled a box with foil and plastic kitchen wrap before remembering that this topic exists.  I'd have done things differently if I'd done more research first; still, in my current situation (lots of sun, lots of heat) I've got a solar slow cooker for cheap.

 

 

This was just a smallish box picked up from a convenience store's stock of not-yet-crushed boxes.  If it had been slightly larger I could have put my cast iron griddle on the base and improved the heat collection.  (That's a dark brown plastic cutting board in the top photo.) I've tried it twice, both times using a clay pot.  Oven temperature reached 186F the first day, but I didn't measure the temperature of the pot's contents.  The second day I didn't get the oven temperature because I was gone most of the day, but as the pot's contents were cooling down I measured 155F. Both times I've succeeded in getting nicely cooked peppers (bell and chili) out of the deal.

 

 

Not bad for a discarded box, aluminum foil and kitchen wrap!  Next time I'll try some of the designs linked above. In addition, I'll be on the watch for a Fresnel lens.

[dcarch]

Sunlight gives you less than 300 BTU per sq. ft. compared to a gas range, which produces 18,000 BTUs.

 

The whole key for a better solar cooker is insulation, insulation and insulation.

 

Also, the cookware should be as black as possible.

 

dcarch

[Smithy]

19 hours ago, dcarch said:

Sunlight gives you less than 300 BTU per sq. ft. compared to a gas range, which produces 18,000 BTUs.

 

The whole key for a better solar cooker is insulation, insulation and insulation.

 

Also, the cookware should be as black as possible.

 

dcarch

 

Thanks for that information.  I'll keep it in mind for future developments. This was just a test run using easily-found and -disposable supplies - something I won't mind 'losing' at the next trash drop.  Even this bush-league setup is working well for quick thaws and rewarming food, though: the glass jar of frozen sauce was thawed within an hour, and my leftovers were plenty warm in 15 minutes.  It is probably relevant that the deck that the rig is sitting on is well over 100F. 

 

[IndyRob]

On 5/9/2011 at 7:51 PM, dcarch said:

See if you can find a throw-away large screen rear-projection TV.

 

Crap.  I believe I have one in my basement that is destined for the dump.  I'll now be obliged to take it apart.

 

But it kinda' seems like the cooking equivalent of wrestling a grizzly bear.

[dcarch]

if I was to make a solar cooker, I would use 1" thick rigid foam for the outside (foam is cheap at HD) box. For the window, I would look at Craigslist for salvaged modern insulating windows for IR reflecting glass.

For interior finish, I would go to a telescope making forum and ask for information about the blackest black paint.

 

Solar light enters the cooker, hits the black surfaces, converts into IR(heat), the IR reflective glass blocks the IR from escaping.

 

You may end up with a real practical solar cooker.

 

dcarch