Solar Energy Cooking?

What has everyone's experiences been like using solar energy to cook? My husband and I are living in a tiny house and cannot stand the heat. We have been looking at alternatives and were wondering if any of you had any success or resources where we could find more information? We found this but it is essentially the only thing we have been able to find of substance. Any chance you guys have some experiences, good resources or information for us to set us on the right path? Much Appreciated!

Here are some links that might be of interest:

https://permies.com/t/13943/kitchen/solar-cooker

https://permies.com/t/2227/kitchen/lots-Solar-Cooking-information

https://permies.com/t/8127/kitchen/Haybox-Cooking-Thermal-Cooker-Box

https://permies.com/t/43076/Double-Solar-Oven

https://permies.com/t/49951/Inflatable-Portable-Solar-Grill

https://permies.com/t/51994/SolSource-mirror-cooker-review-pluses

https://permies.com/t/58271/Solavore-Sport-solar-oven-solar

https://permies.com/t/8799/Good-Solar-Oven-Designs

I've used a couple different kinds of solar cookers at our school in Ladakh, which is high desert, so it's ideal for solar power.

The reflector box cookers are great for the gee-whiz factor, but we never used them regularly. They can bake a small volume of items, and do better with sweet things than not, because I guess the sugar browns nicer. Baking is not a tradition here, and the box ovens we have had were too small to really produce much. I have met people who claim to cook other things in a box cooker, such as rice, but when we tried it, it fogged up the glass and the whole thing cooled down. We have two sitting around impressing people but not being used.

Parabolic reflector cookers that concentrate the sun's rays with a roughly parabolic disk of shiny material have been much more effective for us. The small ones, about 4 feet diameter, work pretty well, but you have to go outside and turn them every 15 minutes or so. They are too small for the numbers of people at our school, but they would be great for cooking for 2 or 3 people, I think. These are more like stovetop cooking and you can cook all kinds of pots of food on them. I've seen two models, one with the dish low to the ground and the pot raised, and one with the dish and the pot at about waist height. They are pretty affordable to put together from shiny aluminum or steel if you can make the frame. In your first week of having one, it is a rite of passage to burn holes in some clothing that you think will dry quickly by draping it on the solar cooker.

At our school we use a big Scheffler reflector type cooker, with a parabolic dish about 8 or 10 feet in diameter, focused on a hole in the (non-flammable) wall and a secondary reflector shining up to the pot. This works very well, and we can cook big pots for 50 people on it. Ours have gone through two models of self-regulating mechanisms, where you'd weight the thing down with a stone, pull it over towards the east in the morning so the stone goes up, and a tick-tock pendulum mechanism would control its speed turning back to the west as the stone pulled down. Both mechanisms failed, and now we just turn it by hand every 15 minutes or so. Either way, you have to make a seasonal adjustment every few weeks. It's a bigger investment, and rather complex engineering to get the angles right, I think. I don't even know where the designs are; I hope they are online as Scheffler cooker. Ours was installed by a Swiss guy in the 1990s who came around and trained lots of local people in how to fabricate and install these, and we've been using both ever since. The others that were installed in our region are no longer used. User motivation is essential.

Friends of mine have started an NGO http://www.solsuffit.be/ They distribute their cooker in Africa in an attempt to stop deforestation in het sahel.

They cook regularly in the Belgian Climate with their cooker.

Kind regards
Erwin

I'd add a couple other threads to Anne's great list above:

https://permies.com/t/84080/Sun-Oven-solar-oven-cooker

https://permies.com/t/46768/GoSun-Grill-Break-Solar-Oven

https://permies.com/t/77531/black-cookware-solar-oven

Solar oven designs:
http://solarcooking.wikia.com/wiki/Category:Solar_cooker_plans
More designs:
http://solarcooking.wikia.com/wiki/Compendium_of_solar_cooker_designs

My design works in a similar way to Scheffler but it is way simpler to build.  I turn it with an airlift pump-waterwheel-winch which is a bit like something from Wallace and Gromit,  but it does work, (there is no electricity or motors near the reflector).  I think it can replace Scheffler cookers for the 1 to 3 sq meter reflectors. Instructables "sun Scoop"  solar cooker details      I also have a playlist about it on youtube.  https://youtube.com/playlist?list=PLkzXlmAwZTZdyYP35Jj9Vg5bz-n2-_QnW&si=ryFvh0XOjPTUXlzM Please check it out  Brian

This was posted a long time ago, but my experience was that where I am latitude-wise we had to turn the cooker into the sun every 20 minutes, following the sun across the sky.   Trying to get things done that take a minimum of an hour or two, like mowing, gardening, clearing brush, got in the way of turning it.  

It acted like a slow cooker, and everything took several hours, so it had to be in a location where it could get several hours in the middle of the day without any shade.  It could get up to 350 F, but unless someone was standing there making sure the sun hit it exactly right to keep it at that temp the entire time, it would fluctuate and take longer.

Someone from India I once had a convo with said they never had to turn theirs into the sun, so latitude matters.

Hi Cristo. Mine turns automatically, its like being on a timer. My current timing method is a bit "clunky" and unnecessarily big and perhaps a bit complicated for others to make.   I put basic plans on the main solar cooking site for a better or simpler timer about a decade ago but nobody with electronics skills (or clock making skills) has yet stepped up to the plate and made the thing. All I need is the little thing like a gear in a box.  It can weigh about half a kg, incl battery and it can just spool out string or fishing line at, say, 2 cm per hour. (Ideally programable so that the speed per hour can be fine tuned.    https://solarcooking.fandom.com/wiki/Ideas_for_low-tech_solar_tracking?file=Gimp_equa_float_pistons.jpg[/img]

Cristo Balete wrote:This was posted a long time ago, but my experience was that where I am latitude-wise we had to turn the cooker into the sun every 20 minutes, following the sun across the sky.   Trying to get things done that take a minimum of an hour or two, like mowing, gardening, clearing brush, got in the way of turning it.  

It acted like a slow cooker, and everything took several hours, so it had to be in a location where it could get several hours in the middle of the day without any shade.  It could get up to 350 F, but unless someone was standing there making sure the sun hit it exactly right to keep it at that temp the entire time, it would fluctuate and take longer.

Someone from India I once had a convo with said they never had to turn theirs into the sun, so latitude matters.

We use our box-type 3 seasons. It's very simple, just a box lined with foil and a larger reflector on top as well, with a glass top to hold in the hot air. We don't 'cook' with it much, but use it constantly to make hot tea, to bring water almost to a boil before cooking on the range, things like that. Saves a lot of time and energy.
As for turning, we do that occasionally as we go about our daily routine, nudge it over to catch more sun. With a bit more effort and a larger reflector it would easily boil water.

Rebecca Norman wrote:I've used a couple different kinds of solar cookers at our school in Ladakh, which is high desert, so it's ideal for solar power.

The reflector box cookers are great for the gee-whiz factor, but we never used them regularly. They can bake a small volume of items, and do better with sweet things than not, because I guess the sugar browns nicer. Baking is not a tradition here, and the box ovens we have had were too small to really produce much. I have met people who claim to cook other things in a box cooker, such as rice, but when we tried it, it fogged up the glass and the whole thing cooled down. We have two sitting around impressing people but not being used.

Parabolic reflector cookers that concentrate the sun's rays with a roughly parabolic disk of shiny material have been much more effective for us. The small ones, about 4 feet diameter, work pretty well, but you have to go outside and turn them every 15 minutes or so. They are too small for the numbers of people at our school, but they would be great for cooking for 2 or 3 people, I think. These are more like stovetop cooking and you can cook all kinds of pots of food on them. I've seen two models, one with the dish low to the ground and the pot raised, and one with the dish and the pot at about waist height. They are pretty affordable to put together from shiny aluminum or steel if you can make the frame. In your first week of having one, it is a rite of passage to burn holes in some clothing that you think will dry quickly by draping it on the solar cooker.

At our school we use a big Scheffler reflector type cooker, with a parabolic dish about 8 or 10 feet in diameter, focused on a hole in the (non-flammable) wall and a secondary reflector shining up to the pot. This works very well, and we can cook big pots for 50 people on it. Ours have gone through two models of self-regulating mechanisms, where you'd weight the thing down with a stone, pull it over towards the east in the morning so the stone goes up, and a tick-tock pendulum mechanism would control its speed turning back to the west as the stone pulled down. Both mechanisms failed, and now we just turn it by hand every 15 minutes or so. Either way, you have to make a seasonal adjustment every few weeks. It's a bigger investment, and rather complex engineering to get the angles right, I think. I don't even know where the designs are; I hope they are online as Scheffler cooker. Ours was installed by a Swiss guy in the 1990s who came around and trained lots of local people in how to fabricate and install these, and we've been using both ever since. The others that were installed in our region are no longer used. User motivation is essential.

 Hi Rebecca,  are you still in the high desert?  My parabolic  "Sun Scoop" works a little similar to the Scheffler,  it's just a lot simpler to adjust  and you can DIY it. I cut mine from an 8 by 4 sheet of abs plastic,  and I made it to have an almost exactly 1.5 sq meter reflector.   There was some material left over from the ABS sheet,  but I still can use that to make a smaller parabolic dish, roughly of 1 sq meter collector size. I hope you look at my "waterwheel winch" method for rotating the dish,  you could probably use it to work your Scheffler too.     I would hate to turn my dish by hand! My seasonal adjustment is pretty easy.  Also, different from Scheffler,  the amount of light collected is the same in Winter as in Summer.   (Scheffler dishes collect a larger area of light in Winter than in Summer).   There is a huge need for a simple "timer",  ideally one that doesn't break down easily or a photodiode arrangement to tell my waterwheel winch when to stop and start.   Something like that could be made for under $20, and enables DIY tracking on equatorial mount everywhere in the world.  Thank you,  Brian