Cob solar cooker. applying the foil + first test

[centervilletn]

could you use old "dish" satelite recievers coverer in mylar? maybe use 2 or 3 in an aray...so the focal point would shift from one to another? advice would be appreciated and shared with others...ive built a solar thermosiphon heater using corrogated metal roofing if anyone needs advice id be happy to share my experience too

[gaiatechnician]

You can certainly use old dishes covered in mylar. But the focal point will not shift from one to another as you suggest. With those dishes you have to have tracking (either manual or powered) and it must be accurate. This is why I have gone to "compound" parabolic dishes in my more recent experiments. They do not need to be moved so often and if you do want to make a tracker, it can be crude, cheap and inaccurate and you compound parabolic dish will still work!

[spaceshuttle94]

does anyone know how to keep the heat in a solaroven mine tops out @170 F or 80 C?

[gaiatechnician]

If your food is cooking at 80 C it is fine for most stuff. Check on an oven thermometer for the safe cooking temps for meats. My digital oven thermometer is really good, 77 C for beef well done 77 for pork 82 for chicken. So that is internal temp. I just cook vegetables myself.

[agungk]

suggestion:

instead of making parabolic reflector from clay, why not try with styrofoam arranged as fresnel reflector. you simple cut it with concentric circles and then cut each circles with certain wedge angles. with simple jig, you could simple rotate the pieces against the cutting tool.

[gaiatechnician]

I have clay, and I do not have styrofoam!

It was an "appropriate technology" idea.

A clay dish or mold is appropriate for me and perhaps also for millions of people in poor countries across the world.

I have since used a clay dish as a mold for a large dish made from a plastic sign.

The ideal mold might be a clay dome but I have not yet made one.

I have a video showing some of the theory of using a dome but I use a globe instead of a parabolic dish. (I didn't have a dish to show it) Brian

[53Aubergine]

Anyone thought of a way to draw energy from snow yet? Canada could power the continent with that :D

Great work. Two of my interests, solar cooking & cob!

[heoquayhp]

lol i doubt theres much energy you can draw from something that is cold. Maybe you can use it to derive hydrogen from the molecule and use it to power hydrogen powered device.

[rimar2000]

This is a test that I still have to do, but for my experience with aluminized films or aluminum foil, I can tell you the following: each wrinkle, be small or big, it works as a hole in the mirror. For that reason this method is not very efficient. On the other hand, the aluminum foil that is gotten at the moment no longer has the refined one to mirror that is needed for a good reflection.

(pardon my "automatic translator" English).

[gaiatechnician]

Nice to see a visitor from Argintina. Thank you for taking the trouble to translate.

The kitchen foil here in Canada is still shiny on one side. Wrinkles are a problem but alu foil is so cheap you can make a bigger reflector for less money.

Please check my mechanical mathematician and solar barbecue video's too.

It would be great for someone to make a spanish version. Good pics are at solarcooking dot wikia dot com

[desiredusername]

Why not fill the whole thing with plaster? Then you have a negative form you can work to make perfect and then cast as many parabolae as you want.

[gaiatechnician]

You are correct. Another way is You turn the mathematician upside down, and use a spring or bungi cord for tension. (Then you are tracing a dome With a parabolic dome, you should be able to make many many dishes from cardboard (or from whatever material you have). And it should be really quick too and require very little precision with cuts.

I am stuck in the sunless gray winter right now but I am just about ready to make a video to clarify the mechanical mathematician