Fresnel lens, Parabolics and Archimedes mirrors

This blog began with details on my lowly solar cooker that took two hours to make, yet, worked very well from mid-March through mid-October.   For friends who really wanted to try solar cooking, but were overwhelmed about making one, I posted how to use that free cooking space on your car dashboard.

Now on to other forms of solar cooking.    Shortly before Thanksgiving 2011, Dan and Denise Rojas of Green Power Science demonstrated how they made Thanksgiving dinner using Fresnel lens, parabolics and Archimedes mirrors.

These cook at a higher heat than a box cooker, and are dangerous to use because they cook with focused sunshine.  Think solar death ray!  If you get in front of that focused light you will get cooked.   If that focused sunlight flashes in your eyes, it could ruin your eyesight.   If, after these warnings, you are still interested in trying these, here are the basics:

The Parabolic can be made with a satellite dish (fiberglass is preferred) with Mylar or reflective tape applied to it.  The dish is set on the ground to reflect sunshine onto the bottom of the cook pot.  The larger the diameter the greater the heat.   The recommended diameter is 3-4 feet.

The Fresnel Lens needs an adjustable stand to hold the lens parallel with the sun.  I prefer to aim the Fresnel at a mirror on the ground so sunshine can be focused onto the bottom of the cook pot.   It is easier to cook with the heat coming from the bottom.

Archimedes Mirror is just two mirrors hinged together.   Making a hinge from duct tape will work.  The hinged mirror is aimed at the cook pot.

To use them, focus the sunshine unto the cook pot.  You will need to re-focus the sunlight about every 7 minutes.   It works best if you use cast-iron cook pot.  And make a metal mesh table for the cook pot.  All this focusing requires intense supervision.

I would use Fresnel lens or parabolics mirrors for frying, popping popcorn, distilling water, and for creative projects like melting sand into glass.

I prefer to solar cook with a box cooker.   Slow cooking tastes better than fast in most cases, and it is more convenient let my food cook unsupervised for a few hours.

My son is enamored with these high-heat cookers so we gathered all the supplies and will post updates when we are ready to use them.


About Hemet Sunshine

I am a homeschooling mom living in Hemet, California. I am interested in building a better community for the ones I love.
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