A little bit of science

You should know that :

• Solar rays are very powerful when the amosphere is clear ( in the countryside, the mountains or on the sea )
• A white or a reflecting surface will send back a major part ( 90%) of these rays at an angle equal to the incidence angle.
• On the opposite a dark surface will absorb 90% of these rays and will heat up quickly.

Therefore we can identify two groups of sensors :

• Absorbing sensors (black)
• Sensors that will concentrate by reflexion (mirors)

The best way to procede is to combine both principles.

Building a boiler

This device can be found in stores but it is way more interesting and pleasant to build it on your own. You have to wind a black polyethylene hose and enclose it in a flat box painted in matt black on the inside.

Insulate the bottom and the side of the box with styrofoam (at least 2" thick). Put the lot in a second box and close it with a large glass pane.

Set the boiler on the ground facing the sun at an angle of 45°. If the weather is nice the water can reach 160°F.

Building an oven

It is the simplest way to put in use the science I just taught you. You have to build either a wooden or a cardboard box and cover the bottom and the sides of that box with styrofoam (2" thick). The bottom of the oven is painted in black and the sides are covered with aluminium foil. The lid will be a glass pane.

Fix on the bottom of the oven one or several egg boxes with cardboard cells and paint them in black.

In the oven you can cook eggs, tomatoes, small potatoes, apples etc ...

 Hints :

• Heat up the oven (towards the sun) before you start cooking.
• Adjust the orientation of the oven every 1/2h
• Cooking times will be 3 or 4 times longer than those you apply with an oven working with fire.