The performance can be increased by making the surfaces smoother and the shapes more parabolic. But the focus does not need to be sharp like e.g. in satellite receivers because it is enough that the sun's energy is concentrated into the bottom of the cooking pot. If the focus is too sharp it can even melt the bottom of the pot! And the sharper the focus the more dangerous it can be for your eyes. REMEMBER TO KEEP YOUR EYES AWAY FROM THE FOCUS!

The construction manpower is about 18 person-hours and the cost of material (principally the aluminium foil) is about $3.

There are many ways you can modify this model. You could e.g. use only one mirror, or maybe five. You could add a tracking system to automatically follow the sun. Or instead of parabolic mirror you could use so called Fresnel mirror for the same result. Litterature offers many ideas of design and use of parabolic solar concentrators, beginning from the war machines of ancient Greece.


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