Building a solar cooker for school

AI Thread Summary
To build a solar cooker for a school project, the goal is to heat 1 liter of water in 80 minutes using a Fresnel lens. A suggested method involves using a translucent jar with copper inside to absorb sunlight and transfer heat to the water. While copper has good thermal conductivity, it is recommended to use black objects for better heat absorption. Conducting small experiments to measure heat absorption and predict the time to reach 100°C is advised. Overall, using a metal with a large surface area, painted black on the outside, is essential for effective heating.
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(Sorry for my bad English, I'm from Germany) Hello! I need to build a solar cooker as a school project. Our build needs to be able to heat 1 liter of water in 80 minutes. My idea was, to heat the water by using a fresnellens. I've bought a 15.6 x 15.6 inches fresnellens for that. I thought about the construction and builded it. Now I have one big question. How am I supposted to heat the water at the focus of the lens? I thought about using a translucent jar with a piece of copper inside of it. The copper is suppost to absorb the sun ray and warm the water inside of the jar. Would this even work?

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Using of copper?
 
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Very hard but possible, first you need big lens, maybe yours will do, copper is good at absorbing heat, but use black objects, they're better at absorbing radiant energy, and the water which is colder with steal the heat from the black body and so on
So, i advice you to do :
Small expirement to measure the heat of the black body while sun is hitting him through your lens and predict by that how much time will it need to reach 100°C and check if your lens work .
I encourage you :)
 
Okay, thank you!
I thought about copper, because it has a pretty good thermoconductivity
 
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Any metal will do. Just make sure that it has an adequate surface area. Color the outside black and the inside shiny or white. 80°C is a lot
 
I'll do that, thank you!
 
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