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# Conductivity of heat through copper? Answered

I have a piece of flat copper, 150 mm X 30 mm X 1mm thick. I put 50 watts onto one (150 mm) end, how much arrives at the other?

so:
Surface area: .00015 m2
Distance: .03 m
thermal conductivity copper: 400 W.m-1.K-1

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## Discussions

25 C, air both sides, homework? Yes, but self prescribed. It's a short length of copper tube that I've cut longwise and flattened for use as a fin, conducting heat from the hotspot of a parabolic trough to a thinner copper tube containing ethanol. I had a look at Fourier's law, but I don't know either end of the temperature gradient.

Not knowing either end of the temp gradient makes this tricky. It's kind of like calcuating how fast a ball rolls downhill without knowing how steep the hill is.

Do you have at least a rough idea of how much you'll be heating the parabolic hot spot and/or cooling the ethanol? (If, for instance, you're going to be running the ethanol through a continually-flowing water bath,  tap water is usually around 60 F.)

The hot spot will contain lets say 50 watts, ie 25 X 20 cm of solar energy. The eths won't be circulating, the point is to boil it. The vapour will be tapped off, so I guess the max temp of that will be 78 C / 172 F. I'm making the thing, so can figure this out in reverse by how long it takes to bring the volume of ethanol to boil, but I'd like to have my head around the physics of it for further optimisation.

Since you have the object, why not just set up an experiment to actually measure what you get at the end when heat is applied? The theoretical calculations should either match up somewhat or see if you need to change the design to suit your needs. Good luck.

You could work that out, but are there any liquids involved and what;s your ambient?

L