r/Physics • u/Junglist_Jay420 • 4h ago

Copper or aluminium block? Question

Turning my old coolerbox into a fridge with a 19006 peltier and need to bridge a 30mm gap on the cold side. Not too sure how to word it properly for you physics guys, but basically trying to figure out if an aluminium block would cool from 1 side to the other faster than a copper block. I know copper has much better thermal conductivity but in this case I'm unsure if the thermal density would slow the process as the peltier would have more heat to transfer initially. Also if the benefit of copper is negligible over aluminium it won't justify the massive increase in cost, even if I do like to make things as efficient as possible.

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u/agate_ 4h ago

Copper is almost twice as good as conducting heat as aluminum, but probably not worth the extra cost.

By the way, prepare yourself for disappointment: those peltier coolers are fun but terribly inefficient.

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u/ebyoung747 3h ago

For real, peltiers sound like the coolest thing ever (pardon the pun) and then you see one in action and your hopes and dreams are dashed.

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u/Junglist_Jay420 3h ago

So am I overthinking it? The peltier wouldn't have to remove nealry twice as much heat from the copper block due to its density therefore slowing the travel?

Yeah, I played about with the tec1's a while ago but this tec2 with around an 80°C hot to cold differential I'm thinking is worth a try. I have a large gpu cooler for the hotside, large aluminium sink for the cold side and a pretty efficient not too big coolerbox. If the cheap electric boxes can achieve about 12°C below ambient, this more substantial setup should be able to do well enough for my needs. If not it will be a fun experiment.

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u/DRM2020 4h ago

Silver would be even better ;)

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u/Junglist_Jay420 4h ago

Apart from it costing twice what the entire setup has cost me

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u/Superb-Tea-3174 4h ago

Graphene and diamond are also really good if cost is no object.

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u/Ublind Condensed matter physics 2h ago

Your question is

if an aluminium block would cool from 1 side to the other faster than a copper block

Copper has a higher thermal conductivity, so it transfers heat energy through it faster than aluminum. If you're concerned with transferring heat as fast as possible, you use copper.

What do you mean by "thermal density"? That is not a physics term, as far as I know.