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Copper (media.piefed.social)
submitted 5 months ago by to c/historymemes@piefed.social
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[–] 24 points 5 months ago (1 child)

Copper has more mass, heat capacity, and thermal conductivity per litre.

Is aluminium actually more effective as a dissipation surface? I hadn't heard that.

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  • [–] 9 points 5 months ago (3 children)

    Copper is better conductor but it's worse at dissipation. Do the experience yourself, heat a block of each and then touch them afterwards.

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  • [–] 11 points 5 months ago (1 child)

    Is that not because the copper holds more heat, so stays hot for longer at the same dissipation?

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  • [–] 5 points 5 months ago* (2 children)

    Maybe you're right, but I remember than in the 2000s I've had identical cpu heatsinks in both copper/aluminum versions, and the aluminum one had better performance. And then they started to make hybrid ones, stating that the copper part was to allow rapid heat transference and the aluminum parts to improve dissipation. But maybe it was all marketing.

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  • [–] 11 points 5 months ago* (last edited 5 months ago) (1 child)

    Aluminium is significantly cheaper, that's why they make coolers with a copper base and alu fins. It's a good compromise.

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  • [–] 2 points 5 months ago*

    I just thought of another reason for using Al this way.
    Since the heat is being transferred to air, which would be much slower than the 2, using larger fins with lesser thermal conductivity might be more desirable than smaller fins with higher conductivity.
    This would also be accompanied with other design changes like greater fin-fin gap, which is better for use with lower pressure fans.
    So overall cheaper design and lesser noise.

    Of course one could still use Copper fins with the same design for marginal performance increase, at the cost of more weight.

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  • [–] 3 points 5 months ago*

    Dissipation = thermal conductivity. Copper is better in both, it's just heavier and far more expensive. Are you sure you put the same amount of energy into both blocks there? A copper heatsink can generally be much smaller than an aluminium one.

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  • [–] 2 points 5 months ago

    The problems and complications with your method:

    1. Suppose Cu is much faster at heat transfer and you only briefly touched it. Your skin does not actually sense temperature, but rate of heat transfer, which depends not only upon the material temperature but also upon how well it will transfer heat. Better use a thermometer.
    2. As explained in https://lemmy.nz/comment/20463232, you need to make sure both have been given the same amount of thermal energy and not just heated upto the same temperature. The best way to do so, is by embedding a heat generator right in the middle of the block and transferring a measured amount of energy. e.g. You can embed an electric heater wire (you will require insulation too. That's your headache (ceramic, perhaps)) and pass current using a power source that gives a measurement of the total energy.
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