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I aim on building a silent, completely passively cooled PC, with no moving parts at all (I am aware that it is cheaper to go for an inaudible computer instead, using low speed fans. This is not the point.).

I came up with the idea to install not one but two CPU coolers, of which in theory one alone should keep a high performance CPU cool only using natural convection, but not in practice. For this I thought of using a triangular shaped piece of copper, with thermal compound between each surfaces.

Will this improve heat dissipation compared to a single heat sink or is the thermal resistance of the copper block a problem? I sketched the idea below:

enter image description here

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  • $\begingroup$ if copper is a problem, use silver :) $\endgroup$
    – Solar Mike
    Commented May 23, 2018 at 15:34
  • $\begingroup$ Yes the heat resistance of the block would be a problem. $\endgroup$
    – paparazzo
    Commented May 23, 2018 at 17:32
  • $\begingroup$ Does it have to be passive, or are you willing to deal with T-E coolers and a slightly more remote radiator assembly? Or, can you put fluid into those Cu tubes and use a heat-pipe methodology? $\endgroup$
    – Carl Witthoft
    Commented May 23, 2018 at 17:49
  • $\begingroup$ Please show your analyses as well as any experimental data to explain how a single sink (of indeterminate height!!) fails. $\endgroup$
    – Carl Witthoft
    Commented May 23, 2018 at 17:50
  • $\begingroup$ If you could thread the heat pipes through the 'wedge' block to draw heat from it efficiently, it should work. If you just stick two radiators on top of a solid (or worse, hollow) metal wedge, you're getting nowhere. $\endgroup$
    – SF.
    Commented Jul 10, 2018 at 13:25

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Well, I would think that two smaller ones rigged up in an "amateurish" fashion (apologies, but that's we both are, right) are going to be worse than just one (sufficiently large) properly mounted heatsink. That giant triangular piece closest to the CPU would probably delay heat transfer -- even if you have excellent cooling on the other side of it.

What I have done was to use just one cooler, and that is sufficient if you choose one that's large enough.

I have one giant case (Antec 182) with a giant heat sink (Thermalright HR-1) which never even gets lukewarm under load of a 3.something GHz cpu.

I have an HTPC case (Streacom FC10) in which the sides themselves are giant heat sinks connected to the CPU and PSU by way of heat pipes. This also works excellently, and is fully enclosed.

Edit: Here's what the case-as-heatsink solution looks like: enter image description here

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    $\begingroup$ I originally wanted a HDPLEX H5, but I now went with two Thermalright Le Grand Machos - but not both for the CPU, I have one for the CPU and one for my GPU. It handles my 1050 ti very well, around 55 degrees Celsius max and my Xeon 1240v3 at least well enough but after around 15 minutes of full load I get close to 95 degrees and it will probably hit 100 sooner or later. But for my general use cases this is ok. $\endgroup$
    – Benjoyo
    Commented Jul 10, 2018 at 8:13
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    $\begingroup$ @Benjoyo, FYI I just added a photo. $\endgroup$
    – KlaymenDK
    Commented Jul 27, 2018 at 22:21
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I was going to suggest a Streacom case, I've had one for years and it works excellently.

Looking at your original design, if you could get the triangular block made as a vapour chamber instead of a solid block it might actually work. You'd need to consult with a company that makes heat pipes to see if the triangular shape would work or not. Given the diagrams I've seen of how they normally work I'm guessing not due to the varying and long distances between input and output surfaces, but would be an interesting engineering exercise that could have unexpected results. Who knows, you might have stumbled on a great design and they could manufacture it for you...

As to your build, these high density heatpipes might be of interest: https://www.fanlesstech.com/2018/09/flat-cool-pipes.html 😉

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  • $\begingroup$ Your answer looks okay, but it looks a little spammy. There are ultra-strong rules against spams. $\endgroup$
    – peterh
    Commented Feb 14, 2019 at 15:44
  • $\begingroup$ For what it's worth, I don't think of drayzen's post as spammy at all. It's an interesting comment and a pertinent link. $\endgroup$
    – KlaymenDK
    Commented Feb 15, 2019 at 20:38

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