PCI CPU cooling

[AETAaAS]

I know standalone PCI blowers have been around a while, but with my recent fascination with mini ITX and cramped spaces they tend to end up with, a weird idea crossed my mind. I was thinking about systems built around things like the Streacom F7C, Silverstone ML05, SG05/06, Thermaltake Element Q, Antec ISK300 and so on.

Especially for people who will use the onboard graphics for things like HTPCs or work/light gaming oriented systems where the PCI slot will may be unused. Perhaps for people who want additional cooling for peace of mind or so they can go for a full voltage CPU.

So I drew it out...


Essentially a strange hybrid of current AIO CPU coolers and blower type GPU heatsinks. I am not familiar with anything like this. If there is one, please do let me know.

[Macadee]

Radiators rely on surface area to exchange heat, the area in font of the blower fan is so small it's insignificant.

[AETAaAS]

What do you mean? The blower design would not be like Asus' DirectCUII or the Windforce systems but more akin to most reference GPU coolers like below.



Essentially imagine the same thing without the GPU and related hardware. Use a blank plastic PCB and replace the heatpipes with water channels.

[scaryjim]

tbh I don't think you'd get enough fins/surface area in the rad to make it worthwhile - you'd end up with a noise/vibration producing pump and a fairly noisy blower fan, to get no better cooling than a decent low profile top-down CPU cooler. To fit on a PCI-sized card the rad would be smaller than for most all-in-one coolers, meaning you'd have to shift a lot of air through it to get good cooling, therefore higher fan speeds and more noise.

That said, it could be a fun mod to existing small form factor cases that can't take a 120mm rad and fan - biggest obstacle would be the custom rad that faciliated lengthwise airflow....

[AETAaAS]

Yep, I was thinking of small cases where there are no mounts for rads or much space for good air coolers. I was hoping that it would not be as bad as GPUs get since they have TDPs in excess of 200W whereas CPUs and in particular Intels and AMDs FM2 (which are the main mini ITX parts) are tend to operate at half that. And most AIO CPU cooler blocks don't tend to make much noise from what I've heard but that may be in relation to other parts in the build in particular the fans.

You are right that some low profile coolers could do better, but in some cases where they don't provide much in the way of fan slots, I was hoping this would more directly remove the heat than let it circulate inside.

[circuitmonkey]

If you where to interrupt the flow of the air over the radiator (for example rather then straight fins make them wavey) would this not increase the surface are of the radiator sufficiently to cool the loop?
That said if your mini ITX case has room for a full height PCI card then I'm sure a more efficient air cooler can be found.

[jimbouk]

Interesting idea. GPU cooler design and water radiator designs seem to be very different though so I'm not sure you could get airflow through one down the long side whilst maintaining enough air/water/metal contact as people have said.

Illustration 1:


Illustration 2:


However, what about some heat pipes going into a cooler like in illustration 1? Something like a cross between that and the fanless case design:


Would be tough to make though!

[scaryjim]

If you where to interrupt the flow of the air over the radiator (for example rather then straight fins make them wavey) would this not increase the surface are of the radiator sufficiently to cool the loop?

Be quite complex to balance the increase in surface area with the reduced efficiency of airflow over the fins - you need to move the hot air away from the fins quickly or it massively reduces the efficiency of heat transfer from the radiator. It would almost be better to make a slim 2x80mm radiator that could be mounted in a PCI slot, with slim 80mm fans blowing air through it in the style of an open frame GPU cooler - although that wouldn't vent the hot air out of the case, of course...

*EDIT: thinking about it - it might be possible to combine a slimline blower fan with 2x80mm slim fans to blow air through a slim rad then funnel it out of the back of the case. Might have to try sketching something up to demonstrate the idea....

... what about some heat pipes going into a cooler ... like a cross between that and the fanless case design:
<image snipped>

You'd have to make different versions for different motherboards to do this effectively, as I don't think you can get flexible heatpipes, but it would be the easiest way to approach it - some of the shuttle cases use a similar method to actively cool the CPU by venting through a large heatsink at the back of the case.

Of course, if someone could come up with a method of creating flexible "heatpipes" (heatcables, perhaps?) it would open up a huge set of new options for cooler design. Challenge for any budding engineers reading this, perhaps

[Lee H]

Fans are old school - if your after silent and good cooling why not look at implementing something like This instead

[Pob255]

Actually it's not that bad an idea/concept, while the opening/exit surface area is small to depth surface area is very large, it's why stock graphics card coolers work in the first place.
The total surface area isn't going to be that large for a single slot cooler, probably similar to a 80x80x25mm rad.

The main issues really would be space, for a case that can take a single pci slot full length & height cooler will probably be big enough to mount a 120x120x25mm rad and fan anyway for the small mini-itx cases they don't have space for full height full length single slot cards, so couldn't use it.
So the market for this would be far too limited to make it practicable or economically viable.
Your best bet for water cooling a small form factor case is probably an external rad.
That and a mini-itx htpc doesn't really generate the load or heat is require water cooling.