Time for a DIY case! (but I'm scared! :/)

niels007 · Post by **niels007** » Tue Mar 22, 2005 3:31 pm

Hey all,:D

As some might have witnessed in the gallery section, my case looks absolutely terrible. Not only that, it is falling appart more or less as well. For ages I've been thinking of making a new case, and now I have found the right places to do the wood working.. A day's work and €25 worth of materials and using machinery should pretty much be it, before painting that is..

What I'll keep the same, cooling wise:8)
- side panel 120mm fan ducted to cpu heatsink blowing air into the case
- side panel 120mm fan ducted to gpu heatsink blowing air into the case

What I want to change:
- imagine a 120mm PSU but put it upside down or on its side, moving the fan outside of the case, sucking cold ambient air into the PSU. A small 'route' for the air, totally unaffected by the air in the case.

The reason::?:
- Cool all 'hot objects' directly (or ducted) with ambient temp. air should allow the fans to run at the absolute minimum speed. Normally the PSU would receive air that is warmed up by the cpu / gpu / mobo / hd.
- Nexus / Yate Loon 120mm fans are so silent that even mounted in a side panel they really are no problem at all until ~500rpm

The Fear
- The unknown...
- Relying on ventilation holes at the top of the case to get rid of the heat instead of the PSU fan

How much is the PSU fan helping case temperatures now?

Would I loose efficiency relying on convection and ventilation holes? (instead of a PSU fan)

What sort of surface area worth of ventilation holes would be optimal?

Basically, what do you guys think is more efficient: extracting the heat though the psu, making it fairly hot, or taking the PSU air route out of the case and hopefully see no need for faster cpu / gpu fan speeds relying on convection and ventilation holes.

What can be said about my fears and questions?

Niels

PS:
drawing of two cases I had in mind:

Tower case
Inclined to go with the higher tower to save floor space, but the distance between PSU and DVD is small and might not allow enough ventilation hole area. Increasing this distance makes the case 'longer' which doesn't go well with saving floor space. The harddisks in the bottom can easily be heatsinked with 300mm long aluminium profile, surely being more than enough.

compact case
In the compact case I would rewire the PSU power cable to the rear. The 3.5'' bays are behind the PSU. More difficult because my 'bodged' 5.25 bay is too large and would need machining to cut down to 2x 5.25". No real space for harddisk heatsinks. Most efficient use of cubic space.

wsc · Post by **wsc** » Wed Mar 23, 2005 7:47 pm

Your PSU idea is pretty clever IMO. Personally I would stick with the compact case design, except slightly modified. I would mount the PSU so that the fan was totally open to the *front*, not the side, exhausting air *into* the case. You would get some positive case pressure which would give you some additional ventilation through the top vents. As far as how big to make the top vents, the bigger the better IMO.

Edit: Also I would swap positions of the HDs and PSU, so your exhausted air would travel up over the HDs giving a bit of cooling effect. I'd imagine you could still have them suspended with little to no negative side effects.

Last edit I swear: Per my changes you would have a big ugly fan visible on the front of your case... trade offs, trade offs... You could always build an additional structure to hide it.. hmm..

RonG · Post by **RonG** » Wed Mar 23, 2005 11:20 pm

Has anyone ever tried setting up the power supply to draw from the outside of one side of the case, and blow to the outside of the other side of the case, without any of that air going into the rest of the case?
It might be a little awkward with the cables, and put the switch in an unconventional location, but if the case is wide enough it might be possible to feet the power cord in from the back and up the side.

VERiON · Post by **VERiON** » Thu Mar 24, 2005 12:26 am

RonG wrote:Has anyone ever tried setting up the power supply to draw from the outside of one side of the case, and blow to the outside of the other side of the case, without any of that air going into the rest of the case?

Yes. Many of us. Search for "psu duct". It is good when you have temp controlled fan on psu. It keeps psu fan from ramping up. It is important when you don't want to mod your PSU (3 year guarantee).

--> wsc

If you are thinking of silent computer try to avoid front and upper holes (intakes/exhausts).
With front and upper openings you will be hearing all the noise.
Instead try bottom intake and back exhaust.

If you want to go completly fanless (not cost efficient

)
you can try open case like YESICO
http://www.pc-look.com/boutik/Plus_700812-002.php

With fanless PSU, fanless VGA, fanless CPU only noise source is HDD. You can than choose 2,5 notebook drive or put your drive in some kind of enclosure.

RonG · Post by **RonG** » Thu Mar 24, 2005 5:52 am

I know many have psu ducts, but they all seem to be front to back. I was wondering if anyone had done frome side to side, and how they dealt with cabling issues, and how the result sounded.

hvengel · Post by **hvengel** » Thu Mar 24, 2005 10:35 am

I think the idea of feeding cool outside air to your heat producing components is a very good idea. But I would be more inclined to use one intake fan that feeds a plenum and has a free flowing intake that has no direct sound paths from the fan to the outside. I would duct/feed air from the plenum to the components that need cooling. I would feed air from the intake plenum to the CPU, GPU, PSU and the disk drives (you left these out).

I would zone the outlet paths from each heat source so that the air would be forced into the system outlet directly from the heat source. That is there would also be an outlet plenum and each heat source would have it's outlet air flow directed into the outlet plenum.

I would not use holes in the top of the case for my air outlet. I would instead use a free flowing but sound baffled air outlet that faces the rear of the case. This would be placed at the top of the cased. I would also place the intake opening at the lower rear of the case. Placing air inlet and outlet to the rear will eliminate a direct path from these noise sources to your ears.

niels007 · Post by **niels007** » Thu Mar 24, 2005 11:01 am

I've given it some more thought and think I'll do the tower design, because I can then use the PSU in the normal way (sucking air out of the case) or turn it 90 degrees to see what happens as situated in the drawing..

WSC, your idea is pretty good as well, I would put the psu in the bottom front, with the fan inside blowing air up into the case over my harddisks.. Then again, I'm sure that 2x 30cm aluminium U profile is more than enough to cool the harddisk passively in the tower situation.

Since I'm getting great results now with the normal psu suck out approach, I tend to go with the big tower as that would allow me go the trusted proven and tested route.. Should be quite interesting to see the differences in case temp and psu fan speed in these situations, I will surely test that

Time to fire up Autocad for some 3D modelling to see what things will end up looking like..

Gorsnak · Post by **Gorsnak** » Thu Mar 24, 2005 3:12 pm

My (extremely successful) DIY case design includes a couple of the elements you're looking at here. Various ideas that came up in my design thread might be helpful. Sooner or later Mike should be posting the article I wrote up about the whole affair, too. If you've any questions (or would just like to see the writeup & attached pictures), drop me a line.