Custom case design: thoughts?

[joshd2012]

I had some downtime at work today, and I came up with this:


2CAN by joshd2012

Everything is as close to scale as I can get it in MS Word, but hopefully I can get a more detailed drawing if this looks reasonable to do. But first, let me explain.

We have begun to see some cases which are isolating the power supply inorder to decrease the amount of heat inside the rest of the case. This is not the main source of heat of a computer. The main source of heat is the CPU, so it only makes sense that you would isolate the CPU to decrease case temperatures. That is no easy task, as that CPU is attached to your mobo which is way to big to enclose on its own. That is when I decided that I must find a creative way to separate the case into two parts or "cans" as I can them.

Can #1
This can contains the CPU, heatsink and memory (using a ASUS A8N board) from the Motherboard and the hard drives. At the front is a 120mm fan (in Nexus orange) with is optional and can be set up as a passive intake. Going back, the hard drives are suspended from the top of the case so that we are looking at the top of one hard drive. This places the long edge of the hard drive in direct contact with the incoming air. They are not facing the fan, because that would cause too much air resistance. This way, air can easily slip by the hard drive(s) which is more advantageous anyway.

The air, which is moving quite freely, easily cools the memory and provides rather cool air to the heatsink and fan. After that, the rear fan, another 120mm, sucks the (now hot) air out of the can. Thus, you have a very efficient way of moving air. One direction and moving quickly, even with very low speed fans.

Can 2
This is the rest of the system. You have a 90mm fan (ignore the 96, that is a typo), which might end up being replaced with a 120mm fan (which would slightly increase case size (now at 28" tall x 30" deep). The power supply has been flipped up-side-down, so that the fan of the power supply is acting as the exhaust fan. This, of course, would be best utilized by a SeaSonic power supply with the 120mm fan.

Because Can 1 had to be on top, the optical drives had to be moved to the bottom. If you are asking where the smaller bays are, there aren't any. I end up needing one for some reason, I will get an adapter. I use only one or two 5.25" bays anyway, so the middle one would probably be opened as another passive input.

Can Cutter
The Can Cutter, or the piece of metal which separates the cans, is removable for easier working environment. It will be held in place between two lips welded to the case. The cable side of the hard drive will stick down through the can cutter so that the power supply and data cable can be attached. It will look like a toaster. The cutter will then form around the motherboard. This does not create an airtight can by any fashion of the word, but if it is close enough, it should provide little loss of cool air.

The whole idea, is that by isolating the CPU in its own can, the case temperature can be substantially decreased as can fan speed and thus, noise.

So what do you think? Is this possible? Will it work? Am I completely nuts?

[Gorsnak]

Three things:

I don't think you're going to need intake fans. Which is good, the fewer fans the better.

The exhaust in the bottom half of your case is working against convection. I think you're going to end up with a bunch of hot air pooling up, likely right where your video card is. There are no huge heat sources, though, so it might not take anything more than one of those Arctic Cooling gpu coolers to deal with it.

All that front intake is going to let noise out. I just made a custom box with all the intake on the bottom, and it worked out extremely well, in no small part because there are no direct paths between my ears and any noise sources. My design thread. There's a full writeup on the project in the pipeline, but Mike says it will be a couple weeks before it's up. It may contain some useful ideas, etc.

[joshd2012]

I included the intake fan space for "just in case" situations. They will begin their life as passive intakes (with covering to limit noise output) and will only become fans if the exhaust fan isn't doing enough.

I know it if working against convention, but I unfortunately don't have the space. I wanted to keep this "realistic" in size - no one uses a full tower anymore. I was hoping that the larger 120mm fan on the power supply would cause enough of a vacuum to pull down the hot air. A GPU fan might be what I need to get that air on top moving. Good point.

The bottom intake for the power supply is a bit scary. I can just see large amounts of dust collecting under the thing. Nice woodwork though. That is amazing.

[Gorsnak]

Thanks. I'm not real concerned about dust, because there's pretty substantial air movement underneath the thing. When I stick my fingers under the lip I can feel the air wooshing by, so I think dust buildup isn't really likely. Definitely don't want to let stuff pile up around it, though, you're right, and periodic vaccuuming is certainly in order.

Now, to the subject at hand. I don't think a Seasonic ST is going to suck air down from the top of the bottom section. The fan doesn't spin very fast at all (unless it gets hot, I guess, but mine never does, what with the seperate intake and all). I don't think this is going to be a huge deal if you have some sort of air movement at the top, though. You don't have any huge heat sources in the bottom section, unless you've got a GeForce 6800GT you're not telling us about. A few optical drives, southbridge, maybe northbridge, and gpu. The psu doesn't count for this, since it isn't adding heat to the lower section. All its heat gets pushed out the back. So, the AC cooler that pushes gpu heat out the back, or maybe an undervolted slot cooler? Doesn't need to move much air, just enough to keep the hot air from pooling up. Or you could stick in a slow fan somewhere in the middle aimed down towards the psu intake. Wouldn't be very audible buried in the middle of the case, and again doesn't have to spin very fast. It's sort of doing the same thing as a ceiling fan....just stirring up the heat gradient.

My big question is still the open front intakes. Hard drive noise and such is going to have a free path out. Any filter-like coverings that allow air free passage will allow sound free passage too. Maybe a bezel of some sort covering the front, so that the intakes take a few jogs? That would help a bit, though some noise would still bounce through, barring carefully designed baffles set up to absorb sound while letting air pass.

[mrscintilla]

If you just want to isolate the cpu, use a duct. Dell cases pervasively use a duct to goes over the cpu to back of the case. It works extremely well.

[joshd2012]

Gorsnak - I would definitely have some sort of baffle on the front, no matter if I used the intake fans or not. Probably something like the Antec 3700 series, or maybe even like the Sonata. The new P160 design looks really cool if that works.

Another way of making sure hot air doesn't collect at the top of can 2, would be to cheese grate the can slicer after the heatsink and allow hot air to escape up into can 1. That would probably require an intake fan, though, so I am still thinking of other ways. Then again, the GPU cooler may be enough.

mrscintilla - Those ducts don't really isolate the CPU. For that, you would need two ducts, one bringing in fresh air to the CPU from the outside, and one taking the heated air out. Otherwise, you will either have the CPU cooling using heated air already in the case (most common) or would be putting hot air back in the case. By isolating the CPU, I have removed the biggest heat source from affected the other components.

[JanW]

I know it if working against convention, but I unfortunately don't have the space.

Why don't you just flip the case as you drew it upside-down?

[mrscintilla]

Gorsnak -
mrscintilla - Those ducts don't really isolate the CPU. For that, you would need two ducts, one bringing in fresh air to the CPU from the outside, and one taking the heated air out. Otherwise, you will either have the CPU cooling using heated air already in the case (most common) or would be putting hot air back in the case. By isolating the CPU, I have removed the biggest heat source from affected the other components.

True, two ducts are needed. So, why not having two ducts, like antec's p180? You will have more concentrated cool intake air than what you have so far, and no intake fan will be needed.

[joshd2012]

Why don't you just flip the case as you drew it upside-down?

Sometimes the simplest solution is the hardest to come to. But that is why I posted my idea here - to get feedback. JanW, that is an excellent idea:



As you can see, this makes my case much easier to build. It looks exactly like a Antec 3700 case except for one major difference - the motherboard has to be mounted on the left side. I tell you what, though, if the only thing I have to do is move the motherboard mount to the left side and alter the rear panel, this is going to make the job a lot quicker.

It actually works a lot better now. The power supply fan will actually work in the way it was intended and prevent hot air from building up. I still have my cpu isolated, and it comes with a lot less work. Thanks for the great tip!

mrscintilla - I don't see anyway to isolate the cpu with ducts. There is no way to isolate the air coming from around the heatsink even if you can control the air coming to the heatsink.

[Tibors]

And now (apart from the HD location) it looks exactly like a Silverstone TJ06 or one of it's cheaper brothers.

I don't see anyway to isolate the cpu with ducts. There is no way to isolate the air coming from around the heatsink even if you can control the air coming to the heatsink.

Build a system that sucks air of the heatsink with an elbow duct. Like in this SPCR article or some of Bluefront's designs. But use a case with the new side intakes. Remove the CAG and build a box arround the CPU area.

[Devonavar]

Hmm ... Now it looks like the Silverstone TJ06 with that CPU duct. One difference though: your hard drive is suspended inside the duct. Which leads to my question: What is this hanging from?

[joshd2012]

Hmm ... Now it looks like the Silverstone TJ06 with that CPU duct. One difference though: your hard drive is suspended inside the duct. Which leads to my question: What is this hanging from?

You guys just made my day. That case, the TJ-06, is exactly what I want. As can bee seen, the only difference is the placement of the hard drives. You guys are awesome!

The hard drives are standing on T-posts, so that they would attach to the side screw holes and support the bottom, while suspending them from touching the bottom. It would probably be a custom aluminum bracket, but something pretty easy to do. Then it would simply be creating the cutter (out of aluminum, are removing the plastic "wind tunnel". Thanks for the help everyone.

[JanW]

I wanted to keep this "realistic" in size - no one uses a full tower anymore.

That case, the TJ-06, is exactly what I want.

That case, the TJ-06, is 22.3" high

[joshd2012]

That case, the TJ-06, is 22.3" high

True, it is higher than a standard mid-tower, but it is by no means a full tower. Its a lot easier to mod an existing case, rather than having to build one from scratch.

I'm pretty sure I'm going to move the hard drives down to the bottom of the case like my plan shows. This will free up that space under the power supply for another fan (if needed). I can then isolate the powersupply as well, giving me three separate zones. But first things first, that CPU has to be isolated.

[Bluefront]

Take a look at this AMS CF009 project...still being tweaked. It isolates the CPU heatsink from the case almost completely. The exhaust is blown into an upper heat collection chamber(which is padded with acoustic foam). The PSU also exhausts into this upper chamber.

There is no intake duct to the CPU needed, because the rear intake is right next to the heatsink. In it's final design there are two intakes....the one at the rear, and another at bottom. This setup has no openings at the front.....and is still reasonably standard.

It usually runs on the two 120s, and the two HD fans. There is a back-up set of fans that only startup at high temps.This case is 20" high, and 8.5" wide.....plenty big for modifications.

link

[joshd2012]

That is a hell of an idea. Creating a heat chamber is an excellent way to limit heat buildup inside the case. What I would do with that case, is build a heatshield for the cpu so that no hot air from the memory or GPU would rise up into the heatsink. It would be a very simple and keep intake temperatures down on the cpu, resulting in better cooling.

I would love to see some documentation with those pictures; there is a lot of neet stuff going on there.

[Bluefront]

When I'm finished I'll do a complete write-up. Really there's no need to further isolate the video cards (there's two in there now). The CPU (P4-3.2) runs plenty cool. Idles about 36C @1100 and maxes at 43C @1400. Thats running two instances of CPUBurn.