Cooling dilemna

[TheBigZ]

I have 4 pc's at my desk. About 2 years ago I got sick of 4 cases and looked into the idea of a rack system that might fit under the one side of my L shaped desk. When I saw the price on ordinary rack system stuff, I figured I was outta luck. Then I remembered seeing that folks were building pc cases out of plastic. So I found a local place that sold sheets of cast acrylic and I set about building my own rack system. The whole thing is built out of plastic... it has a removable front cover and 8 slide-out shelves inside. Each shelf will hold a complete PC... MB, power supply, hd, floppy & cdrom. It also had a couple of case fans mounted in it. I keep my KVM switch, cable modem & router are on the shelves not used by computers.

Well, took a week or so to put it all together, and when it was all done & running, what I had actually built was a little EasyBake Oven©. <G> I had a little room left on one end of the box, so I attached a ventilation/filtration box. It has 3 131cfm (or something like that) fans and a replacable filter. That helped a lot. But, it's obviously quite loud, and even with just 4 computers in it right now, it's still plenty warm. The CPU's all have upper-end copper heatsinks with good fans... but the ambient air temp in the box reduces their effectiveness.

So here's what I'm thinking. I'm thinking about a sort of passive liquid cooling approach. Find myself some proper sized alum radiators & mount them inside the top of the box. Then attach tubing which carries the liquid down into the basement where it will be attached to another radiator. The idea being, that the heat rises to the top inside the box and warms the water. Using a low flow speed pump, I'd circulate the water down to the much cooler basement, where the radiator dissipates the absorbed heat. I'm not looking to so much actively cool the box, as I am to just carry the heat away. I also thought of maybe running the water through something like an apartment sized fridge in the basement. But I don't have central air, and only run the window units when it gets really hot. So I'm concerned that the heat & humidity could cause some condensation issues inside the box if I used refrigeration. I can envision problems from condensation dripping off the radiators onto the computers & equipment below.

So the questions are... given the setup I've described, do you think a passive system like I've described would take enough heat away to justify the effort? If not, would something as simple as adding fans to the radiator in the basement make enough difference. Am I off the mark in thinking that radiators inside the box would be enough to collect the heat & transfer it to the liquid in the system... presumably that enviro safe anti-freeze stuff? And finally, any other options you might suggest?

Thanks for you time & advice.

 

[sodcha0s]

It sounds like a good idea. What I would do is instead of just mounting the radiator in the top and letting it absorb heat, attach a fan to it to suck the air from inside and blow it over the coil, and maybe cut some slots in the top of the case to let the air escape. You wouldn't need a big cfm fan for that and it would make it a lot more efficient. What size (diameter) are those fans you have now? What voltage are they? Maybe you could put them on a rheobus to slow them down a bit and make it a little quieter.

Also, the refrigerator would be nice, but it would make the whole setup a lot more complex. Naturally it would absorb a lot more heat, but as you mentioned condensation would be a problem. If you could somehow rig a drip pan under the coil to catch it then drain the water out it would work, but I'm not sure that's the best idea. A fan blowing over the coil in the basement would do just fine most likely. Let us know what you decide and tell us how it works out!

 

[cainsdive]

That's quite the oven alright. Pics would be good. Sounds good in theory, but I have to wonder weather it would be efective. As far as I under stand it , the transfer of heat that way would not be very efficient. Of course I could be totaly wrong! If these comps are all on seperate shelves, would it not be better to put a 120mm fan at each level on the side? They move a lot of air with little noise. Or maybe go fridge cold water with fan -vary flow of water vers temp to stop condensation. Put the radiator in the bottom of the case and blow air over it upwards. As sodchaos said , let us know what happens:beer:

 

[Cogman]

humm, Might need two pumps in order to get it up the stairs. but yes it does sound interesting. If this is your setup
_______
|Radiator|
|_MB1__|
|_MB2__|
|_MB3__|
|_MB4__|

Then you will neet to make sure that there is a proper flow upwards. Also, I think that It might be just as effective to put a blowhole on top and blow the hot air out. And on the bottom blow in cool air, maybe lift it up a bit and have a flow from the bottem to the top.


Pictures of the current setup would be nice.

 

[TheBigZ]

That's pretty much the layout Cog. There is a space in the back (for cabling) and a space in the front (just sorta came out that way)... so the hot air does rise unabated. As it sits now, the whole box is ~almost~ airtight... except of course for the air intake & outflow from the fan/filter box on the side. Basically, there's a one foot cube on the one end of the box where the fans & filter reside, and a tube (all this is built out of the same plastic) that delivers the air intake to the far end of the box, and the air is draw out at the end with the fan/filter box.

I did take some pictures as I built the unit, but being that it's made out of clear plastic... they don't really do the box justice, or allow you to really see the detail. But I'll look around for a place to stick em up anyway.

The 2 pumps thing is a good point.

 

[Cogman]

The big problem I see with this is getting the Radiator to absorb the heat. I know that you will need to have holes from MB5 to MB1 so that that heat will rise, but this could create a Problem for MB1 (higher you go, hotter it will get). If you have enough room to add a fan and an open area, I would try and make sure you do this. The air will circulate on its own, but you take a chance of it sitting around and getting hot. BTW, Ive heard that makeing Plastic Cases it pretty hard, Good Job (Really, this is the real resion people want to see your case )

 

[moonshinemadness]

Depending on how much you are looking at spending you could go for something like This but i dont know whether thats what your looking for, if not your idea sounds a very good one

 

[sodcha0s]

What is the coil made of Z? The coolant will undoubtedly be much cooler than you air temp, so heat transfer should be fine, but will be best with a copper tube, aluminum fin coil, unpainted, with a forced air setup.

Since your layout is as Cog displayed, your best bet would be a side/side arrangement for the fans and coil if possible. The way the mobos are installed, trying to remove heat from the top will be more difficult. Remember this: heat, by itself does NOT rise, warm air is what rises. Heat always tries to move to a cooler place. So, if you can control the airflow then you control where the heat goes. Having fans blow straight across all of your boards will get the best results.

 

[TheBigZ]

Ok, it's not ideal, but I threw a couple pics up quickly at Picturetrail. The username is TheBigZ. Like I said, pics of something made completely out of clear material, don't really do it justice or show great detail. It's basically just a large rectangualr box, with 4 slide out shelves on either side. There is space in front of and behind the shelves to allow for some airflow. The center partition/support also is notched in the front and back for the same reason.

Bear in mind that I've been using this box for almost 2 years now. With the fanbox addition I made last year (best seen in the 4th pic), the heat is bearable. The issue I'm trying to address now is three fold... 1) I'd like to elminate (or at least minimize) the noise from the fanbox. 2) While the fanbox does get a lot of heat out of the box, it dumps it into the room, right under my desk. Not a real big problem in the winter months, but in the summer I sweat my prunes off. So the option of moving the heat to the basement appeals to me. 3) It could be cooler. I'm OC'ing a little bit, and of course the more heat I can get out of the box, the longer my equipment will last.

Moon: Not looking to actively cool anything at this point... 'specially at that price!

Sod: I haven't actually chosen any material for the radiators yet. I've accepted the fact that I may even have to have something fabricated to get the max coverage in my usable space. But yeah, I would assume aluminum. I plan on getting a couple thermometers and determining the temp diff between the inside of the box and the basement, but I gotta think I'm looking at 30-40 degrees at least. I'm hoping that would be enough to transfer heat.

Thanks for the think tank guys