Edit: I started this project wanting to use that Rosewell PSU as the basis for a one-fan system. Since it's not currently available, I used a standard PSU which ended up working perfectly. I am even able to use std 3.5" drives without any heat problems....read on. And it's mostly finished now. I've updated the photo album as I went along, so the album shows a few changes as I completed the project.


Here's my latest brain-storm, which may be of interest to you. I am always looking for ways to reduce the number of fans in my computers, at the same time quieting everything, and keeping things cool. It's not easy.......

So far I haven't found a PSU that will run fanless, stay in the case, and at the same time not heat everything up. Scrap that Idea.

The fanless Zen (NCU 1000/2000) requires airflow, a fan, to run at a reasonable temperature with a powerful CPU.

So here's my idea (not completely new for me).......I'm going to use an Aluminum PSU with a bottom 120mm fan, to cool the whole computer, including the CPU. At the same time I won't have to run the fan wide open, and everything will stay cool. Here's how:

First you need a case about 8" wide, giving about an inch clearance on each side of the PSU, this PSU, a Rosewell model.



Then you need a high quality tower-type cpu heatsink, such as an Aero-cool HT101, or an NCU 2000, or something similar from which you can remove it's fan and shroud, pointing up at the PSU fan. I'm also going to move the PSU back into the case about two inches, so the 120mm PSU fan is directly over the heatsink. A short duct may be necessary to force airflow more directly over the heatsink fins.

Now here's the tricky part....may be hard to discribe. I'm going to enclose the PSU in a box (wood to prevent heat transfer back into the case). Only the 120mm fan opening will be visible. The wood box will be as wide as the case......but it won't have a top. Directly above the psu I'll cut a hole in the case, slightly smaller than the top of the PSU.

What this will do is allow airflow out the sides of the PSU (see the photo), without letting the hot air get back into the case. This airflow will go around the sides of the PSU, up to the top of the case, over the top of the PSU (aluminum), then out the vent hole in the top of the case. Since there's no direct opening to the PSU fan from the top......this opening should stay reasonably quiet, at the same time allowing heat to escape out the top. The rear of the PSU will remain stock.....blowing most of the heat out the rear.

With airflow completely around the PSU, it should stay cool, even though it's carrying the load of the CPU heat. You could could use a steel case with this setup because of the Aluminum PSU case....which will transfer quite a bit of the heat. I expect you could run this whole computer on one 120mm fan, at about 1600 rpms. And If you were to use a Laptop hard drive, HD heat problems could be avoided.

Suggestions?

Let me see if I understand right ... your wooden box will enclose 4 sides of the PSU, leaving the top and back open. The top will be open to the outisde through a cutout in the case, and the back will be open to the outside via the normal rear exhaust opening. So, with the PSU fan running, no PSU heat will ever enter the case interior.

Sounds like a great idea to me. You will obviously have a negative pressure case. I'll have to think some more about it, and maybe have suggestions.

Tim

Yeah you got it...and it would be a negative pressure case if you only used the one fan. A large intake on the bottom of the case would reduce the negative pressure effects.

Nice to see that even though I've been away, BlueFront is still coming up with crazy cooling ideas. Looking forward to seeing some pictures.

Sounds like a quite good plan that I think will work very well.
Since you have no direct path out from the PSU fan you have very good possibilities to put some dampening materials to absorb the noise from the fan.
If you mount the HDD close to the bottom intake and have most of the other openings in the case sealed you should not get any problems with harddrive heat.

Now to the minor problems I see:
1. Graphics card might get very little airflow depending on how powerful graphics you want you might get a heat problem here.
2. Since you will run only a single fan it will need to run at fairly high speed (e.g. 1600 RPM), and that might generate more noise than two slower spinning fans would produce.

Please keep us informed on the progress!

Well if you use hot components in a computer....a Prescott, a hot graphics card, you are definately have to increase airflow with higher rpms, or more fans, water cooling aside.

There is a possibility that two slower fans will be quieter than one faster fan. It completely depends on how everything is arranged. You have to try these things to know for sure.

I like the idea of one fan cooling everything. With this setup the CPU heat and the PSU heat are exhausted directly out of the case. With proper dampening, one 120mm fan deep inside the case, even at 1600 rpms can be plenty quiet.

hey bluefron, another great idea

btw i was thinking about something similar:
your idea + second compartment for hdd + duct for vga




pros:
-direct exhaust of hdd heat
-fanless exhaust of vga heat (no vga heat building up in cpu area)

cons:
-hdd noise, unless you put a hdd in a sound absorbing enclosure with aditional passive heatsinks
-vga duct may be difficult to construct (not enought space)

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+ it is more silent-vise to mount the HDD close to the bottom, and hopefully the psu fan will deal with the additional hdd heat
+if you are a hardcore gamer, you can add temp. controlled fan in a vga exhaust hole - starting up ONLY on very high temp. (intensive 3d gaming)

Bluefront: Very interesting idea, I have had the same idea for some time now (only the PSU case) just like the HD case long before you made it!!! Yeah, that's the problem. I'm thinking a LOT, but nothing happens...... yet.

My thoughts:

What about a bigger PSU case with decoupled fan? If you have room for it that is, there's at least enough room in my AOpen H700B!

Like this (just PSU with case):



The small spaces on each side of the fan should be filled with som kind of foam. What do you think?

VERiON.....I'm not following your design completely. Is there airflow over your hard drives? If so, how does it enter? I wouldn't attempt to use airflow out the PSU to cool the drives.....I'm estimating PSU output temps of 34-36C. The drives probably would run cooler at the bottom of the case, over an intake vent.

A duct over the graphics card would be a difficult build.....it would probably be easier just to find a vga cooler that exhausted out the slot. Of course this is all educated guess-work.

Mats...You know I've had the same idea to use the area above the PSU in a full tower case to construct a modified PSU (taller), attempting to get better overall airflow through the PSU.

I like the 120mm PSUs, but they do have an airflow problem...back pressure, clogged airways, etc. That Rosewell model looks pretty good....but only if the hot air goes outside the case, as it will with this mod setup I propose.......

FWIW...here's a link to an airflow mod I did to a Fortron 120mm PSU. It also has comments regarding my first attempt at using the PSU as the only output exhaust, using a fanless Zen cooler. (That setup is still going strong).

Nice idea there Blue, is this just an idea or are you actually going to go ahead with it? Have you found a suitable case yet? But it looks like you will have to forego your usual intake filters, being a negative pressure case.

Verion - if the only case fan in your system is the PSU one that would make it a negative pressure system, which would mean the VGA hole and HDD vent (not sure from your drawing if HDD compartment is isolated?) would be intakes. That might also mean you could close off the bottom intake, as there are no other hot components down there.

It would also mean the VGA hole would be better below the VGA card, especially as that's the hottest side anyway (plus it would be easier to mod as you could just remove some PCI slot covers instead of cutting big holes in your case )

pangit.....I've got almost all the pieces to build another computer using an Ahanix d-box case (it's the right dimensions). But I might just modify an existing d-box setup I've been working on. This PSU idea could be combined with an intake fan, giving a quiet two-fan system and much easier to filter.

As far as filtering goes.....it's an absolute must for me. My last few projects have been almost neutral pressure due to the amount of surface area of the filters, combined with low-restriction filters. That's just another problem to deal with..

There are several ways to incorporate this PSU venting setup....one would be to cut vent holes in a std 120mm fan PSU (imitating the Rosewell design with a steel PSU). Another way could construct a muffled exhaust box a few inches tall that would attach to a std case directly over the PSU area. This is still a design on paper....and depends on obtaining the right PSU. That Rosewell model is new, not available right now.

If you can't get hold of the PSU you want right away this would be the way I would go. I would probably pick the lazy route to cut round holes and place normal fan grills on the holes. A slightly better approach would be to cut away almost all the metal and put a mesh there instead. By leaving enough of the metal to make the PSU strudy enough the mesh will just be to limit magnetic field and to keep fingers etc out of the PSU, so the mesh would not need to be sturdy.

Great idea Bluefront, just when I think I have seen it all.

Well I haven't been able to acquire that Rosewill PSU yet, so I built the prototype using a SOYO Raptor 350w....120mm fan but a steel case, from which I removed the fan, but did not cut and additional vent holes. Eventually this might be changed.



The 120mm fan will be attached to an external controller. That's an Aerocool HT-101 with the shroud removed. The fan is within 1/2" of the heatsink. The little duct you see in the first photo, forces airflow more directly over the heatsink, as well as the Northbridge and other hot-spots on the board.

The fan and the PSU are attached to the bottom board, and the whole setup slips out without touching the heatsink or motherboard. The outer wall and the rear wall of the PSU box are attached after everything else is in place. Makes assembly easier....

This setup is looking good to me...I'm excited about this project. I think it'll be a very quiet setup.

More Photos

Out of curiousity, how's it look from the outside top?

Until I can find an aluminum PSU that I think will work, I won't cut the upper vent hole in the case. The idea for that upper hole was to make use of heat off the aluminum case. Using a steel PSU makes an upper vent in the case less useful. I'm going to try the setup as you see it....make temp measurements everywhere, then re-think everything.

BF - when the Zalman NEPS400 external PSU comes out, I'm going to attach that to the case's PSU cut out (as intended), and cut a 120mm blow hole in the top of the Chenbro Gaming Bomb/Xpider case directly above the CPU.

Underneath, I'll attach a Nexus Real Silent 120mm, with a duct (a large Coke bottle!?) going down to the NCU-2000. This will be the only fan, as I'll block off the rear grill with acoustic insulation.

As for HD's, a regular Samsung Spinpoint PATA runs < 35C in a SilentMaxx enclosure, in the bottom of the case.

I've recently wedged a 120mm Acousti where the HD cage used to be, using a strips of acoustic insulation. It works great, and it cools the HD enclosure down to just 16C! OK, so it does add noise...

Edit: Are you sure the 120mm PSU won't ramp up under load? That's the problem I'm having with my NX-3500. I'm reluctant to buy an NX-4090 or Seasonic 400FB as I suspect they'll just do the same.

jools....that setup you describe is similar to my "cookie jar" computer. I used an NCU 1000 and a Fortron PSU. Works good.

The reason I didn't use a fanless PSU in this setup is that none of them are designed for air-flow cooling. The things have plenty of vent holes, but none of them has any internal space for airflow. And trying to blow CPU heated air through them would invite over-heating. (IMHO)

That fan can't ramp up because it is not being controlled by the PSU. It will be controlled with a front panel fan controller. I'll monitor output temps to see what to set it at...

Time for the moderators to rename the forum "The Blue Front". He's practically dominating it

More tinkering......Before I assemble the new setup, I made one more mod to the PSU. I removed the two sides and bottom (one "U" shaped piece) of the steel PSU. This really opens up the PSU for increased airflow.

The effect is noticeable.....much increased airflow at the rear opening. A seat-of-the-pants check by hand, estimates at least 25% improvement. I'll be able to run the fan much slower.

This particular mod could be applied relatively easily to any PSU with a bottom fan. Just looking at it you can see how much more airflow can go through the PSU. I doubt I'll buy that Rosewell PSU now.......



four more photos

sorry for not answering your questions:

> bluefront: Is there airflow over your hard drives?

front intake (not on a drawing) thru 5,25'' bay

> pangit: if the only case fan in your system is the PSU one that would make it a negative pressure system, which would mean the VGA hole [...] would be intake.

VGA is heating air in its compartment > hot air raises and escapes thru the exhaust hole above the VGA > cold air comes in thru the hole under the VGA

to prevent VGA exhaust holes from being intake holes VGA compartment should be isolated completly

I think you've got to isolate VGA from the rest of the case, otherwise it is going to add to much heat for q one-fan-system can handle (at low fan speed)

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Blue
- what about a HDD, is it at the bottom of the case?
- what VGA are you planing to use?

Your isolated video card idea sounds like a very difficult project. In my setup the board has built-in radeon 9200. I may also use an ATI AIW (fanless) card....still pondering that.

What type of HD setup this case will have depends on temps. I'll work on that after it's running....

well... in your case (no pun intended) vga heat won't be a problem (lucky you ). But since I want to use something more powerfull (and hot) than 9200 i've got to figure out how to transfer the heat from passive zalman heatsink to outside (without adding heat to the case).

I've got the point - it si difficult (or impossible), because there is too little space between agp and processor to construct properly working convection duct.

The project is a complete success. I constructed a HD/front filter setup I've been wanting to try. I removed the std HD cage, shortened the bottom feet, and de-coupled the whole thing with a foam pad on top of the drive cage, a foam pad on the bottom of the case, and foam on the front mount brackets. It is held to the case by two cable ties/foam spacers in front, and the snug fit in the foam top/bottom.

There is a louver panel on the PSU output hole, forcing the exhaust upward, away from the rear intake filter right below it.

The one fan in the computer, a 120mm generic fan (CompUSA $4.88 cheap), is mounted exactly 3/8" from the AeroCool HT-101. The fan is rated at 62cfm, 2000rpms, 40dBA at 12v.

During this testing period I'm running it on a fanmate controller. The TIM hasn't set yet, but here are the initial temps...

Idle, 26C ambient, fan@ 1534rpms

CPU 33C
Board 35C
PSU heatsink 34C
HD 34C

100% CPU usage, 26C ambient, fan@1534rpms

CPU 44C
Board 35C
PSU 36C
HD 34C

This is a Celeron D 2400mhz, Asus PVR800-V Deluxe, 512mb ram, Maxtor 7200 60gb,Ahanix dBox case, SOYO Raptor 350w PSU (fan removed).

So far this setup has exceeded my expectations....With the fan mounted as it is, deep inside the case, even at 1500rpms it's quiet. When I get a proper fan controller, maybe a quieter (read more expensive) fan, I should be able to run the system on one fan @ 1300/1400rpms, maybe less.

FWIW....this is a negative pressure case, but with a large filter area, and everything sealed well, I should have no dust problems. I've got a ways to go with this setup, like adding an agp AIW video card, a modem, maybe a card with more USB ports......but for now I'm happy.

Eleven more photos

That's a great result Blue, especially considering you've got intake filters. It proves your point that with enough surface area filters do not need to restrict airflow significantly. Once again some great practical ideas that other people could use.

I would like to try something like that myself (with the PSU box bit at least), but I don't think I've got enough room in my current case. A good excuse to buy a new one?

Any particular reason you put a filtered intake on the rear instead of bottom? I suppose without a hot video card you don't need much airflow in the bottom half of the case except over the HDDs. And also that would mean raising the case on castors.

Thanks for the kind words.....The heart of this setup is that PSU modification/box. It dramatically improves airflow through the PSU, meaning you can blow CPU heat through the PSU without causing heat problems. I have a temperature probe in the center of the PSU, under the heatsink so it is not in the airflow. And it runs very cool, even under load. I suspect if you constructed this PSU box for a standard setup, the PSU fan would remain on low speed, no matter what.

This setup proves computer case makers could add high-quality easily serviced intake filters to their case line-up. If I could pull this off with a standard case and a pair of tin-snips, a case maker certainly could. This setup has more filter area than any of my other setups.

I didn't use a bottom intake because that rear case area was available for a large filter. And with this dBox case I had a pretty good front intake setup. I just had to enlarge both openings, to fit the filters. Both filters just pull out for maintenance.....no sweat, no dust.

More updates...I found a thermo-controlled fan I forgot I had, and tried it out. It's a Colorful brand from CompUSA, with about the same specs as the one I was using, except for the thermal-control.

The sensor sticks out about an inch or so, and just touches the PSU heatsink when installed. Nice change......it now idles at 1270rpms and goes up to 1330 at max usage. Amazingly the range of temps is almost the same as the other fan which had a fixed 1534rpms.

This may be due to a slightly lower ambient (24.1C) and the setting of the TIM. Anyway the 200 rpms lower made this computer inaudable to me from the front, 3 feet away. From the rear I can hear it, barely. Goes to prove what a fan change can do.....

28 photos total

Added an AIW 7500 video card, and two other pci cards. Testing how the new cards affected airflow revealed only a slight PSU temp increase of 1C.....looks like it's good to go.

good to hear that!

I know this is not a setup for hardcore gamers, but can you measure temps with hotter video card running 3dmark or similar? That would be great!

If your setup can handle additional heat (when gaming) only by ramping up a fan - that would be great way to go for a occasional gamers (like me), especially the one using headphones

My main machine can go up to 225x12 (2700Mhz - PR3800+ rating ) using just one fan - in the PSU - as well



I managed it by fanless watercooling

http://ax2.old-cans.com/galerie.php?p=wc&d=1&v=v2

Heh....My gas water heater in the basement sits in a big catch pan, which has a attached drain hose leading to the drain against the rear wall. Should the water heater spring a leak, the finished basement probably won't get hurt. You know a person could get one of those big drain pans and set his leaky H2O/computer right in it. That way the anti-freeze wouldn't stain the carpet or the hard-wood floors.