A fanless home-made system?

snobben · Post by **snobben** » Sat Jun 25, 2005 11:55 am

Would it be possible to build a fanless system? Say we use these components:

- Lian Li aluminium case
- Etasis 300W PSU
- Intel Pentium M (around 2GHz)
- A Scythe SCNJ-1000 Ninja heatsink
- A pretty good videocard like the 6600GT or something like it from ATI passive cooled by the Zalman ZM80D-HP.

Or any other component/cooling device on your suggestion? Or will it all run to hot and burn up?

// Snobben

Ooops. You had some of my personal notes, in Swedish, in this text...

tlinna · Post by **tlinna** » Sat Jun 25, 2005 12:03 pm

It isn't possible. You need at least one fan to blow the hot air out from the case. Otherwise it would just get hotter and hotter inside with no means to get the heat out of the system.

Shadowknight · Post by **Shadowknight** » Sat Jun 25, 2005 12:26 pm

Due to a problem with my Raptor last night (while I was sleeping) it disrupted the power going to my fan controller (both were on the same rail).

End result - PSU thermal protection kicked in, EVERY PIECE OF METAL, from the PSU, to the case, to the CPU H/S, to the fan controller was too hot to touch.

So no, it's not possible.

Bluefront · Post by **Bluefront** » Sat Jun 25, 2005 12:58 pm

I think such a setup might be possible....but without a conventional case. The PSU would have to be remotely mounted (external). The case design would be unconventional, relying on induced airflow current created by large diameter vent piping. (maybe tapped into a home ventilation system).

Hot as is is today in St Louis, a large air-pipe from the top of a computer to the attic, would be sucking a bunch of heat out of the setup. This effect would be less in cooler weather, but would still be present. Heat always rises.....and pulls cooler air from down below. I've seen few setups using this princible to it's full potential.

perplex · Post by **perplex** » Sat Jun 25, 2005 1:42 pm

Bluefront got any pics of that ?

Bluefront · Post by **Bluefront** » Sat Jun 25, 2005 2:43 pm

Sorry......The single fan running this computer I'm using full-time now, is virtually inaudible to me. No sense going to the next step (no fans).

I guess if I was a hard-core silent freak (I'm not), I might give it a try. If you have a house with an attic space, this free airflow is going on all the time. The ridge-vent is pouring out heat....drawn by the heat rises princible, from the vent openings under the roof over-hangs (hip-roof).
If you ran an air duct from the top of your computer into the attic, the ridge vent on the top of the roof would be sucking air (hard) out of your computer. This would work even in the winter, and even if your attic did not have power venting.

The down-side (there's always a down-side) is if your house had air-conditioning, this computer vent would be blasting your cool air, right out the roof. Cool computer=hot house.

Post by **MikeC** » Sat Jun 25, 2005 2:56 pm

Actually, minus the VGA card, it's probably possible to cool it fanless, but as Bluefront already mentioned, only in a custom case where you can take advantage of a chimney effect. PSU and CPU would have to be in separate themal zones. If there were no other cards except the VGA card, maybe if you could get a huge HS on it, you could have another separate chimney for it. The side of the MB that has the I/O panel would be top or bottom.

But it would be a lot of work for probably little real gain. A system like you're talking about can probably be cooled by a single Nexus 120 runing at slow speed -- which is inaudible in most cases anyway.

Shadowknight · Post by **Shadowknight** » Sat Jun 25, 2005 2:59 pm

My experience indicates that if you have a VGA card with a thermal output similar to the 9800pro, and you're trying to run it fanless in a system otherwise only cooled by an undervolted 120mm Nexus, the card will die/be permanently damaged. So consider putting a 92mm Nexus in to cool the card off in a system with that low an airflow.

flyingsherpa · Post by **flyingsherpa** » Sat Jun 25, 2005 3:01 pm

sure it's possible... it's just not easy. you could copy what commercial fanless systems do: generally use heatpipes from the hot parts and connect them to large / massive heatsinks outside the case. a few people on these forums have done similar things... don't have time to search right now, but one guy hooked up heatpipes to his CPU and connected them to a really big heatsink on the side of his case. someone else converted his psu to passive by gutting it and attaching huge heatsinks exposed to free air (not inside a case).

are you seeing the trend here?---> hot parts connected to very large heatsinks exposed to ambient air to take advantage of thermobuoyant flow. with the parts you suggested i do not think it is possible without a lot of hacking. with something like a via mini-itx system with integrated graphics, it would be much easier (and has been done).

but really, as Bluefront said, it is not necessary (except maybe for bragging rights). it is MUCH easier and cheaper to use a few very quiet fans. these can usually be made inaudible from your sitting position.

but if you still wanna try, we'd sure all like to see what you come up with

shades_of_blue · Post by **shades_of_blue** » Sat Jun 25, 2005 3:22 pm

with a pentium m system i'd say it's possible to run fanless. go with an antec phanton 350 psu, that huge tower like heatsink from thermaltake, a zalman zm80d-hp as you referenced to and any generic case with it's side panels off or cut the upper 1/4 section off so heat would be allowed to escape.

the pentium m would step down if it got too hot or shut off completely. all the intel chips i've dealt with have caused the system to turn off after it hits critical temperatures. hell, i've ran a pentium m 1.7 with no heatsink for over 24hours with no side effects, other then it stepped down to it's lowest setting, 600mhz. now i'd never do that with an amd, but that's another story.

even if you did something like that you've still got to silence your hdd. because of the hdd, i don't think creating a fanless pc is worth the effort. but i've never been into suspended hdds and other mumbo jumbo, my data is far too critical to risk such things. specially with me carelessly kicking things in the dark lol

and yes, I know that nasty looking sky scraper heatsink from thermaltake gets it’s ass handed to it by the xp120, but when going fanless I’d recommend the most surface area you can get your hands on and that looks like it.

frostedflakes · Post by **frostedflakes** » Sat Jun 25, 2005 3:46 pm

Completely passive cooling is nothing more than a novelty IMO. As others have mentioned, with one or two undervolted 120mm fans, you can make a computer that is, for all practical purposes, inaudible. Not to mention that it'd be a real drag if you spent large amounts of money eliminating fan noise, only to have a hard drive negate this.

However, if you just want a fun/unique project, this could probably be accomplished if you put your mind to it. One option that I think sounds very promising is liquid metal cooling. There is a company that does this, and I believe it's supposed to be relatively (Sapphire is actually releasing a video card with liquid metal as an OEM cooling option).

If you're serious, I'd recommend getting in touch with them. The liquid metal used in these loops supposedly has ~40x the cooling capacity of water. But what I think would be most attractive is the fact that low-power, silent magnetic pumps are used to move the fluid, rather than the traditional centrifugal style pumps found in most water systems. If you were to attach this to all the heat producing parts of the system (CPU, GPU, maybe NB/SB, PSU, HDD, and RAM if you really wanted to sink a lot of $$$ into the project), and have the pump move the fluid to a passive radiator, you could have noiseless, yet effective, cooling.

Here's the company - I have no idea if they build solutions for end-users, you'd have to get in touch with them.

http://www.nanocoolers.com/products_cooling.php

Another option would use a similar idea, but with water as the cooling fluid. Innovatek makes a pretty effective passive radiator, that can be bolted to the side of the case. However, silencing the pump would probably require enclosing and decoupling it from the case.

Probably the least effective option would be heatpipe cooling.

BrianE · Post by **BrianE** » Sun Jun 26, 2005 12:06 am

The idea of running a duct up into your attic through a computer case sounds like a pretty wild idea. I think it would probably work, but another drawback (besides the A/C problem) would be that in the winter it would pull cold air into the house, much like a fireplace can. In my home there's a heat exchanger type fireplace, and it works.... but it makes the rest of the house colder because the vacuum of burning the fire and expelling it out the chimney pulls in cold air through all the cracks in the house.

I've always wanted to run an intake duct from an exterior wall for it to fix this problem. I think that would be the ideal setup for the "house convection PC cooler" setup.

Bluefront · Post by **Bluefront** » Sun Jun 26, 2005 3:56 am

Since this thread was pointed toward "home-made" passive cooling, my thoughts on the subject involve how I could pull this off using pieces that might be found easily......maybe in my basement or garage.

Running an air duct into the attic, is different from the standard chimney effect. In this experiment you wouild be using the entire area of the attic as a heat collector.....and bleeding off the hot air in a partially restricted manner (it usually works this way anyway). This is what makes it possible to run an air-pipe down to the special computer case that actually sucks a lot of air. Having worked on a few roof projects, I can attest to the power of this suction.

On a hot day, heated air is trying to escape the attic with much force. Open up holes in the top of the roof (like a ridge vent) starts the upward airfow. But the attic must have lower openings for cooler air to enter, and displace the hot air. That's what would make such a computer/attic vent work.

Take it one step further.....run another vent pipe from your computer to your basement. This would pull cooler air from the basement, through the computer, up into the attic. And all this venting could be done through the wall spaces of your home.....so It wouldn't look unusual.

It could be done...and would work good. Better on sunny days for sure. But all the time without the use of fans, electricity, expensive heat pipes or other unusual equiptment.

BrianE · Post by **BrianE** » Sun Jun 26, 2005 6:26 pm

Bluefront wrote: Take it one step further.....run another vent pipe from your computer to your basement. This would pull cooler air from the basement, through the computer, up into the attic. And all this venting could be done through the wall spaces of your home.....so It wouldn't look unusual.

Hmm... thinking about those central vacuum cleaner system tubes running through walls already these days....

IsaacKuo · Post by **IsaacKuo** » Sun Jun 26, 2005 6:48 pm

I've got to disagree with the others. IMHO, it is easy to build a fanless system--using old components. For a while, I ran my Pentium III 550mhz system fanless. The PSU was simply an old PSU with the fan removed. It definitely got hot, but it worked.

The secret? The components were all in open air. Theoretically, a chimney effect could have provided superior convection airflow, but in any case simply having the components exposed to open air was better than cramming them into a stuffy case.

I'm not too familiar with the listed components. I imagine an underclocked/undervolted Pentium M with a Scythe Ninja would be comparable to my Pentium III with Zalmand ZM-80A.

The video card? I'd replace it with a low end Radeon. My Radeon 7000 with stock fanless heat sink had no problems whatsoever with passive cooling.

That leaves the PSU. Of all of the components in my fanless setup, the PSU was the one I was most worried about. I was never retarded enough to try touching the heat sinks, but merely putting my hand near the PSU I could feel the heat eminating from it. For the PSU to survive fanlessly, minimizing the heat it generates would be critical. That means starting with an efficient PSU and minimizing the load on it. Forget a powerful video card. Use a notebook drive instead of a 3.5" drive.

If you lose the standard computer case, and I think you've got a fanless system pretty easily.

All of that said, I agree with everyone that it is not a good idea to run a fanless system. When my system was running fanless, I was always worried about it overheating. I soon chickened out and put a near silent fan on the PSU. That kept the PSU cool and stable, at practically no noise cost.

wim · Post by **wim** » Sun Jun 26, 2005 8:18 pm

IsaacKuo wrote:All of that said, I agree with everyone that it is not a good idea to run a fanless system. When my system was running fanless, I was always worried about it overheating. I soon chickened out and put a near silent fan on the PSU. That kept the PSU cool and stable, at practically no noise cost.

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