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passively cooled radiator?

O

oShy

n00b
Joined
Sep 30, 2006
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1
Hi guys, i've looked at various water cooled setups and i am thinking of going for the silent route. To do this i want a passively cooled radiator, now i have looked at a few passive radiators but none of them have taken my fancy. So my question to you guys is could i use a normal dual radiator mounted externaly without any fans on it directly to just cool my cpu and gpu?
 
I would think you could, but I would use a 3x120mm radiator instead of a 1x120 or 2x120, just so you have more surface area. I'll be honest, I have two adjustable speed fans on my BIP240, and I leave them at the lowest setting. My computer is almost silent, and I think it provides the best silence / performance bargain.
 
You probally know this already, but ...



yes and no, mostly no. It has been done but the results were less than stellar, goggle "passive cooled PC" .

In short, most rads in common use are DESIGNED for air to flow thru them to remove the heat. The heatercore types most commonly used are more so than others. Once you give up airflow. you have to go for hugely increased surface area and depend on natural convection which is problematic due to the size. Look at the rad on the back of a fridge for example.

With no overclocking and the moderate (compared to what are now older processors) heat loads of Conrore cpu chips its more possible but still problematic. If you put a high performance GPU in the loop you are in for trouble.

I would suggest a 2x120mm rad with extreamly low speed (1500 rpm max) fans, speed contoller, and a shroud would be almost silent and would be hundreds of times more efficient at removing heat. Mounting the rads where they would suck cool ambient air would be greatly better than in a case sucking warm warm air from inside the case.

I guess you have found silentpc.com

It can be done but I wouldnt try it with a common heatercore type rad.


this is interesting:
http://www.informit.com/articles/article.asp?p=337318&seqNum=2&rl=1
 
The only really good Passive Rad that I've seen so far (that isn't external and doesn't look terrible) is the Cape Cora passive radiator. The largest version is pretty much enough to cool anything.

Note, that most of these radiators are VERY sensitive to room temperature... there's a definite diminishing return between outside temps and water temp, because of a lack of moving air.

Also, these are mostly aluminum radiators, which of course, produce corrosion over time. Most people, however, agree that with proper prevention steps, corrosion is almost a non-factor.

They're also expensive and HEAVY.

Just go for a BIP 240 or 360, and slap on some yate loons (4$ at Jab-Tech) at 7v and it'll be totally silent.
 
Oh keep in mind that once you WC the processor you remove the airflow around the voltage regulator mosfets that typically surround/are near the cpu area. You should cool those somehow for reliabiliy
 
If you did want to use a 240mm radiator passively, you'd almost definitely have to mount it horizontally...
 
Use a big car radiator like in the article......LOL that reminds me that i have a huge window ac rad thats in good condition. I was actually thinking of doing the same thing when i got it but i havn't gotten around to using it on something yet.
 
Before TopNurse comes here with her AquaComputer gear, you can look into getting the AquaComputer Airplex Evo 1800 which is known to run passively well plus you can add 15 really quiet fans like YateLoon/Nexus's 120mm modded to run at 5V which will give you incredible but inaudiable performance

Alternatively, have you looked at Innovatek's Ultra passive radiator + booster fan?

Either of these solutions will give you much better passive performance than a dual radiator. The only one that will come close to performing acceptably well passively is the Thermochill radiator as it has fairly widely spaced fins, but even a very slow fan would really boost its performance.
 
pawstar said:
Before TopNurse comes here with her AquaComputer gear, you can look into getting the AquaComputer Airplex Evo 1800 which is known to run passively well plus you can add 15 really quiet fans like YateLoon/Nexus's 120mm modded to run at 5V which will give you incredible but inaudiable performance

Alternatively, have you looked at Innovatek's Ultra passive radiator + booster fan?

Either of these solutions will give you much better passive performance than a dual radiator. The only one that will come close to performing acceptably well passively is the Thermochill radiator as it has fairly widely spaced fins, but even a very slow fan would really boost its performance.
Click to expand...

There's a setup cooled by a MORA2 somewhere in the gallery...

looks pretty pimp :D
 
In my experience, there are two decent passive radiators. The one from Innovatek and the Reserator 1 Plus from Zalman.

I'm currently running the Reserator (been using it for over a year now) and it cools the CPU and GPU in total silence, quite well.

My CPU idles around 35, 50C under load. Temps are the same for the GPU (water temp doesn't change much).

A buddy of mine is using the Innovatek kit, the external radiator. He has an X2 4400+ and it idles at 30C, load is about 36C.
 
My system is only slightly audible over room ambient noise with 2 of those Yate Loon fans at 5v on a BIP X-flow 240. CPU was at 2.6 (till it died :() and my GPU was clocked to 513 in sig. Idle temps of 29'c and triple Load temps of about 41 (Orthos and RBTHDRBL)
 
n00btard said:
There's a setup cooled by a MORA2 somewhere in the gallery...

looks pretty pimp :D
Click to expand...

Look no farther than the Coolermaster Gallery.

Passive is possible. I don't recommend it simply because tests show that a heatsink with no air, is shown to have about a 2.3 C/W. Just a single low RPM fan (<800rpm) and that number is down to under .3 C/W.
 
The headache of designing a passively cooled radiator usually isn't worth it.

Sinceyour motivation is to have a completely silent computer (ie No fans at all), then you should know that your motherboard and other components are designed to run with some form of airflow over them since they all generate heat. Also since your hard drive will make noise, you might as well use some low speed fans and put the air through the radiator and then through your system.
 
If you insist on a passively cooled computer, take a look at Zalman's TNN-500AF fanless case. Even then, its still a good idea to run a single really silent fan volt modded that barely turns.
 
dunno if this will help but i used to have a sorta-ghetto rig setup that i ran passively with better cooling than with high-speed air.

i had my vid card and cpu cooled with a large (11"x5"x1.5") heatercore and a really big reservoir that held approximately 1.5 liters in the res itself. the res would get slightly warm but overall i had 0 problems with it running passive, although most of the time i ran with a pair of 120mm fans on 7v just for peace of mind.


if you don't mind higher temps then you can do it passively without breaking the bank, i imagine that if you used 2 or 3 suitable rads then you'd be plenty safe.
 
I'm running a Zalman res1 plus over the CPU and GPU with one 120mm (Wish I could remember the name. But it's only like 11db and pushes 35+cfm) fan in my qpack and if you put your ear to it you still can't hear it. My man goal was a completely silent pc since it sits in my bedroom and I'm happy with the results.

My only down side is I'm looking to upgrade my GPU and might go SLI. I don't think the Res1 can handle the heat from all 3 sources. I might need to add an inline 120 rad behind the fan.
 
I ran a Reserator on one X24800+ and two 7800 GTX cards in SLI for a long time, and it was fine. The tank would get hot, but the cards never went over 60C or so.

On stock air-cooling they usually get up to 70C or thereabouts. Don't sweat it. The reserator can handle a CPU and two GPUs.
 
Definatly not SilenX. Silenx = silenbullshit.

Yate Loon D12SL12 might be what you want. It's not rated as overinflated as silenx (ahem.. 14db 90cfm, bullshit), they aren't overpriced like SilenX either ($28 for a 120.. Bullshit), and they don't squeek, rattle, clank, tick, scratch, etc.

www.jab-tech.com
 
To help a passive radiator work more effectively, stick it near the bottom of an upright wind tunnel.
ie create a tube the same shape as the radiator, stand it upright with plenty of space to let air in the bottom and put the radiator less than halfway up it so all air has to pass through it (not round it).

The hot air will rise and drag cooler air into the bottom of the wind tunnel giving the effect of a very slow fan :)
 
Chernobyl1 said:
To help a passive radiator work more effectively, stick it near the bottom of an upright wind tunnel.
ie create a tube the same shape as the radiator, stand it upright with plenty of space to let air in the bottom and put the radiator less than halfway up it so all air has to pass through it (not round it).

The hot air will rise and drag cooler air into the bottom of the wind tunnel giving the effect of a very slow fan :)
Click to expand...

What you are thinking of is basically a chimney. :p There are some calculations on the web (http://www.naiad.ca/chimney/) that help you find the cfm vs area and height. The problem with this is that in order for the chimney to have an impact on the cooling, it must have a reasonable height.
 
pawstar said:
What you are thinking of is basically a chimney. :p There are some calculations on the web (http://www.naiad.ca/chimney/) that help you find the cfm vs area and height. The problem with this is that in order for the chimney to have an impact on the cooling, it must have a reasonable height.
Click to expand...


The pictures are for a fixed height chimney, they dont show the variance with height
"It is assumed in the calculations that the chimney is 59 inches tall,"
The calculations are provided in a nice spreadsheet and do include height.
Thats a really good post :)

Given the surface area of the radiator is likely equivelant to at least a 6 inch wide chimney, for the height specified the CFM values are pretty good for a silent cooler
15 to 33CFM for 6" diameter
23 to 50CFM for 8" diameter...

Using a small height chimney will give a better efffect than using no chimney so it should still be worthwhile.
 
Chernobyl1 said:
The pictures are for a fixed height chimney, they dont show the variance with height
"It is assumed in the calculations that the chimney is 59 inches tall,"
The calculations are provided in a nice spreadsheet and do include height.
Thats a really good post :)

Given the surface area of the radiator is likely equivelant to at least a 6 inch wide chimney, for the height specified the CFM values are pretty good for a silent cooler
15 to 33CFM for 6" diameter
23 to 50CFM for 8" diameter...

Using a small height chimney will give a better efffect than using no chimney so it should still be worthwhile.
Click to expand...

Yeah, the graphs are for a fixed width chimney. If you download the XLS file and plug in some numbers you get what the CFM will be for your particular configuration.
 
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