Has anyone tried passive watercooling on a system? Since I put AcoustiPack in my SLK3700, my ambient and CPU temps has gone thru the roof. Most likely due to the Zalman ZM80 on my GF4 Ti4600 which gets hotter than hell. I dont have any problems running the system at these temperatures (CPU 55c/Amb 42), but it would feel much better if it was cooler in there. All watercooling I have looked at requires a fan on the radiator. Im sure it would be possible to run some without fans. But I have no idea what to look for in terms of size of the radiator.

Check out this thread:

http://forums.silentpcreview.com/viewtopic.php?t=5403

There was an artical in overclockers.com that have passive water cooling. The guy use copper pipes attached to the outside of the case. Also, I read an article (overclockers.com?) about a guy running copper pipes in the garage as the radiator and used pvc pipes into his computer case.

Conventional water cooling isn't passive...
Check out this article about convective water cooling.

Yes, I meant fanless. I know there is a pump involved.

I am currently running a passive water coolled system right now. It's a dangerden setup with a maze 3 waterblock and 3/8 inch tubing. The radiator is 120mm and is attached to the top of the case where I put in a blowhole. The CPU temp without a fan is around 115 degrees, but right now it's a 122 becuase the water is filled with bubbles and I havn't bothered to de-bubblefy it yet. The CPU is a 1.33 Ghz Athlon Thunderbird, one of the hottest cpus around. Watercooling is excelent in terms of noise and cooling power, and you can run even a very hot cpu without a fan. Of course, temps depend on pump speed, tube size, radiator size, and the waterblock.

surprised u can get away wid lil rad and no fan, maybe its the position of the rad, youve not got stalled air

I am suprised that you are running with bubbles, my Eheim screams if there is any air in the water.

Calm Computers A/S are launching the worlds first noiseless PC.

A PC that replaces fans with a patented liquid cooling system, rendering fan-coolers a thing of the past. Noise, dust and stress are completely eliminated, resulting in a better working atmosphere and greater sense of wellbeing in the workplace.

Through its unique condenser system, CALM cools without any noise or electricity. Units that require cooling are fitted with a refrigeration unit into which a cold liquid runs via a pipe. As the liquid heats up, it evaporates, at which point it is let out through another pipe in the side of the case. One side of the case functions as a silent cooling plate, where the vapour cools to become a liquid once again, before continuing its journey back to the refrigeration unit.

can u say vendor or pr person?
if u didnt copy and paste that im scared

http://www.calmsystems.com/show.asp?lang=gb-en

Well the big problem I can think about with this is the amount of heat the pump puts in the water. When I was leak testing mine I had a temp monitor taped to the bottom of the block just to see temps, when the fans were off it was much more hot than even my air cooling was. I wouldn't recommend it, I would even think a large passive heatsink would work better.

ive seen some ppl say pumps heat there water lots but i dunno :\ maybe duff pump?:\