Ambient air for CPU cooling?

Bluefront · Post by **Bluefront** » Fri Jan 31, 2003 4:04 am

The coolest air most of us have available for CPU cooling is outside the case. Your case fans blow this air into your computer. Why not take this one step further? Blow the cool air directly on the CPU heatsink by ductwork, a shroud, or some other method.

The new Dell computers I've taken apart do just that. They have a rear case fan blowing on a CPU heatsink through a short duct. My Dell 1.8 p4 at work is setup like that....and it's dead silent. To top that it also runs cool...about 30c at an idle.

I duplicated the setup on my own case (Antec 2600). The CPU runs only about 4c over ambient (celeron 2.0). Seems to me more companies would be making an add-on package to take advantage of the cooler ambient air. It wouldn't be an expensive package...a plastic adjustable duct with a few mounting brackets. Since Dell is banking on this cooling method, the rest of could learn something here.

ChiefWeasel · Post by **ChiefWeasel** » Fri Jan 31, 2003 4:43 am

Yeah, it is a good idea. The trouble is how many different setups are there? If you think about how many different cases there are, and then mobos can have the CPU in different positions, and there are different height heatsinks, it makes it very difficult to manufacture something that will work properly!

IMO, the best way is to contruct something yourself... It will probably work out cheaper and will fit perfectly, jus need the time to do it

bluehat · Post by **bluehat** » Sat Feb 01, 2003 7:05 am

Deltatronic CPU heatpipe works this way. Heat is transferred outside case and cooled passively. According to Deltatronic it is able to cool fastest P4 processors. How to get these heatpipes?

PassiveMan · Post by **PassiveMan** » Sat Feb 01, 2003 7:55 am

bluehat wrote:Deltatronic CPU heatpipe works this way. Heat is transferred outside case and cooled passively. According to Deltatronic it is able to cool fastest P4 processors. How to get these heatpipes?

Nah this is probably the best passive cooler there is..

http://www.tsheatronics.co.jp/zen/engli ... 000_e.html

Out of stock at the moment but when they are in stock, I will definetly get one. I emailed them and they said it should be in stock this month. It cost less than $50 US + shipping cost.

bluehat · Post by **bluehat** » Sat Feb 01, 2003 8:01 am

PSU fan and/or case fan is needed for ncu-1000. Deltatronic heatpipe solution is completely passive and works with deltatronic fanless psu.

GamingGod · Post by **GamingGod** » Sat Feb 01, 2003 12:24 pm

anyone seen any reviews in english for the ncu-1000?

Bluefront · Post by **Bluefront** » Sat Feb 01, 2003 5:27 pm

I'm certain many new methods of CPU cooling will appear. But I'm suggesting something most people could apply to their own computers, right now...for very little cost. If somebody would come up with a universal kit, a few adaptors for various sized rear fan ports....more of us would use the method.

I'm totally convinced this method used by Dell and others, is the best cpu cooling method....when all things are considered. It's cheap, low-tech, reliable and best of all....quiet. One rear case fan does double-duty, allowing the total removal of the cpu fan.

In my own case, I use a variable speed, thermal controlled fan, with a remote sensor in the cpu heatsink. The duct is slightly larger than the heatsink, so a small amount of the outside air is also blown directly on the chipset heatsink, as well as the ram chip. Works for me....

Well I'll be....I just saw the Badong Duct thing(there's another thread on it). This is exactly what I'm talking about. I even made a little aluminum scoop to divert the P/S flow upward. Heh.

fmah · Post by **fmah** » Fri Apr 18, 2003 8:40 pm

Everyone keeps stealing my ideas! Heh.

dan_hxff · Post by **dan_hxff** » Thu Apr 24, 2003 3:30 pm

Bluefront wrote:I'm certain many new methods of CPU cooling will appear. But I'm suggesting something most people could apply to their own computers, right now...for very little cost. If somebody would come up with a universal kit, a few adaptors for various sized rear fan ports....more of us would use the method.

I have an HP Vectra cooled the same way. It's only a Pentium II 350Mhz and runs on less watts than a P4. But same principle with a 120mm fan. You can cut a hole in side of PC and duct air straight to the CPU. Use a plastic soda bottle to make the duct or you can buy one --->

http://store.yahoo.com/directron/cnps5700dcu.html

http://search.store.yahoo.com/cgi-bin/n ... query=duct

dan_hxff · Post by **dan_hxff** » Thu Apr 24, 2003 3:37 pm

Also Dell and others use proprietary motherboards. If they want the CPU to be right near a fan duct that's what they order. A lot different than what the home builder must contend with

Just to be sure: The Dell fan blows in rather than sucks out? And is there another fan on board?

Dan

Bluefront · Post by **Bluefront** » Fri Apr 25, 2003 3:15 am

I opened two new Dells recently....they both blew the air in, through a short plastic duct which covered the cpu and northbridge. There were no other fans other than the PSU. The heatsinks were rather large.

Others on this board have seen Dells blowing out, using the same ductwork.

Here's my latest duct using ambient air to cool everything....

http://photos.yahoo.com/bc/bluefront100 ... yahoo.com/

dan_hxff · Post by **dan_hxff** » Fri Apr 25, 2003 4:34 am

May I ask what size fans for CPU you've seen on the Dells? 92mm? My guess is ducting quiets fan noise too. Ducting is the way to go as far as I'm concerned so the photos of your rig gave me ideas. My upcoming quiet cooling project will definitely have ducts for processor and hard drive. Duct for hard drive will come from fan at floor of the computer with entry hole cut into the floor. Processor duct probably from wall of computer with air blown in (I am tempted to use a 120mm) and a fan still on processor. So 2 quiet fans for processor. Dell has leg up on us because it designs motherboards & cases to keep ducts short. Longer the duct the more problems you get, though you sealed yours very well.

All I really need to cool are CPU and hard drive. I see a total of 5 quiet fans for this project while Dell slides with just 2?

o One in the P/S. (exhaust)
o Two for CPU (blowing in and on heatsink)
o One for hard drive (blowing in)
o One 80mm blow hole fan rearmost roof of computer. (exhaust)

http://www.spodesabode.com/content/arti ... uide/print

Bottom of thread you'll see my Dell URLs for diagrams of inside various Dells --->

http://forums.silentpcreview.com/viewto ... highlight=

Searching the internet I see no projects of those who want to copy Dell. Mod their machine using Dell cooling ideas which to me are state of the art. All kinds of wild and crazy mods but no one copying Dell.

Dan

Post by **Ralf Hutter** » Fri Apr 25, 2003 5:11 am

dan_hxff wrote:Also Dell and others use proprietary motherboards. If they want the CPU to be right near a fan duct that's what they order. A lot different than what the home builder must contend with

Just to be sure: The Dell fan blows in rather than sucks out? And is there another fan on board?

Dan

1)Dell motherboards are still somewhat proprietary but the position of the components on the board does indeed conform to the ATX standard. The CPU is in the "normal" location on Dell MoBos. They just have some third-party supplier fabricate the custom ductwork to fit it to the back of the case where:

2)A 92mm fan (either a thermally-controlled 92mm NMB or JMC/Datech) sucks air from the CPU to the outside of the case. This is the only fan in the case except for the PSU fan.

dan_hxff · Post by **dan_hxff** » Fri Apr 25, 2003 5:44 am

Many thanks for the details to the Dell CPU duct puzzle. Custom made ducts are the key. Boy, would I like to get some of those Dell ducts and mod them for me own nefarious purposes!

I have one motherboard (Asus A7N266-VM) out of three with the CPU very clear of capacitors etc. so it's easy to put in a duct to the outside. I'm sure Dell motherboards have their CPUs similarly situated.

1) Ideal motherboard would have the CPU area clear of caps, coils etc

2) Have the CPU slot oriented north/south or east/west depending on the heatsink you wanted to install. The ideal heatsink having simple fins oriented north/south so a fan can be mounted behind heatsink and blowing north/through fins/through shroud & duct/out top blow hole.

Dan

GamingGod · Post by **GamingGod** » Fri Apr 25, 2003 6:04 am

Is there any plastic that is thin and easy to mold when heated but will keep its shape when it cools down?

SpyderCat · Post by **SpyderCat** » Fri Apr 25, 2003 6:28 am

GamingGod wrote:Is there any plastic that is thin and easy to mold when heated but will keep its shape when it cools down?

When kids (and I) can work with this stuff, you should be able too

http://www.martindalejmi.herts.sch.uk/o ... tazote.htm

and

http://www.atlasortho.com/sub%20Product ... tazote.htm

The advantage of PlastaZote is that it is a firm foam that dampens vibrations.
Hard, thin materials might vibrate and produce noise.
I work at a hospital, and have easy access to this stuff.
Use Google, and try to find some close by you.

Edit:
Not what you asked, but you could also make nice ducts with epoxy
and some cloth (glass is preferred, cotton would work too)

dan_hxff · Post by **dan_hxff** » Fri Apr 25, 2003 6:59 am

Paper mache ducts anyone? Shape the exact duct out of aluminum foil. Cover with a layer of nylon window screening. Then slap paper mache onto it.

Or use close mesh steel fencing or aluminum window screening to mold duct ...... cover inside and out with paper mache. Make sure all steel gets covered and tape edges with duct tape to make sure.

Dan

Bluefront · Post by **Bluefront** » Fri Apr 25, 2003 3:46 pm

dan_hxff.....A few years ago I built a small form factor computer using a mini-Biostar board, K6II+450. The CPU was at the very top of the computer next to the edge of the board. (It had an external power supply) I removed the cpu fan, and cut a hole in the top of the case. Then I rigged a small fan to blow through the fins and out the top hole. Some ductwork sucked air from the bottom of the case (a bunch of vent holes), across the hard drive and chipset. The whole thing worked very well with that one fan. Heh...it's around here somewhere.

Too bad this setup would be difficult to duplicate with an ATX board.

aphonos · Post by **aphonos** » Fri Apr 25, 2003 7:46 pm

dan_hxff wrote:Paper mache ducts anyone? Shape the exact duct out of aluminum foil. Cover with a layer of nylon window screening. Then slap paper mache onto it.

Or use close mesh steel fencing or aluminum window screening to mold duct ...... cover inside and out with paper mache. Make sure all steel gets covered and tape edges with duct tape to make sure.

Dan

I can't tell if you are serious about the paper mache or being facetious. So forgive me if I'm missing the joke or if you're offended by the fact that I think you may be joking when you're being serious....

What would be the advantage of paper mache? Why not just cover your mesh with duct tape inside and out? They even make some decent looking duct tape (ie. shiny foil) these days if you have a case window and care about appearance.