Ducting idea

[sfa ok]

I have a Delta 38 sucking the heat from my Alpha PAL6035. This obviously is the greatest source of heat in my case. Could I get some plastic ducting or some other kind of tubing and have a exhaust going directly out of the case? I noticed that the air flow from the Delta seems to go out to the side instead of straight. But while I'm at it, I could mod it to use a high CFM 80mm fan, getting rid of the Delta's noise. Any thoughts, experiences, etc?

 

[William]

sounds solid. would work better with a pep66 with the way it blows through the fins though.

 

[Door Knob]

That is kinda what I plan on doing to my alpha pep66. Mine should be really interesting when I am done. I'll have to get some pic's up. The top of the delta is 1 1/4 away from my power supply. I am gunna have a wide plastic duct, in the shape of a V if you were looking down at it, bringing air in from the outside and exhausting it throuh the rear case fan...should be interesting.
Yours sounds like a pretty sweet deal as well.

 

[0dan0]

It sounds like a good idea although i dont know how effective. I mean if you have enough case cooling it really wont make a difference, because all the air is being replaced about once every 5-10 seconds. So that will get the heat directly out of the case but that is probably where it is going anyways if you have good airflow.

-Dan

 

[bdf24]

It will raise your cpu temps a bit but lower your overall system temps. Ducting the air around the cpu causes the hot air to linger around a bit longer and will cause the chip to run a bit warmer. Although it will cause your cpu to run a bit cooler under a load which is good.

I tried it with my cpu with this 86w peltier and it didnt like it at all. Although I used a flexable aluminum tubing which got very warm very fast! I did try it with cardboard with my 50w peltier once and it worked good. I ran my heat from the cpu out the back of the case. Reason being I didnt want to run it out the side and have the air travel around the front and get sucked back into the case.

My thermastat is right above my pc desk. It normally says the temp in the house is around 85 degrees cause it's picking up the heat being tossed out of the computer down below! And thats after the air comes out of the case and it has to travel around 5ft up before it hits the thermastat and it is still at over 80 degrees! If I dont move this thing or get my water cooling before summer I'll have high utility bills due to the air being on all the time cause it thinks it's so warm.

 

[Kryten]

Great minds think alike I just put up a post asking the same question, If I had read yours first I wouldn't have bothered, I think this Idea has some merit after all the heatsink air would have to be the hotest air in the case.
I can't see how this wouldn't improve both CPU and system temps after all the air in the case would have to be significantly lower, the hottest the air in the case should get is the ambient temp outside with a little risidual heat off the heatsink.
hmmmm the more I think about it you would want to enclose the heatsink as well this may cause a heat build up if the air couldn't get away quick enough.

 

[Kryten]

Just a thought...
The old saying the shortest path between two points is a straight line...I think this has some relevence in this topic, for two reasons unless you have an ultra wide case, the side would have to be the shortest distance and two if there are no bends in the pipe (e.g. straight) it would have to move the air more effeciently.

 

[Bartman]

Newby2OC (Apr 12, 2001 09:53 p.m.):
Just a thought...
The old saying the shortest path between two points is a straight line...I think this has some relevence in this topic, for two reasons unless you have an ultra wide case, the side would have to be the shortest distance and two if there are no bends in the pipe (e.g. straight) it would have to move the air more effeciently.

You could run the duct from the CPU HSF right to an extra 80mm exhaust fan perhaps... So it would not only get pushed out, but pulled out... Just an idea.

Maybe if you already have a 92 or 120mm exhaust, you could run the duct within an inch or 2 or the fan, this would let the warmer air just get sucked out of your duct/case.

 

[Kryten]

Bartman (Apr 13, 2001 12:37 a.m.):

You could run the duct from the CPU HSF right to an extra 80mm exhaust fan perhaps... So it would not only get pushed out, but pulled out... Just an idea.

Maybe if you already have a 92 or 120mm exhaust, you could run the duct within an inch or 2 or the fan, this would let the warmer air just get sucked out of your duct/case.

Was thinking much the same, kind of rather than putting all the load on the CPU fan to push it out, put a larger fan on the side case to help pull the air out of the tube.

 

[bdf24]

Well that is what I did was have it run too the 80mm fan in the back of my case. If you have very good air flow in your case, everything sealed off except for the intake and exhaust fans. Which means air is constantly going in the front and out the back. The heat being blown off the cpu has more area to disperse itself. Then it hits the draft inside the case and is moved out of the case.

Ducting is a good idea, But I believe it depends on how much heat you are trying to move away. Think about it. if you have your cpu ducted all the way around that is a far smaller area for the heat to disperse then having the whole case! As the hot air in a sense has to wait in line to get out of the case. It cant spread out and get away from the cpu as fast. Yes your system temps are going to be a lot lower but cpu temps will rise.

Right now the way I have my system running. With my fans swithced to 7v's my cpu temp is around 16c to 17c. and my system temp is around 30c. With my fans swithced to 12v cpu temp is around 13.5c to 14c. And system temp is steady around 24c which is 75 degrees, And thats about room tempature. Which you cant really get any better then that.

 

[Kryten]

bearing in mind that this is theory only, I don't have a new heatsink to try this with yet but...lets say for argument sake the CPU fan produces 30CFM now if our external case fan produces 80CFM, to my way of thinking if these 2 are sealed both ends tightly and a tube goes between them with both of them blowing air out of the case there would be a 50CFM vaccuum between the 80 and the 30 fans this would have to aid and make the 30CFM fan more effecient due to to air space it's trying to push it's air into is a negetive pressure area.
what do you think does that make sense?

 

[sfa ok]

My thinking behind this is that without ducting, the hot air from the heatsink is exausted out of the case....eventually. But the hot air is still being blown out somewhat close to the heatsink, so it could be sucked back in. By adapting a high cfm 80mm or 92mm fan and exausting it directly out of the case the system temp will go down, especially around the cpu (hopefully), and cooler air will be pulled through the heatsink, cooling it better. I hope that all made sense, I'm pretty tired right now.

 

[sfa ok]

One other thing, I would have the air going directly out the side, straight line.

 

[bdf24]

All I have to say is stick atleast a 50w peltier on your cpu and run it unducted. Then Take the same cpu with the 50w peltier, stick some sort of ducting on it. Wether it be out the side or the back. I know for a fact that the cpu will run warmer!

 

[Kryten]

Gafrioni (Apr 13, 2001 10:34 a.m.):
My thinking behind this is that without ducting, the hot air from the heatsink is exausted out of the case....eventually. But the hot air is still being blown out somewhat close to the heatsink, so it could be sucked back in. By adapting a high cfm 80mm or 92mm fan and exausting it directly out of the case the system temp will go down, especially around the cpu (hopefully), and cooler air will be pulled through the heatsink, cooling it better. I hope that all made sense, I'm pretty tired right now.

that makes sense if I understand you correctly, your suggesting not using ducting but still using the fan on the side of the case directly above the CPU to suck out the hot air being sucked out the CPU fan not allowing the hot air to circulate and come back to have another go at the heat sink.
This is a simular idea that they use in tractor pulling where they run staged turbo setups.
the first fan gets the air moving which supplies a quantity of air to the second larger fan to blow it out the case.
This is usually a sealed system as I would suggest, but it may just work all the same if the second fan is big enough and the distance between the CPU fan and the case fan aren't to great.
I was just thinking that maybe a combination may work even better, sealed at the case end so the air can't get back into the case it must go out the side fan and using ducting (something hard like PVC tube) with a loose fit over the CPU end so that the CPU fan would be blowing the air up the tube but if it couldn't move enough air fast enough it still has the opportunity to escape into the case which shouldn't increase the CPU temp because the air is freely moving....

As I said earlier this is purely theory until I have chance to test it.

I think adding a peltier to the system would require a whole different system, they HAVE to be used with a water systen don't they?

 

[bdf24]

Newby2OC (Apr 13, 2001 07:25 p.m.):

I think adding a peltier to the system would require a whole different system, they HAVE to be used with a water systen don't they?

No You do not have to have a water cooling system to use a peltier. I have a PIII alpha cooler with an 86w peltier. Works great, keeps my temps nice and cool. But hopefully I will have my water cooling by this summer! Hopefully way before this summer with my peltier! Super cooling baby!

 

[stool]

You have a very good idea. If you search around various oc sites you will find ducting setups ranging from cardboard to sheetmetal, mostly in the form of shrouds. The Alpha's with their outward airflow, seem to be custom made for this type of setup. If you apply an 80mm on your heatsink, and directly vent it out of the case, that seems to be one of the most efficient heat reduction things you could do.

 

[Kryten]

stool (Apr 13, 2001 11:13 p.m.):
You have a very good idea. If you search around various oc sites you will find ducting setups ranging from cardboard to sheetmetal, mostly in the form of shrouds. The Alpha's with their outward airflow, seem to be custom made for this type of setup. If you apply an 80mm on your heatsink, and directly vent it out of the case, that seems to be one of the most efficient heat reduction things you could do.

So this work well enough with just a 80mm on the cpu do you feel there would be any benifit to one on the case or is it overkill...

So far I hadn't heard of anyone using a peltier without water (but then again I've only been here 5 minutes)
what size would I use and can It be run constantly?

Would this REDUCE the need for so many case fans trying to get it cool?

I had the perfect thing to make shrouds out of but I gave them away when I moved..

They were plastic speaker ports about 66mm round with a flange on one end and 4 holes in the flange to mount it.

They would have been ideal, I guess they weren't that dear I could buy some more..

 

[bdf24]

If you were to duct your cpu, You would'nt have as much need for all the case fans depending on how hot your video card gets. Because your taking the biggest source of heat and running it directly out of the case. I know this website has an article about ducting a PIII 600 with an Alhpa blowing down onto the heatsink. It is sucking fresh air from the side of the case onto the HSF.

http://www.overclockers.com/tips285

 

[kat]

i did this with my hedge hog and my swiftech and it made a great deal of difference in my system temp droped almost 10C cpu droped about 5c

ive only heard one point against this idea and that is if you dont have enough case fans with air comming in you will create negitive pressure in your case and this might suck dust into your floppy,cd rom and dvd player

before you hack up your case try it with a card board template and some duct tape, you might decide to go to water cooling later ,in which case you wouldnt need that big hole in your case ;D