cooling peltiers?

[borat]

i have just been reading about processor cooling techniques and i am considering a peltier.does anyone know if you can just use a heatsink and fan with these things instead of a waterblock.i dont want water near my machine for obvios reasons and i dont need the sub zero temperatures acheived with waterblocks and peltiers. i was thinking of an 85 watt one but 150 watt is also an option. any advice appreciated. the reason i want to do this is so that i can run a near silent zalman fan on the top of it and have a superquiet cool and overclocked system without going to liquid cooled lenghts.thanks

[Greebe]

Yes this can be done... but not as easily as you currently think. Sounds like a plan when adding a high power pelt to a Zalman HS setup. But the biggest concern with implementing this 'plan' is that Pelts have a high end temp which must not be exceeded or it'll fry. If it does you will lose the cpu also (exception being later models of Intel cpu's). So taking that into consideration you would have to put a MUCH larger (and noisier) fan on the HS to dissapate the massive amount of heat generated. It's not just the cpu but the heat generated by the pelt itself (all additive).

This is the reasoning behind using a water cooling setup when utilizing pelts for additional cooling prowess.


Lest not forget the power which the pelt itself requires. 95% of the time you will need to add another PS (adding yet more noise).

[DuRaNgO]

Air cooled peltiers

As Greebe says, it takes a little bit 'o planning...
My second system (which used to be my 1st system ) is a P-3 700e slot 1 running @ 1053 using a Swiftech MC-1000 peltier setup with 2 LOUD fans, a blow-hole pointed directly at the hsf, a 400wt. power supply and another fan in the front of the case (can you say turbine )

Adding water to this setup would have lowered the case temp as well as the noise
jim

[ALBPM]

Forget about using a Zalman....

As Durango said you'll need a good solid Heat Sink and a delta fan.

Here's my Hedgehog all prepped up for an 83 watt Peltier.




Paul

[Greebe]

I'd put your Hedgehog up against a Zalman CMPS 3100G any day Paul

[Slougi]

I've been water-cooling since 6 months, and have never had a problem. The computer will be so much more silent as well.
I haven't tried peltiers though

[borat]

the main idea was to be as quiet as possible so i guess air cooling is out of the question if it involves delta's.so watercooling is the only option.surely the hotter the heatsink is the more heat it can dissipate so if the heatsink is at say 70 degrees C then it will be able to dissipate far more heat than at 40 meaning that it might be possible for a normal zalman with quite fan to deal with the peltier and processor or am i talking rubbish?

[Greebe]

I think the problem lies with 'quiet'... you're not going to have it when cooling a CPU HS/Pelt with enough airflow to prevent it from burning up. It can be reduced by going with a larger fan but quiet won't be part of it's vocabulary (yet another reason to go with water cooling

[KvHagedorn]

I hate noise. I used to think it was tres cool to have 15 fans whirring away in my server case here, but I can't listen to music or anything. I would love to find a minifridge with zero humidity to use as my next case.. The thick insulated walls would help defay any noise from what few fans I'd need to use. Anyone have any ideas? What about a wine case?

[Greebe]

Using a fridge in that manner would be horribly ineffecient Chuck. You would be better off with water cooling with a peltier.

[Wombat]

Originally posted by borat
.surely the hotter the heatsink is the more heat it can dissipate so if the heatsink is at say 70 degrees C then it will be able to dissipate far more heat than at 40 meaning that it might be possible for a normal zalman with quite fan to deal with the peltier and processor or am i talking rubbish?

Sounds like rubbish to me. Although the heatsink may dissipate heat to the air more quickly thanks to the higher temperature gradient, the heatsink has to take the heat from somewhere, and a hot heatsink will not cool its intended target nearly as well as a cold one. Also, your CPU isn't putting out nearly as much heat as the peltier would be.

[borat]

i see your point wombat but these guys got it to work really well with a heatsink/fan C/W rating of just under0.3 this is similar to a zalman and he got really low temperatures from this.
i want temperatures of around 20 degrees more than this at max so it could possibly work:

http://www.gideontech.com/guides/peltier/

ps how many watts approx does a 2 gig p4 produce and how many does a radeon 8500 produce?

[borat]

ok so here are the calculations i have made based on the quoted website:
a p4 produces about 50 watts of heat
therefor a 100 watt peltier is needed
100 + 50 = 150 watts total
heatsink temp = c/w rating * totals watts + ambient temp
c/w for a copper zalman flower = 0.28
so heatsink temp = 28(ambient) + 0.28 * 150
= 70 degrees C
this sounds reasonable as the cpu will be a lot cooler than this
so maybe it is in fact possible

[Dr Mordrid]

hehehe....

maybe I should loan you one of my astronomic Peltiers.

It cools the big scopes CCD to about -30C on a warm night

Dr. Mordrid

[Greebe]

c/w for a copper zalman flower = 0.28
so heatsink temp = 28(ambient) + 0.28 * 150
= 70 degrees C

Problem... this CW rating on the Zalman is at the very best low compared to what others have tested. I myself have got it down to ~0.18 but that's with a 120mm 136cfm fan ducted around it with the case open. Other have tested and gave it a cw rating of somewhere between 0.38-0.54! Additionally the deltaT max of the typical pelt is ~79c (disentegration point) based on Tellurex's website. This gives you headroom of only 9c. Now you calculation of 28c case ambient is nice but not typical. It's normally in the 30-34 range which would drop the headroom down to only 2 - 7c. Now factor in changes in roon temp and the safety margin could easily be exceeded unless a blowhole is added blowing cool air in.

The point of having a pelt is to achieve cooling results much greater than what is attainable through passive cooling techniques. Meaning that the lower you hold the peak max temp the lower the cpu will be cooled.

To me having a space heater in my case is not only impractical but will put a strain on all other componets.
And the noise... OMG the NOISE!!!

-------------------- edit

Gave this some additional thought...

note: the Zallman sounds like it may work at first glace. But since the base has a narrow copper strip made up of thin copper plates held together by two thin aluminum blocks the hot side of the pelt will not dissipate the heat as it's intended and thus dTmax most likely would be exceeded. Sooooo in this case I would suggest looking for a different HS (like Paul's HedgeHog).

You may wish to read up more on pelt cooling...

http://www.tellurex.com/resource/intro9.htm

BTW you are not going to find a pelt that exceeds 78 watts... any company that specs a higher power rating is full of marketing gumbo