Peltier Power/Performance, lotsa ?????

[Ani_Mator]

I've had a 172W pelt for about a year and, now I wanna use it. Here are the Specs. Got it from Danger Den

172W

Imax = 11.3 Amps

Qmax = 172 Watts

Vmax = 24.6 Volts

Delta Tmax = 69 (C)

Size = 40mm X 40mm X 3.2mm

What amperage would this draw at 12v, and how would it perform at 12v? I'd like to run it off my 480W Antec Truepower.

Gonna be cooling a 2.8Ghz P4, hopefully at 3.3Ghz or higher. 1.75vcore's the highest I'll go. I'm not looking for supercooling here. Maybe 25C at full load.
And about Sealing the socket. Will using Neoprene be enough? Or do I need silicone, dialectric grease and the whole nine yards?
Thanks in advance for any help you guru's might provide.

 

[Wicked Klown]

Yes use Dieletric grease and if you want put a bead of silicone around the socket.

 

[Ani_Mator]

Thanks for the insight Klownin.
I tested the Pelt assembly(not on CPU) for about 30min last night and the cold plate had about an 1/8" of frost on it after 10min. So I'm guessing the PSU is supplying anough power for it. Am I correct in assuming this?

I've been watercooling for over a year now, and feel I'm ready to go to the next level. Just want to do it right. I might go to a dedicated PSU later, with maybe a larger pelt, but want to see it running for a while first. Am I being too positive in my temp goal, or should I expect higher/lower?

Ambient temps are about 23C, case is about 28-32C. CPU says it's about 41C idle, and 48C load, which is Waaay inaccurate, by the gains I've gotten over aircooling, so I don't put much stock in that. Running a Maze 3, Eheim 1250, and Heater core and Shroud from Dtek Customs with enermax adjustable 120mm fan. Also got a GPU block from Danger Den on my 9700 Pro, which runs at 400/720 24/7(up from 385/690 with stock cooling).

Also, Most of the tech talk about peltier performance flys right over my head. Really need someone to explain my questions, on my level

 

[Warlord2]

hmm I dont think the atx psu is going to be powerful enough for the p4, the full 172w would still be pushing it at max volts. but hey go for it if you have everything, no harm in trying.

 

[Lt. Max]

the psu will only supply wit 12 of the 24 volts so only half efficiency no ? i think this will b too little for a cpu.. you should find a lower voltage pelt. ur PSU will b able to supply about 20 amps max..

 

[Since87]

The pelt will be drawing 5 Amps at 12V. It shouldn't be a problem running it off the PSU.

You won't get a lot of cooling out of it with the heatload you are talking about. I don't know what kind of heatload a 2.8GHz P4 at 3.3Ghz puts out. I used the Computernerd calculator to calculate the power consumption of a P4 2.53 with a FSB of 173 and Vcore of 1.7 V. The result was 105.1 Watts.

I calculate the CPU temperature at around 44.5 C using the setup you described with a heatload of 105.1 Watts. You wouldn't be a whole lot higher using water alone.

Using the 172 Watt pelt at 12V wouldn't be a bad way to cool a Radeon 9700, but a P4 at 3.3Ghz is likely to be a different story entirely.

 

[Ani_Mator]

Much thanx for the replies. I think I'll go ahead and give it a shot and see what happens. Heck, if I get 10C lower temps than I do now, It's better than nothing until I get a dedicated PSU and a larger pelt.

BTW. Is there any pelt out there that I can safely run on this PSU that will give me better temps than the 172W I have now? My PSU does 22A on the 12v rail.

 

[ssjwizard]

i think there is a 156W 12V pelt out someplace that will work better at the 12V psu for cooling your system.

 

[Opie420]

I have the same pelt running on my 9700 pro with a dedicated water cooling setup. It wants and needs LOTS of power. I'm running a dedicated Meanwell 200w PSU and it draws the 24v down to 19v. With a water temp of 35c the back of my card is barely cool to the touch. I would never consider trying it at 12v for my graphics card, let alone a CPU...

So my advice is to get a dedicated 24v power supply. Or I've seen a 226W 12V TEC which could be a lot of fun. I'm buying one next weekend in hopes of breaking 450mhz core on my 9700

EDIT: Here is the dedicated PSU I am using http://www.meanwell.com/product/SP-200/default.htm fits perfect in a 3.5" drive bay

 

[Warlord2]

damn I would think a 172watt tec would be plenty for any gfx card out right now. you can get a nice psu at becooling for a kick a$$ 226watt tec setup.

 

[Since87]

I have the same pelt running on my 9700 pro with a dedicated water cooling setup. It wants and needs LOTS of power. I'm running a dedicated Meanwell 200w PSU and it draws the 24v down to 19v. With a water temp of 35c the back of my card is barely cool to the touch. I would never consider trying it at 12v for my graphics card, let alone a CPU...

Opie, I'm confused. In this thread you say that the video card gets very cold. In this thread you say it barely gets cool. So which is it?

 

[Warlord2]

war would like to know too

 

[Opie420]

During bootup (which takes about 5 minutes with the prometia) I get condensation on the back of the card. But once XP is running the temp rises above zero (I actually use rivatuner because powerstrip maxes out around 400). Lately I have been waiting to turn on the 24v psu (which in turn powers on the tec and water pump) until the system is about to boot.

But I think I fried the peltier last night. I hooked up my old vapochill to the watercooling setup REAL ghetto hoping to finish 3dmark at 438mhz core (used zip-ties to hook up a t-bird waterblock to the vapo). I let it cool the water down to 8c before I turned on the prometia. But what I didn't realize is that the waterblock on the vapochill froze solid before the system booted up. I cranked everything up in the bios and right before saving it everything got really funky. Reboot and no post. I reached down and burned my finger on the 9700 waterblock. I let the vapochill's waterblock unfreeze and booted back up without turning on the vapochill, but there isn't any load on the 24v psu anymore (voltage reading 27.9V) and my water temps don't rise hardly at all. The card seemed undamaged, windows worked fine at 426mhz but benchmarks crashed. I'm pulling it all apart right now (posting from my old PC). Maybe if I'm really lucky the pelt still works.

Here are some pics. More to come when I have something presentable. My system is a mess right now.

 

[Ocelaris]

Why not just get a cheap PSU for the pelts?

Can't you get a cheap 300w PSU and join the 12v and 5v rails to get a 17v PSU? I think that would be more than enough for a spare 300w PSU to handle... Best, Bill

 

[Since87]

+12V - +5V = 7V

 

[Ani_Mator]

I was thinkin something like that. But maybe hooking the + line on he Pelt to the +12, and the - on the pelt to the -5. Would that work well?

 

[Paxmax]

Nope.....

Sorry, that won't work either. The -5V rail usually only supplies about 0,5 to 1 ampere. The current from the +12V rail would overwhelm the -5V and probably cause the protection to trip within the PS OR it will blow up !

Running the 172W TEC (24Volt version) at 12V would give you about 5,5 A. Total power input into TEC= 12*5,5 =66W.
Thats no match for almost any PC PS.

This is a guess though: Total amount of heat it will move at that power is roughly 90% of input power = 90% of 66 W == 60W.
My guessimate is that you've got around 60W of COOLING power at you hand when running that 172W TEC at 12V.
All in all it will probably work OK when the processor is in idle, but when overclocked and running loaded it will be much worse than air or watercooled alone.

Good luck though, using it for graphix would be ok.

/Paxmax

------------------------------
"Well.... at best, faith is only hopeful ignorance..."
-Giullermo del Toro

 

[Since87]

Pelt cooling capability is very nonlinear with voltage.

I calculate that the 172 Watt pelt will have an operating Q of 112 Watts when running on 12V. The pelt would only be drawing 60 Watts itself. It would probably be better than straight water cooling for maximum heatloads of 70 Watts or less. To add some safety margin, I would not use it on a heatload greater than 60 Watts.

Different numbers, but they still indicate that this is not really enough cooling for a CPU, but more than enough for a GPU.

BTW Good post Paxmax.

 

[Ani_Mator]

So, It's probably a good idea to use a pelt with rougly twice the wattage rating than the cpu outputs?

Do use guys think this 156W pelt would do better than the 172?

Imax = 16.1 Amps

Qmax = 156 Watts

Vmax = 15.8 Volts

Delta Tmax = 69 (C)

Size = 48mm X 48mm X 3.4mm

 

[Since87]

Yes, it is a good rule of thumb to choose a pelt with twice the power rating of the device to be cooled.

The 156 Watt pelt is definitely better than the 172W pelt if you are going to run it at 12V. (roughly 10C better for a 70 Watt heatload with very good watercooling.)

You can get more cooling out of the 172W pelt if you can come up with the higher voltage though. The problem is power supplies in the 12V to 14V range are readily available. Power supplies in the 16V to 19V range are a lot harder to come by.