Hidden dangers of a peltier

[Stoanhart]

Hi,

I just bought a XP 1800+ system (Actually, I bought the parts. Building it myself). When I purchased the parts, I never even though of overclocking and just bought a basic HSF and 1 80MM chasis fan. Im expecting CPU load temps at around 55C.

Anyway, after coming to overclockers.com, I found out this wouldn't be enough. I now want a watercooling setup. I haven't decided what kind yet, but I want a peltier in there.

I was checking prices, when on Heatsinkfactory.com, it said that I needed extreme colling to get the hot air away from the CPU and out of the case. This is for a 78 watt peltier, as I only have a 300W PSU.

I know a peltier moves heat from one side to the other, but does it also generate heat? Also, do I need extremely good ducting if I plan on using watercooling? Are there any other dangers I might not know of when it comes to using a peltier? Can I use a stronger peltier with a 300W PSU.

I'd appreciate the help. Im gonna overclock this thing and mod the case, a basic 4 bay, 2 floppy 18 inch 300W ATX case. I plan on w window, a kick @$$ painjob, and some LED fans.

[Diggrr]

Welcome to the forums!

Do not try using an 80 watt peltier on an XP1800! The processor will overpower it very fast, and die an ugly smoking death without the correct (high performance) heat sink.

You should probably start with a good air cooler, a very good one. Some of the other guys can help you with that, I watercool.
I just wanted to stop you before you bought.

When cooling a peltier, you have to get rid of the heat the processor is pumping, and the heat the pelt makes.

I'd suggest going to the front page of this site, www.overclockers.com and checking out the tips and how-to link at the top. There is a very good bunch of info here. Keep in mind that if you see one using a peltier around 80 watts, they're using a much smaller/cooler running processor.

There is one person in here that I know of using an 80 watt peltier on his XP1800, he uses the MCX462 from Swiftech. Judging from the size of this heatsink, he's just handling the power involved, but I'd say get it...it's working. You can add the peltier later, after you get the aircooling tweaked out correctly.

[Diggrr]

After rereading your post, I had a couple more thoughts I'd like to mention.

The articles at the link I gave are to give you an idea of what you'll need. There's litteraly hundreds, if not thousands of ways to setup a cool rig. You may find you'll be happier with air cooling, maybe not.

The guys in here are very happy to answer questions, but reading the articles gives you an idea what to ask, and the parts that are involved.

If you still would like to go with a watercooled rig, great. Just know you can cause real damage to your new equipment if you don't take your time and gather some information first. We're happy to welcome another Overclocker to the fold.

Again, Welcome to the forums!

[muddocktor]

I will be building my first watercooled rig(with a 120 watt pelt) after Christmas. I did a lot of reading on the subject before deciding to go watercooling because it is so easy to ruin a bunch of good equipment with uninformed or poor choices in equipment. I will be powering my peltier with a separate 24 volt psu(it's a 24.6 volt pelt) so I won't be have psu problems. Also, from everything I've read, it's best to have around double the wattage on your peltier over what your proc is using. This will be a P3 tualatin system because it doesn't have as high a heat and power requirements as an Athlon system.

[Robbie]

I wouldn't use an 80 watt pelt with only a 300 watt ps. Your CPU is already sucking up alot of power, and if you use an AGP video card those use alot of power.

Just my two cents.

Rob

[Billvill]

I use water cooling and would suggest trying it without a pelt. I do not use one and have great temps ( CPU usually about 39 ) . Make sure you use a good thermal compound ( artic silver ) between the block and cpu .

For what it is worth , Billy

[Wonko The Sane]

A dedicated power supply for the pelts is definitely better. you can pick them up pretty cheap from e-bay. That's what I did and I got a 15v 12A ps for like $28 with shipping.

[Silver]

I would listen real good to these guys and not put that 80w on that beautiful xp 1800. Great way to ruin a smokin chip.

[Stephen Castles]

i'd say a 120 watt for good temps, A 156 watt for extreme cooling, and a 172 watt if you just want to freeze the hell out of the chip. you CAN'T run any of these off a 300w power supply, you need a stand alone power supply, Like a hobby type power supply. You also need to protect from condensation. make sure you get a potted peltier, these are safer. For an XP1800+, you need at least a 120 watt for overclocking purposes.

[Stoanhart]

Thanks all of you for the help. I'm far from making any decisions. I may or may not use a pelt. I probably wont combine the two (pelt and WC), since they both seem to have their dangers and I'm a bit nervous about it. It'll either be an aircooled pelt or a WC system, most likely closed, not a bong. First I have to make it work, though.
I've had horrible luck with computers (one of the reasons I'm nervous). Every time I have ever bought anything electronic, something didn't work. Even my Dreamcast last christmas had to be exchanged. Anyway, when I got my parts, and had it assembled, it wouldn't start. I could press the power button, and not a single LED, fan, or device so much as did a thing. I figured it was the PSU, and like an idiot, RMAd it without testing. I got the new PSU, still didn't work. Voltage tested the PSU, it works. CRAP! I made sure EVERY wire was plugged in correctly, believe me there is no mistake. I called tech support, they told me take everything out of your system, even CPU, and try to turn it on. Nothing happened. So, the motherboard has been sent back,a nd the new one should arrive tomorrow (EP 8KHA+). I'm praying it will work. If not, you can expect me on the forums. Oh yeah, I made sure it wasn't the button on the front either, by plugging the Reset Switch into the Power On spot and trying to turn it on like that.

Wish me luck!

[Diggrr]

Hey Stoanhart, I was looking for your reply back, I wanted to make sure I didn't discourage you in your new endeavour.

First thing to do is get comfortable with your system at stock speeds and cooling...small steps. Learn how the airfow effects your cooling. Study how the water cooling rigs are assembled and what to look for with them.

There's plenty to learn, and I wasn't sure where you were at on the "Geek Scale". Stick around, read the posts, ask questions.

I know the hot rods look cool, but everyone needs to start with a Ford first hahaha. I really hate to see a beautiful computer die.

[Stoanhart]

Don't worry, I don't discourage that easily. I've got great plans for this system, and I will keep it alive. Before this thing reaches the end of it's life, I plan on having that hot rod. Window, LED fans, Watercooling (or pelt/air), blowholes, Cooling System Controller (http://www.overclockers.com/articles292/), custom paint job, etc. Since discoverying this forum, I've spent all my spare time learning what I can, and I hope soon i'll be the guy with 1000 posts helping out the newbies!

[Silver]

Diggrr and the guys are right on, get some experience under your belt first. There may be some costly lessons ahead if you do not take your time. The guy running on the mcx462 is using a pelt on the same power supply and he is right on the edge. I thought it was a xp1600 though. Never mind, I believe his name is david.

[f155mph]

Hey Dude,

You might also want to consider the noise level before you jump into anything. I got a Swiftech 462 with a 68 cfm delta on it. It working great but the noise is driving me crazy. So now I am setting up my first H2O system. I got most of the parts but still waiting for my cube case to arrive. Anyway if noise is not an issue just get a good hsf like swiftech or Sk6. Go to sidewindercomputers.com to hear how loud the fans are. Make sure you do your homework, unless you got $$ to burn.

:cool:

[Stephen Castles]

you might just start out with a basic watercooling system, and peltierize your video card or something just to get some experience.

[Yodums]

They all have good suggestions although mine is different.

Just don't be nervous when setting up stuff because the more nervous the more cautious you'll be and they can end up you trying to be too careful and end up breaking something.

Don't trust over yourself saying "Did I do it right or not." You will have to trust yourself on this one and just do everything one step slower and more carefully.

If you want to put a peltier it is advised you use water cooling with it, since the peltier will not cool as well with air cooling and think of the noise.

Although water cooling is probably an easy setup and most efficent cooling.

And your system will be very peaceful and quiet.

Just don't let fear hold you back in anyway.

[donny_paycheck]

Check my sig. An 80 watt TEC works great with the XP1800+. Palominos don't get nearly as hot as tbirds and the 80w is enough. I power it with the case PSU - why I got the 550w enermax monster. I air cool it too. The MCX462 is pretty much acknowledged as the extreme bad as$ of air cooling and it's enough to get the 80w from the TEC plus the 40-50w of the CPU off into the air and then out of the case. Neoprene works well for insulating. Make sure to use dielectric grease and also silicone RTV or conformal coating around the socket. Making everything below the cold side airtight is the goal there. My temps:

XP1800+ (1533) @ 1800 (150x12), 1.75v core:
idle in CMOS: 4C
full load (Prime95) in xp for 20 minutes: 9C
temps measured with digidoc thermocouple drilled into cold plate

Air cooling a TEC works well if it's a low-wattage module like mine. Anything more and these guys are right - water cool it. Since you've got the same chip as I do I say go with 80 watts, a big case PSU and think about an awesome air cooled HSF unit that bolts through the board. Of course I'm biased, but it'll save you $$ and time, plus you'll still get temps WAY below ambient. Water cooling is, of course, awesome. I'm just too lazy to do it. I wish I wasn't. Here's a pic of mine, but with an older MC462 HSF (it still worked pretty much just as well):

[flounder43]

I just got dyslexic for a second and read the thread subject as "The dangers of a hidden peltier"!!! Errrr, to much beer last night, I guess...;)

[donny_paycheck]

Originally posted by flounder43
I just got dyslexic for a second and read the thread subject as "The dangers of a hidden peltier"!!! Errrr, to much beer last night, I guess...;)

crouching heatsink hidden peltier

[flounder43]

Originally posted by donny_paycheck


crouching heatsink hidden peltier

It hurts, it hurts...laughing out loud!

:p

[Diggrr]

Hey Donny, I was hoping you'd chime in here, you're the one I was refering to. Didn't know if it was a palomino or a t-bird.
I'm kind of thinking that since you're pushing the 80 watter as far as it can go, wouldn't the t-bird be too much?
Also, I don't know if a 120 watter could be air cooled well enough.
I have seen 112's though.

[Stoanhart]

Thanks to everyone for all the awsome input. Some great ideas. I'm definately going to watercool. I think it'll be a basic, in case system. Ill make a Waterblock at school, get a copper coldplate, and probably use the Beckett G90AG water pump with .5 inch tubing and an old heatercore. I'll put my current Volcano II on top for a failsafe/additional cooling. Eventually, I'll probably put in an 80Watt Pelt, but they still scare me. Condensation is the enemy! I'll most likely keep the PSU i have now for the comp, and run all cooling gear off a second one with a control pannel in one of the bays.

[flounder43]

Donny, I like your setup, what did you do to deal with condensation problems?

[donny_paycheck]

Originally posted by Diggrr
Hey Donny, I was hoping you'd chime in here, you're the one I was refering to. Didn't know if it was a palomino or a t-bird.
I'm kind of thinking that since you're pushing the 80 watter as far as it can go, wouldn't the t-bird be too much?
Also, I don't know if a 120 watter could be air cooled well enough.
I have seen 112's though.

With the hot side temps reaching 30-40C I think the HSF's at the edge of it's envelope. Maybe you could run a 112w and be safe, but I'm suspicious that anything more than I've got right now would be too much for the HSF to handle and end up making the cold side hot. Yeah, I think the tbird would be way too much of a load for the 80w to handle. A 120w TEC might work but I'm not going to push air cooling any further than I have so far....not until I finish ghost recon, at least.:D

[donny_paycheck]

Originally posted by flounder43
Donny, I like your setup, what did you do to deal with condensation problems?

Neoprene, silicone RTV and dielectric grease to fill the gaps. I tried to make it as airtight as possible:
*edit: I know it's messy but it works and the insulation keeps it colder too.

[ButcherUK]

Originally posted by donny_paycheck


With the hot side temps reaching 30-40C I think the HSF's at the edge of it's envelope. Maybe you could run a 112w and be safe, but I'm suspicious that anything more than I've got right now would be too much for the HSF to handle and end up making the cold side hot. Yeah, I think the tbird would be way too much of a load for the 80w to handle. A 120w TEC might work but I'm not going to push air cooling any further than I have so far....not until I finish ghost recon, at least.:D

An 80W TEC would just be a nice heater for a tbird, you hit 80W at around 1.4G if you run at only 1.85V, higher volts and higher clocks add more heat. Personally I wouldn't use anything below a 172W, dual 120s or a 220 is even better.

[donny_paycheck]

Originally posted by ButcherUK


An 80W TEC would just be a nice heater for a tbird, you hit 80W at around 1.4G if you run at only 1.85V, higher volts and higher clocks add more heat. Personally I wouldn't use anything below a 172W, dual 120s or a 220 is even better.

You mean two 120 watt modules stacked in series? Damn, that's some horsepower....maybe I should look into water cooling.

[ButcherUK]

Originally posted by donny_paycheck


You mean two 120 watt modules stacked in series? Damn, that's some horsepower....maybe I should look into water cooling.
No, series TECs don;t work, I mean two 120s in parallel (makes a 240). Parallel TECs give bigger max heatload, Series TECs give bigger temp difference. You have to stack big on small though and it's not practical for CPUs. What I want to see is a dual 220 setup :)

[donny_paycheck]

Originally posted by ButcherUK

No, series TECs don;t work, I mean two 120s in parallel (makes a 240). Parallel TECs give bigger max heatload, Series TECs give bigger temp difference. You have to stack big on small though and it's not practical for CPUs. What I want to see is a dual 220 setup :)

Yeah I was thinking of the stacking I've read about being done to attain lower temps.

[Silver]

Donny, this is what I have been looking at and 120s can be powered with atx power supplys (which are readily and cheaply available). These supplies would also give the tecs head room on amperage.

[Stephen Castles]

if you use a ATX 300w power supply to run a pelt, be aware since it's only about 12.25v , your not gonna get the full watts out of the pelt, secondly, dont use a cheap power supply, cheapies might have an early failure running at that load, plus the chepos dont put out as clean power as a better one, clean power will keep you peltier running longer. I would recommend a sparkle 300 if you choose the ATX route, they are cheap, but good.

[donny_paycheck]

Originally posted by Silver
Donny, this is what I have been looking at and 120s can be powered with atx power supplys (which are readily and cheaply available). These supplies would also give the tecs head room on amperage.

Doesn't the most effecient voltage that a TEC will operate at increase with it's wattage? Like my 80w peaks at 12v but I've seen the big 172s use like 18-20 volts sometimes.

[Silver]

Ok Donny, I just ran out to get the volt and amp on a 118w tec. Here we go 118w at 15.8v 14amps. This would work out at (hope the math is good) 12/15.8=.759 14ampsX.759=10.626 amps. Now if I give myself 110% on the amperage I get 10.626x1.1=11.69amps. There are many power supplies available that can supply 12 amps on the 12v. Now (and I do not know this to be true) if I take 118wx.759 I get 89.56w per tec. Not too terribly bad to cool. 89.56x2=179.124w. Now if I get somewhere between 80-85% efficiency on the thermal transfer then I am looking at 143.3w to 152.26w and this is exactly where I would like to be in order to have a shot at 1.8Ghz on this t-bird 1.4. Now most everywhere you check maximum energy efficiency is achieved at 75% of rated power. I have checked and there are many power supplies that can achieve these numbers with plenty of amperage to spare. The dual setup would of course entail dual power supplies for the tecs but this can be done at a substantial savings. The problem for me would be do I wish to take up the whole back of the competer for psu's. I am hoping to cut them down and insert two psus into two of the six 5.25 bays. This allows for only one located in the stock area and all fans and whatever else may be located normally.

Now the bigger question for me is handling 140wcpu + 145w =285w total heat to disipate. I believe that my present bong setup will handle it but am not sure about this if I move all to the case. I would look to those with good experience in the water cooling and pelts to help me with this. I have some ideas but not enough info as of yet.

[donny_paycheck]

Originally posted by Silver
Ok Donny, I just ran out to get the volt and amp on a 118w tec. Here we go 118w at 15.8v 14amps. This would work out at (hope the math is good) 12/15.8=.759 14ampsX.759=10.626 amps. Now if I give myself 110% on the amperage I get 10.626x1.1=11.69amps. There are many power supplies available that can supply 12 amps on the 12v. Now (and I do not know this to be true) if I take 118wx.759 I get 89.56w per tec. Not too terribly bad to cool. 89.56x2=179.124w. Now if I get somewhere between 80-85% efficiency on the thermal transfer then I am looking at 143.3w to 152.26w and this is exactly where I would like to be in order to have a shot at 1.8Ghz on this t-bird 1.4. Now most everywhere you check maximum energy efficiency is achieved at 75% of rated power. I have checked and there are many power supplies that can achieve these numbers with plenty of amperage to spare. The dual setup would of course entail dual power supplies for the tecs but this can be done at a substantial savings. The problem for me would be do I wish to take up the whole back of the competer for psu's. I am hoping to cut them down and insert two psus into two of the six 5.25 bays. This allows for only one located in the stock area and all fans and whatever else may be located normally.

Now the bigger question for me is handling 140wcpu + 145w =285w total heat to disipate. I believe that my present bong setup will handle it but am not sure about this if I move all to the case. I would look to those with good experience in the water cooling and pelts to help me with this. I have some ideas but not enough info as of yet.

So the 118w module peaks in effeciency at 15.8 volts, but won't a higher wattage module have a higher peak effeciency voltage? Like a 156w at 18v or something. After looking at modules everywhere it always seems that this is the case.

[Silver]

Yes, here is an example: 156w at 15.8v and 18.5 amps. This works out at 12/15.8=.759 thus 18.5a x .759 = 14.04a now if I take 14.04a x 110% (for overhead) = 15.44a. Now if you look around at psu amperage on 12v line you will find many that can handle 16amps. You will not however find many with an amperage rated much above this. Once you get into the 172s then you are looking at dedicated external units or possibly tieing two at power supplies together.

The 156 will give 118.4w of cooling potential per tec. )156x.759=118.4)

It seems to me that the two 118s is something worth considering at least in my case and with the xp running a little bit cooler then this set up would allow for a future upgrade on my part.

[TruckChase!]

Originally posted by donny_paycheck


So the 118w module peaks in effeciency at 15.8 volts, but won't a higher wattage module have a higher peak effeciency voltage? Like a 156w at 18v or something. After looking at modules everywhere it always seems that this is the case.


Nah, they make them in all sorts of different Vmax's... the required Amps will just raise in accordance.

[Silver]

The last is of course true. I did however use a real life type 118 and 156 that is available on the web.