Frost!

[Blackima]

Firstly: sorry if this doesn't interest any of you guys or this seems really trivial but I'm so darn chuffed, I felt like sharing :p

Well here it is. Right next to me, nearing the end of May, I have frost:

Seeming you're in the overclocking forum, you probably already know what this is. But for those who don't know, it's a peltier also known as a TEC (thermo electric cooler). What happens is you pass current through it, thus causing heat to transfer from one side to the other, making one side freakishly cold and the other side freakishly hot.

I've had this 170W peltier for almost a year now and the coldest I've been able to get the "cold side" has been about 10-20C (not very impressive) so all I've gotten has been a lot of due forming

But this summer I was determined to have another go. I had failed before because a) my power supply I used to power it simply wasn't powerful enough and more importantly b) I was not able to keep the hot side from getting too hot.

This is without a doubt the toughest part of dealing with peltiers (I reckon), with powering and condensation coming in 2nd and 3rd. Peltiers try and create a temperature difference between the two plates. My one can have a maximum theoretical temperature difference of 69C. This means if the hot side of the plate is at 100C, the lowest the cold side of the plate can be is 31C. If you can keep the hot side of the plate below 69C then the cold side of the plate can go into sub-zero temperatures.

Now trust me, these peliters produce a lot of heat. This one on it's own produces up to 170W of heat. Your typical prcoessor produces about 100W and we all know how hot those get. So last year I had naively thoguht I could use my old 3000+ heatsink to keep the hot side cool.

I was wrong.

The heatsink rapidly got incredibly hot (too hot to touch) and the cold side ended up being mildly warm!

This time I was going to make no mistakes...Well I did, but not as many as last year.

I researched into heatsinks and found a lovely little ?17 heatsink and fan called thearctic freezer pro 64>. I know that there are better heatsinks out there, but this one specifically said it could dissipitate up to 250W of heat. So for a peltier, which on it's own produces up to 170W of heat, this was perfect. And was mostly right.

Mostly

Turns out that while my peltier is 50x50mm , the base of the heatsink was only 40x40mm. Argh! This would not do. Peltiers do not conduct especially well (i think) so any part of the hot side not in contact with the heatsink gets very hot and will not allow heat to flow to other parts of the peltier which are in contact with the heatsink. This is what I mean:

So, pretty simple solution to the problem actually. Just plop on a piece of copper 50x50mm in between the peltier and heatsink. As copper is a FANTASTIC conductor of heat (almost twice as good as aluminium) I hoped that it'd be able to transfer heat from the "bare" ends of the peltier to the part of the peltier where heat was being taken away by the heatsink. And this is what I got:

And so now, my little peltier which I got a year ago is now producing sub zero temperatures:DD

Here's a bit more frostage:

[edit] lol, that post started off as a bit of a disaster. Clicked "post topic" instead of "preview topic" while I was in the middle of writing it and thus the last half was just a mad rush to get everything in as quick as possible:pp

Edited May 18, 2006 by Blackima

[asha_b]

Unreal

[Guest]

ok...so now what're you suppost to do with the frost?

[Blackima]

ok...so now what're you suppost to do with the frost?

Lol, good question :)

Usually, people use peltiers as an extreme form of cooling their processors

So the next step is to pop this onto your processor to bring down temps close to 0C and thus being able to do some immense overclocks

Right now I'm testing things out and not confident enough with the peltier to put it into my computer. Though I am considering attaching it to my watercooling loop so as to cool the water down to sub-ambient temperatures and thus bring processor temps down.

[NiceCarpet]

Thats some nice work there indeed (Y),

If you where to put that on your cpu or such, sort of asking I noob qestion I think, but how would you put it on (The sub zero heat sink and the cpu?) and how do you plan to keep the arctic freezer pro 64 on it, that ruberband does not look to strong or is it fooling me?

Eather way, good work

[Blackima]

Thats some nice work there indeed (Y),

If you where to put that on your cpu or such, sort of asking I noob qestion I think, but how would you put it on (The sub zero heat sink and the cpu?) and how do you plan to keep the arctic freezer pro 64 on it, that ruberband does not look to strong or is it fooling me?

Eather way, good work

Don't worry, they aren't noobish questions at all, all very valid.

The little setup I photographed was a testing step to see whether I could get this peltier to get down to sub-zero temperatures at all. The rubber bands are just there to stop the rather top-heavy heatsink sliding off during this testing phase :p

When you put it into your computer it's an entirely different ball game. As mentioned before the peltier uses up 170W of power and thus gives off 170W of heat on the hot side. The heatsink/fan is designed to dissipitate up to 250W of heat so can happily take care of this heat.

However if you put the peltier on top of the processor, you've got the heat from the processor being "sucked" up the peltier into the heatsink as well as the heat the peltier produces on it's own. A processor can give off about 100w of heat. Which means 100w of heat is going from the prcessor into the peltier. The peltier pumps out that 100w of heat into the heatsink as well as the peltier's own heat (170w)

So 270W of heat going into the heatsink. The heatsink can only dissipitate 250W. There's a problem. This is the reason why you rarely see anyone use air cooling to cool their peliter in their computer. Air cooling just isn't efficient enough! Which is why if you ever pop a peltier into your computer the hot side of the peltier has to be cooled with something more efficient like a watercooling setup which can quickly take the heat away outside the case and into large radiators which can dissipitate MUCH larger amounts of heat.

There are other problems as well such as condensation forming around the peltier and thus water forming on the motherboard. So craploads of foam and insulating grease is used to prevent the water from basically destroying your computer :p

So basically I'm not planning on putting it directly onto my motherboard. At least not yet. The watercooling setup I have is a VERY noobish, cheap, premade one which isn't much more efficient than the heatsink I used. So I'm more likely to use the heatsink+peltier to cool the water itself in my watercooler. If the water in the watercooler is cooler then the processor gets cooler :)

I'm taking this slowly as I don't have much of an income so I can only buy parts in 6month / 12 month intervals :p. This'll do for know ^^,

[NienorGT]

How mush it cost to get a thing like that?

I can't imagine how must powerfull would be my PentiumD 805 at more than 4GHz... O_O

[Blackima]

How mush it cost to get a thing like that?

I can't imagine how must powerfull would be my PentiumD 805 at more than 4GHz... O_O

The 170W peltier I got second hand off ebay for ?9.50 inc. delivery (a real bargain). I used an old 400w power supply I had and the "Arctic Freezer 64 Pro" heatsink set me back ?17

[NienorGT]

The 170W peltier I got second hand off ebay for ?9.50 inc. delivery (a real bargain). I used an old 400w power supply I had and the "Arctic Freezer 64 Pro" heatsink set me back ?17

WHHAAT???

Where I can get that thing in Canada???

For the Watt prob, I had planned to buy a Corsair Nautilus 500 whatercooling thing.

This can remove up to 500W...

http://www.hexus.net/content/item.php?item=4751&page=2

Edited May 19, 2006 by NI3NOR

[Circaflex]

Ni3nor: It really isnt worth it, once you put it on a CPU its best to use Watercooling not a heatsink and fan to cool the hot side. You also have to deal with condensation and usually have to buy a different kind of powersupply because you cannot run the pelt off your everyday psu with everything plugged in.

Here are a few examples with difference watt TECs cooling a modern processor which usually generate around 60+ watts of heat. Practice the formula on at least one of these examples before calculating Delta T for your own project!

*) A 40watt TEC cooling a modern processor generating 60-watts of heat.

Delta T = -34C (negative 34C). That?s an INCREASE in temperature on the cold side, so the processor would have been warmer than before! Using an under powered TEC can destroy the processor. Cooking your CPU with your TEC is NOT a good thing, avoid this common mistake.

*) A 60-watt TEC cooling a modern processor generating 60-watts of heat.

Delta T = 0 (no change in temp). Congratulations, you?ve accomplished nothing!

*) A 176-watt TEC cooling a modern processor generating 60-watts of heat.

Delta T = 46C. That?s a decrease in temperature on the cold side, making the cold-side 46C cooler than the hot-side. Not bad.

*) A 226-watt TEC cooling a modern processor generating 60-watts of heat.

Delta T = 51C. That?s a decrease in temperature on the cold-side, making the cold-side 50C colder than the warm-side. Even better, but it took a lot more energy from the TEC (28% increase from 176-watt TEC) to get an additional 5C (only 11% increase in Delta T).

Conclusions from the Examples

The larger the wattage of the TEC in proportion to the watts of heat generated by the heat load (CPU) the closer delta T approaches the theoretical limit of 69C. But, the closer you get to the theoretical limit (in this case 69C) the more and more watts it takes for the TEC to achieve it. Thus the less efficient it becomes. Fortunately it?s not like TECs were the kings of efficiency to begin with.

As we have seen from the example above, you must control the hot-side?s temperature to achieve a given temperature on the cold-side. This, however, can be more difficult than it seems.

Let?s say Bob wants to cool his XP 2000+ which generates 60-watts of heat. Bob just so happens to have a ?Magic Heatsink? that magically cools a heat load of 60-watts to room temperature (in this case room temp is 25C, remember that). Not a bad heatsink (must be a Thermalright). So Bob figures, ?If I attach this bad boy to the hot-side of my 226-watt TEC then I can maintain room temperature on the hot-side of 25C, then the cold-side will be -26C assuming a Delta T = 51C.? Bob is about to get a rude awaking.

What?s Bob?s problem? The heat load generated on the hot-side of the 226-watt TEC is not just 60-watts anymore (the original heat output of his CPU). It is the original heat output of the CPU (60-watts) plus the Cooling Power of the TEC (226-watts). 60watts+226watts = 286-watts of heat generated on the hot-side of the TEC. That?s enough watts to heat 1 liter of water by 4.1C in one minute. See Bob?s problem? Well, it?s about to become yours.

-

The Ultimate Guide to TECs

Edited May 19, 2006 by Circaflex

[:No-Frost:]

Well the peltier it's a prettygood way to cool the CPU, but you have to be carefull...

[NienorGT]

Ni3nor: It really isnt worth it, once you put it on a CPU its best to use Watercooling not a heatsink and fan to cool the hot side. You also have to deal with condensation and usually have to buy a different kind of powersupply because you cannot run the pelt off your everyday psu with everything plugged in.-

The Ultimate Guide to TECs

Awww... too bad...

Anyway... the upcomming Core 2 Duo will clash my system away...

Better to get that CPU and a new mobo and replace this P4D 805...

Will be WAY more powerfull, and WAY less complicated than all thoses "MATHS" things...

Still, where I can get thoses things? If it's not for the CPU, I can try others cool things with this...

[brad72]

I had a peltier system at one time called by ActiveCool AC4G it was manufactured and redistributed by I believe was Thermaltake (might be wrong on that one) but anyway I recently dug it out of my closet and took apart the Heatsink from the peltier and cold plate.

To my surprise it appears to be a dual peltier side by side as you can look at the sketch I did in Paint on the top (hot side) it is 2 separate peltiers on one solid what appears to be a ceramic plate on the bottom (cold side) with wires being attached to the negative on one peltier and on the positive on the other peltier with the + & - being linked with solder in the middle. I was thinking about removing the solder and carefully cutting the 2 peltiers apart. From what I can tell on www.activecool.com website they use 130W peltiers.

They use a pci card controller to control the fan speed and temperature of the peltier. Which they used some sort of temp probe in the 3/8" aluminum cold plate with copper insert.

I understand about what you are saying with the frosting and condesation. I was wondering though if using a less Wattage peltier one that was matched with the wattage output of the CPU would there still be condesation or would it be basically evaporated as soon as it was produced? I was going to look at either this peltier I have or one that is the same wattage as my OPTY 170. The peltier I have now is the exact size as the Heatsink base on my XP90c (Thermalright).

I am not worried about getting sub zero temp or even close but if I could get it around mid 20c<30c would there be condensation?

From my understanding is that the CCB1E 0550 VPMW runs a bit hotter than other OPTERONs which mine is idle at 45c and tops out between 52-55c under full load it is OCed to 2.65ghz on 1.32V and the same temps on stock settings as well....which I have heard with the cpu and mobo combo running dual SLI video causes some people temp problems and I feel as though I am safe on my temps...as I have seen on AMD site that that this OPTY is 110W which with my understand with what was stated earlier I have to add that to the 130w which in turn gives me 240w heat I have to disapate? Not sure what the Thermalright xp90c is rated at but if it was rated at 200w-240w would that work without producing condensation? and I believe like what was stated if the heatsink was over the 240W then it would keep the cold side of the peltier even cooler thus producing the frosting/condensation.

Maybe I am complete off track here but with what I have written here could you maybe direct me into a better understanding of things that would be safe. I am really not into going towards water cooling as of yet.

[Blackima]

After my recent successes, things seeming to be going downhill a wee bit :p

My initial plan was to first get my peltier to work properly and then see if I could use the peltier to cool the water in my watercooling setup down (10-20C)

However I had forgotten one very important thing about water: It doesn't like changing temperature!!

The reason why watercooling works so well is that it can take a LOT of heat energy and it's temperature doesn't change much at all. It takes 4,180 joules to change the temperature of 1 litre of water by just 1 degree C while it only takes 385J for copper and 900J for aluminium to cause the same temperature change. So when the water passes over the processor it takes up a lot of the processor's heat energy, while the water doesn't raise in temperature very much.

However this works both ways: it takes a lot of energy to raise the temperature....the same way it takes a lot of energy to lower the temperature.

So when I decided to connect the cold side of my peltier to the cpu block of my water cooler (no processor or anything, only the peltier) in the hope of lowering the temperature of my water, it took 30-60 minutes to get the 3kg of water to drop by just 7C!!!

I'm very dissapointing to say the least :(

And now I'm not entirely sure what to do

Perhaps I'm thinking about this the wrong way. Yes it takes a long time to cool all the water in my system by 7C, but that's not what matters anyway. In every second the cpu adds 100J of heat energy to the water (as it uses 100w of power). If I had a peltier in the water loop in means that every second 170J of energy is being removed from the water loop (as it can transfer 170w of heat). So what if it doesn't cause all 3kg of water to fall in temp? All I want to do is to cool the water down right before it hits the CPU.

Do you think this makes sense?

Anyway, I hope you guys are able to get something out of all this. I've always found the thermodynamic aspect of all this very interesting and have learnt a lot (and still learning) as I go. Hopefully you've been able to pick up on some of this.

And for those who are interested in getting a peltier. Yes it's a hell of a lot of work. But I've found it a hell of a lot of fun. If you do get one. don't get it thinking of what amazing effects it'll have on your processor, but get it out of curiosity of what this rather odd little piece of semiconductor can do. Peltiers ahve been around for a long time, but hasn't been used all that much, so there's plenty of room for innovation!

And in answer to brad's question on condensation: find out what the "dew point" in your area is. Once something goes below the "due point" temperature, condensation starts forming like crazy. Over here I can go down to 17C quite happily without a hint of condensation.

[KC]

Has anyone ever tried stacking peltiers? Place the cold side of one on the hot side of another?

[Blackima]

Has anyone ever tried stacking peltiers? Place the cold side of one on the hot side of another?

yup yup :yes:

I've seen a lot of people do that and seen people sell special cascade/stacked peltiers. Peltiers are complex enough, and the thought of more than one makes my head hurt :p

Here's a site that mentions a stacked peltier:

http://www.digit-life.com/articles/peltiercoolers/

[brad72]

Ok I just found out the dewpoint for my area today is 45F/7C so as long as the CPU stays above 7c there would be no condensation is this correct?

Does anyone know how much heat that the xp90c can actually disipate? can I rewire the peltier to run off the power supply itself it only has 2 wires a positive and negitive. I doubt I want to put a wire mod to run it from MOBO but if I was to use a 4pin molex would that work? which ones out of the four would I use? I have a very sturdy power supply that is 600w and never drops any rails.....

[Circaflex]

You cant run it off the same psu that is powering the pc sucks too much juice. And blacklima what exactly did you do to cool the water? Did you stick it on the res or something? I dont understand your logic of cooling water with a pelt, usually water is used to cool the heat off the pelt.

[Blackima]

Circaflex is right, it's best not to try running apelt from the same powersupply as your computer. You may think that because you have a 600w powersupply, that should easily handle the 170W of a peltier, leaving 430w "free" for the rest of the computer. Unfortunately it doesn't work that way. Usually a peltier runs off a single rail, for me the 12V rail, and each rail has a maximum power rating. The 400w psu I used for the peltier can supply only 216W to the 12V rail. So with a peltier in there that only leaves 46w on the 12V rail for any other components

For cooling the water, it was just an experiment (pretty much everything I've done so far is just experimenting). My watercooling setup is just resevoir>radiator>pump>cpublock. So what I did to see how well the peltier could cool the water, was remove the cpu block from the cpu and attatch the waterblock to the cold side of the peltier. So when I turned on the watercooler and peltier, the water would pass through the cpu block, being cooled in the process. It managed to bring the temperature of all the water down by 8C.

I always knew that most people connected the peltier to their cpu and used watercooling to remove the heat from the peltier. However I don't trust my cpu to my peltier as if the peltier lost power (as it often did in one of my tests) it would cause the cpu to overheat and burnout. A risk I wasn't willing to take. So I tried to see if there was another way of utilising the cooling power of the peltier (I have it, might as well use it).

I had found that my cpu was almost always 10C hotter than the water in my resevoir. On hot days when the resevoir was warmer, the cpu reached higher temps, but always around 10C hotter than the resevoir. I figured if I could cool the water itself down, then it would also cool the cpu down (heat from the cpu transfers much faster if the temperature difference is greater). I recognise that this method would most certainly not get anywhere near sub-zero, but would be able to bring the cpu down to as low as ambient which I would be real happy with.

Not many people have tried chilling the water as opposed to using the water to cool the peltier. I wanted to see if it was possible. I may still buy a GPU waterblock and attach it to my peltier so I ahve a resevoir>radiator>pump>peltier-cooled-gpu-waterblock> cpu-heated-waterblock. If I find it doesn't work very well, I jsut use the gpu waterblock on my video card and use the peltier as a drinks cooler :p

[Michael_C]

This is on plain air cooling with a Venice 3200+ at stock speeds, no special coolers needed. :p

[Circaflex]

And another one falls victim to believing the onboard sensors are right. Whats your ambient? I really feel that those are wayyyyyyyy off. Take a look here http://xtremesystems.org/forums/showthread.php?t=91438

[AkFuttySeben]

will the ice keep getting bigger and bigger until you have to chip it off? :)

[Michael_C]

And another one falls victim to believing the onboard sensors are right. Whats your ambient? I really feel that those are wayyyyyyyy off. Take a look here http://xtremesystems.org/forums/showthread.php?t=91438

The heatsink is cold to touch and the temp outside was -3oC, not sure what it was in my room but it was pretty cold.

[_sphinx_]

...

I think I'll stick with the fan...

[callumy]

The heatsink is cold to touch and the temp outside was -3oC, not sure what it was in my room but it was pretty cold.

:| :| :|

My god that is freezing (literally :whistle: )! How can you sit in a room at a computer while the temperature of your room is enough to keep your CPU under 20 degrees? -3 outside, well it mustn't have been much more inside!

Circaflex: That page about the incorrect sensors was mostly about the inbuilt sensor being about five degrees higher than an added modded sensor. This appeared to be cause by the fact that the CPU's sensor is right on the silicon and not external to the device. I read halfway down the page and then became bored - it was mostly utter crap. Who cares if the sensor is off by a few degrees. There is always a margin of error and you should never take what a sensor reads as gospel - look at speedometers in cars! And isn't an overstatement of the actual temperature a good thing? That way you won't push your device too far...

Cal