Anyone Peltier instead of using a radiator?

Farleytron said:

Does anyone know how to calculate the hot side thermal output of a peltier at full load (maximum)?

Click to expand...

You need the TEC's specs to know this. You should be able to find out the following specs:

dTmax (Maximum temperature differential between the hot and cold side)
Vmax (The voltage across the TEC at dTmax)
Imax (The current through the TEC at dTmax)
Qmax (Maximum heat pumped in Watts)

For a 172 Watt TEC these specs are:

dTmax = 67C
Vmax = 24.6V
Imax = 11.3A
Qmax = 172 Watts

So if you were running it full out with no heat flowing into the coldside, the TEC would be drawing 278 Watts. (Which shows up as heat on the hotside.) If the TEC is pumping 100 Watts of heat while powered at Vmax, the heat showing up at the hotside will be around 378 Watts.

If you really want to understand this stuff, this thread is a good place to start.

Farleytron I believe you have my stapler. The avitar is funny.

I'm still using my pelt chiller, I'm still happy. Look here to see what I have.
My experience suggests that you need 175 watts of pelt cooling to handle that cpu.
wj

Hmmm.... Interresting. I'll have to read more about this later.

Since87 said:

So if you were running it full out with no heat flowing into the coldside, the TEC would be drawing 278 Watts. (Which shows up as heat on the hotside.) If the TEC is pumping 100 Watts of heat while powered at Vmax, the heat showing up at the hotside will be around 378 Watts.

Click to expand...

Ummm, I don't believe that's 100% correct buddy. Because a device pulls a load of 278 does not mean that all them watts are wasted as heat...some of it actually has to be running the circuit and returning back through the neutral (or negative) wire. Even a single nichrome wire heater would only give off a percentage of it's wattage as heat. Otherwise, you could disconnect the ground wire after it started, cause it wouldn't be needed anymore as all the electricity going in would be converted to heat.
A TEC's efficiency is abhorent, but it's not zero (zed), Only government is 0% efficient.

WYMJYM LINK = GOOD WORTHWHILE READ

be sure to scope out wymjym's link if you are interested in this thread, i visited his site when i read the original "not too extreme" thread. it is a good, well executed setup.... of course it wouldnt be very cost effective, but for someone like him who had the parts around anyway, it was a fun project im sure and he went about implementing it successfully. it proves (somewhat) what has been doubted in this thread, that is, it proves that peltier waterchillers can work if set up correctly. of course, the ill-sayers were probably referring to the fact that you can spend about the same amount of money, if you dont have the parts laying around already, and get a better cooling solution.

for those who don't want to visit his link, the important difference with his setup is that the pelts are still being watercooled, when i believe most probably assumed (i'm assuming) the "water-chiller pelts" would be aircooled, but wymjym used a double water loop - one on the waterchilled side, and one on the hot water side. the heat exchange capacity from water to air by means of a heatercore, and moderate fan use, is greater than a heatsink. This is enough in this setup to remove enough heat from the hotside of the tec to keep the coldside just above the dew point... and probably colder if he ran his setup at full tilt.

farleytron - long post, but read this

I'm changing topics now, so excuse the seperate posts...

The reason everyone is telling you it can't be done, farleytron, is because doing it so it would work would be fairly expensive and perhaps not the best way of doing it... and they are right, especially concerning your method - the way you are discussing doing it simply wont work for two reasons. One, the pelts you are talking about arent strong enough. nearly matching heat output to the power of pelts in use will get you hardly any, if any, cooling capacity; most likely it will act as a heater... the lowest i would consider on a recent amd proc is a 172 watt tec (or equivalent - 2x smaller tec's), but 226 watt would be a better choice; two, the amount of heat that needs to be dissipated cannot be done by such conventional means (with a heatsink and a fan).

i like the idea behind the idea you had, to a point, for a few reasons. i like the idea of simply having a waterblock on the cpu, and not messing with sandwiching the tec in there, it simplifies the tim joint and i like that. so i would prefer a tec waterchiller to one integrated into the waterblock assembly if i were considering employing a TEC in my cooling.

however in your original idea, as i said, air cooling a tec is no way to go to get good results in cpu cooling - people have tested air cooling pelts, the results havent been good from what ive seen. if you could dig up some of these tests perhaps you would be more convinced one way or the other. if you looked at wymjym's setup then you see how you can over come this... all it takes is a couple extra waterblocks, some extra tubing, an extra pump, and a radiator. i really like how he did it, i especially like the accuracy with which he can control his water temperature to prevent condensation.

Does anyone know how to calculate the hot side thermal output of a peltier at full load (maximum)?

Click to expand...

if you want some real anwers to this question, you can try pm'ing doc. he is a very smart man and is extremely patient in explaining the various equations involved in these sorts of peltier calculations. you could also do a search for his postings as they often discuss peltiers. he explained a lot to me, but after looking at what he told me, i discovered i wasnt going to have any fun really figuring out how to calculate what i wanted to... after all, this is supposed to be a hobby. the largest problem i found, was that i would not be able to calculate the error in the equations once i plugged everything in, so i would have these values, but have no idea if they are accurate to a few decimal places, or off by tens - so basically the calcs would be useless.... this is due to various secondary heat paths where heat can dissipate and that cannot be easily accounted for, and heat transfer through various materials, and across various interfaces. As you can see, this isn't a fun area (atleast imo).

if you want to tackle trying to do these calculations, great. i wish someone would, but it wont be me, im busy enough in school. good luck.

Diggrr said:

Ummm, I don't believe that's 100% correct buddy. Because a device pulls a load of 278 does not mean that all them watts are wasted as heat...some of it actually has to be running the circuit and returning back through the neutral (or negative) wire. Even a single nichrome wire heater would only give off a percentage of it's wattage as heat. Otherwise, you could disconnect the ground wire after it started, cause it wouldn't be needed anymore as all the electricity going in would be converted to heat.
A TEC's efficiency is abhorent, but it's not zero (zed), Only government is 0% efficient.

Click to expand...

No, what you quoted is not 100% correct, but not for the reasons you mentioned. (For simplicity's sake I left out some stuff related to the reduction in Seebeck voltage when the TEC is pumping 100 Watts, which will result in an amount of heat showing up at the hotside which is greater than 378 Watts.)

I'm not sure where your confusion lies, but you are misunderstanding some aspect of this. It appears to me that you are confusing current, and power.

Current is the flowrate of electrons through a device. DC current only flows through loops. If there is a device in the loop, and you cut the loop, no current flows through the device. There would be no "electricity going in".

Power is consumed in a device (excluding superconductors) when electrons flow through the device.

In the case of DC current, the power consumed (in Watts) is the voltage across the device, multiplied by the current through the device. All of this power ends up turning into heat at some point. (In the case of power into a pump, some portion of the power is turned into kinetic energy in the form of moving water, but that kinetic energy is eventually converted to heat, due to friction between the water and whatever it is flowing through.)

Paraphrasing what I said earlier: When the TEC is powered with 278 Watts, and is pumping 100 Watts of heat out of a CPU - 378 Watts of heat will be flowing through the hotside of the TEC. This is not 0% efficiency. 100 Watts of heat is being pumped, and the CPU will be cooled somewhat if the hotside of the TEC is kept to a low enough temperature.

Diggrr said:

TEC's are awesome little devices. They pump heat from one side to the other, but at a great cost in efficiency. I've heard mentioned they're as low as 20% (or less) efficient.
Now the problem with building a pure TEC radiator is that you'll have a really difficult time in getting enough surface area meeting the water to extract it's heat. Radiators are built for air and can be any number of shapes, but to find a shape that's got both humongous water surface area and a 40mm square area on the other side of it is a daunting task, even for engineering and R&D departments. Air works easily because it's a fluid (so to speak) that can be blasted all over whatever surface we decide using the brute force of a fan...not so easy with a 40mm square piece of ceramic.

You starting to get the idea? Even a small computer fan can push 30 cubic feet of air per minute, yet the TEC is still using the static 40mm square. It's not that the design of a radiator is more efficient, it's that it's cooling medium is easy to work with, pliable, and can "brute forced" with the cheapest of equipment, the lowly fan.

I had seen a web-page at one time, where two students used a TEC to cool a single processor with an HSF mounted on it, all hanging out the back of a computer.
The problem translating that idea to an Athlon is that that was a pII 300 processor, which drew almost as little wattage as the case fan did. Their processor still got pretty warm too.

Click to expand...

Did a bunch of thinking and researching on this as well and came to the same conclusion as Diggr. Efficiency has to be increased (possibly through numerous channels or extremely low flow) in order to even consider the possibility. After which the tec wattage would become a concern among others. There have been numerous articles on attempts (some with a small measure of success) however one which I read actually gave a temp decrease on ambient water of .5c after the block versus before. Again, a dramatic increase in efficiency through application would have to be achieved prior to considering tec size. I do not think that anyone is putting you or your idea down, just letting you know that it has not really been done effectively. This of course could serve as bait for one willing to venture into this area. Be warned though that experimentation can get rather pricey. Food for thought, large companies in need of ice do so frequently by passing thin, slow sheets of water on prechilled tubes. This allows for large amounts of ice to be produced over relatively short periods of time (read low volume). Take Care All

Thanks to all of you guys....and although my idea was flawed to the "Nth" degree, I think I would still try it ONLY if I can locate the parts I want at dirt cheap prices. Of the costs associated exceeded the point where I would spend more than my arbitrary pre-set limit then I am not going to do it.....

That being said, I have seen dual loop water cooled peltier rigs now that I think about it. I was just hoping to remove one loop and still manage to keep the cpu-side coolant below ambient (when I say below ambient I mean 1-10 degrees C below room temp).

Oh and... Office Space is one of THE funniest movies on the planet if you have EVER worked in a corporate office environment. A sleeper hit if you ask me!

Farleytron I believe you have my stapler. The avitar is funny.

Click to expand...

http://www.moviesounds.com/office/oface.mp3

http://www.moviesounds.com/office/stapler.mp3

Memorable Quotes from
Office Space (1999)

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Milton Waddams: [talking on the phone)] And I said, I don't care if they lay me off either, because I told, I told Bill that if they move my desk one more time, then, then I'm, I'm quitting, I'm going to quit. And, and I told Don too, because they've moved my desk four times already this year, and I used to be over by the window, and I could see the squirrels, and they were married, but then, they switched from the Swingline to the Boston stapler, but I kept my Swingline stapler because it didn't bind up as much, and I kept the staples for the Swingline stapler and its not okay because if they take my stapler then ill set the building on fire.

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Drew: I'm thinking about taking that new chick from Logistics. If things go right I might be showing her my O-face. You know: Oh! Oh!

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Tom Smykowski: It's a "Jump to Conclusions Mat"! You see, you have this mat, with different CONCLUSIONS written on it that you could JUMP TO!
Michael Bolton: That is the worst idea I've ever heard!
Samir: Yes, this is horrible, this idea!

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Samir: This is a f*ck!

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[Peter, Michael, and Samir around copier]
Peter Gibbons: Our high school guidance counselor used to ask us what you'd do if you had a million dollars and you didn't have to work. And invariably what you'd say was supposed to be your career. So, if you wanted to fix old cars you're supposed to be an auto mechanic.
Samir: So what did you say?
Peter Gibbons: I never had an answer. I guess that's why I'm working at Initech.

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[Staring at the constantly malfunctioning office printer.]
Michael Bolton: "PC Load Letter"? What the f*ck does that mean?!

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Michael Bolton: That question is bullsh*t to begin with. If everyone listened to her, there'd be no janitors, because no one would clean **** up if they had a million dollars.

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Joanna: How dare you judge me? Look at you! You're just some penny-stealing...criminal...man.
Peter Gibbons: Well that may be, but at least I never slept with Lumbergh!

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Peter Gibbons: [Talking about plan to steal from Initech] We have to promise right now we don't tell anybody about this, no friends, no family members, no one but us.
Samir, Michael Bolton: Agreed
Lawrence: [From the next apartment through wall] Don't worry man I won't tell anyone either.
Michael Bolton: What the f*ck is that.
Peter Gibbons: Don't worry he's cool.

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Lawrence: Hey Peter, check it out, channel 9, it's the breast exams!

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Samir: No! Not again! Why does it say paper jam when there is no paper jam! I swear to God one of these days I'm just going to kick this piece of sh*t out of the window.

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Peter Gibbons: He's going to ask me to work on Sunday and I'm going to do it, because I'm a p*ssy, which is why I work at Initech in the first place.
Michael Bolton: Hey, I work at Initech and I don't consider myself a p*ssy.
Samir: Yes, I am also not a p*ssy.

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Peter Gibbons: What would you do if you had a million dollars?
Lawrence: I'll tell you what I'd do, man, two chicks at the same time, man.
Peter Gibbons: That's it? If you had a million dollars, you'd do two chicks at the same time?
Lawrence: Damn straight. I always wanted to do that, man. And I think if I had a million dollars I could hook that up, cause chicks dig a dude with money.
Peter Gibbons: Well, not all chicks.
Lawrence: Well the kind of chicks that'd double up on me do.
Peter Gibbons: Good point.
Lawrence: What about you, what would you do?
Peter Gibbons: Besides two chicks at the same time?
Lawrence: Well yeah.
Peter Gibbons: Nothing.
Lawrence: Nothing, huh?
Peter Gibbons: I'd relax, sit on my *ss all day, I would do nothing.
Lawrence: Well you don't need a million dollars to do nothing, man. Just take a look at my cousin, he's broke, don't do sh*t.

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Samir: No one is this country can ever pronounce my name right. It's not that hard: Nayee-Nanajar. Nayeenanajar.
Michael Bolton: Yeah, well, at least you're name isn't Michael Bolton.
Samir: You know, there's nothing wrong with that name.
Michael Bolton: There WAS nothing wrong with it. Until I was about 12 years old, and that no-talent-*ss-clown BECAME famous and started winning Grammy's.
Samir: Why don't you just go by Mike, instead of Michael?
Michael Bolton: No way! Why should I change it? He's the one who sucks.

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Peter Gibbons: I don't like my job and I don't think I'll go anymore.
Joanna: You're just not gonna go?
Peter Gibbons: Yeah.
Joanna: Won't you get fired?
Peter Gibbons: I don't know. But I really don't like it and, uh, I'm not gonna go.
Joanna: So you're gonna quit?
Peter Gibbons: Uh-uh. Not really. I'm just gonna stop going.
Joanna: When did you decide all that?
Peter Gibbons: About an hour ago.
Joanna: So you're going to get another job?
Peter Gibbons: I don't think I'll like another job.
Joanna: Well what are you going to do about money? Bills?
Peter Gibbons: You know I never really liked paying bills, I don't think I'm going to do that either.

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Steve: Hi, my name is Steve. I come from a rough area. I used to be addicted to crack but now I am off it and trying to stay clean. That is why I am selling magazine subscriptions.

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Michael Bolton: We're not going to some white collar resort prison. No, no, no! We're going to federal POUND ME IN THE *SS prison!

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Peter Gibbons: Hey Lawrence, you wanna come over?
Lawrence: No thanks, dude. I don't need you f*ckin' up my life, too.

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Peter Gibbons: So I was sitting in my cubicle today, and I realized, ever since I started working, every single day of my life has been worse than the day before it. So that means that every single day that you see me, that's on the worst day of my life.
Dr. Swanson: What about today? Is today the worst day of your life?
Peter Gibbons: Yeah.
Dr. Swanson: Wow, that's messed up!

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Bob Slydell: Looks like you've been missing quite a bit of work lately.
Peter Gibbons: Well, I wouldn't say I've been MISSING it, Bob.

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Bob Slydell: Milton Waddams.
Bill Lumbergh: Who's he?
Bob Porter: You know, squirrely looking guy, mumbles a lot.
Bill Lumbergh: Oh, yeah.
Bob Slydell: Yeah, we can't actually find a record of him being a current employee here.
Bob Porter: I looked into it more deeply and I found that apparently what happened is that he was laid off five years ago and no one ever told him, but through some kind of glitch in the payroll department, he still gets a paycheck.
Bob Slydell: So we just went a ahead and fixed the glitch.
Bill Lumbergh: Great.
Dom Portwood: So um, Milton has been let go?
Bob Slydell: Well just a second there, professor. We uh, we fixed the *glitch*. So he won't be receiving a paycheck anymore, so it will just work itself out naturally.
Bob Porter: We always like to avoid confrontation, whenever possible. Problem solved from your end.

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Peter Gibbons: You're gonna lay off Samir and Michael?
Bob Slydell: Oh yeah, we're bring in some entry-level graduates, farm some work out to Singapore, that's the usual deal.
Bob Porter: Standard operating procedure.
Peter Gibbons: Do they know this yet?
Bob Slydell: No! No, of course not! We find it's always better to fire people on a Friday. Studies have statistically shown that there's less chance of an incident if you do it at the end of the week.

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Peter Gibbons: It's not that I'm lazy, it's that I just don't care.

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Peggy: Now Milton, dont be greedy, lets pass it along and make sure everyone gets a piece.
Milton Waddams: yea but last time i didnt recieve a piece.
Peggy: Just pass.
[the cake passes and everybody but Milton gets a piece]
Milton Waddams: [whispering] I could set the building on fire.

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Milton Waddams: Excuse me, I believe you have my stapler.

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Milton Waddams: Excuse me? Excuse me, senor? May I speak to you please? I asked for a mai tai, and they brought me a pina colada, and I said no salt, NO salt on the margarita, but it had salt on it, big grains of salt, floating in the glass...
Mexican Waiter: Lo siento mucho, senor. (Under his breath) Pinche gringo.
Milton Waddams: [As the waiter walks away] And yes, I won't be leaving a tip, 'cause I could... I could shut this place down. Sir? I'll take my traveler's checks to a competing resort. I could write a letter to your nation's board of tourism and I could have this place condemned. I could put... I could put... strychnine in the guacamole. There was salt on the glass, BIG grains of salt!

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Peter Gibbons: What am I gonna do with 40 subscriptions to "Vibe"?

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Peter Gibbons: You know the Nazis had pieces of flair they made the Jews wear.

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[Stuck in traffic]
Samir: Mother-sh*tter! Son of an *ss! I just-
[punches steering wheel]

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Bill Lumbergh: Oh, and next Friday...is Hawaiian shirt day...so, you know, if you want to you can go ahead and wear a Hawaiian shirt and jeans.

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Rob Newhouse: You know, minimum security prison is no picnic. I had a client in there once. He said the trick is kick someone's *ss the first day, or become somebody's b*tch. Then everything will be alright.

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Milton Waddams: I was told that I could listen to the radio at a reasonable volume from nine to eleven, I told bill that if Sandra is going to listen to her headphones while she's filing then I should be able to listen to the radio while I'm collating so I don't see why I should have to turn down the radio because I enjoy listening at a reasonable volume from nine to eleven.

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Milton Waddams: Mr. Lumbergh told me to talk to payroll and payroll told me to talk to Mr. Lumbergh and I still have not received my paycheck and they moved my desk to storage room B and there was garbage on it.

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Tom Smykowski: Well-well look. I already told you: I deal with the god damn customers so the engineers don't have to! I have people skills; I am good at dealing with people. Can't you understand that? What the hell is wrong with you people?

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Peter Gibbons: I did absolutely nothing, and it was everything that I hoped it could be.

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Lawrence: [as Peter leaves to confess to Lumbergh about stealing money, knowing he may go to prison] "Peter ... Watch out for your cornhole..."

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[Peter, Michael & Samir are trying to figure out how to launder money]
Peter Gibbons: I cannot believe what a bunch of losers we are. We're looking up "money laundering" in the dictionary!

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[Drunk, singing]
Samir: Back up in your *ss with the resurrection.

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Peter Gibbons: When you come in on Monday and you're not feeling real well, does anyone ever say to you, "Sounds like someone has a case of the Mondays?"
Lawrence: Sh*t, no man. I believe you'd get your *ss kicked saying something like that, man.

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Michael Bolton: You haven't even been showing up for work, and you got to keep your job.
Peter Gibbons: Actually I'm being promoted.

Since87 said:

I'm not sure where your confusion lies, but you are misunderstanding some aspect of this. It appears to me that you are confusing current, and power.

Click to expand...

Nope. Actually I'm not confused at all, now (sleep=good). I just forgot one simple rule of math...zero's.
example: 10A x 110V = 1100 watts going in, 0A x 110V =0 watts out. I was thinking zero watts equated to zero voltage...duh.

And yes, I do know that there would actually be amperage coming through the negative line also, just not the amperage that's being drawn by the TEC, the TEC is in series with it's power supply.

farleytron ~ in regards to your original proposal i've only seen ONE of these type of ideas succeed with two very high powered TEC's and custom machined aluminum heat exchange blocks. and the two TEC's weren't aircooled they were watercooled with a separate, second loop (like 156W or something each I think). someone from forumoc.com a long time ago.


edit: though i haven't been able to access forumoc lately, maybe they disintegrated.

you can reach the guy (maybe) who made the system on www.mods4me.com his username is "below ambient" i think he was trying to sell them a little while ago