Trying to get some serious cooling going here, got a few questions.

[m0tion]

Ok, lemme just break it down for you. Here is the setup I'm going to be using:

2 Dtek Heatercores
Eheim 1250
Custom Res
Undecided block for CPU
226W peltier powered by Meanwell S-350-13.5

Ok, so here are my questions. First off, is this a good order to have the system flow?

Res -> Heater Cores -> Block -> Pump -> Res

Second questions is, should I run the rads in series or parallel?

Third questions is, if I add a GPU block with an 80W peltier to the mix, is this a good order to have the system flow?

Res -> Heater Cores -> Block -> GPU -> Pump -> Res



Thanks! =)

[dicki]

welcome to the board :)

well regarding the layout of componants in the system as long as they are all in series i personally don't beleive it matters too much, the temp at 2 different points in the circuit will be basically the same because the water never stays in one place long enough to loose or gain a great amount of heat.

from a scientific point of view radiators are most efficient when supplied with hot water so i would place the rads after any heat sources, also i would be careful about using 2 peltiers in one cooling loop... you will have several hundered watts of heat going into that water and things will get very hot if your not careful

cpu = 100watts
pelt = 226watts
pelt2 = 80 watts
gpu = 50 watts (maybe)

which comes to 450 watts... thats a whole lot of heat. personally i would start with just the cpu and see what happens to your water temps, then decide if it's safe to add a gpu block because your cpu temp will go up in relation to your water temps.

dicki

[Player0]

Some points here:

Your orders look fine. As dicki said the water temperatures dont vary much from point to point. The only thing is that you want the pump to go first, so its pushing water not pulling water:

Res -> Pump -> Rads -> CPU Block -> GPU Block -> Res

You want to mount the resevoir as close to the pump as possible so it sucks out water at 0 head.

As for the radiators, two heater cores should be enough, but you will have alot of watts. Although Dicki's estimates are off.

The 226w peltier at full load actually produces 375w of heat by itself. Another 100-140w depending on the CPU. 115w from the 80w peltier. And 40-50w for the GPU.

So figgure for like...650w of heat maximum, if your running the pelts at full power that is.

[dicki]

ahh really?

can you explain peltiers a little to me player?

my understanding was the 226watts quoted was the amount of heat they could move... they operate at say 90% effiency so they only give 200watts actuall cooling

if i'm reading your stuff right they actually produce 375watts of heat and only move 226watts of heat at 90% efficiency?

i'm just trying to get the image right in my head

dicki

[m0tion]

15.2V@24A ... multiply them together you get 364.8W. Thats how much energy it's consuming and your going to have to dissipate that somehow. The phrase "watts of heat" is sort of flawed, it's not "watts of heat"... it's just watts.

[mdzcpa]

Darn good discussion going on here. Please continue this thread guys....I'm taking notes (seriously).:)

[Player0]

M0tion has the answer for you dicki, I think.

Peltiers are usually listed by their QMax rating. This is the amount of watts of heat they can pump from their cold side to their hotside at their default voltage.

So at 15v 24a, the 226w peltier can move 226w of heat from the cold side to the hotside.

BUT! The peltier is producing heat to do this. In fact, the peltier acts like a big resistor. The peltier actually creates 15v x 25a = 375w of heat, give or take.

Since it takes 375w to move 226w, that makes the peltier about 60% efficient.

Also remember that 375w + 226w is almost 600w of heat, which is the maximum the peltier might actually create on the hotside in some applications. Luckily the CPU is more like 120-130w depending, so 500w is a better number. Still high...but dual rads will take care of that easy.

PS - One of the misnomers floating around right now is that running a 15v peltier at 12v is the best way to do this because thats the peltiers 'sweet spot'. I hear people mentioning that all the time. People have misunderstood some information from like TeDist.com which first mentioned this. A peltier may have the best efficiency at 75% power, but will still work best at 100%.

[m0tion]

Thats a very good point, it's true that when you provide a peltier with 80%+ of it's maximum voltage the efficiency of the peltier decreases... but thats the EFFCIENCY. All that means is that for the voltage you give it past about the 80% mark you will recieve diminishing returns on the amount of heat it is able to move, but it still moves more heat. Just because it's less efficient doesn't mean it cools less. Point being, if the maximum voltage of your peltier is 15V and you run it at 12V it may be more efficient PER VOLT, but it will still move more heat running at 15V than at 12V.

[m0tion]

While we're on the topic of things, I think it's a good idea to bring this up. Lets say you have a peltier that has a Vmax of 15V and an Imax of 24A. You take that peltier and you run it at 12V. One thing I think people get confused about it how much amperage the TEC will draw when it's run at 12V. Well, the answer is pretty simple. The amperage decrease is going to be linear with the voltage decrease (ie. 12 is 80% of 15, so at 12V it will draw 80% of what it would draw at 15V, 19.2A).

Another good thing to mention is that it seems like a lot of people think it's a good idea to run their TEC off of their system ATX powersupply, or a spare ATX powersupply. I know that my Enermax 365 can provide a maximum of 17A on the 12V line, and it's a pretty powerful powersupply. It would be a VERY bad idea to run a 226W peltier thats rated for 15.2V@24A at 12V off of this powersupply because it's going to try to draw 19.2A. This powersupply WON'T be able to safely provide that. What will end up happening is over time (and i'm not sure how much, could be a couple weeks, could be a day, depends on the components) the components inside the powersupply will overheat and the unit will fail. This is extra bad if your using the TEC to cool your processor at the time, because when that powersupply fails your TEC stops moving heat and all of a sudden you've got a very unhappy Athlon (or Pentium).

[Amd Man]

Hmmmm I have to agree with Mike, I like this thread, please tell more, the more I read the more I understand these TEC's, so keep on posting anything relavant to pelts... Espcially some of the misunderstandings of how pelts work...and the Psu's that are best for the huge pelts...

[m0tion]

Well, as for powering TECs I can tell you what I'm going to use. Like I've mentioned before I'm using a 226W peltier thats rated for 15.2V@24A. I plan on using a Meanwell S-350-13.5 to power mine. It provides 13.5V@25.8A. At 13.5V this TEC will draw a little over 21A, so it will provide it with plenty of power. You can purchase this powersupply from www.peaktopeakpower.com for about $105. Unfortunately, right now they are out of stock and are getting more in from Taiwan (should be here sometime in Aug =\). Hope this helps, also, Peak to Peak power sells a lot of other Meanwell powersupplies, I suggest going by their site and taking a look.

[Amd Man]

Why not get the S-350-15? the thing still puts out 25amps or soo at 15v....or is this something you dont want to do? running your pelt at 100%...

I also have the chance to get a Samlex Sec-1223 23amp 13.8v Power supply, is this anygood will it power my 226w pelt anygood? There is NO wattage rating on it...

[dicki]

thanks for clearing that up :)

[m0tion]

Well, the S-350-15 provides 15V@23.2A. My TEC draw 15.2V@24A. Too close for comfort =). You should always leave your powersupply a little room anyway. Lets say I found a power supply that supplied exactly 15.2V@24A. This wouldn't be a great idea for my 15.2V@24A TEC. You need to the the unit a little room to breathe, can't have it slammed against the wall 24hrs a day.


That powersupply sounds like a really good one for your situation assuming your 226W TEC have the same VMax and IMax as mine. The wattage rating on the power supply would be about 300W (V*A=W, 13.8*23 ~ 300).

[Amd Man]

Thanks, right now I have my 226w pelt running off a Antec 510w psu. It's only giving my pelt 11.7v right now so I figure if I can get another 2v to the pelt that it will help alot...:D

[Hundekot]

Along the lines of the Power supplys, I'm not too sure about some of the new bigger (ATX) ps's, but on a lot of the older AT ps's you could open it up and most of the time there's an adjustable pot in there that'll let you up the voltage a little more. I have an old 350W AT ps that I was able to crank up to 14.2V, of course, as you crank up the V, your rated amperage is also going to go down.

Something else you can do is link 2 old AT (read cheap) power supplys together to get double the amperage or voltage depending on how you wire them. If nothing else, it's a good read. I did this for my 172W 24V pelt and it worked pretty good. Even though it was getting enough voltage, the amps weren't quite there so it didn't work too well.

I think that a lot of people are too concerned with getting the voltage as close as possible to the rated volts, personally, I think you should be shooting for as many AMPS as possible. If you have 10-15 amps over the pelts rated amperage and maybe down a volt or 2, that's going to work much better than perfect voltage, but lacking in the amps.
Just some of my exrperience...
Hundekot.

Here's the link for linking the 2 AT power supplys.....

DUAL POWER SUPPLYS
http://www.procooling.com/articles/html/linking_multiple_psu_s_as_one_.shtml