does this sound like a good deal?

[maxim]

here is a peltier seller on ebay. they have both 40mm and 50mm pelts for sale and the prices are speaking my language.

40mm x 40mm
Imax = 10 Amps
Qmax = 85 Watts
Vmax = 15.2 Volts
DTmax = 68 Deg C


50mm x 50mm
Imax = 15 Amps
Qmax = 130 Watts
Vmax = 15.2 Volts
DTmax = 68 Deg C


1. im planing to use it with a 2" wide block, can i use the 50mm pelt? the size of the actual waterflow area will be about 1.7"=41.65mm, while the block at 2" will just cover the 50mm pelt completely. could i still use the 50mm, even though it's not completely covered by water area?

2. how are these pelts looking to y'all? i am going to put it on the system in my sig. what differences in temperatures can i expect between these two TEC's?

3. 40mm is rated at 10A and 50mm at 15A. can i use a regular PSU dedicated? i just bought one on ebay, has a 15Amp 12v output. considering i'll have to run the TEC at 12v instead of 15.2, i should be well within the power requirement. right?

[winewood]

ouch.. I would avoid those..

unless, the 85w is for a gpu. Otherwise its underpowered, and you won.t be able to do what you want with it.

The 50X50 are quite large, and although they can "fit" under your block, you won't have any room to put the screws in for clamping pressure. No clamping pressure, the thing will suck eggs. You will only get 50-70% MAYBE of the efficiency of the pelt. Don't expect for the clamping pressure of the block to the CPU to be sufficient. I suggest buying a TEC block and a real 40X40 good pelt. Over time you will save money, because you won't have all the small pelts eating your budget.

[maxim]

sorry, the block is 2" wide, but 3" long, so i'll be able to screw that cold plate to it real good

is there a good cheap pelt? aka, NOT sold by brand name watercooling companies like DD.

[winewood]

Not that I have found.

and I have looked quite a while for some.

[joemac]

A 50 x 50 pelt covers the area of a AMD CPU. A 40 x 40 pelt seems to work better though – I am not going to go into why I think this is but here is a pic for those like me that are pic happy

[maxim]

here is the datasheet for what seems to be the most powerful pelt Marlow makes. looking at the graphs i see that if i apply 90W of heat to the cold side and manage to keep the hot side at 50C, then my cold side temp should be about 27C.

now, let's look at my current WC system. i estimate its C/W to be about 0.21. with the pelt it'll have to dissipate more heat. so if the pelt is run at it's maximum and guessing 50% pelt efficency, i would get about 212W of heat out of it. then plus the 90W from the cpu itself, and i have to get rid of 302W of pure heat. with the system i have now, it results in dT of 64C ! so if my room temp is 25C, my hot side will be at 89C omg. that means even higher cpu temp than 27C. so after all this my cpu will deff run hotter than it does now, when cooled by water directly.

am i thinking right with my calculations here? if i am, then how are people getting all those nice temps with pelts? i dont have a very high level WC system here, but i'd need a LOT more cooling power to accomodate for even that 141W pelt.

[winewood]

If I were in your shoes. I would buy a large pelt, which could easily run hotter, yet still be efficient. I bought a 224w pelt at 24v and 10 amps. I will control it using a variable Voltage controller. This way, I always have the needed power no matter what I am dong.

I wouldn't puchase anything using those projections. I have found that everytime I do that, something comes up that throws one of them off for one reason or another, and I am back to sqare one. Over buy, then have a way to lower the voltage. This way, if say... your cpu isn't as hot as you think, you don't have condesation and no way to lower the output.