TEC Cold Plate?
digitaltree
Suffern, NY
I am thinking about putting a TEC in for cooling on my computer, using it, of course, with water cooling. But I don't understand the cold plate. Is it necessary to put a cold plate between the TEC and the CPU, or can I just put the TEC on the CPU itself?
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http://www.heatsink-guide.com/peltier.htm
Generally you want to use a coldplate (about 1/2" thick piece of copper) to ensure good contact with the core. The surface of a peltier is not always the best for direct contact on a CPU. I think there may be other reasons for that as well, but I don't recall off the top of my head.
Peltiers can be a lot of fun, but be sure to do a LOT of reading first. It is very easy to damage your system without the correct preparation as Armo has mentioned. Also, you'll definitely want to look at all of the pros and cons before investing any money into a TEC setup. There are some strong cons, including electrical and thermal inefficiency. You'll dump a lot of heat into your room via the WC system and a lot of electricity will be required to run a decent sized peltier.
Why is the surface of a peltier not good for direct contact on a CPU? Is it the same concept of why you use thermal paste on heatsinks and such: to fill in the micro-valleys in the metals? Or is there another reason? And is 1/2" the best to use, or can it be thinnner; say, 1/4" or 1/8"?
That is how I understand it. I believe sandwhiching the TEC between the coldplate and the block also helps to ensure good contact. The copper cold plate will be much harder than the tec as well. When mounting pressure pushes it against your CPU, it will not buckle or compress like a pelt surface. I don't think the width matters much, just so long as it is solid and flat.
That all depends on how cold you want to get, and how much power you have to supply the peltier. A 226W pelt is going to need at least 20-25A on a +12V supply. This is usually hard enough to manage, so I'd probably recommend sticking with 226W. You should get some awesome temps with a pelt like that.
What WC setup are you planning to use with this? Also, what type of AUX PSU are you using?
muddocktor has a lot of experience with TECs. I'm hoping he'll stop by and provide some advice too.
I remembered after that last post that my aux PSU is 300W, so I'll just stick with the 226W pelt. It's a Meanwell II 300W that I'm buying from CrazyPC. And I'm using 1/2" tubing in a Swiftech setup, and I'm considering using Coollaboratory Liquid PRO TIM.
You need a cold plate for the reasons that lemonlime posted. A tec has to be firmly clamped between the waterblock and cold plate with all it's suface area being covered with the coldplate and waterblock or it will definitely burn out due to hot spots. The cold plate for my Maze1C-1 is 1/4" thick copper.
As far as your thermal interface material is concerned, stay strictly away from any tim that contains metal, be it that coollaboratory crap or AS5. I believe that the coollabs crap is conductive, which you definitely don't want anywhere near that tec element. And I had foiling problems with AS3 with my tec too, which lead to the leads smoking on the 120 watt element I was using. The silver in the AS3 actually plated out on the tec element under the intense cold and pressure and I believe it became somewhat conductive and eventually shorted the power leads on the tec. You would be much better off using something like Arctic Alumina or Ceramique instead, since they contain no metal.
What waterblock/coldplate and radiator are you planning to use with this setup? Also, how do you plan to insulate the socket area to prevent condensation problems?
Thanks for the advice on the TIM. I wasn't aware a metallic material would affect the TEC like that.
As for my water cooling, I was looking for something not too complicated to set up, like the Aquian 510 by Koolance, but because of it's lower heat dissipation, I am going to add another rad with another 120 fan. I'm thinking the HX-360 from Koolance, as well. As for my waterblock, I'm looking at the Swiftech Storm.
As for insulation, I was planning on using a silicon conformal coating around the socket and PCB as well as using neoprene to enclose the socket and pelt, using RTV or some kind of rubber adhesive to seal it.
How does this sound?
DD also sells some neoprene kits with an assortment of thicknesses for insulating around the socket. On the socket itself, you will need to fill the zif socket with some dielectric grease to prevent moisture within the socket itself and you will also need some neoprene on the back side of the mobo in the socket area for the same reason. For your RTV, look for some without acetic acid or at least as low an acetic acid content as possible to prevent it from eating up components and traces on the mobo.
For a radiator, I would choose no less than a large, triple 120mm fan rad such as the Black Ice GTS Stealth 360 or something similar to it. Just remember, you will be dumping a heat load similar to watercooling a cpu plus 2 high end gpu's such as the X1900XTX gpu's due to the peltier element and you will need all the radiator surface area you can get.
For a pump, I would choose an Eheim 1250 if you want to go with a 120v pump. For automating powering up the pump, DD has this relay kit. For a 12v pump, I think the D-5 pump might be a good choice, but to tell the truth I'm not up on the latest on 12v pumps myself. Csimon could probably fill you in on 12v pumps better than I.
I hope this helps your planning out, digitaltree. At least it will give you lots to think about.
Thanks. I guess it always helps to talk to someone who's done it. One thing I'm confused on is whether that DD waterblock comes with a pelt. It sounds like it doesn't. I just want to know whether I need to buy one specifically, or whether I'll already have one.