Project: Dual TEC Block on LGA2011 (i7-3930K) - Page 2

Yes, I refered to Elloquin's results. In those tests the cpu did have low voltages except for overclock >4.5GHz.
I guess we have to define the satisfactory standards first. I will consider it decent if the block holds cold plate at a dT of -20C with respect to water temperature, under full load.
Unfortunately Elloquin only posted core-temps (please correct me if I'm wrong), and I have to estimate the cold plate temp.

I choose the dual tec block scheme because it is relatively easy for me to make. I would go with 4 if I had a mill (like the "safe" you made ). Maybe that will be my next project.
BTW, are you planning to sell any large direct block except for the single TEC one?

I totally understand your concern. Actually I have done some rough simulations to calculate the optimal cold plate thickness. You readings of -10c at end and 20c in the middle is close to my simulation result.
I have a question, What size (thickness) of cold plate did you use in that test?

Here is the simulated temperature distribution across the center line on the top of 10cm by 5cm cold plates (400W cpu power). Note that all temperature is relative, so only take the dT reading.

4mm thickness:


10mm thickness:


Graph for 10mm:


As the cold plate gets thicker, the temperature at the cold side of TEC gets more uniform. But thicker means larger value of C/W value from CPU to TEC, too. The optimal thickness is between between 8-12mm. Certainly this aspect affects the performance of the block. But overall it's not too bad because in the center the hotter area compensates the lost heat transferring across TECs at the two ends, as Qmax is a semi-linear function of temperature.

Yeah, heat pipes will help. I bet you have though about a sandwiched version of direct die block, which the water block is in the middle and on the top and bottom there are two TECs with cold plates linked by heatpipes. I like chillers, with their ever expanding Qmax. Adding more TECs easily fixes the efficiency problem. My only concern is the complexity of two loops and insulation issues.

Part 1.3. The water block

The water channels are cut with a 5/32 inch end mill bit on my drill press. My drill press is terrible at milling copper, but I found an interesting way to cut channels which is cut download (plunge cutting) and have overlap on each cut.


In this way I can cut 8mm deep channels easily. It is just very time consuming to do this manually. It took me 8 hours to cut this water block. The bit is still sharp after I finished the block though. No breaking bit Enjoy the pictures:

Part 1.4. Cold plate

I though the cold plate would be easy, using the same method I cut the channels of water block. But it turns out it's much more difficult to do plunge cutting on a straight edge (not in a channel). I almost broke all my end mills
In the end I did it with the normal milling style. It took me much longer to finish the cold plate. I desperately hope I had a cnc mill.

They look quite good after some polishing. I don't have fly cutter, so I know the surface is not flat for the TECs. I will live with that first.