TRUE TEC Module (with pics)

[Uncle Jimbo]

The fans are at 12V, but I'll be dropping them all to 7V when everything is said and done. When I was testing the module with no load, the hotplate temerature went up 3C as I dropped the fan voltage to 7V.

You can see the cold plate probe in the insulation picture. The hot plate probe is in the middle of the plate just between the corner edges of the TRUEs

Using 12730 TECs at 9.2V, you should be pulling about 18A with a 50C hot side and 50C differential. That's a heat load of about 160W from the TEC itself. The other data you provided suggests you are pumping about 50W with each TEC, for a total heat load of 210W per TEC.

Based on what I can see from other performance reviews, the TRUE has a thermal resistance of about .1C/W with a good fan, so with 210W load, I would expect a 21C rise above ambient. You indicated the probes were at 23.5C with no power, so if we take that as ambient, we would expect the hot side at 45C, so your second test seems about right.

But if the comments by the other posters about the capacity of the heat pipes are correct, then you may be approaching the max for those coolers. I think that you might not be able to put much more heat load on - but I don't have that cooler so I really can't verify experimentally.

This data also suggests the CPU heat load is only 100W - otherwise you would see a bigger heat rise. Your first test had a 60C differential, and with your voltage, you could only have been moving 70W or so and achieve that differential.

All in all your work is impressive, and certainly very pretty. Getting close to 0C is an achievement, and you can play with TEC size and voltage if it turns out you need more cooling with different CPU settings. That would also give you a way to see how close to the edge you are with the coolers - if you increase the voltage and the heat runs way up or the differential does not increase, you may be at the limit.