Ferrotec has some nice on-line curves and you can adjust to compensate for hot side temperature. I've been looking at their 9506/031/600 B which is 03160 spec.

The coefficient of performance (COP) is the amount of heat pumping divided by the amount of supplied electrical power. Max CoP for this unit at 30C hot side is 3.3, and occurs at 7.5A and .6V for a 10C differential. For only 4.5W in, it moves about 15W, which is mighty fine efficiency (but not much cooling).

That's a 55mm size, at a nice fat 4.85mm height. Efficiency drops pretty fast as current goes up, with the 50% point (CoP of 1) at 37.5A with 2.3V required, which draws 86.25W to move 86.25W.

Going to the 2.5 CoP point (15A 1V) moves 37.5W across a 10C differential at 30C hot side. So 5 of those on a 5V supply draws 75W and moves 180W. Using 5 of these with 12V PCM control and a 200W cooling design center, we draw 90W on average, and can move 450W at 12V with a total power in of about 480W. That would probably do the job for keeping even a big OC system with dual graphics nice and cool, and with good efficiency (most of the time)... but at max cooling, the hot side cooling needs to unload the power in and the power moved, close to 1000W. Need a big pump and big rad to handle that. But if we are willing to let the cold side rad do some of the cooling, which means we have to let the outlet temp rise a few degrees, we might decide to clamp PCM at the 1.5 CoP, which provides 350W of cooling for 230W in, and a total heat load of under 600W at max load. That setup does not seem totally crazy - it would maintain below ambient for all but the highest loads, and even then would only go a few degrees above ambient.

For the totally freeze crazy, with a big enough cold side setup, you could run 2 sets of 4 of these on a 12V supply. If you can keep the hot side at 40C, you can drive the cold side close to 0C while moving 360W. You will need to unload close to 1500W, but hey, formula 1 is about performance, not cost...

The graphs are fun to play with - for this TEC they are at http://www.ferrotec.com/products/the...ail.php?id=119