377/437W Peltier Qmax Rating

[DNA]

While were beating this peltier rating subject to death, the 62mm square 437W Qmax peltier stocked by Frozen CPU also has 2 Qmax ratings.

Th = 50C
Qmax = 437.3W
I(Qmax) = 32.8A
I(dTmax) = 25.2A
Umax = 26.7V
dT = 74.5K

Th = 26.8C
Qmax = 376.8W
I(Qmax) = 30.4A
I(dTmax) = 23.7A
Umax = 24.8V
dT = 66.0K

[laxman]

yes and so do all peltiers, peltiers are more effective and higher temperatures. thus the Qcmax is always lower and 30c then 50c. Personally I do not think that this big of a pelt is needed for effective cool and it would generate so much on the hot side that you would probably get the same proformance from a 270 qcmax pelt.

[DNA]

Originally Posted by laxman

Personally I do not think that this big of a pelt is needed for effective cool and it would generate so much on the hot side that you would probably get the same proformance from a 270 qcmax pelt.

One of the primary justifications for using phase-change to cool high thermal load CPUs is to achieve a better overclock at a lower Vcore. To carry that reasoning a step further is why a high Qmax peltier is beneficial based on ones anticipated thermal load.

One case in point, an AMD X2 4800 running at a conservative overclock of 2.8Ghz with a Vcore of 1.5 would produce a thermal load of ~153 watts. I doubt that a 270W Qmax device would allow one to reach those levels.

[laxman]

That wasnt my point, it is how are you going to cool a massive 430 watt pelt. A 430 watt pelt moves 430 watts in perfect conditions but to be real lets say it moves 350w. So you have to cool 350w it moves plus the around 100w it generates meaning a total of 500w. Lets say you have a cool which has a c/w of .1, then the hot side temp will be 45 degrees above ambient (if ambient is 25c then it is 70c). At 153 watts your pelt will have a Dt of around 45. This means the cold side temp will be around 35c. Lets do the same thing with a 270 qc max pelt. Lets say it moves about 200 watts and generates 50w for a total of 250 and a hot side temp of 50c. This would make for a Dt of 30 meaning a cold side temp of 20c. This shows two things one it is hard to cold a large heat load and the hot side of the peltier. Although still a 270 watt peltier does better because it produces less heat and the hot side is cooled better.

[DNA]

Originally Posted by laxman

That wasnt my point, it is how are you going to cool a massive 430 watt pelt. A 430 watt pelt moves 430 watts in perfect conditions but to be real lets say it moves 350w. So you have to cool 350w it moves plus the around 100w it generates meaning a total of 500w. Lets say you have a cool which has a c/w of .1, then the hot side temp will be 45 degrees above ambient (if ambient is 25c then it is 70c). At 153 watts your pelt will have a Dt of around 45. This means the cold side temp will be around 35c. Lets do the same thing with a 270 qc max pelt. Lets say it moves about 200 watts and generates 50w for a total of 250 and a hot side temp of 50c. This would make for a Dt of 30 meaning a cold side temp of 20c. This shows two things one it is hard to cold a large heat load and the hot side of the peltier. Although still a 270 watt peltier does better because it produces less heat and the hot side is cooled better.

I use a 377W device (Th = 27C) with a dTmax of 66. Pc = 19.9V x 24.6A. The estimated thermal load with the pumps heat contribution is 143W. Under sustained maximum load conditions, the coolant temp is 30.4C, Tc = -14.6C and Ta = 20.3C.

As for how to cool it, http://forums.procooling.com/vbb/showthread.php?t=11683

Using the same hardware and ambient condition that yielded these results, it is not possible to duplicate the noted Tc with a 270W Qmax device. With Pc = 15.4V x 30A, Tc would be in the range of -4C to 2C.

[killernoodle]

Originally Posted by DNA

One of the primary justifications for using phase-change to cool high thermal load CPUs is to achieve a better overclock at a lower Vcore. To carry that reasoning a step further is why a high Qmax peltier is beneficial based on ones anticipated thermal load.

One case in point, an AMD X2 4800 running at a conservative overclock of 2.8Ghz with a Vcore of 1.5 would produce a thermal load of ~153 watts. I doubt that a 270W Qmax device would allow one to reach those levels.

Whats the point of running it at a lower Vcore if you are gonna peltier it? If it does the same OC on water with a higher Vcore, why go through the trouble?

The whole point is being able to overclock higher, not volt lower.