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Brians256 · 09-24-2003, 10:02 PM

I agree, Joe. There have been some posts in this thread which seem negative and without value to this discussion. Not terrifically obnoxious, all things speaking, but not nice. In other words, kind of like real life, and not worth getting all excited and putting on the super-mod hat. People are showing whether they can be adult and polite. Or not.

We all know that there are terrifically smart and knowledgeable people here. What is most important to remember is that lots of knowledge does not mean that some beginner doesn't deserve an explaination geared to his level. If someone does not understand your first explaination but still wants to learn (and is not simply a troll), I suggest trying again (with patience) using different analogies etc. Someone may simply be new, or may not have understood previous explainations. Remember: everyone learns in a different way and one explaination may not work for everyone who is listening.

Now for the obligatory "Adding something worthwhile to this thread" portion of my post:

Does anyone other than BillA understand why a peltier would behave differently than a radiator in terms of the flow-rate vs. CpuTemp graph? I can understand BillA not wanting to leak all his company proprietary info to public domain.

My thought is that an active device is fundamentally different than a passive device. Having the water in the pelt device longer results in more heat extracted per unit time because the pelt can deal with a much higher DeltaT on the hot side. So, as the flow rate is decreased, the hot side deltaT goes way up, causing higher efficiencies in dumping heat. At the same time, the pelt is removing similar amounts of heat (calories) from less water. So, a low-end maxima in the SYSTEM efficiency curve is seen.

The sweet spot would therefore be where the heat moving efficiencies in hot-side deltaT best combine with the efficiencies of the low-side. There should be a sweet spot simply because both functions are monotonically increasing in different directions on the X axis. There would not, of course, be any maxima if both functions were perfect inverses, but there definitely is an observable maxima.

Note that none of this has any mathematical rigor, so feel free to tell me I don't have a clue as long as you attempt to explain yourself. Because of the fact that I do not have good training in this area, I have kept my mouth shut in this thread until now.

Flames away!

09-24-2003, 10:02 PM	#77
Brians256 Pro/Staff Join Date: Oct 2001 Location: Klamath Falls, OR Posts: 1,439	I agree, Joe. There have been some posts in this thread which seem negative and without value to this discussion. Not terrifically obnoxious, all things speaking, but not nice. In other words, kind of like real life, and not worth getting all excited and putting on the super-mod hat. People are showing whether they can be adult and polite. Or not. We all know that there are terrifically smart and knowledgeable people here. What is most important to remember is that lots of knowledge does not mean that some beginner doesn't deserve an explaination geared to his level. If someone does not understand your first explaination but still wants to learn (and is not simply a troll), I suggest trying again (with patience) using different analogies etc. Someone may simply be new, or may not have understood previous explainations. Remember: everyone learns in a different way and one explaination may not work for everyone who is listening. Now for the obligatory "Adding something worthwhile to this thread" portion of my post: Does anyone other than BillA understand why a peltier would behave differently than a radiator in terms of the flow-rate vs. CpuTemp graph? I can understand BillA not wanting to leak all his company proprietary info to public domain. My thought is that an active device is fundamentally different than a passive device. Having the water in the pelt device longer results in more heat extracted per unit time because the pelt can deal with a much higher DeltaT on the hot side. So, as the flow rate is decreased, the hot side deltaT goes way up, causing higher efficiencies in dumping heat. At the same time, the pelt is removing similar amounts of heat (calories) from less water. So, a low-end maxima in the SYSTEM efficiency curve is seen. The sweet spot would therefore be where the heat moving efficiencies in hot-side deltaT best combine with the efficiencies of the low-side. There should be a sweet spot simply because both functions are monotonically increasing in different directions on the X axis. There would not, of course, be any maxima if both functions were perfect inverses, but there definitely is an observable maxima. Note that none of this has any mathematical rigor, so feel free to tell me I don't have a clue as long as you attempt to explain yourself. Because of the fact that I do not have good training in this area, I have kept my mouth shut in this thread until now. Flames away!