Quote:
Originally posted by iggiebee
Having said that, the article in question is well written and quite extensive, BUT you have to admit that does not seems to have been written by any expert authority in such matters, and has to be taken with a grain of salt, as such most of what is said are simple "personal" hypothesis IMO.
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Actually, there are very few involved in watercooling forums who have anywhere near the expertise of Dave Smith.
Quote:
Originally posted by iggiebee
I found some contradictions: "Copper's higher conductivity means is that a thinner copper fin can transmit as much heat as a thicker aluminum fin.".. This affirmation is very hard to swallow, what are the basis for making such statement. Are thin fins impossible to make if using aluminum?
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The basis for the statement is contained in the statement.
Copper has a higher thermal conductivity than aluminum. Do you dispute this?
Granted that copper has a higher thermal conductivity than aluminum, then
by definition a thinner section of copper will move the same amount of heat for a given temperature differential than a section of aluminum.
Manufacturing feasibility has nothing to do with it.
Quote:
Originally posted by iggiebee
The the author contradicts himself when saying that: "However, on a weight-basis, aluminum can conduct more heat than copper. "
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There is no contradiction, the earlier statement was discussing heat conduction as a function of the
volume of the material.
This statement is discussing heat conduction as a function of the
mass of the material.
What contradiction do you think you see?
Here's a quote from your link (with some added commentary pointing out some flaws in the author's statements):
"This model demonstrates that an Aluminum heat sink is as good as a Copper heat sink for a uniform heat source. [Previous sentence should have said 'nearly as good'. The author's own graphs show that aluminum is not "as good" - Since87] When the heat source becomes smaller a Copper heat sink might be advantageous depending on the source size. [The fact of the matter is that when cooling small CPU dies, the lower spreading resistance of copper is a very significant advantage.] Also at higher velocities, percentage difference between Copper and Aluminum becomes more pronounced. [Translate this to 'At higher convection coefficients such as when watercooling rather than aircooling, the percentage difference between copper and aluminum becomes significantly more pronounced.']"
Furthermore, the author's statement:
"Optimally designed Aluminum heat sinks meets or exceeds thermal performance of Copper or Copper based heat sinks."
Only holds true when weight is considered as part of "optimally designed". When weight is not a consideration, copper always beats aluminum for steady state heat transfer. The author of that article has not stated, much less proved, that aluminum exceeds the thermal performance of copper when the heatsinks compared are of equal volume and geometry.
Edit: Punctuation