[luau] Underclocking / Aluminum cases

[yuser at hi.net]

On 2 Jul 2002 at 16:33, Ray Strode wrote:

> > My feeling is that copper would tend to hold the heat, for example  a 
> > copper clad bottom on a pot or skillet.  I'm pretty certain that 
> > aluminum cooling fins are the most efficient, although aluminum car 
> > radiators aren't very good while car radiators with copper fins are 
> > common  and easy to repair. 
> 

The reason for large copper bottoms is for even heating (and the reason that only the bottom is copper).  Since copper can dissipate heat very well, the heat is spread 
across the pan more evenly.  It is "large" to limit warping, provide a reserve, and still provide even heating when cold food is thrown on it.  A copper pan of will actually cool 
down (and heat up) quicker then a aluminum or cast iron pan of equal size.     


> Actually, I read somewhere (my physics book? not sure) that copper, 
> aluminum, silver, and gold were all good conductors of heat, but the 
> order of best to worst
> is: silver, copper, gold, aluminum.  
> 

Correct..
Higher number means more heat transfer

Thermal Conductivity, W/cm-K
Aluminum 2.165 
Copper 3.937 
Gold 2.913 
Iron .669 
Silver 4.173 


> The idea is, if it's a better conductor of heat, then when it's used as 
> a heat sink, the heat will away from the chip to it. where it can be 
> cooled by the air (That's why
> heat sinks are in fins i think).

The fins increase the surface area exposed to the air flow allowing more cooling.  Just as a soda dumped on a hot sidewalk will warm up much quicker then if it was sitting 
in a can on the same sidewalk.   

 
> Anyway, i'm certainly no expert, and could probably be wrong.  Maybe one 
> of the other people on the list that are, could verify what i'm saying.
> 
> --Ray
> 

Here is an interesting page about copper and aluminum  (I used a Google cache because I could not get to the leading page from the site directly) -->

http://216.239.35.100/search?q=cache:pXcbnqmZaPkC:www.benchtest.com/alum%26copp.html+specific+heat+capacity+aluminum&hl=en&ie=UTF-8