Madshrimps Forum Madness

Quote:

Originally posted by 8-ball
When will people learn that HSF manufacturers only use aluminium because it is:

cheaper
lighter
cheaper
easier to manufacturer
cheaper

and did I mention cheaper.

I will concede that aluminium DOES radiate thermal energy better than copper. However, raidation is simply not a significant mode of heat dissipation unless you are cooling something in a vacuum. It also needs to be significantly hotter than the surroundings to get a reasonable amount of heat dissipation.

As for convection.

Convective heat transfer, the process by which thermal energy is transferred from a solid into a moving body of fluid, such as water in your water block, or air flowing through a rad, is INDEPENDENT of the material of which the rad/block is manufactured.

The only bearing the material has on the heat transfer is getting the thermal energy to the surface. Once it is at the surface, it may as well be glass for all I care. The only thing which determines how well the thermal energy is dissipated in to the air flow, is the physical properties of the liquid/gas, the flow regime, and the geometry of the transferring surface.

8-ball

Quote:

Originally posted by 8-ball
Aluminium IS a better radiator, in that its radiating properties are closer to that of a black body than copper.

However, as I said, radiation simply doesn't figure significantly enough for using aluminium to perform better than copper due to the performance hit associated with the conduction of thermal energy to the dissipating surface.

Just about the only scenario where aluminium's better radiating (and let me point out, that it isn't that much better) properties justify it's use are in space, where ALL thermal energy must be dissipated by radiation due to the vacuum.

As long as there is some medium to carry the heat away by convective heat transfer, then radiation properties are pretty irrelevent.

8-ball

Quote:

Originally posted by 8-ball
As i understand it, the myth that aluminium is a better radiator, (and a common myth) is down to the radiative properties of the materials. It is true that aluminium is a better radiator, but radiation doesn't playa big enough role for this fact to outweigh it's much poorer conductivity.

As I alos said, and you correctly backed up, cost is the predominant factor in using aluminium over copper for thermal management applications, and maybe weight.

8-ball

http://www.xtremesystems.org/forums/...threadid=30286