[Amps] making sinks black

Tom W8JI w8ji at w8ji.com
Sat Jul 22 17:00:47 EDT 2006


>>  Black bodies radiate and absorb heat many times
>> more efficiently than a white or shiny body.
>
> I have heard it said that this is largely true at extreme
> temperatures.  Might be nice to have someone dissipate a
> "real world" amount of power (say 100 watts) in a heat
> sink of raw aluminum and do it again with an identical
> sink that is black.  I have a hunch that the heatsinks 
> will
> have similar temperatures

That might be true. Very often the largest portion of 
cooling is through contact with moving air.

This is the same as several others have said, but it might 
be useful to repeat it anyway in different words....

The only advantage to a dark color is when the heatsink is 
surrounded by cooler objects and a substantial portion of 
cooling is through infrared radiation and not through 
cooling by contact with a moving airstream.

If we force air cool or convection cool a heatsink that has 
a "view" of hotter surfaces, things are generally better 
with a clear surface.

73 Tom 




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