Actually, the surface causes a change in both emission and absorption or radiative heat. "Black bodies" are good at emission and absorption of radiative heat, not one or the other. I'm not sure what the "first principles" are, because they don't seem to agree with the laws of thermodynamics.
Radiation is fairly counter-intuitive in some ways - compared to conduction and convection, radiation is considerably more complex.
Finally - found a link that's not too cryptic:
http://www.phys.virginia.edu/classes...radiation.html
And some sample emissivity values:
http://www.engineeringtoolbox.com/36_447.html
However, I still don't think the radiative energy is going to make much of a difference in a radiator application (ironic they're named the same).
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Originally Posted by #Rotor
so let me get this right.... a black object will radiate energy better than say a white or shiny chrome object... Is it not the other way around... and in "other way around"... I'm referring to a black object absorbing radiated energy ( light for instance) better. I can not see how the color can have any effect on an object's ability to radiate energy.
from first principles, the color of any object is but nothing more than a reference to it's ability to not absorb a particular set of frequencies in the EM spectrum. Thus an object to appear black in color, needs to absorb close to 100% of the energy in the complete visible spectrum that falls on it.
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