Emissivity is one factor, but it is dwarfed by the T^4 term. Sure, maybe if you use exotic materials you can get from 0.9 to 0.95 emissivity, but why bother? Just run the radiators a little hotter.
replyThe equation is:
A ~ (1000 P) / (2 e k T^4)
A is the radiator area in square meters
P is the power in kilowatts
e is emissivity (usually 0.9)
k is the constant 5.67e-8
Emissivity is an important factor here because as I said, and as the sources I linked for you to reference clearly stated convective radiation is not taking place in space.
replyBoth Google and NASA are worried about this for a reason, if you think they are wrong, you should offer your assistance to them, rather than debating me.
My point is you don't need fancy/expensive materials for your radiator. Anodized aluminum is at 0.8. With inexpensive coatings you can get to 0.9.
replyIf your argument against space datacenters is "radiator materials are too expensive" then I just think that's not a very good argument.