zlacker

Space (with a sunshade) is a nearly perfect medium into which to radiate heat, in the sense that there’s nothing better.

But I agree with your general point. At 100°C, you can radiate about 1kW/m^2. That’s 1000m^2 of radiator per MW of datacenter, assuming you can operate with the radiator at 100°C. You can fudge this a bit with a heat pump (to run the radiator hotter, paying a linear-ish power penalty and gaining a fourth-power radiation benefit), but that’s expensive and that power isn’t free.

Here on Earth, you can cool by conduction or evaporation, which isn’t an option in space.

>>amluto+(OP)

  > Space (with a sunshade) is a nearly perfect medium into which to radiate heat, in the sense that there’s nothing better.

There is radiation but zero convection. As anyone with an oven or PC will tell you, even a very tiny fan makes a big difference in the ability to dump heat. We're not putting our PCs into vacuum chambers for a good reason. A small fan in your oven not only makes for more consistent heating in your food, but it requires less power

>>amluto+(OP)
I guess you could cool by conduction in space if you build it on the moon?