[el_nahual]

Radiator size scales linearly with power but, crucially, coolant power, pumps, etc do not.

Imagine the capillary/friction losses, the force required, and the energy use(!) required to pump ammonia through a football-field sized radiator panel.

[FinnKuhn]

Additionally, I feel like a datacenter is going to produce a LOT more heat than the ISS.