You use radiation for cooling in space. That obeys the Stefan-Boltzmann law with power scaling with T^4 (so you want the radiators as hot as possible). You can use passive elements, like heat-pipes to move heat to the radiators, but active elements like pumps for forced convection could make sense; and most importantly heat pumps are an active element that can boost the temperature of the radiators vs the thing you're keeping cool (thereby increasing the heat rejection capacity of a given radiator size).
Thanks. Since (like the answer by a "Fluid/Thermal Engineer" with a PhD says) the ISS uses mechanically-pumped fluid loops to transfer the heat to radiators, certainly a server farm in space (with its much higher energy density) should, too, rather than relying on a simpler, but less efficient passive-cooling design in which heat gradients cause the convection or movement of the fluid -- and ISTR reading that heat gradients don't even cause convection in the absence of gravity.
