Mainframes used to use a pair of chillers, essentially small air conditioners. Lots a problems. As noted above, you need to prevent condensation by knowing temp, humidity and air pressure (which affects heat transfer). Then you need something with thermal inertia because rapidly cycling cooling is a bad idea, letting the CPU get hot is bad, getting it too cold gets condensation. Modern mainframes are closed loop water cooling that is chilled by cold external water or a radiator. Works great.
All that said, I love my heatsink/fan and would not goto water without a real good reason.