Water has the big advantage that it's plentiful, cheap, and environmentally benign. Sure, it'll take some more upfront engineering to design a system/rack/data

Water has the big advantage that it's plentiful, cheap, and environmentally benign. Sure, it'll take some more upfront engineering to design a system/rack/datacenter for water cooling than just immersing a server in a tank of inert liquid (flourinert or whatever they use these days), but I'm quite sure that at some point water cooling will be the standard solution in data centers.