I cannot help but chuckle at how what is old is new again here. In the 70's and early 80's all of IBM's mainframes supported liquid cooling. Basically when a co

I cannot help but chuckle at how what is old is new again here. In the 70's and early 80's all of IBM's mainframes supported liquid cooling. Basically when a computer "uses" X kW of power it really means that it generates that many kW of heat while it is operating. Removing heat at scale has been a thing for a long time. And what was alluded to in the video is the thermal mass of 'air' kind of sucks. So the old design of chilling air down to 67 degrees and filling a room with that air so that it can circulate around electronics putting out prodigious amounts of heat, and then collected and re-cooled, is not nearly as efficient as one would like. Cooling water, piping it to the heat exchanger in the back door of the rack and then (unlike the video's idea) sucking air through it first, and then pushing the cooled air over the electronics to 're-heat' it, works better. Then you don't really care what temperature the air in the data center itself is as long as the heat exchanger can remove 'x' watts of heat from it before it gets blown over the computers. Suck air in from the floor (the coolest air) and blow it out the top (where it continues on to the ceiling). Still, that only doubles the power capacity of the racks (maybe 2.5x if the heat exchanger is filled with actively chilled water) Prior to heat exchanger doors people would have "cold" aisles and "hot" aisles. The cold air from the CRAC units would come up from the floor behind the servers, get sucked through them and exhausted forward into the "hot" aisle. There is a whole little mini industry of "cold air containment" which has stuff to build doors/covers for the cold aisle so that all of that air is sucked through servers.