Re: It's still the same heat
This is about the efficiency of moving that heat from the server chips to the chiller plant.
Air-cooled means big fans in the A/C cold outlet to cool air and blow it into the cold aisles, big fans in every server to blow lots of air over the heatsinks, and big fans to move that hot air out of the cabinets and through the A/C intakes to transfer the server heat plus all the fan motor heat into the chiller warm water feed.
Liquid cooled replaces all those fans with a far more efficient pump, that has to move far less volume of liquid.
On top of that, you don't need the chiller to cool the liquid to as low temperatures as the air-cooled, because the heat transfer is so much more efficient. That makes the chiller far more efficient as the temperature difference is greatly reduced. In many climates you might not even need a chiller at all, as your "cold water" feed can be 20 or even 30C, so much higher than ambient.
The difference is several orders of magnitude, assuming you've got a lot of servers.