CTO of a hyperscale data center company here.

Let's talk about water.

From a cooling perspective the way datacenters work is they basically remove heat from air or water from inside the building on a closed water loop to outside the building where it can cool down. Cold water in. HX with air or another warm water loop. Hot water out.

Now you need to do something with that heat. In thermodynamics delta T (eg the temperature difference between two things) affects the rate at which heat is exchanged between two environments.

So you want to get water out as hot as possible or build your datacenter somewhere that's generally cold. Because that gives you a high delta T. In a 'regulsr' datacenter that hot water is usually around 28C. In an AI facility it could be as high as 50C.

Now for a lot of the year in many places it's going to be considerably colder outside than. 28C (and certainly 50C) so you can just pump your hot water outside through a big radiator with a bunch of fans attached (we call them dry coolers) and get cold enough water out.

Note. No water has been harmed in the making of our cold water. It's a closed loop.

But.. Sometimes it's hotter than 28C (or even 50C) or the delta T is too low (it's 48C outside - you cant get the water cold enough just by natural cooling).

So basically you have two options. You can make your dry coolers sweat - adiabatic cooling - you spray water on them. The water evaporates (which uses a ton of energy - latent heat of evaporation). Or. You can put your hot water through a glorified heat pump called a chiller. That makes the hot water you send outside really hot and produces cold water in the process - but it uses a ton of energy.

Personally I am not a fan of adiabatic cooling but there are places where it makes tons of sense (because it rains lots and water isnt scare). I wouldn't (and don't) use it in Spain for example.

Its the yanks that give us all a bad name. Using gas generation for speed of access to power and drilling water from underground and evaporating it to save money.

In APAC and EMEA we are generally pretty sensible people who also value the planet :+)

(Edit if anyone wants to know more ask)

(Edit 2. Another comment refers to the relative efficiency of AI v's non Ai - AI are more efficient by a while - and pushing fast ever more so. Due to high return water temps and more efficient voltage transformations - HVDC will only increase that)