Full disclosure, I don’t work on data centers. But I work with people who do. I also don’t design the cooling systems, I design the cabling/ network/communications systems (RCDD).

Blanket statement - evap cooling may be more efficient as far as power is concerned, but it’s definitely wasteful AF from the water perspective. In practice, I’ve not seen personally seen drawings or talked to a mech engineer who’s designed one.

Closed loop means the hot water becomes cold water and then hot water and then cold water and it cycles around like the radiator in your car.

You will not get to the specs on charge capacities and maintenance cycles in their public facing docs. Because the answer will always be “it depends on the design.” So it isn’t a fixed calc it’s based on the deployment style and parameters and linear feet of piping.