Rubin

Rubin-generation racks go fully liquid: every chip and switch sits on a cold plate, no fans, with 75% water and 25% glycol in a sealed loop. A 50MW site is pitched at over $4M a year saved on cooling and water.

Practitioners say the catch is climate. You need outside air below about 37C to guarantee a 45C outlet, so most sites still keep cooling towers for the hot days.

And the bigger water sink stays untouched: power generation, not the building, is where most of a data center's water actually goes.