W45
ASHRAE's liquid-cooling classes keyed to maximum facility-water supply temperature, where a higher number means warmer water: less chiller capex and heat-reuse potential, less thermal headroom.
Also written as: W17 · W27 · W32 · W40
Current numbers
~45 °Cwarm-water inlet band (W40/W45) GB200 & Rubin target — enables near-year-round chiller-less free cooling