The Definitive Guide toAI Data Centers
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Guide › Glossary › Facility water

Facility water · FWS

The building's water loop that ultimately rejects heat to the outdoors, kept separate from the clean chip-cooling loop.

Current numbers

~41 °C FWS -> 45 °C rack coolantNVIDIA’s named 41°C FWS/45°C rack-coolant example can support dry rejection when the local approach and ambient envelope permit it; OCP’s October 2024 roadmap separately proposes 30°C at the silicon/TCS interfaceas of 2026-03-16 · register ↗
~3–5 °Ctypical CDU heat-exchanger approach temperature (lower = warmer facility water, more free cooling)as of 2025 · register ↗
~3–5 °CCDU heat-exchanger approach (FWS→TCS); Deschutes 2 MW CDU targets ~3 °C ATDas of 2025 · register ↗

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