Quiz: AI Data Center Cooling & Liquid Thermal Management (Part 5)

What density should the facility be designed to clear, per the guide?

today's accelerator generationthe rack two generations out — density decides the cooling architecture, and structure is hard to retrofitthe average of the fleetwhatever the first tenant needs

Around what rack power does air cooling become untenable?

~5 kW~15 kW~40 kW (rear-door stretches further)~500 kW

Single-phase vs two-phase cold plates in 2026: what's the state of play?

two-phase dominatessingle-phase is the default (~55% of the liquid market); two-phase sits behind PFAS and fluid-economics questionsboth are obsoletesingle-phase only works below 500 W

The OCP flow rule of thumb for direct-to-chip loops is roughly…

0.1 L/min per kW1.5 L/min per kW for a ≤10 °C coolant rise15 L/min per kWflow doesn't scale with power

The CDU's core job is to…

chill the water below ambientisolate the rack loop from the facility loop and control its ΔT/flowreplace the cooling towerstore thermal energy

The single number from which free-cooling hours, heat-reuse grade, and rejection choice all follow is…

the site's latitudethe ASHRAE liquid class (W17 → W45+) your facility loop is designed to deliverthe chiller COPthe number of racks

GB200 NVL72-class racks accept coolant at approximately…

7 °C supply, chilledup to ~45 °C supply / ~65 °C return classexactly 20 °C or throttling occursany temperature below boiling

Water-side economizing versus mechanical-only cooling cuts annual cooling energy by roughly…

~5%~15%~40–65%~95%

The heat-reuse decision starts with which question?

which utility buys electricity backat which grade you capture heat — the ~30–40 °C air-side stream or the hotter DLC returnwhether pipes can reach the citywhether ERF is mandatory in the US

Why do cooling-control slew rates matter uniquely in AI halls?

regulations cap pump speedsCDU valves and pump VFDs must chase synchronized GPU load steps without oscillatingslow controls save energy with no downsidethey don't — thermal mass absorbs everything

Check your understanding: Cooling & Thermal Management