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

10 questions from Part 5 of the guide. Score instantly; every explanation links to the chapter that derives the answer.

What density should the facility be designed to clear, per the guide?
today's accelerator generationthe average of the fleetwhatever the first tenant needsthe rack two generations out — density decides the cooling architecture, and structure is hard to retrofit
A planned rack sits in the overlap where air, a water-fed rear door, and direct-to-chip liquid might all work. What evidence decides the cooling path?
ambient temperature alonea universal rack-power cliffOEM heat split and airflow limits, inlet and outlet envelopes, static pressure, fan power and acoustics, facility-water availability, service constraints, and the density roadmapthe cooling method used by the previous tenant
Single-phase vs two-phase cold plates currently: 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 guide's water heat-balance flow result per kW of liquid-captured heat is roughly…
flow doesn't scale with power~1.43 L/min per kW at a 10 K coolant rise15 L/min per kW0.1 L/min per kW
The CDU's core job is to…
isolate the rack loop from the facility loop and control its ΔT/flowreplace the cooling towerstore thermal energychill the water below ambient
An OEM says a rack is compatible with ASHRAE W45. What must the plant designer establish next?
use the class maximum as the operating supply temperaturepair the class maximum with the highest return temperature found in any vendor recordselect dry coolers without checking climate binschoose an actual design supply, return, flow, coolant, CDU approach, and heat-rejection point that close the rack and plant heat balances
Two vendor records both use the W45 label but publish different coolant figures. What may the designer combine?
the highest supply limit from one and the highest return from the othernothing until the platform and profile match and each figure is classified as an acceptance bound, operating example, or derived design pointthe flow from whichever record is largerall values, because the class label makes the profiles interchangeable
Water-side economizing versus mechanical-only cooling cuts annual cooling energy by roughly…
~95%~5%~40–65%~15%
The heat-reuse decision starts with which question?
what temperature and useful heat reach the offtaker after the actual rack design point, exchanger approaches, distribution losses, and any heat pumpwhether pipes can reach the citywhich utility buys electricity backwhether ERF is mandatory in the US
Why do cooling-control slew rates matter uniquely in AI halls?
CDU valves and pump VFDs must chase synchronized GPU load steps without oscillatingslow controls save energy with no downsidethey don't — thermal mass absorbs everythingregulations cap pump speeds

Check your understanding: Cooling & Thermal Management