Liquid Cooling System for Data Center Commissioning

What is the primary function of the Coolant Distribution Unit (CDU) in a Direct Liquid Cooling (DLC) architecture?

• To act as a reservoir for all facility water in the data center

• To directly cool the chips using facility water (FWS)

• To isolate the facility water loop (FWS) from the IT coolant loop (TCS) and manage flow/pressure

• To convert AC power to DC power for the liquid-cooled racks

Which of the following is the main reason for using a Propylene Glycol mixture (e.g., PG25) in the Technology Cooling System (TCS) secondary loop instead of pure facility water?

• It has superior heat capacity compared to water

• It is cheaper than De-ionized (DI) water

• It provides necessary electrical conductivity for grounding

• It provides corrosion and freeze protection, isolating the IT equipment

In a full-scale liquid cooling system commissioning sequence, what critical activity is typically performed during the high-load testing phases (Cx3, Cx5)?

• Chemical flushing of the FWS primary loop

• Performing a hydronic pressure test on the rack connections

• Performing a heat load test (HLT) at 100% IT load using liquid-cooled load banks

• CDU sensor calibration and alarm verification

What is the purpose of the multi-stage flushing process (Dynamic, Chemical, and DI water flushing) performed on the TCS piping?

• To test the pipes for pressure leaks

• To achieve system start-up and initial coolant circulation

• To introduce the initial PG25 coolant mixture

• To ensure the piping is free of debris, oils, and chemical residues before filling with the final coolant

Which loop is referred to as the primary cooling loop and is typically responsible for transferring heat to an external rejection source, such as a cooling tower?

• Facility Water System (FWS)

• Technology Cooling System (TCS)

• Coolant Distribution Unit (CDU)

• In-Row Cooler System (IRC)