CDCS Power & Cooling Systems Flashcards

In data center power design, what does a 2N power path architecture mean?

Answer: Fully redundant dual power paths from utility to every rack outlet

2N architecture provides two completely independent power paths (A-feed and B-feed) from utility through UPS to each rack, so any single component failure in either path does not affect the load.

What is an economizer (free cooling) mode in data center HVAC, and when is it most beneficial?

Answer: Leveraging cool outdoor air or water to reduce or eliminate mechanical chiller operation

Economizer mode uses outdoor ambient air or cooling tower water to reduce or eliminate compressor-based chilling when outdoor conditions are cool enough, significantly lowering energy costs.

Which standard does BICSI TDMM follow for data center power and cooling infrastructure documentation?

Answer: TIA-942

TIA-942 is the Telecommunications Infrastructure Standard for Data Centers, defining structured cabling, power, and cooling infrastructure design tiers and documentation requirements.

What does the term 'stranded capacity' refer to in data center power management?

Answer: Provisioned power capacity that is allocated but not actively consumed by IT loads

Stranded capacity refers to power (or space) that has been allocated or reserved for equipment but is not actually being consumed, reducing overall data center utilization efficiency.

Which type of generator automatic transfer switch (ATS) can test the generator under load without interrupting the critical load?

Answer: Closed-transition (make-before-break) ATS

A closed-transition (make-before-break) ATS briefly parallels the generator with the utility during transfer, allowing load testing with zero transfer time and no disruption to the critical load.

What is the purpose of a flywheel UPS (FESS) compared to a traditional battery-based UPS?

Answer: A flywheel UPS stores kinetic energy to bridge the gap until generators start, offering higher power density and longer cycle life than batteries

Flywheel UPS systems store energy in a spinning rotor, providing high power density for short bridging intervals (10–30 seconds) with virtually unlimited charge/discharge cycles and no chemical degradation.