CDCS CDCS Power & Cooling Systems 2

Question 1

What is the ASHRAE A1 thermal envelope recommended inlet temperature range for most enterprise IT equipment?

Accepted Answer

59°F–89.6°F (15°C–32°C)

Answer

ASHRAE A1 class specifies an allowable inlet temperature range of 59°F to 89.6°F (15°C to 32°C) for standard enterprise servers and storage equipment.

Question 2

Which cooling technology uses water-chilled rear-door heat exchangers attached directly to server cabinets?

Accepted Answer

Rear-door heat exchanger (RDHx)

Answer

Rear-door heat exchangers (RDHx) mount directly on the back of server racks, capturing hot exhaust air at the source and transferring heat to chilled water before it enters the room.

Question 3

What does N+1 redundancy mean in the context of data center UPS systems?

Accepted Answer

One additional UPS module beyond the minimum required for full load

Answer

N+1 redundancy means one extra capacity unit beyond the minimum (N) needed to support the full load, so the system tolerates one unit failure without losing capacity.

Question 4

What is the primary advantage of using a hot-aisle containment (HAC) system over cold-aisle containment (CAC)?

Accepted Answer

HAC keeps the general room air cooler and safer for personnel

Answer

Hot-aisle containment captures exhaust heat directly at the hot aisle and routes it to cooling units, so the ambient room temperature remains at a comfortable level for personnel working outside containment.

Question 5

Which metric describes the percentage of time a data center's power infrastructure is expected to be available per year?

Accepted Answer

Uptime percentage (nines)

Answer

Availability is expressed as uptime percentage (e.g., 99.9999% = six nines), which correlates to Uptime Institute tier classifications for annual downtime tolerance.

CDCS - Certified Data Center Specialist Practice Test

CDCS - Certified Data Center Specialist Practice Test

CDCS CDCS Power & Cooling Systems 2