Cooling and Environmental Control Flashcards

What is the primary purpose of a containment system (hot aisle/cold aisle containment) in a data center?

Answer: Prevent mixing of hot exhaust and cold supply air

Containment systems physically separate hot exhaust air from cold supply air, dramatically improving cooling efficiency.

In a data center, what does CRAH stand for?

Answer: Computer Room Air Handler

CRAH (Computer Room Air Handler) uses chilled water coils—rather than refrigerant like CRAC units—to cool the air.

Which metric is used to measure the efficiency of a data center's cooling system relative to total IT load?

Answer: COP

COP (Coefficient of Performance) specifically measures cooling efficiency as the ratio of cooling output to electrical energy input.

What is the recommended approach when a data center experiences hot spots despite adequate overall cooling capacity?

Answer: Add blanking panels and seal cable cutouts in affected racks

Blanking panels and sealed cutouts prevent bypass airflow and recirculation, directing cold air where it is needed.

A data center is transitioning to a higher rack power density of 20 kW per rack. Which cooling approach is most likely required?

Answer: In-row or rear-door heat exchanger cooling

High-density racks (above ~10 kW) typically require in-row or rear-door heat exchangers to remove heat closer to the source.

What is the ASHRAE A1 thermal envelope's recommended inlet temperature range for IT equipment?

Answer: 64.4°F–80.6°F (18°C–27°C)

ASHRAE A1 specifies an allowable inlet temperature range of 59°F–80.6°F (15°C–27°C), with 64.4°F–80.6°F as the recommended range.

Which type of economizer cooling uses outdoor air directly to cool the data center without mechanical refrigeration during favorable weather?

Answer: Airside economizer

Airside economizers draw in cool outdoor air directly into the data center, bypassing the chiller when conditions permit.