Cold-aisle containment
In a cold-aisle containment system, two ITE rows face front-to-front, with the cold air coming up through vented floor tiles of the common aisle. Cold air is isolated from the rest of the room air with curtains and/or Plexiglas panels (Figure 6). This ensures that only cold air is drawn into the ITE racks. The warm exhaust air exits the rear of the racks and is collected conventionally by the CRAHs.
Figure 6: Cold-aisle containment strategy
ITE racks
Basic room requirement:
Raised floor
CRAH
Cold-aisle containment is generally the easiest strategy to implement in a data center. There are no restrictions for cable trays above the racks, and IT systems are easily scalable. But because much of the data center room is at the hot air stream temperature, cold air meant to cool personnel in the room will mix with the warm air from the ITE racks, resulting in cooler air returned to the CRAH. Low return-air temperature can reduce cooling system efficiency, causing it to use shorter compressor cycles and/or re-adjust the chilled-water flow more often.
If you retro-fit an existing data center with an air containment strategy, you must adhere to fire codes. Fire suppression systems must have access to the face of the ITE racks.
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