Data Center Cooling.

The new high-density servers in our data center have posed quite a serious cooling and power consumption anxiety. Within the span of two years, our typical 1U server purchases have more than tripled in BTU output (from 221 to 780)¹ and more than quadrupled in amperage draw (from .54 amps to 1.91 amps)¹. Despite how well the data center might have been designed, these demands are technically beyond its inherent capacity. Special steps must be taken for those cabinets where we have a high concentration of the newer servers.

One recent step was to optimize the cool airflow within the cabinet enclosure. After some trial and error with several different options, we settled on the Delphi Enclosure Blower -- a 2U, 250 CFM device uniquely designed for this particular application. The cooled air in our data center is supplied at the base of the cabinets through a raised floor, and exhausted into the room through the top of each cabinet. The Delphi Enclosure Blower directs a portion of the cooled air up the inside front to ensure that adequate cooling reaches the intake for all the equipment in the cabinet. Delphi's research claims a 15^o F improvement for equipment at the top of a cabinet (where traditional hotspots occur). Although our temperature monitoring equipment is not configured to measure the front of our cabinets, I do not doubt the claim's validity. My anecdotal experience leads me to believe that Delphi's research is pragmatic.

Improved exhaust flow remains a challenge for the cooling project. The 500 CFM fan at the top of the cabinets aren't powerful enough to expel the heated air so as to keep the temperature differential between the base and the top under 20^o F. Using the basic rule-of-thumb that the cabinet exhaust fan should have a rating roughly equivalent to the sum of all the housed equipments' exhaust fans, we're about 400 CFMs shy of what we really need.

¹ The noted BTU and amperage values are nominal, and can represent as little as 50% of the peak BTU or amperage ratings of the equipment. In practical terms, the nominal values are accurate for regular operation.