Air Flow Key to Coping With Cooling Challenges

Ninety five percent of IBM's blade customers are using air cooling, rather than next-generation fluid cooling solutions.

Many of the speakers at last week's Data Center World (AFCOM) conference discussed the data center of the future, a facility fully engineered for cooling high-density blade server installations. But most companies can't build that state-of-the-art facility just yet, and only a modest number of data center operators are actually making the transition to cooling their "hot spots" with water or fluid refrigerants.

As a result, there was also plenty of discussion about how best to soup up the data center of the present. In the short term, many companies will focus on making the most of air cooling as they prepare for a future transition to a new facility or new cooling systems.

How many data centers are using water or refrigerants for cooling? The best clue came from IBM, which provided details on its next-generation of blade server technology. "Ninety five percent of IBM's blade customers are using air cooling," said Steve Simon, director of IBM's eServer BladeCenter strategy. "Sometimes you have a spot problem that requires water cooling." "Right now, what the market will bear is air cooling," said Bret Lehman, senior engineer with IBM's xSeries Thermal Engineering team. "We plan on working with air."

In many cases, the primary challenge is not the volume of cold air being generated, but getting the cold air to where it's needed. Several discussions at Data Center World focused on design solutions that rework the existing data center space to control the flow of cold air and hot air in sections of the facility set aside for high-density computing, and focus the flow of each in the most efficient manner using hot and cold aisles.

An example is the "chimney" approach, in which hot air exiting the rear of the equipment rack is collected above the ceiling, and then routed directly back into air conditioning units at the exterior of the raised floor area. This prevents the hot air from re-entering the rack or recirculating into the cold aisle.

Data center operators are also partitioning the space beneath the raised-floor, trapping the cold air in a concentrated area of the sub-floor where it can be guided through open tiles in the floor and into the cold aisle of the equipment area.

As air flow control takes center stage, there was strong interest in computer modeling services that can provide detailed maps of airflow within a data center, such as TileFlow from Innovative Research or CoolSim from Fluent.