Page 170 -

8: What About Chillers, Cooling Tower Fans, and All That
Cooling Equipment Usually Ignored by IT? 135

relaxed clock speed, which helps keep the heat down…. Retrofitting and
greenfielding [a data center for liquid cooling]…add both cost and complex-
ity. The real answer is don’t put the heat into the data center and you don’t
have as much to take out.” So, the back-to-the-future direction of using liq-
uid cooling in the data center is not without controversy. In truth, liquid
cooling never actually left the data center because computer room air condi-
tioners (CRACs), typically scattered about data centers, use chilled liquid
from the chillers (outside the computer room) to generated cold air for cool-
ing the IT equipment. A certain amount of controversy can help assure that
standards for the new data center IT liquid cooling technology are well
tested.

Strategies for Increasing Data Center Cooling Efficiency

The following data center cooling efficiency strategies were based on a
white paper from Emerson/Liebert (see the Bibliography). The white paper
indicates that as electricity prices and IT power consumption continue to
rise, IT-related energy costs are getting increased scrutiny. Cooling accounts ptg
for approximately 37 percent of electricity usage within a well-designed data
center and, in many cases, represents a significant opportunity to reduce IT
energy costs.
Some proven strategies for increasing data center cooling efficiency are as
follows:

■ Proper sealing of the data center environment: A vapor seal plays a
critical role in controlling relative humidity and reducing unnecessary
humidification and dehumidification.
■ Optimizing air flow: Rack arrangement, computer room air conditioner
placement, and cable management all impact the amount of energy
expended to move air within the critical facility.
■ Using economizers where appropriate: Economizers allow outside air
to support data center cooling during colder months, creating opportuni-
ties for energy-free cooling.
■ Increasing cooling system efficiency: New technologies, such as
variable capacity systems and improved controls, are driving increased
efficiency of room air-conditioning systems.
■ Bringing cooling closer to the source of heat: Supplemental cooling
systems bring cooling closer to the source of heat, reducing the amount
of energy required for air movement.