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8: What About Chillers, Cooling Tower Fans, and All That
Cooling Equipment Usually Ignored by IT? 143

Together, the efficiency of the refrigerant and the location of the cooling
modules can reduce cooling system energy costs by 27 percent. Additionally,
refrigerant use reduces chiller capacity requirements by 20 percent. This
increases energy-savings and also enables additional cooling capacity without
adding additional chillers.
Traditional floor-mounted cooling systems with under-floor air delivery
will continue to play an essential role in data center environmental manage-
ment. It is recommended that traditional systems be configured to deliver
the required cooling for the first 100 watts per square foot of heat load, as
well as solve the room’s full humidification and filtration requirements.
Supplemental cooling can be deployed for densities beyond 150 watts per
square foot.

Fuel Cells for Data Center Electricity

Fuel cells have been proposed to power data centers. For instance, the pol-
luting diesel backup generators that most data centers rely on might be
replaced by fuel cells. In 2008, Fujitsu began using a fuel-cell generator to ptg
power its data center in Silicon Valley. Fuel cells have also been proposed to
be used in an emergency or during peak demand to take some of the load off
the grid. Hydrogen-powered fuel cells are environmentally desirable because
the only output, in addition to energy, is water. The problem is in obtaining
the hydrogen. Currently, hydrogen is usually produced through an energy
intensive process using natural gas and immense amounts of electricity.
When technological breakthroughs enable us to produce hydrogen effi-
ciently, fuel cells for data center energy will be a significant step forward.

Other Emerging Technologies for Data Centers

Energy costs will likely continue to rise in the future as will the comput-
ing requirements of most organizations. Taking steps today to increase the
efficiency of the cooling system can offset the impact of rising energy costs
when newer, higher-efficiency technologies are deployed. Three technologies,
in particular, have potential to significantly enhance data center energy
efficiency as follows:

■ Multicore processors
■ Embedded cooling
■ Chip-level cooling