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70 70 P P a r t I I : a r t I I : C C o n s u m p t i o n I s s u e so n s u m p t i o n I s s u e s

Dynamic Smart Cooling is an intelligent solution, and rather than turning your
datacenter into a meat locker, the system allows air conditioners—managed by specially
designed software—to regulate the cold air delivered to a room based on the needs of
specific computers.

NOTE HP has also looked to some of its earlier inventions to solve the cooling cost problem. The
company modified its inkjet printing technology to create a cooling solution where a device
sprays liquid on semiconductor chips to cool them down.

Dynamic Smart Cooling uses the datacenter’s airconditioning system to adapt to
changing workloads with sensors attached to the computers. If the system senses that a
computer is warming up too much, air conditioners will send more cool air.

Optimizing Airflow

Air exchange is important. To deliver the precise cooling environment, air must be
exchanged at a sufficient rate. Normal office environments must change air over twice an
hour. In high-density datacenters, air has to be exchanged 50 times an hour. If enough air
is not exchanged, cooling air will heat up before it reaches the equipment, and disaster
could occur.
Finding the latest and greatest in cooling technology is certainly a useful tactic in
reducing your cooling costs. But some good practices can help minimize your costs without
you having to buy the newest product.
This section looks at some best practices that can help optimize the airflow around your
servers and other networking equipment.

Hot Aisle/Cold Aisle
Equipment is typically designed to draw in air from the front and then blow the exhaust out
the rear. As Figure 4-4 shows, this allows equipment to be arranged to create hot aisles and
cool aisles.

Hot aisle Cool aisle

Exhaust Air intakes

Equipment racks
FIGURE 4-4 Equipment can be configured in a hot-aisle/cool-aisle configuration.