Cooling
‘Statistics
show that
cooling in
the data
centre space
accounts
for 40 per
cent of the
power used
in the entire
facility.’
Rack airflow
management using
chimneys
Similar to my experience with
running, I’ve found that operating
an efficient data centre also takes
constant evaluation and adjustment.
I recently read an article
which stated that cooling the data
centre accounts for 40 per cent
of the power used throughout
an entire facility. My experience
has taught me that an area ripe
for fine-tuning in data centres
is airflow management at the
cabinet level, particularly by
using chimney systems.
For data centre managers to
optimise their cooling efforts
through implementing chimney
systems, it is important to
first recognise the similarities
and then note the differences
between active and passive
chimney systems. Both active
and passive chimney systems
will use a well-sealed cabinet,
designed to minimise the
amount of hot air that can
escape back into the cold aisles.
In both configurations, the goal is
the same: To get cool air to pass
through critical rack equipment
and move hot air into a return
plenum using air containment.
With active cooling, cabinets
rely on energy efficient exhaust
fans positioned at the top of racks
to assist with pushing air into
the return plenum. As a result,
airflow becomes less reliant on
server fans. An active system is
more responsive than a passive
system. This is because the speed
of the fans being used to direct
hot air into the return plenum
can adjust to make up for back
pressures in return plenum or for
varying airflow of the equipment
in the rack.
A passive system relies
entirely on the server fans to drive
the flow of cold air through the
equipment and to subsequently
channel the exhaust through a
duct, back to the return plenum.
In turn, passive cooling could
expend less energy than active
cooling if a negative return
plenum pressure is maintained.
August 2017 | 19