END USER INSIGHT
purchase three Liebert Smart Rack PDUs
MPX from Vertiv and to test the DCD
air-water cooling doors in a two-month
trial period.
The result of the proof-of-concept was
clear: with 20 to 25 kW per rack, the new
solution had still not exceeded the power
limit. Another benefit was the huge
space saving.
The price was also unbeatable which
meant the decision was quickly made and
the new data centre was equipped with
just under 30 racks.
The results: Higher performance
densities for the servers, cost
reductions, space saving and
greater energy efficiency
in addition to the high-performance
computers, the EPFL uses racks where
output amounts to a maximum of 10 kW.
The initial plan was to use the CoolTherm
solution for high density (up to 30kW) and
hot-air containment for lower needs (up
to 10kW).
After consulting with Vertiv’s experts in
depth, it was decided that the Knürr DCD
Water Cooled Rack Doors from Vertiv were
the best cooling solution for all the racks.
The air-water cooling door from Vertiv is
an air-water heat exchanger integrated in
the rear door of the server rack. The cold
water is used in a closed heat exchanger
system directly behind the servers in the
rear door of the rack. All the heat of the
integrated IT equipment is dissipated via
the water circuit which feeds the rack
door with cold water and carries away
warmer water.
The water cooling solution has also
resulted in a lower risk of failure, greater
system reliability and fewer error sources
than with a solution based purely on air
cooling. This type of cooling also reduces
energy consumption through electrical
loss and the cooling process.
The optimised heat exchanger structure
and short air paths without diversions
also mean there is no need for additional
fans in the cooling unit. Cooling via the
DCD air-water cooling door achieves
power usage effectiveness (PUE) values
of 1.06. The same pipes are used for
the new water cooling system as those
previously deployed for the transport of
water from Leman Lake, thus reducing
investment costs.
As the water is used directly in the DCD
air-water cooling rear door rack exchanger,
the EPFL used 30% to 50% less space
compared to conventional air cooling
systems despite integrating more servers.
The cooling effect occurs when the warm
outgoing air flows through the heat
exchanger in the rear section of the server
cabinet. The cooling air flow is driven
solely by the server fans. Today, up to 90 DCD Cooling Doors carry
out the cooling of the 300 m2 data
centre. The temperature is regulated
via thermostatic valves which control
the water flow in the heat exchanger
depending on the current load in the rack.
Additional fans in the cooling door are
not required. Boisseau initially decided to This means the water volume can be
adjusted to the power density in the
www.intelligentdatacentres.com
racks and vice-versa – the DCD Cooling
Doors can be deployed as the sole
cooling solution in the entire data centre
regardless of the various performance
densities in the racks.
“When it comes to cooling servers and
racks with different power densities or
high-performance servers, Vertiv’s water
cooling solution with the DCD air-water
cooling doors is an outstanding solution,”
said Aristide Boisseau Data Center
Architect and Operations at the EPFL.
“It stands out due to its low PUE values,
higher energy efficiency, lower costs and
easy installation compared to conventional
air-cooling systems. If the volumes of data
to be processed and power densities at data
centres increase, data centre managers
should definitely consider this innovative
and future-oriented method of cooling.”
Looking ahead
In 2015, Boisseau realised that the
capacity of the new data centre
commissioned in 2012 was running short.
One of the older data centres also had
to be completely upgraded to meet the
increasing requirements.
He therefore began planning a new
data centre which is set to be put into
operation by 2021 at the latest and to
upgrade the old data centre.
In accordance with WTO guidelines, the
EPFL as a government-run university has
to put out a new invitation to tender for
the construction of the new data centre.
Vertiv will take part in the tender process
with its innovative and application-
oriented water cooling solutions. ◊
TODAY, UP TO
90 DCD COOLING
DOORS CARRY
OUT THE COOLING
OF THE 300 M2
DATA CENTRE.
Issue 09
0
49