cooling
KEEPING IT COOL IN A HIGH DENSITY WORLD
Steve Davis of Next Generation Data gives some guidance on how to get more efficiency out of your cooling system .
Cooling , together with power and energy management , is critical to data centre resilience and uptime as well as in determining a facility ’ s overall power usage effectiveness
( PUE ). With cooling typically accounting for 40 per cent or more of a data centre ’ s total energy bill , the more that can be done to optimise and reduce cooling the better from cost , environmental and legislative perspectives .
There are various options and alternatives available – some only within the grasp of new build rather than legacy facilities – including the harnessing of climatically cooler locations that favour direct air and evaporative techniques ; installing intelligent predictive cooling systems ; using water , liquid or nano-cooling technologies ; along with prerequisite aisle containment techniques – hot or cold .
A fundamental step towards improving cooling efficiency is to move away from perimeter cooling whereby CRACS circulate cold air via raised floor plenum . Instead , adopt a hot aisle / cold aisle configuration with racks aligned in rows and server exhausts facing one another to create the hot aisle . Combined with the separation of hot and cold air streams through either hot ( HACS ) or cold ( CACS ) aisle containment , this approach will enable cooling systems to be set to higher temperatures , saving more energy while still providing safe operating temperatures for IT equipment .
Often used in combination with traditional perimeter cooling , the CACS approach encloses the cold aisle to separate the hot and cold air streams allowing the rest of the data hall to become one single hot air plenum . The addition of cold aisle end curtains or doors and ceilings will further reduce the mixing of air streams .
Inherent inefficiencies While CACS is certainly a big improvement on cooling efficiency compared to the sole reliance on a perimeter only approach , there are inherent inefficiencies . This is due to the distance and pressures and therefore energy required for distributing sufficiently chilled air from the perimeter CRACS to the servers .
There are also limitations with CACS on rack cooling densities ( over 6kW ) due to the limitations of distributing sufficiently cold air through raised floors . Higher densities require higher airflow and producing and driving larger volumes of cold air
24
cooling
KEEPING IT COOL IN
A HIGH DENSITY WORLD
Steve Davis of Next Generation Data gives some guidance on
how to get more efficiency out of your cooling system.
C
ooling, together with
power and energy
management, is
critical to data centre
resilience and uptime
as well as in determining a facility’s
overall power usage effectiveness
24
(PUE). With cooling typically
accounting for 40 per cent or more
of a data centre’s total energy
bill, the more that can be done to
optimise and reduce cooling the
better from cost, environmental and
legislative perspectives.
There are various options and
alternatives available – some only
within the grasp of new build rather
than legacy facilities – including the
harnessing of climatically cooler
locations that favour direct air and
evaporative techniques; installing
intelligent predictive cooling systems;
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