The Clusteron rack enclosure brings the necessary fresh outside air to
each chassis, and carries the heated air away, so that it cannot short-circuit
back through another chassis. Fresh cool air enters the rack through the
bottom and front. It is ducted to the front and left side of each chassis,
and metered into the chassis. The hot air from the rear and right side
of each chassis is sucked out and ducted up through the top of the enclosure,
where it can then be removed from the room. The Clusteron is the only
rack enclosure that ducts all incoming and exhaust air, and prevents them
This is an
animated diagram visualizing the airflow within the Clusteron cabinet.
Blue arrows show cool air, the red, hot air. The right angle arrows represent
the flow in and out of the individual Clusteron nodes. The straight arrows
represent the airflow within the cabinet itself.
In the Clusteron, the design of the individual chassis is integrated
with the design of the rack enclosure to work together to provide the cooling solution. In each chassis, fresh
cool air is sucked in through the front and left side, and ducted directly
to the CPU's by a CCSI Wind Tunnel. Two blowers, with static pressure
much higher than a fan, provide the force necessary to move the air through
the sidewall resistance. The power supply is also cooled with fresh air
from outside the chassis. The heated air from both the CPU's and the power
supply is exhausted out the right side and rear of the chassis. This ensures
that heated air is not blown back over a CPU. In this Quadra-Side cooling
solution, air flow is directed through the chassis to ensure that hot
components are always cooled by fresh air from outside the chassis.
CORRECTNESS CAN ELIMINATE CPU THROTTLING
As a self-protection feature, some Intel CPU's incorporate internal temperature
monitoring and a throttling circuit. This thermally controlled governor
will reduce speed to prevent the CPU from overheating, and thus provides
for a stable system even when built into a chassis that is not thermally
correct. The flip side, however, is that the governor limits the performance
by automatically lowering the CPU speed. You don't get the performance
that you paid for, and, what's worse, you have no way of knowing how much
your system performance has been degraded. Tests and observations may
show the server running perfectly, while it is actually only walking,
or even crawling.
CCSI assembled a task force of engineering experts to solve these
thermal obstacles and build "future proof" thermally correct high-density,
high performance servers. The goal was to provide adequate cooling, not
only for today's processor speeds, but also for the 3 and 4 GHz. Processors
we will have soon, and even for new processor designs such as the AMD
Opteron. The result of this research is the CCSI Clusteron.
In most server installations, the air heated by the high speed CPU's
must then be cooled by huge air conditioners. The cost of the air conditioning
is substantial, and the cost of backup power to run the air conditioning
through a power failure is even greater. Recirculating the same air, and
cooling it, is an expensive proposition. With the Clusteron, the hot air
can be exhausted from the room, and fresh outdoor air brought in, instead
of cooling the same air. The outside air requires little or no cooling,
and no backup power is required for the air conditioning system. What
a cost savings! Also, the heated air exhausted from the Clusteron can
be salvaged, possibly to heat other buildings. The greatest savings of
all, though, is in the increased reliability of Clusteron installations.
High quality computers are far more reliable than air conditioners, so
when the functioning of a computer depends on the proper functioning of
an air conditioning system, overall reliability is unavoidably compromised.
And that costs money.
CCSI's Clusteron™ Cooling Technology
CCSI's Clusteron represents a breakthrough in cooling technology for
high density rack mounted servers. The Clusteron carries cool, fresh,
outside air directly to each CPU, rather than recirculating warm air within
the enclosure. This ensures thermally correct cooling of each CPU, and
permits high density installations to operate at maximum speed 24/7. In
today's high power, high density servers, the cooling is the technology
that makes the difference.
In legacy tower server chassis and in low-density rack chassis installations,
there was ample real estate in the front and rear and on the sides of
the chassis for mounting intake and exhaust fans. In 1U enclosures, however,
there is just not enough wall space to bring in adequate cooling air,
just using fans, to offset the heat produced by 2 high speed CPU's.
When more fans are added, they just recirculate the warm air within the
enclosure, so their ability to cool the CPU is limited. Add it up:
Ambient air temperature 95° (outdoors on a summer day)
+ Offset based on heat transfer ability 60° (typically - depends on fan)
= Total CPU operating temperature 155°
The CPU "absolute maximum" temperature ratings are typically
185°. If recirculated air is used for CPU cooling, and it has already
been heated to 130°, then the equation becomes 130° ambient + 60° offset
= 190° - and the CPU will be damaged or destroyed. Every degree rise in
intake air temperature to the CPU cooler directly translates into a corresponding
rise in the CPU junction temperature. Recirculated air cannot adequately
cool the CPU's in a 1U or even 2U rack mounted enclosure.
©Copyright 2003 CCSI (Computer &
Control Solutions, Inc)