Thermal Management Solutions … from APW President
Thermal
Management
Solutions
from
APW President Systems
Thermal Management Solutions … from APW President
… the story so far
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

In the beginning power dissipation
levels in Cabinets were low ……………….
typically 300-600 watts
With the advent of rack mount servers,
the power dissipations increased ………..
typically 1000-2000 watts
Now, with use of 1U Servers becoming
widespread, these levels are set to cross.

Floor space in Data Centres is expensive.
The trend is to pack as many servers in
one cabinet as possible

But conventional cooling methods are
inadequate when the “ceiling” is reached
6 KW in a 42U cabinet!
$ 20,000.00/sq.ft
3.6 KW in a cabinet
Thermal Management Solutions … from APW President
So what do we do? We start with the basics!
Fundamentals of Heat Transfer…. revisited
• What happens inside Electronic Equipment
• What happens inside Cabinets containing electronic equipment
• Typical arrangements in Datacentres and Computer rooms
• Introducing the CoolRack from President – and how it works
• The CoolRack – a real life solution
• What the CoolRack solution will do for you
• A summary of benefits
• More COOLING options from President
Thermal Management Solutions … from APW President
General Cooling Methods
1
All electrical components
and devices emit heat.
At low energy levels
radiation is a good enough
way to dissipate this heat
2
At higher dissipation
levels, radiation alone
will not suffice and heat
has to be conducted
away by using heatsinks
3
At todays power levels
radiation and conduction
methods are inadequate.
Heat has to be “convected”
away by moving fresh
air past the heat-emitting
devices
Thermal Management Solutions … from APW President
Todays high performance Rack-Mount Servers consume as much as 300 Watts of power in a
1U high format. This power is dissipated as heat within the cabinet
1U Server
2U Server
3U Server
A 1U Server
uncovered
Current Trends
• Power Dissipation
• Packing Density
• DC fans to evacuate the heat
• Individual fans for critical devices
• Prevention of hot spots forming
due to still air
Thermal Management Solutions … from APW President
Internal view showing devices with heat sinks for conduction and DC fans set up
to create strong air currents from the front of the equipment towards the rear.
Thermal Management Solutions … from APW President
Thermal Management Solutions … from APW President
In general, professional grade equipment have
adequate cooling provisions designed into them
so that they are able perform normally to their
published specifications given the required
ambient conditions…….
provided those required
ambient conditions are maintained unimpaired.
Equipment stacked inside a Cabinet encounter
a very different environment from the freestanding equipment in an air-conditioned room.
Thermal Management Solutions … from APW President
Conventional cooling methods for computer equipment in cabinets
… generally adopted arrangements
Light thermal loads
When heat dissipation is 300 watts or less, no special arrangements for airflow
are needed. The metal skin of the cabinet provides sufficient heat transfer
through radiation.
Thermal Management Solutions … from APW President
Moderate thermal loads
Exhaust fans
cause cabinet
air to flow to
the top
The warmed up air flows out
from the top after collecting heat
from the equipment inside
Air is drawn into the
cabinets through
vents at the sides
Note: This arrangement works fine
as long as cabinets are not placed
side-by-side, as this will prevent
airflow into the cabinets
When heat loads are between 300 – 600 watts conventional arrangements
for dissipating the heat by means of air convection are adequate.
Thermal Management Solutions … from APW President
Heavy thermal loads
In the case of rackmounted Servers that
have their air intakes
in the front, or rows
of cabinets placed
side-by-side, air flow
MUST be from the
front to the rear of
the cabinets
When the heat load inside cabinets with rack- mounted Servers
exceeds 1000 watts, then strong airflow has to be set up in the frontto-back direction. But these conventional methods have limitations
Thermal Management Solutions … from APW President
The type of arrangements for cooling of equipment inside
cabinets just seen is the conventional approach. These worked
fine till now when heat loads were fairly light. But these
methods have severe limitations in todays situation.
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Conventional cooling methods are 30 years old

Conventional designs compromise equipment reliability

Conventional cooling systems are expensive to build
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Conventional design is expensive to operate
here’s why……….
Thermal Management Solutions … from APW President
In many Computer Centres it is common to have the AC Inlet and Return ducts running
along the top of the room. This results in airflow patterns that are far from ideal for the
equipment inside the Cabinets.
Incoming
air at
16-18 C
Return air temp.is
25-28 C at best
Inlet air will take the line
of least resistance.A large
proportion will flow into the
return duct
Air exiting the cabinets
Will be at 27-30 C
Air flowing down is diluted by the
room air.Temp.will rise to 22-25 C
by the time it is drawn in at the
bottom of the cabinets
Thermal Management Solutions … from APW President
The newer computer facilities may have both false ceilings and raised plenums with the inlet
AC ducts below the raised floors while the return air ducts are above. This leads to more
effective equipment cooling
Air temp
at top of
will be 2023 C
Most incoming air still
flows into the room.Its
temp.rises to 20-23 C
Inlet air at 16-18 C
Is drawn into the
Cabinets at the bottom
Air inflow at 16-18 C
Thermal Management Solutions … from APW President
Same room showing cabinets positioned over the AC inlet
Return air ducts
Incoming air at 16-18 deg. C
Thermal Management Solutions … from APW President
Airflow patterns and temperatures in a typical Computer centre
“Delta T” is 10 deg
typically
Thermal Management Solutions … from APW President
Possibilities with the “CoolRack” arrangement
A “ Delta T” of as
much as 20 deg is
possible
Thermal Management Solutions … from APW President
How does the CoolRack concept work ?
• Conventional Datacentre set-up
With a delta T of 10-11 degC and 3.6 kilowatts power dissipation
Airflow required = 569 CFM
• With the CoolRack set-up
And a delta T of 20 degC, with 3.6 kilowatts power dissipation
Airflow required = 284 CFM
• Thus the CoolRack method uses half the airflow !
• Half the airflow means a 50% reduction in Air Handling capacity
• Each AC unit transfers twice as much heat energy
• Reducing the airflow by half means 50% fewer fans motors
Thermal Management Solutions … from APW President
• In a typical data centre, fan energy accounts for 28% of the total cooling plant
energy
• The CoolRack approach reduces the cost to cool a data centre by 14%
• It also reduces the initial investment outlays because …..
Half as many AC units are needed, and associated ducting
Reduced cooling plant size (due to less fan motor heat)
Reduced emergency power requirements
Leading to a net saving on initial investments of 5% or more
Thermal Management Solutions … from APW President
Introducing the CoolRack --- a configured solution for your thermal problems
Thermal Management Solutions … from APW President
CoolRack – an internal view
Thermal Management Solutions … from APW President
Presidents
CoolRack
A side view showing the
Internal airflow paths
Thermal Management Solutions … from APW President
Same views - but showing airflow arrangements
Thermal Management Solutions … from APW President
Presidents CoolRack - the reality
Thermal Management Solutions … from APW President
Thermal Management Solutions … from APW President
Thermal Management Solutions … from APW President
Inside the CoolRack:
Accessories include vertical Cable Managers and
an AC Power Channel with high- reliability
universal IEC Sockets. Note also the provisions for
Cable entry
Thermal Management Solutions … from APW President
Thermal Management Solutions … from APW President
Here’s what has been happening
39 Servers in 42U of
Cabinet space!
Thermal Management Solutions … from APW President
Fans shown mounted directly on the
Rear Door so as to create a front-toback air flow
Thermal Management Solutions … from APW President
Thermal Management Solutions … from APW President
Benefits of the CoolRack solution
• Ability to house more Servers in a Cabinet ……. Upto 42 in a 42U cabinet
• Equipment runs cooler- therefore more reliability…… MTBF is increased
• Optimal use of the AC plant capacity …………… less capacity needed
• Initial costs for Air Conditioning plant reduced …… upto 7% savings
• Running costs for electrical energy reduced ………. upto 14%
Thermal Management Solutions … from APW President
What will the CoolRack do for you ?
•
Provide the means for utilizing your air conditioning capacity more efficiently
•
More efficient use of AC capacity means that you need use less cooling
power
Net Result
Increased MTBF
Savings in investment and operating costs