Precision Cooling for
Business-Critical Continuity
Taking Heat Removal To The X-treme.
Liebert XD™ Series Supplemental Cooling Solutions
2
NEW TECHNOLOGY IS CREATING NEW CHALLENGES
The Trends Are Now Realities
Data centers, network operations
rack, concentrating extreme power
and web hosting facilities are very
and heat densities—a situation
different today than they were
that must be addressed to assure
just a few years ago. Smaller, faster,
maximum reliability.
more powerful blade servers,
This increasing density leads to
communications switches and
more heat output, placing a premium
other electronics are being packed
on mission-critical cooling solutions
into tighter and tighter spaces.
that can prevent thermal overload and
Equipment that used to fill an entire
keep equipment up and running.
room is now contained in a single
10,000
8,000
6,000
Density
Communication - Extreme
e and Custom
Computer Servers - 1U, Blad
Communication - High Density
2U and Greater
Computer Ser vers -
4,000
2,000
1,000
800
600
400
200
100
y
ensit
me D
xtre
E
n
icatio
mun
rs
Com
v
r
Se e
puter
Com
s
r
e
v
r
ge Se
Stora
alone)
(stand
tations
Works
age
Tape Stor
Storage Servers
Workstations (standalone)
100,000
60,000
20,000
10,000
6,000
4,000
Tape Storage
2,000
800
60
1992
1994
1996
1998
2000
2002
2004
2006
2008
2010
2012
2014
Year of Product Announcement
ASHRAE, Datacom Equipment Power Trends and Cooling Applications, 2005. © American Society of Heating,
Refrigerating and Air-Conditioning Engineers, Inc., www.ashrae.org
Heat load per equipment footprint (watts/equipment sq.m.)
Heat load per equipment footprint (watts/equipment sq.ft.)
More Power Consumption Means More Heat Output
More Heat Can Mean
Less Usable Space
Reliability is paramount to any data center or hosting
facility. There are other factors, however, that must be
taken into consideration when planning for availability.
3
50W
Watt Per Rack
The rapid growth in microprocessor capability has
created equipment that is much smaller. What was a
1kW rack now may exceed 10 kW per rack.
This has caused a shift in focus from “Watt per square
As processor capabilities
increase, so will computer
room power densities —
from 50 Watt per square
foot (540W/m2) to over
300 Watt per square foot
(3200W/m2). Without
new cooling solutions,
your usable space will be
consumed by cooling
equipment.
foot” to “kW per rack” when creating cooling solutions.
This is significant, since it represents a change from
a typical room-based view of cooling, where the
focus is removing heat from the room, to a rack-based
view, with more focus on ensuring proper cooling of
300W
individual racks.
More Efficient Use Of Space
Proven mission-critical Liebert air conditioning systems
are the foundation of the proper solution—but hot spots
or zones require targeted cooling. If typical cooling
configurations are used to support this high density
growth, they may simply take up too much floor space
to be practical. The solution is a combination of a
room-wide system along with a supplemental cooling
system designed to target hot spots where they occur.
600+W
New Liebert technologies allow you
to extend your existing infrastructure
investment
Further risks are created
because this higher heat
load may not be evenly
distributed throughout the
room, creating extreme
“hot spots” where power
densities can grow into
the hundreds of Watt per
square foot. Typical cooling
solutions simply cannot
properly handle
this level of demand.
Liebert XD systems handle heat loads of 20kW/rack
while requiring minimal to no floor space, allowing your
choice of rack manufacturer selection, requiring less
energy for cooling than any other technology and using
refrigerant—not water—in your controlled space.
H2O
The Mission-Critical
Cooling Difference
4
Mission-critical cooling systems
are designed to run the same hours as
your operations—continually, year in
and year out, around the clock. These
systems are specifically designed to
maintain both temperature and
humidity levels to equipment
manufacturers’ specifications and
do it in the most energy-efficient
method possible.
Mission-Critical Air
Conditioning Systems
Typical Comfort Air
Conditioning Systems
High sensible heat ratio
High sensible heat ratio,
typically .85-.95
Low sensible heat ratio,
typically .60-.65
High-efficiency air filtration
Minimum MERV rating of 8
Typical MERV rating of 5
Humidity control
Integral with control system
Typically an add-on system
with separate controls
Year-round operation
Positive operation to outdoor
ambients as low as -30°F
Typically used May to October,
no low ambient control
High airflow
500-600 CFM per ton
of cooling
300-400 CFM per ton
of cooling
Required Attributes
Design
Considerations
for any
Computer
Room or
Data Center
Environment
By contrast, standard building air
conditioning is designed for one thing:
to keep people comfortable, typically
operating less than 1000 hours per
year. Also, unlike people, computers
generate dry (sensible) heat, but not
humidity. Only about 60-65% of a
comfort system's total capacity is
dedicated to the removal of
sensible heat, while 35-40% is for
dehumidification. With a large
percentage of their total capacity
devoted to the removal of moisture,
comfort systems can lower room
humidity far below acceptable
standards and have no provisions
for adding moisture. Improper
humidity levels can cause static
electricity discharges during dry
seasons and condensation
forming within the electronic
equipment during wet periods.
Additional design
considerations are
required for high
density environments
such as concentrated
airflow to high heat
areas and well planned
back-up in case of
isolated equipment
failure. These issues
can only be addressed
using unique, specific
solutions as described
on page 6-7.
BEST PRACTICES FOR DATA CENTER DESIGN
Step One:
See also white paper “Adaptive Cooling In The Data
Center: The Roadmap For Growth” at www.liebert.com
HIGH AVAILABILITY INFRASTRUCTURE
Start With The Best
A Liebert Deluxe System/3 or Liebert DS mission-critical
cooling unit is ideally suited to handle the heat load
generated by today’s 50-100 Watt per square foot room
(540-1100 W/m2). As part of a high density solution, it
provides the base cooling, humidification and air filtration
control. Supplemental Liebert XD cooling capacity is added
as heat loads increase.
Limitations Of The Hot
Aisle/Cold Aisle Approach
As you can see below, even using a hot aisle/cold aisle
configuration, the limits of standard underfloor cooling
are soon reached as rack heat loads increase.
Temperature
°F °C
100 / 38
80 / 27
RACK
RACK
RACK
RACK
90 / 32
70 / 21
60 / 16
Heat Load = 3 kW Per Rack
Without Hot/Cold Aisle Layout
COLD AISLE
RACK
HOT AISLE
RACK
COLD AISLE
RACK
HOT AISLE
RACK
COLD AISLE
Temperature
°F °C
87 / 31
One of the more widely
recommended methods of
improving the performance
Temperature
°F °C
98 / 37
rows of equipment racks are
arranged in alternating "hot"
COLD AISLE
RACK
HOT AISLE
RACK
COLD AISLE
RACK
HOT AISLE
RACK
COLD AISLE
approach. In this configuration,
66 / 19
60 / 16
technology in high density
been the “hot aisle/cold aisle”
73 / 23
Heat Load = 3 kW Per Rack
With Hot/Cold Aisle Layout
of existing raised floor cooling
rack-based applications has
80 / 27
88 / 31
79 / 26
69 / 21
60 / 16
Heat Load = 6 kW Per Rack
With Hot/Cold Aisle Layout
COLD AISLE
RACK
HOT AISLE
from under the raised floor.
RACK
101 / 38
COLD AISLE
that allow cool air to come up
RACK
115 / 46
HOT AISLE
aisles have perforated floor tiles
RACK
Temperature
°F °C
COLD AISLE
and "cold" aisles. Only the cold
87 / 31
73 / 23
60 / 16
Heat Load = 10 kW Per Rack
With Hot/Cold Aisle Layout
Note: Analysis via Fluent© AirPac™ tool
5
Mission-critical heat removal systems can now be configured to target cooling directly at hot spots. This capability is
especially valuable in facilities with high numbers of heat-generating electronic components. New cooling equipment designs
handle high heat loads without consuming additional floor space.
6
Targeted Supplemental
Cooling
Adding targeted supplemental cooling is much more cost-efficient than
trying to lower the temperature of
localized hot spots by increasing the
overall room air conditioning capacity.
To assure a cooling path that follows
the growth of heat load, planning
ahead to add targeted cooling as
demands grow is a way to simplify
installation and reduce costs. The key
is to put the necessary piping in place
ahead of time and then add cooling
units and chillers as the need arises
for more cooling capability.
Liebert X-treme Density missioncritical cooling systems are specifically
designed to address the higher heat
loads generated by tightly packed
electronic rack enclosures. Individual
systems can improve interior air flow,
cool hot air ejected from the enclosure
or cool hot spots near the racks.
LIEBERT XD COOLING SOLUTIONS: AN ADAPTIVE
MISSION-CRITICAL COOLING ARCHITECTURE THAT
ACCOMMODATES CHANGES
Step Two:
MANAGING GROWTH
Liebert XD™ Series Zone
And Spot Cooling Units
Are Available In Several
Configurations:
Liebert XDC
Chiller
Liebert XDP
Pumping Unit
The XD Solution Starts With An
Innovative Coolant Application
A Coolant Chiller Designed For
Direct System Configurations
Pumping Unit
Designed For Indirect
System Configurations
This unique application of an offthe-shelf product makes the Liebert
XD solution very energy efficient.
The XD Coolant operates at low
pressure and becomes a gas at room
temperatures, making it ideal for
use around electronic equipment.
The Liebert XDC Coolant Chiller is a
specially designed indoor unit that
connects directly to the Liebert
XDO or XDV systems and provides
XD Coolant circulation and control.
It ensures that the coolant is
constantly above the dew point
in the room, eliminating concern for
condensation. Available with several
heat rejection options.
When a building chilled water
system is available, the Liebert
XDP Pumping Unit serves as an
intermediary to isolate the building
chilled water circuit from the XD
Coolant circuit. It circulates coolant
to the XDV or XDO at a temperature
always above the dew point to
prevent condensation.
DIRECT SYSTEM CONFIGURATION
Liebert
Heat
Rejection
Liebert
XDC Coolant
Chiller
Liebert
XDC Coolant
Chiller
XDO / XDV
XD Coolant
Building
Chilled
Water
Liebert
XDP
XDO / XDV
XDO / XDV
XD Coolant
XDO / XDV
XDO / XDV
XD Coolant
INDIRECT SYSTEM CONFIGURATION
Liebert
XDP
XDO / XDV
XDO / XDV
COLD AISLE
HOT AISLE
COLD AISLE
HOT AISLE
COLD AISLE
HOT AISLE
COLD AISLE
HOT AISLE
COLD AISLE
HOT AISLE
COLD AISLE
HOT AISLE
Liebert XDO
Liebert XDV
7
The Liebert XD units also enhance the hot aisle/cold aisle design of raised floor applications by efficiently
drawing hot air out of the hot aisle and discharging cool air into the cold aisle.
Temperature Profile of XDO System
Temperature Profile of XDV System
Temperature
°F °C
95 / 35
86 / 30
77 / 25
68 / 20
60 / 16
The XDO and XDV fill the cold aisle with air at the temperature
required for proper operation of the electronic equipment.
Note: Analysis via Fluent© AirPac™ tool
Liebert XDO
Overhead
Cooling
Module
Liebert XDA
Air Flow
Enhancer
Liebert XDV
Vertical
Top Cooler
Cost-Efficient
Solution Eliminates
Internal Hot Spots
The Overhead
Cooling Solution
Space-Saving Solution
That Cools From The Top
The ceiling-mounted
Liebert XDO mounts directly
overhead in the cold aisle.
It draws in hot air from the
hot aisle, and then discharges
cool air into the cold aisle.
This energy-efficient system
takes up no floor space.
Uses XD Coolant.
The Liebert XDV mounts
vertically above or on the IT
rack enclosure, drawing hot
air from inside the cabinet
or from the hot aisle. It then
cools the air and discharges
it down to the cold aisle.
Uses XD Coolant.
H2O
H2O
The Liebert XDA Air Flow Enhancer
pulls air through an enclosure—
eliminating internal rack hot spots
in densely loaded racks. This lightweight fan unit mounts to the
exhaust side of any enclosure. It
moves the heat away from the IT
equipment to the hot aisle where
the cooling system is designed to
handle it.
H2O
Liebert XDV System With
3kW Heat Load Per Rack
Racks
Perforated
Raised
Floor Tile
Mission
Critical
Cooling
Unit
Liebert XDV System With
5kW Heat Load Per Rack
FLEXIBILITY FOR
FUTURE GROWTH
The Liebert XD Piping system makes it easy
to plan and expand your Liebert XD cooling
system in response to a growing heat load.
Liebert XD Piping is pre-fabricated
distribution piping that is installed in
anticipation of a growing system,
then XD cooling modules are added
as required and are quickly made
operational with flexible connection
piping with quick-connect fittings. This
unique system allows the room cooling
capacity to increase to more than 500
Watt per square foot (5400 W/m2)
with no additional disruptive piping
installation. The flexible connection
piping also allows the cooling modules
to be re-positioned without interruption
in operation.
XDV Module
Above Rack
XDP/XDC
Liebert XD Piping
8
Mission
Critical
Cooling
Unit
Mission
Critical
Cooling
Unit
Mission
Critical
Cooling
Unit
XDV Modules
Above Rack
XDP/XDC Units
Liebert XDV System With
8kW Heat Load Per Rack
Mission
Critical
Cooling
Unit
Invest Now, Save In
The Future
Mission
Critical
Cooling
Unit
XDV Modules
Above Rack
XDP/XDC Units
Liebert XD Piping provides for future
expansion and simplifies both the
installation of additional units and
the reconfiguration of components as
needs change.
Liebert XDV & XD0 System With
16kW Heat Load Per Rack
Mission
Critical
Cooling
Unit
Mission
Critical
Cooling
Unit
XDP/XDC Units
Ceiling-Mounted
XDO Modules
XDV Modules
Above Rack
9
To ensure business continuity in your mission-critical facility requires the ability to
monitor what is happening in the critical space at any given moment—and having
the assurance that service and maintenance support is immediately available to
respond to any problems.
ADAPTIVE MONITORING ARCHITECTURE: INCREASE
AVAILABILITY AND REDUCE SUPPORT COSTS
Facilities Mgmt.
System/ Third Party
Integration
Liebert Monitoring
Applications
BAC net
Velocity
Jbus
Remote Monitoring —
Always There, Always Alert
MODBUS
HTTP
No matter where your facilities are
SNMP
located, continuous 24-hour remote
Protocols
IT/Network
Management
System
User Applications
monitoring of mission-critical cooling
Local Browser
Session
units, UPS/power conditioning
equipment, fire detection and other
facility systems is available through
the Liebert Global Services or Remote
Liebert monitoring technologies allow easy information maneuverability
to key recourses, whether you need to integrate critical system data with
your Network Management System, Building Management System or enable
a Web browser interface.
Monitoring Service.
10
See also white paper “Life Cycle Costing For Data Centers: Determining
The True Costs Of Data Center Cooling” at www.liebert.com
HIGH DENSITY ROI: A LIFETIME OF VALUE
Performing A Life Cycle
Cost Analysis For High
Density Cooling Methods
To illustrate the true costs of a
Liebert XD solution, consider
this example:
We will consider two different
cooling methods.
A clear way to compare the cost
of a Liebert XD solution to a typical
conventional cooling configuration
is through a life cycle cost analysis.
When evaluating alternative solutions,
life cycle cost analysis is a key to
understanding your return on
investment and making purchasing
decisions based on true costs versus
only initial costs.
An existing small data center with
typical raised floor cooling will be
updated to accommodate racks with a
heat load of 6 kW per rack instead of
the current 1 kW per rack. This results
in an approximate heat load for the
room of 330 Watt per square foot
(3500W/m2), including aisles and
service space. An existing chilled
water system in the building will be
sufficient for the new racks.
■
Liebert XD Solution—solves
the upgrade by utilizing an
overhead Liebert XD high-density
supplemental cooling system that
requires minimum floor space and
is more energy efficient than the
Typical Solution.
■
Typical Solution—utilizes
an increased number of standard
mission-critical air conditioning
units in a raised floor environment.
High Density Cooling Life Cycle Cost Comparison For 10 Years
Liebert XD Solution
Life Cycle Costs-Over 10 Years
200,000
Total Cost ($)
180,000
160,000
140,000
i
Typ
120,000
100,000
So
c al
b
Lie
80,000
er
lu t
ion
S
t XD
olu
tio n
Equipment and Installation Cost
All hardware and installation costs
(material, labor and project expenses)
unique for the solution
$ 48,000
$35,500
Opportunity Costs
Costs associated with one alternative but
not another. In the example, Liebert XD
occupies 5% of the floor space and the
alternative solution occupies 18% of the floor
space, resulting in a lower opportunity cost
for Liebert XD. $ 100/sq.ft total floor space
cost used in the example.
$ 2,500
$ 9,000
Annual Maintenance Cost x 10
$3,000
$10,000
Annual Operation (Energy) Cost x 10
@ $ 0.07/kWh
$116,000
$140,000
Total Life Cycle Cost
$169,500
$194,500
60,000
40,000
0
5
Years
10
Typical Solution
Note that when the total life cycle cost for the expected operation of each system is
calculated, Liebert XD is shown to be significantly less expensive than the typical solution.
Data Center Cost (New Construction)
$30,000
Cooling System
$25,000
Building Cost
Less Cooling
$20,000
$15,000
$10,000
$5,000
50 W/sq.ft
(500 W/m2)
150 W/sq.ft
(1500 W/m2)
400 W/sq.ft
(4000 W/m2)
80,000
27,000
10,000
$0
Building Size (sq.ft.)
Study - Data Center Cost (New Construction)
400 racks with an average heat load of 10 kW each. Cost for building, power,
cooling, lighting, fire protection, security, etc. included. Cost of land not
included.
Scenario 1: 80,000 sq.ft. (8000m2), 18" (450mm) Raised Floor, Designed for
50 W/sq.ft (500W/m2), Traditional Precision Air Conditioning units
for cooling.
Scenario 2: 27,000 sq.ft. (2700m2), 36" (900mm) Raised Floor. Designed for
150 W/sq.ft (1500W/m2),Traditional Precision Air Conditioning
units for cooling.
Scenario 3: 10,000 sq.ft. (1000m2), 18" (450mm) Raised Floor. Designed for
400 W/sq.ft (4000W/m2), Traditional Precision Air Conditioning
units (for basic cooling and humidity control) and Liebert XD.
Power Usage Consumption Comparison
kW input power / kW cooling
Total Data Center Cost (less land)
($000)
Fixed Load of 4,000 kW
0.30
Overall 18% lower power usage
0.30
64% lower fan power
0.25
0.20
0.15
0.10
Total Savings
@75% load=> 22%
@50% load=> 50+%
0.05
0.00
Traditional
Cooling CW
Liebert XDP
with XDV
System Type
Evaporator Fans
XD Refrigerant Pumps
Refrigeration System
(compressor, condenser)
Why The Liebert XD System
Makes So Much Sense
Investing in a facility that utilizes
a higher rack density design offers
a significant cost savings advantage
in terms of building size and
energy usage.
To meet the challenge of high
heat loads, the Liebert XD system
delivers cooling where it is needed
most. It also requires 18% lower
energy consumption compared to
typical solutions.
The flexible configuration of the
Liebert XD system modules allows
scalability for future growth, as well
as the ability to add redundant units
for maximum reliability in the most
mission-critical applications.
The Liebert XD approach
significantly improves floor space
utilization compared to an installation
using only floor-mounted cooling
units. Because of the cooling module
size and placement, installing more
XD capacity uses virtually no additional
floor area.
Talk To Liebert First
No one knows more about
protecting mission-critical
facilities—and no one has
more solutions to your high
density cooling needs. For more
information, contact your local
Liebert Representative or visit
us at www.liebert.com.
11
Ensuring The High Availability Of
Mission-Critical Data And Applications.
Liebert Corporation
Emerson Network Power, the global leader in enabling business-critical continuity,
ensures network resiliency and adaptability through a family of technologies —
including Liebert power and cooling technologies — that protect and support
business-critical systems. Liebert solutions employ an adaptive architecture that
responds to changes in criticality, density and capacity. Enterprises benefit
from greater IT system availability, operational flexibility, and reduced capital
equipment and operating costs.
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While every precaution has been taken to ensure accuracy and
completeness in this literature, Liebert Corporation assumes no
responsibility, and disclaims all liability for damages resulting
from use of this information or for any errors or omissions.
© 2005 Liebert Corporation. All rights reserved throughout
the world. Specifications subject to change without notice.
All names referred to are trademarks or registered trademarks
of their respective owners.
® Liebert and the Liebert logo are registered trademarks
of the Liebert Corporation.
SL-11265 (R1/06)
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The global leader in enabling business-critical continuity.
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