Upload
elson-lin
View
102
Download
2
Embed Size (px)
Citation preview
Interested in conducting your own webinar? Email [email protected]
Room Cooling in the Data Center
Containment Strategies to Improve
Performance
Joe Capes
Director – Business Development, Americas
Cooling Line of Business
Archive www.missioncriticalmagazine.com
Add to your favorites
Room Cooling in the Data Center
Containment Strategies to Improve
Performance
Joe Capes
Director – Business Development, Americas
Cooling Line of Business
5
Agenda
●Data Center Cooling Trends
●Containment Methodologies
●Economizer Technologies
●Economic Considerations
●Final Recommendations
6
Agenda
●Data Center Cooling Trends
●Containment Methodologies
●Economizer Technologies
●Economic Considerations
●Final Recommendations
7
Traditional Data Center Cooling Methods
• Many data center professionals have inherited traditional data centers
Characteristics of Traditional Cooling
• Designed with energy efficiency as a low priority
• Cooling units located at outside perimeter • Raised floor • Hot air mixes with cold air • Inconsistent hot / cold aisle arrangement • Oversized power and cooling components • Low IT rack power densities
Present Trends
• New emphasis on high efficiency and low carbon emissions • Row cooling and separation of hot and cold air streams are new
breakthrough technologies to help to remedy the situation
Introduction
8
Today’s Main Cooling Architectures for Air-
cooled Servers
Central Air Handling Unit
Room Based Architecture
Computer Room Air Handler
Room Based Architecture
InRow Air Handler
Row Based Architecture
9
Room Row Rack
Different Cooling Architectures for Air-
Cooled Servers ● The two main cooling equipment functions are to…
● Provide the bulk cooling capacity
● Distribute the air to the IT loads
● The major difference in architectures lies in how they perform the second task. ● Airflow is crudely constrained by room design, is not visible in
implementation, and varies considerably between installations.
Floor plans showing the basic concept of room,
row, and rack-oriented cooling architecture.
10
Raised Floor Architecture for Air Distribution
One such possible constraint…
11
Capacity Utilization
Claimed Capacity vs. Usable Capacity
0%
20%
40%
60%
80%
100%
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
Average Per-Rack Power Density (kW)
Usab
le C
RA
C C
ap
acit
y
row-oriented cooling
rack-oriented cooling
rooom-oriented cooling
Usable air conditioner capacity as a function of average
rack power density for the three cooling architectures
12
A Hybrid Approach to Cooling
● Most Data Centers will have a mix of heat densities and therefore
cooling solutions
● IT Refreshes happen every 2-4 years resulting in a mix of distributed
IT assets
● IT management of blades and storage deployments is often in
clusters
● Concentrated high density loads
● Traditional server assets may be well served by room cooling units
d
Row-
oriented Rack-
oriented
Room-
oriented
13
World Power Consumption Growth Ranking
Data Centers Average % Projected Growth in Power Growth 2011-2012 (Data Center Dynamics)
Actual Projected Sample kw/Rack
●1st Turkey 85% (60%) 110 MW 3.61 kW
●2nd Colombia 50% (40%) 90 MW 3.60 kW
●3rd Brazil 48% (45%) 280 MW 3.05 kW
●4th China 46% (28%) 500 MW 2.75 kW
●5th Argentina 41% (36%) 120 MW 3.14 kW
●9th Eastern USA 22% (13%) 320 MW 4.35 kW
●22nd Western USA 2% (3%) 100 MW 5.32 kW
14
Room Cooling
● Ducted supply air for delivery to heat load
● Open or ducted return air for heat removal
● Fixed fan speeds to deliver consistent plenum
pressures
● Airflow restrictions in under floor plenum
● Non-uniform airflow distribution
● Fixed flow tiles/grates
● Limited capacity resolution
● Delivery of colder air to the space
● Reduced Sensible Heat Ratio (SHR)
CRAC/CRAH Airflow Configurations
Front Suction with
Top Discharge
Bottom Suction
with Top Discharge
Front Suction with
Top Front Discharge
(Plenum and Grille)
Rear Suction with
Top Discharge
Top Suction with
Bottom Discharge
(Plenum and Grille)
Top Suction with
Bottom Discharge
(Floorstand)
UP
FL
OW
D
OW
NF
LO
W
16
CRAC/CRAH Checklist
High efficiency in all operating conditions
Optimized air flow management with EC fans
Compact dimensions
Front service access only
Competitively priced
1rst Year Parts/Labor/Travel
17
Agenda
●Data Center Cooling Trends
●Containment Methodologies
●Economizer Technologies
●Economic Considerations
●Final Recommendations
The two basic approaches to airflow containment
COLD-aisle containment HOT-aisle containment
The key benefit of both methods comes from SEPARATION of
cold supply air from hot return air
COLD air free in the room
HOT air free in the room
Cold aisle
Hot aisle
19
Common Characteristics:
• Prevent Hot and Cold air streams from mixing
• Cooling systems can be set to a higher temperature
• Reduction of humidification and dehumidification costs
• Better overall physical infrastructure utilization that enables rightsizing
Those benefits lead to energy savings and better equipment utilization compare to traditional cooling methods
Containment Approaches
Hot and cold containment force different operating temperatures
If personnel space temperature is held constant, then hot containment
allows higher air conditioner operating temperatures
If person
is 25 C
If person
is 25 C
Return is
25 C
Return is
35 C
Supply is
15 C Supply is
25 C
COLD-aisle containment HOT-aisle containment
21
CACs Unique Characteristics
• Typically used with traditional perimeter cooling – cold air supplied via raised floor and perforated tiles. Alternatively CACS is designed with row based cooling system
• The rest of the room becomes large, return hot air plenum
Cold Aisle Containment Limitations • Perimeter Cooling – Longer air paths and higher air pressure resistance -
higher power consumption by fans • Less than optimum return air temperature – lower cooling capacity and
efficiency • Limited power density per rack - limited by the raised floor and perforated
tiles • Limited predictability – variable room and raised floor dimensions • Limited ride through during cooling failure - confined to Cold Aisle air volume • Room acts as the Hot Aisle – contradicts with perception that data centers should
be cold. Peoples’ expectation when entering the room need to be adjusted. • Room acts as the Hot Aisle – difficulty in cooling free standing racks and
equipment • Not modular & scalable due to room cooling architecture
Cold Aisle Containment System (CACS)
22
HACs Unique Characteristics
• APC by Schneider Electric holds the concept patent • Often used with Row cooling – hot air is captured and neutralized via cooling units
placed within the row of racks and supplied to cold aisle • The rest of the room becomes large, cold air plenum, no raised floor or ducting is
required Hot Aisle Containment Advantages • In-Row Cooling is Closed Coupled: Short air paths and low air pressure
resistance - lower power consumption by fans (See White Paper #130) • Higher return air temperature – higher cooling capacity and efficiency of the
cooling system • High power density per rack – all heat is neutralized and there is no limitation
with the raised floor and perforated tiles • Predictable solution – independent of room and raised floor dimensions • Higher ride through during cooling failure – significantly larger cold aisle air volume • Room acts as the Cold Aisle – in agreement with the perception that data centers
should be cold Continued....
Hot Aisle Containment System (HACS)
23
Hot Aisle Containment Systems (HACS)
InfraStruXure High Density
InfraStruXure InRow RC
In-Row Air Conditioner Cools hot
chamber air
Chamber Doors
Access to hot aisle, locks for
security
Hot Aisle Ceiling Tiles/Cable Trough
Seals in hot air, prevents
mixing with room air
● High Density Zones
● Supports InRow products
● Hot air scavenging system
● Ducted Return / Free Supply
● Optimize InRow Cooling
● Increase efficiency
● Improve predictability
● Use at any density
24
Agenda
●Data Center Cooling Trends
●Containment Methodologies
●Economizer Technologies
●Economic Considerations
●Final Recommendations
25
Trends - Economizers
• Air Side Economizer • Requires ‘cool enough’ outside air to
maintain desired temperature in data center
• Outside DRY BULB temperatures from
40°F (4.4°C) to 80.6°F (27°C)
• Humidity control required when outside of
control range typically less than 40% or greater than 60% RH
• Requires pre-treatment & filtration of outside air to mitigate
potential for particulate contamination within data center
• Need to have ‘control’ of the real estate and zoning regulations
around you
• Water Side Economizer • Requires ‘cool enough’ outside air to chill water/glycol
• Outside WET BULB temperatures 40°F (4.4°C) to 64.4 F (18°C)
26
Economizer Requirements
None - 1a, 1b, 2a, 3a, 4a
> 19kW - 3b, 3c, 4b, 4c, 5b, 5c, 6b
>40kW - 2b, 5a, 6a, 7, 8
27
ASHRAE 90.1 Climate Zone Economizer Requirement Map
No requirement
Data Centers >19kW
Data Centers >40kW
Basically, if you’re blue, economizer use is mandated!
28
Economizers – Summary of Legacy
Situation
●Complex infrastructure
requires special controls,
installation, and maintenance
●Multiple vendors involved
●These systems have a higher
chance of failure and
emergency maintenance
Custom Economizer Systems
Complex System
Economizers – Installations into
Existing Data Centers Cooling
Equipment
Type
Water Side
Economizer
Air Side
Economizer Comment
Direct Expansion
Large External Air
Handling System Not Practical Possible
Additional coil sections would be required making it impractical to consider a water side
economizer. An air handling system located outside or within close proximity makes
consideration of outside air economizer possible.
Traditional Floor
Mounted
CRAC/CRAH
Not Practical Not Practical
Dual coils are required to implement a waterside economizer on a DX system, and would
require additional coils to be added or units replaced. Typically, CRAC/CRAH units are in
the interior of the building and would not lend themselves to ducting to the outdoors for air
side economizer.
Close Coupled
Cooling Not Practical Not Practical
Dual coils are required to implement a water side economizer on a DX system, and would
require additional coils to be added or units replaced. Close coupled units are installed
within the rows of IT equipment making it difficult to access outside walls and provide
ducting to support an air side economizer.
Chilled Water
Large External Air
Handling System Likely Possible
Adding a plate and frame heat exchanger with valves and controls is likely to be considered
with a chilled water system. An air handling system located outside or within close
proximity makes consideration of outside air economizer possible.
Traditional Floor
Mounted
CRAC/CRAH
Likely Not Practical
Adding a plate frame heat exchanger with valves and controls is likely to be considered
with a chilled water system. Typically CRAC/CRAH units are in the interior of the building
and would not lend themselves to ducting to the outdoors for air side economizer.
Close Coupled
Cooling Likely Not Practical
Adding a plate frame heat exchanger with valves and controls is likely to be considered
with a chilled water system. Close coupled units are installed within the rows of IT
equipment making it difficult to access outside walls and provide ducting to support an air
side economizer.
30
Economizer Competitive Analysis
1.09 466,518 45%
1.10 503,999 48%
1.14 728,195 70%
1.16 846,039 81%
Fresh Air Econ 1.14 718,159 69%
1.20 1,044,073 100%
5) All system have fan control proportional to IT load % of design
Relative
PowerPartial PUE kW-Hr/Yr
4) Does not reflect humidification losses
EcoBreeze
Air Econ w/ Heat Wheel
Water Cooled Chiller w/ Econ
Air Cooled Chiller w/ Econ
DX Fluid Cooled CRAC w/ Econ
1MW Design Data Center @ 60% Load
1) Hot Aisle Containment 101.5°F Return to A/C
2) Supply Air / Cold Aisle 77°F
3) Bin Weather Data Saint Louis, MO
System Architecture
31
Agenda
●Data Center Cooling Trends
●Containment Methodologies
●Economizer Technologies
●Economic Considerations
●Final Recommendations
32
Financial Comparison
● Data Center Sizes – 60, 120, 480, 1200 kW
● Rack Density – 3, 6, 12, 20 kW per Rack (120 CFM/kW)
● Raised Floor Air Distribution for Room Cooling – 100 Euro/ m2 ($8/ft2)
● Raised Floor Pricing range from 30 Euro / m2 to 400 Euro / m2($50/ft2)
● Does not consider fire suppression under floor ($4-$10/ft2)
●Drop Ceiling for Room Cooling Hot Aisle Containment – 36 Euro / m2 ($4/ft2)
● Based on RSMeans Cost Works Data Base – Typical Drop Ceiling
● Does not consider fire suppression in drop ceiling range ($4-$10/ft2)
●Active Floor for Room Cooling with CAC and raised floor for high density (12
and 20 kW per rack)
●Piping costs based on RSMeans Cost Works Data Base – Steel Piping
● Cost of Energy = 0.1 Euro / kWh
●EcoStream Analysis Tool used to determine airflow required for each scenario
Benefits of Containment – Room Cooling
€ 290,000.00
€ 310,000.00
€ 330,000.00
€ 350,000.00
€ 370,000.00
€ 390,000.00
€ 410,000.00
€ 430,000.00
€ 450,000.00
3 kW 6 kW 12 kW 20 kW
Fir
st
Co
st
Density (per Rack)
480 kW Data Center - First Cost
Room w/ raised floor
Room CAC w/active floor
Room HAC no Raised Floor
Room HAC w/ raised floor
€ 60,000.00
€ 65,000.00
€ 70,000.00
€ 75,000.00
€ 80,000.00
€ 85,000.00
3 kW 6 kW 12 kW 20 kW
An
nu
al
Op
era
tin
g C
ost
Density (per Rack)
480 kW Data Center - Operating Cost
Room w/ raised floor
Rooom CAC w/active floor
Room HAC no raised floor and Room HAC w/ raised floor
First Cost
• Higher first cost of adding containment to
room cooling
• Room Cooling with no raised floor and Hot
Aisle Containment (HAC) most cost
effective solution
Operating Cost Improvement
• HAC no raised floor ROI over raised floor • 3 kW per Rack = 3 years
• 6 kW per Rack = 1.5 years
• CAC with raised ROI over raised floor • 3 kW per Rack = 4.3 years
• 6 kW per Rack = 2.5 years
Effect of Active
Air Distribution
Annual Operating Costs
€ -
€ 2,000.00
€ 4,000.00
€ 6,000.00
€ 8,000.00
€ 10,000.00
€ 12,000.00
3 kW 6 kW 12 kW 20 kW
An
nu
al
Op
era
tin
g C
ost
Density per Rack
60 kW Data Center
€ 10,000.00
€ 12,000.00
€ 14,000.00
€ 16,000.00
€ 18,000.00
€ 20,000.00
€ 22,000.00
€ 24,000.00
3 kW 6 kW 12 kW 20 kW
An
nu
al
Op
era
tin
g C
ost
Density per Rack
120 kW Data Center
€ 50,000.00
€ 55,000.00
€ 60,000.00
€ 65,000.00
€ 70,000.00
€ 75,000.00
€ 80,000.00
€ 85,000.00
3 kW 6 kW 12 kW 20 kW
An
nu
al
Op
era
tin
g C
ost
Density per Rack
480 kW Data Center
€ 130,000.00
€ 140,000.00
€ 150,000.00
€ 160,000.00
€ 170,000.00
€ 180,000.00
€ 190,000.00
€ 200,000.00
3 kW 6 kW 12 kW 20 kW
An
nu
al
Op
era
tin
g C
ost
Density per Rack
1200 kW Data Center
35
Agenda
●Data Center Cooling Trends
●Containment Methodologies
●Economizer Technologies
●Economic Considerations
●Final Recommendations
36
• Hot Aisle and Cold Aisle Containment eliminate air mixing and are a superior solution compared to traditional cooling architecture
• Hot Aisle Containment System (HACS) is a more efficient approach than Cold Aisle Containment System (CACS) because the HACS methodology allows for the channelling the hottest air directly into coolers
• HACS used with In-Row cooling architecture provides closed couple cooling that allows higher cooling capacity utilization and efficiency
• HACS is more flexible, it can be deployed anywhere within the room, it is more predictable and scalable solution, it better addresses the higher IT density requirements
• HACS has higher potential for better heat utilization and using free cooling approaches
• Hot Aisle Containment has better ride through capability
CACs vs. HACs Summary
37
Characteristic Cold Aisle Containment Hot Aisle Containment Comment
Efficiency improvements
Yes Yes
HACS is more efficient than CACS because HACS typically operates at a higher return
temperature due to isolation of the hot air from the rest of the room.
Ability to increase cold air supply set
point without impacting entire data
center No Yes
With HACS, cooling set points can be set higher while still maintaining a comfortable
work environment. Increasing CACS cooling set points results in uncomfortably high
data center environment.
Leverages maximum number of
potential free cooling days
No Yes
By increasing cooling set point, containment systems allow for increased free cooling.
However, increasing the set point of CACS results in increased room temperatures
which is undesirable from a free cooling day perspective.
Room neutral solution
No Yes
A HACS deployment is a “drop-in” solution. CACS impacts the surrounding data center
infrastructure.
CACs vs. HACs Head to Head
38
Characteristic Cold Aisle Containment Hot Aisle Containment Comment
Ease of deployment with room
cooling
Yes No CACS is preferred when using room level cooling with a
free return system which draws its return air from the room.
A HACS without in-row cooling would require special return
duct work or ceiling plenum.
Ability to scale for high density No Yes CACS is often implemented with raised floor and inefficient
fan assisted floor tiles are needed in order to achieve higher
density.
Room neutral design No Yes HACS is “room neutral”—it does not impact the outside
room temperature in any way. CACS makes the air outside
of the contained rows hotter.
Adverse temperature impact on non-
racked equipment
Yes No With CACS, because the cold aisles are contained, the rest
of the data center is allowed to become hot. Equipment
outside the contained areas would have to be evaluated for
operation at elevated temperatures.
Head to Head (cont.)
39
Existing Data Center Suggestions (Brown Field)
Out of Capacity Stranded Capacity
Low Density
0-6 kW per Rack
High Density
> 6 kW per Rack
Add Room Cooling Cold Aisle Containment
Close Coupled
Cooling Zone for Rack
Expansion or Existing
Racks
Cold Aisle Containment
+ Active Floor
Air Removal Unit or
Vertical Exhaust
Duct(VDE)
IT Load to be
Deployed
40
Final Recommendations
● Always use containment for optimal TCO
● Payback is immediate with close coupled cooling
● 3 year ROI for Room Based Cooling improves with density
●Hot Aisle Containment preferred approach for new data center builds
● Eliminates variable of cold air distribution with or without raised floor
● Improved Flexibility keeping data center cool available for non-racked
equipment and personnel comfort.
●Cold Aisle Containment – Retrofit for existing data center
● Adapt to existing room cooling systems
● Active floor to assist with cold air distribution from raised floor to ensure
sufficient air flow is available in contained aisle.
● Efficiency Gains Require elevating room temperature