The Economics of Data Center Air Flow Containment.

The Economics of Data Center Air Flow Containment

An Employee-Owned Corporation 800-834-4969 | www.chatsworth.com

Course Description

This course will explain:

1. The acceptable range of equipment inlet conditions

2. The value of supply air set points versus return air set points

3. The value for maximizing the separation between supply air streams and return air streams.

4. The benefits for maintaining air separation including:• elimination of equipment hot spots• elimination of bypass and re-circulation waste• reduction in fan energy• improvements in cooling coil efficiency• ability to support trends toward higher rack heat density• improvement in chiller plant efficiency• access to increased hours of economization cooling• increased overall design flexibility


Learning Objectives

At the end of this program, you will be able to:

1. Discuss the three basic methods for achieving air separation through hot aisle containment, cold aisle containment, and vertical exhaust ducts.

2. State the relative advantages and disadvantages for the different separation topologies along with application appropriateness.

3. Quantify the cost-benefits for a well-designed air flow management.

4. Explain the overall value of good air flow management, and how it can be achieved using design elements that can enable or compromise best results.


What is the source of your pain?

• Hot spots?

• Cost for energy?

• Growth and/or technology refresh constrained?

• High cost of eliminating hot spots or reducing energy costs or positioning for growth?


Uptime Institute 2012 Data Center Survey


HOTAISLE

COLDAISLE

HOTAISLE

COLDAISLE

FRONTFRONT

BACKBACK

BACK

• Bypass airflow under the cabinets

• Hot air recirculation from the hot aisle into the cold aisle

Limitations of Hot Aisle – Cold Aisle


6

The New ASHRAE Recommended Environmental Envelope

for Class 1 Electronics

What is the target?

2004 Version 2008 Version

Low End Temperature 20°C (68°F) 18°C (64.4°F)

High End Temperature 25°C (77°F) 27°C (80.6°F)

Low End Moisture 40% RH 5.5°C DP (41.9°F)

High End Moisture 55% RH 60% RH & 15°C DP (59°F DP)


14

Typical Set Point Management

72°F (22°C)

55°F (13°C)


15

Mixing of supply air and return air in typical data center



• Hot spots

• Return air could cool an entire data center


72°F (22°C)

55°F (13°C)


17

All the hot return air is isolated from the supply air

• No hot spots.• No concern about return air temperature.

Supply Set Point Management


-Completely preventing hot and cold air from mixing

-Completely capturing either hot or cold air

-100% is probably unrealistic

-leakage is important

-many design trade-offs

-Several design strategies

What is Hot Air Isolation


1. Eliminates hot spots

2. Supports 4x higher heat and power densities (6 kW to 30+kW)!

3. Effectively utilizes 100% of supplied air and reduces chilled air waste!

4. Transfers server equipment ΔT directly back to the HVAC unit!

5. Increase chiller efficiency through higher set points!

6. Can increase economization through higher set-points!

7. Allows supply air delivery from ceiling, wall or floor.

Benefits of Hot Air Isolation


86

83

81

78

75

72

70

67

64

62

59

Elimination of Hot Spots


High Density Cooling

4 IBM H 8852 Blade Servers25kW actual heat load

4 HP c7000 Blade Servers22kW actual heat load


Elimination of Excess Supply Air

600kW IT load6 Stulz CCD-1800-CWE CRAH units (N+1)

Standard Hot Aisle – Cold Aisle Data Center• Air handlers operate @ 83% capacity• Maximum inlet temperature range = 58.6°F – 79.7°F• CRAH fan energy = 32.1 kW or 280,937 kW hours/year

Data Center with Hot and Cold Isolation• Air handlers operate at 73% capacity• Maximum inlet temperature range = 75°F – 76°F• CRAH fan energy = 21.6kW or 189,216 kW hours/year

91,721 kW hours energy saved by eliminating need to produce excess bypass supply air


Cooling UnitSupply Air

TemperatureReturn Air

TemperatureCooling Capacity

Stulz CCD-600-CWE

Labeled as 10 Tons

60˚ F

70˚ F 7.8 tons

90˚ F 15.5 tons

105˚ F 20.7 tons

Stulz CCD-1800-CWE

Labeled as30 Tons

70˚ F 23.0 tons

90˚ F 46.0 tons

105˚ F 61.3 tons

CRAC Efficiency with Supply/Return Isolation

Almost a 3x improvement in cooling unit efficiency!


38% Energy Savings

38% savings = $168,5211MW example

Chiller Efficiency at Higher Set Points

Chart from ASHRAE Data Center Design and Operation Book#6: Best Practices for Datacom Facility Energy Efficiency


538.5kW

Load

Increase Economization Through Better Separation Between Supply and Return Air


Design Flexibility

Return

Supply


Strategies for Air Isolation

Hot air isolation (chimney or VED)

Cold Aisle Containment

(CAC

Hot Aisle Containment

(HAC)


Containment Starts Inside the Cabinet

Blanking Panels

Floor Tile Cut-out Grommets

Cabinet Air Dams

http://www.chatsworth.com/uploadedFiles/Files/34537_datasheet.pdf

http://www.chatsworth.com/uploadedFiles/Files/13336_datasheet.pdf


Cabinet Air Re-Circulation

CFD Model Thermal Imaging Photograph

1” rail set-back = 5+ RMU open space between hot area and cold area


538.5kW

Load




37


538.5kW

Load

Hot Air Isolation with Cabinet Vertical Exhaust Duct


538.5kW

Load

Hybrid Containment with Chimney Cabinets and Hot Aisle Containment


What Is the Best Containment?

DataCenter 2020: Hot-aisle and Cold Aisle Containment Efficiencies Reveal No Significant Differences

Copyright © 2011 Intel Corporation.

The DataCenter 2020 is a joint T-Systems and Intel data center test laboratory in the Munich-based Euroindustriepark.

www.datacenter2020.com



Easy integration of fire suppression

Hot aisle working environment @ 90 – 130⁰F

Flexible supply air delivery architectures

Better low density thermal ride-through

Raised floor not required

Pod deployment

Compatible with row-based cooling



Data Center working environment @ 90 - 130⁰F

Better high density thermal ride-through

Easier retrofit of working data center

Raised floor (usually)

Separate “volume” for fire suppression

Pod deployment

Possibly sensitive to over-pressure

Compatible with row-based cooling


Cabinet Containment

Working environment @ 74 - 80⁰F

16’ pitch may impact fire suppression

Raised floor not required

Thermal ride-through (variable dependent)

Cabinet deployment

3050 CFM density threshold

Flexible supply air delivery architectures


Case Study

• 300kW IT load

• 2000 square feet

• 150 watts per square foot

• 60 cabinets

• 1,025,567 BTU/hr

Case Files


12kW to operate 5 cooling units @ 64% capacity41.8kW to operate chiller @ 65°F H2O leaving temperature0.06 kW for fresh air (N+1)0.56kW for electrical room (N+1)0.06kW for battery room (N+1)15kW for substation (N+1, but not simultaneously running redundancy

608,119 kW hours per year

$60,812 cooling budget at $0.10 per kW hour

(1.23 COOLING ONLY PUE)

Cooling Cost Roll-up


Savings Comparison

• 44% cooling energy savings over original data center

– 35.8% reduction in chiller plant energy

– 73.7% reduction in CRAH fan energy

• 30% cooling energy savings over optimized hot aisle – cold aisle data center

– 30.8% reduction in chiller plant energy

– 52% reduction in CRAH fan energy

• No economizer in any scenario


Benefits of Airflow Management by Containment

• Eliminates hot spots

• Suitable for low, medium and high density

• Eliminates wasted capacity and saves fan energy

• Improves cooling unit efficiency

• Supports supply air set points

– Reduced chiller plant energy use

– Increased “free cooling” utilization

• Facilitates greater design and deployment flexibility


Questions?

Thank You For Your Time

Glen ter Horst(708) 990-0798

[email protected]

This concludes The American Institute of Architects Continuing Education Systems Course

The Economics of Data Center Air Flow Containment.

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