Reducing Energy Consumption with

Passive Cooling

Fernando Reyna

Chatsworth Products

November 2012

Energy Trends: Gartner Group – Sept. 2007

Traditional data centers have been built to specific design specifications, which

struggle to house current (and future) generation high-density servers.

User switch to new technology results in an

initial sharp drop in energy consumption.

Typical users energy consumption curve of

infrastructure.

Underlying energy consumption curve of infrastructure.

Technology platform requires a sharp

increase in energy driven by volume.

2006 2012 2018

En

erg

Co

nsu

mp

tio

n

in D

ata

Cen

ters

Energy Facts

• Data center energy consumption as a percentage of total United States electricity use has doubled since 2000, and data centers and servers will double their energy consumption again – to 100 billion kilowatt-hours by 2012 (EPA)

• Gartner predicts energy costs could soon consume as much as half of an organization's IT budget, moreover, Gartner estimates that 60 percent of a data center's energy consumption is wasted.

• “It is our No. 1 expense. I pay more for electricity than I do for rent,” said Wayne Sawchuk, CEO and co-founder of ColoSpace, which provides co-location services in six data centers composed of more than 4,000 servers across 35,000 square feet in Massachusetts and New Hampshire.

Energy and Inefficiency

• By 2010, for every $1 spent on hardware, 70 cents will be spent on power and cooling

• By 2012, for every $1 spent on hardware, $1 will be spent on power and cooling

• 46% of data center managers don't know how much they spend on power and cooling

Source: IDC Report

What contributes to the heat load that must be factored in to estimate the

total AC requirement ?

EYP Missions Critical Facilities Inc., New York

Sources of Data Center Energy Consumption

Data Center Energy Realities

• Servers do not require 50º to 55ºF supply air.

• Data Centers are “sub-cooled” to compensate for infrastructure shortfalls.

• A properly designed Data Center requires far less cooling tonnage, and air volume–saving equipment, energy and operational expenses.

Data Center Cooling

• Generation – CRAC’s, or Central Station

• Distribution - Remove obstructions

• Consumption – Use only what you need

• Evacuation – Isolate exhaust air

• Recirculation – Return air directly to A/C unit

– EFFICIENT Design of D, C, E and R dramatically effects G and

associated $$$$$’s.

1. Protect and Deliver Supply Air

2. Minimize Bypass

3. Reduce Recirculation

COLD

AISLE

HOT

AISLE

Cabinet

Cable Tray, Electrical, etc…

Data Center Layout +Supply, Utilization, and Return

Chiller

Loop

Basic Hot Aisle – Cold Aisle Layout

CRAC

CRAC

50 °F

Supply

Air

COLD

AISLE

HOT

AISLE

80 °F Return Air

Vented Floor Tiles

Cabinet Cabinet Cabinet

HOT

AISLE

COLD

AISLE

HOT

AISLE

COLD

AISLE

• Data cable tray should run down hot aisle and be ¾” from bottom of floor tile

• Power cables and conduit should be below and in the cold aisle

Underground Cable Pathway Option

Limitations of Hot Aisle – Cold Aisle

HOT

AISLE

COLD

AISLE

HOT

AISLE

COLD

AISLE

• Bypass airflow under the cabinets

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

Poor Data Center Cooling

Insufficient Cold Air Delivered Through Raised Floor

Recirculation and Mixing of Source Air and Return Air

Pre-cools Return Air Temperature

Forces Cooling Units to Operate at Lower Efficiencies

Retains a Lower Chilled Water Temperature

Reduces the opportunity for Economization

Place cooling units at the ends of hot

aisles 8 feet from perforated tiles.

Hot Aisle

C

R

A

C

C

R

A

C

8 Ft Min

Cold Aisle

Cold Aisle

Too Close!

Cooling Unit Placement

CRAC

Air Pressure = 10,000 CFM to over 20,000 CFM

Assumed Underfloor Air Flow

CRAC

Higher Velocity

Lower Pressure

Lower Velocity

Higher Pressure

Cooling Unit Air Flow Reality

Supply Air Distribution Patterns

HIGHEST

FLOW RATE AND PRESSURE INCREASE FARTHER AWAY FROM CRAC

CRAC CRAC

FASTER SLOWER

VELOCITY

SLOWER FASTER

VELOCITY

GREATEST

AREA OF

UNIFORMITY

IS MIDWAY

BETWEEN

CRAC UNITS LESS

UNIFORMITY

LESS

UNIFORMITY

How can you instantly increase your data

center cooling capacity up to 40%

1. Seal all unnecessary access floor openings

– around perimeter walls

– behind cooling units

– behind cabinets

2. Seal all sleeves and wall penetrations.

3. Use vented tiles on only in cold aisles.

By reclaiming wasted bypass air!

Bypass Air Flow

Have at least 64% Open Perforation front and rear metal

cabinet doors to allow sufficient air flow.

Reducing Recirculation Perforated Doors

Use Blanking Filler Panels and Air Dams to seal

between, and around equipment.

Server

BAD

Server

GOOD

Cabinet

without

blanking

panels

and air

dams.

Reducing Recirculation: Filler Panels and Air Dams

• Hot air re-circulates around the

sides and top of the cabinets

• Hot air mixes with cold air

increasing the server inlet air

temperature.

• Blanking panels by themselves

are not sufficient.

Cabinet Air Re-Circulation

The Problems with Cabinet Fans

• Can’t keep up with airflow requirements

of higher density blade servers.

• Will not evacuate hot air out of the

cabinet

• Inhibits hot air from escaping the cabinet

• Adds back pressure to server fans and

slows them down

Air movement capacities of typical cabinet door fans VS.

Air movement requirements of a cabinet full of IBM or Dell Blade Servers

CFM Fan Capacity

400 – 500 Typical Cabinet Top Mount Fan

1350 Highest Standard Top Mount Fan on Market

900 - 1000 Typical Rear Fan

CFM Blade Server Air Movement Requirements

1820 4 IBM eServer Blade Centers

2400 6 Dell PowerEdge 1955

Effect of Fans

Cabinet Fans Cause Hot Spots

Air Flow – Fan Top

Fan Removal Reduces Cold Aisle Temperature

20 Degrees

Cooler!

Air Flow – Solid Top Panel

Why is it Simply Efficient™?

Because it IS very simple and 100% efficient!

Passive Cooling®

It’s Passive Cooling – No moving parts!

Simply utilizes the Laws of Thermodynamics! - Bernoulli Principle - Venturi Effect - Vena Contracta - Sensible Cooling - Thermal Isolation of Supply and Return Systems

Nothing to “back up” when scaling up Tiers !

No single Points of Failure

Nothing to “pipe to”

No Power Requirement

No Heat Generation

It’s Green!

Passive Cooling

Old Paradigm - The cabinet is a box for housing IT equipment.

Take airflow management

beyond current best

practices and open the door

to numerous other benefits

air containment.

Changing the Cabinet Paradigm

New Paradigm – The cabinet is an integral part of the Data Center architecture as an extension of the cooling system.

Why? Because the cabinet is the architectural feature in the data center that secures the isolation between supply air and return air.

1. Completely isolate cold supply air from hot return air!

2. Ensure that all chilled supply air passes through the server!

3. Maintain a constant temperature data center of 77°F!

5. Maximize economization potential !

4. Significantly reduce mechanical costs for power and cooling!

Using Passive Cooling, you can…

6. Earn up to 8 LEEDS Points !

Passive Cooling – Simply Efficient!

Isolate Cabinet Return Air

High Densities 0 – 30kW per Cabinet

Changing the Cabinet Paradigm

Passive Cooling:

• Supports extreme heat loads – 30 kW and above

• Transfers equipment ΔT to the CRAC/CRAH

• Contains and prevents hot exhaust air from re-

circulating over or around cabinet and entering front of

equipment

• Allows room to be flooded with cold air delivering

uniform cold intake air temperatures to all equipment

• Allows CRAC/CRAH the be 100% efficient!

5. “Vena Contracta Effect” in which air flow through the

constriction increases in velocity and creates another low

pressure area that draws the hot air out of the cabinet!

It’s the Bernoulli Principle!

What makes it work?

3. Low pressure area forms along back side of cabinet.

and pulls hot exhaust air from the other servers into the

stream.

2. Exhaust air from bottom server is turned and

increases in velocity as it rises.

4. Virtual constriction formed in exhaust duct.

1. Chilled air is pulled into the server.

Mechanics of Passive Cooling

H

L

Ducts remove hot air

from the cabinet and

room.

Installing air

segregation

accessories helps.

Air re-circulates

inside the cabinet

and into the room.

TYPICAL BETTER BEST

The Problem with Typical Cabinets

No More Hot Aisle!

Cold Aisle

Hot

Aisle

Blocked

Recirculation

Passive Cooling Cabinet Thermal Image

The Vertical Exhaust Duct

• Isolates hot air from the room

eliminating hot air recirculation over

cabinets (between hot and cold

aisles)

• Attaches to the top of 48” deep

cabinets at the rear of the cabinet

• Guides hot exhaust air from the back

of the cabinet to the space above a

drop ceiling or to a hot air return duct.

• Eliminates the need for fans

Air Flow Director (Turning Vane)

Directs hot exhaust air upward from

bottom of cabinet

• Prevent hot and cold air from

mixing within the cabinet

• Closes and seals open rack-

mount spaces

Snap-In Filler Panels and Air Dams Snap-In Blanking Panels

• Attaches to cabinet frame

• Creates an air flow barrier between the

door and equipment along the top, bottom

and sides of cabinet

• Prevents hot and cold air from mixing

within the cabinet

• Creates higher supply-to-return temperature differences (ΔT’s).

• Increases CRAC cooling capacity 2X to 3X allowing use for higher equipment densities and energy cost savings.

• Equalizes room temperature creating a constant temperature situation.

• Equipment intake temps are the same from top to bottom across the cabinet.

• Allows increased room temperature and higher set-points on cooling equipment and chilled water temperatures, for more free cooling hours using low-cost economizers.

Isolation Benefits

Passive Cooling Air Flow

CRAC or

CRAH

Building Roof or Slab of Upper Floor SIMPLY EFFICIENT!

Hot Spots

Inconsistent

Temperatures

115

109

103

97

91

85

79

73

67

61

55

Cabinets 2.5 to 3kW per cabinet

Cabinets 2.5 to 3kW per cabinet

Cabinets 2.5 to 3kW per cabinet

Cabinets 20kW per cabinet

Floor Tiles

Floor Tiles

Floor Tiles

°F Traditional Hot Aisle – Cold Aisle Layout in a

Mixed Environment of HD and LD cabinets.

Supports 4X Higher Heat and Power Densities

No Hot Spots

Ideal

consistent

temperature is

created with

PASSIVE

COOLING

solution!

100

95

91

86

82

77

72

68

63

59

54

Cabinets 2.5 to 3kW per cabinet

Cabinets 2.5 to 3kW per cabinet

Cabinets 2.5 to 3kW per cabinet

Cabinets 20kW per cabinet

Floor Tiles

Floor Tiles

Floor Tiles

Installed Ducted Cabinets

°F

Ceiling

Cooling

Grates

SCALE CHANGE 15°F COOLER!

It’s SIMPLY

EFFICIENT!

Supports 4X Higher Heat and Power Densities

Same Layout with Passive Cooling solution implemented!

80°- 90°F

77 °- 80°F

58 °- 77 °F Zero Temp Deviation

Standard Hot Aisle - Cold Aisle with

Sealed Openings Same Room with VEDS Installed

CFD Analysis HACA vs. Passive Cooling

Standard Data Center Temperature Variation 86

83

81

78

75

72

70

67

64

62

59

°F

Typical 72 to 73°F Setpoint

Increase Economization Through Higher Set Points

Temperature Variations with VED Isolation

77°F Setpoint

Zero

standard

deviation

between

the

plenums!

Increase Economization Through Higher Set Points

What about LEED points?

Possible Points Category

15 Sustainable Sites

5 Water Efficiency

17 Energy and Atmosphere

13 Materials and Resources

15 Indoor Environmental Quality

5 Innovation and Design

69 Total Possible Points

We contribute

3 to 8 points.

LEED Points

LEED Point Certification Levels

Level Required Points

Certified 26 - 32

Silver 33 - 38

Gold 39 - 51

Platinum 52 - 69

Energy Savings Points

10.5% 1

14% 2

17.5% 3

21% 4

24.5% 5

28% 6

31.5% 7

35% 8

38.5% 9

42% 10

High Density Cabinets with Passive Cooling

• Remove hot air

– Rely on server fans and high flow doors or no doors

– Avoid cable congestion – Biggest Problem!

– Do not use Top Mount Fans

Cabinet Air Flow Best Practices

• Prevent hot air re-circulation (internal and external)

– Use filler panels

– Seal off sides of equipment

– Use side panels in bayed cabinets … if required

• Deliver chilled air to critical point of use

Thank You!

Q & A

Fernando Reyna

562-480-9218

freyna@chatsworth.com

I’d be delighted to discuss how CPI products and

services can benefit your data center.