Optimizing Network Performance through PASSIVE AIR FLOW MANAGEMENT IN THE DATA CENTER

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PASSIVE AIR FLOW MANAGEMENT IN THE

Optimizing Network Performance through

DATA CENTER

BICSI Baltimore 2011

Lylette Macdonald, RCDD Legrand | Ortronics

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Agenda:

Discuss passive thermal management at the…

Rack Level Aisle Level Facility Level

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What is Layer Zero y

^TM

?

• Solid foundation

• Best practices in network design

Improved network performance, energy efficiency

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Physical Infrastructure Is Critical to the Success of the Network

Success of the Network

• Racks, cabinets, cable management and airflow

systems address the needs of today’s data centers, including:

Ai fl M t D it P f & P t ti

– Airflow Management, Density, Performance & Protection, Flexibility, Scalability, & Energy Efficiency

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RACK LEVEL

Thermal Management at the

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Understanding Thermal Management

Management

• Thermal management is:

– Consistent cooling of IT equipment – Maximizing rack populationMaximizing rack population

– Maximizing IT footprint

• Thermal management is NOT:Thermal management is NOT:

– Not an air conditioning thing – Not a facilities issue

– Not all about energy

50%+ increase in cooling capacity

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Changing the Way You Look at Your Network Look at Your Network

With the right planning, the defining elements of capacity, density, efficiency and scalability can be

li d th h th i f t t

aligned through the infrastructure.

One basic best practice: adopt the rack as the basic building block for data

as the basic building block for data center density.

– Energy Efficient Data Center Solutions and Best Practices, CISCO

CISCO

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Racks & Cabinets Optimized for Cisco Nexus Switches

• Use racks designed to maximizeUse racks designed to maximize the benefits for the Nexus 7000 Series switches

– Passive cooling capabilities for high density server environments

Ad d bl t t

– Advanced cable management system reduces cable congestion and

protects signal integrity

– Built with a high weight threshold to support a fully configured switch

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Passive Thermal Management

 Built-in at the rack/cabinet level

g

 Built-in at the rack/cabinet level

 Baffle system maintains efficient cold-

aisle/hot-aisle airflow, providing maximum cooling for side-vented equipment

cooling for side vented equipment

 Side rails remove the barriers to network equipment airflow

Cisco Nexus 7018 in Server Rack

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Open Rack Airflow Management p g

Typical EIA relay rack with vertical cable management

The same EIA relay rack with the addition of airflow baffles

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AISLE LEVEL

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Containment design lowers energy costs for cooling

energy costs for cooling

Data center managers can save 4% in energy costs for every degree of upward change in the ambient temperature

temperature.

– Mark Monroe,

Director of Sustainable Computing Director of Sustainable Computing Sun Microsystems

The higher the temperature set-point, the greater the potential savings.

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Hot or Cold Aisle Containment?

Use the natural properties of airflow

• Cold air requires containmentCold air requires containment

• Hot air naturally rises Both hot and cold air must be managed

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Enhance Energy Efficiency gy y

• Use passive thermal management to:

– Prevent hot and cold airflow from mixing Isolate redirect airflow from side vented – Isolate, redirect airflow from side-vented

equipment

– Open airflow to network equipment C t li ith t dditi l f – Create cooling without additional fans

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Air Control Components p

Floor Mid-level

Top-of-rack

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FACILITY LEVEL

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Types of CFD’s yp

• Tracks the air pressure in the subfloor

Under Floor

• Tracks the air movement in the ambient room

Above Floor

• Tracks the air movement through the rack

Rack

• Tracks all of the above as one airflow envelope

Facility

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Data Intensive

d

• Factors to consider:

– Rack thermal load data, including specific d

equipment data – Obstructions

– AC characteristics

• A single, comprehensive CFD can take several hours to run

Good data in, good data out

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The Power of CFD modelingg

Visualize Analyze Predict Visualize Analyze Predict

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Visualize

• Data center airflow is complicated due to the

i bl f h l l d d b h IT

variable of thermal loads created by the IT equipment.

• The CFD process allows for an engineer to see the invisible. Track a 1 micron particle as it

flies through the room.

• Once we can visualize the airflow we

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can take the next step to analyze the

wherefore and the whys.

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y

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Analyze y

• Air temperature and Relative Humidity

• Airflow direction and volume (CFM)

• Supply to the thermal loadpp y

• Return path to the AC

• Actual cooling tonnage based on return air

• Actual cooling tonnage based on return air temperature

2

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Predict

• How changes to the airflow will increase

li i

cooling capacity

• How failure of each AC unit will impact the IT equipment cooling

• Energy savings due to optimized airflow gy g p management

3

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Living Document g

• Accurate inventory of thermal load producing i

equipment

• Regular update new IT inventory and its affect on the cooling solution

• Plan new installations such as high density g y servers

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Most Data Centers Employ Flood Cooling

A i d i

Flood Cooling

Associated issues:

 Lower than necessary temperature set points

 Higher than required humidity set points

 Poor airflow requires fans to run more often

 Cold return air to CRAC intake reduces efficiencyy

 Wasted rack space

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Most Data Centers Are Too Cold

ASHRAE guidelines have just changed

just changed

recommended operating temperatures in a data te pe atu es a data center

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Reasons the cooling system may not be efficient

be efficient

 Cold air pumped into raised floor not rising through

perforated tiles perforated tiles

 Mixing of hot and cold air through spaces in racks and cabinets

cabinets

 CRAC units pulling in cold air instead of hot

 Too many obstacles for good airflow

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CFD Services should address:

S bfl b l i

 Subfloor pressure balancing and cable cutout management

 Elimination of cabinet

l l l l

level cool air loss

 Loss of cooling air from cold aisle areas

Baseline 9000 S Ft

 Return air mixing with cooling air

 Loss of cooling air to

9000 Sq. Ft.

Data Center The air patterns show areas where hot air

g cold aisle and

isolated equipment

is mixing with the cold supply air

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Thermal Management applied in a

DATA CENTER

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Baseline CFD Subfloor

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Step One Step One

CONTROL THE SUPPLY AIRFLOW

• Two impediments to desired air flow

– An imbalance of subfloor air pressure

– Subfloor plenum is leaking cold supply air into the room

Goal: Have 140-160 CFM per floor tile in the cold aisle

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Optimized CFD Subfloor p

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Baseline CFD Ambient Room

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Baseline Room

Temperature

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Step Two p

PREVENT SUPPLY AIR FROM FLOWING THROUGH THE EQUIPMENT RACKS THROUGH THE EQUIPMENT RACKS

Blanking Panel

Goal: Stop hot exhaust air from recirculating into the equipment intake.

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The Results

From blocking raised floor openings, disrupting air velocity, and adding blanking panels in unused rack and cabinet space and adding blanking panels in unused rack and cabinet space

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Step Three p

PARTITION HOT AND COLD AISLES ABOVE PARTITION HOT AND COLD AISLES ABOVE

THE RACKS

• Two cold aisles contained with Air Curtain Vinyl Panels and Air Curtain Vinyl Strip Doors

Th ti bl d th h t ff f

Note: This solution does not limit

• The separation enabled the shut off of one 22T CRAC unit

Note: This solution does not limit the use of overhead cable routing which is a common problem when using ducts or chimneys.

C t i Curtains

Goal: Contain hot or cold air

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Baseline Intake Airflow

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Step Four p

DIRECT HOT EXHAUST AIR TO THE AC COIL THROUGH THE DROP CEILING VOID

• Prevent mixture of hot and cold air by funneling exhaust directly into the drop

funneling exhaust directly into the drop ceiling void

• Raise set point 10°F p

CRAC Extension

Goal: Increase CRAC unit efficiency

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Optimized CFD Problem Area p

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The Results

Floor Plugs, Air Disrupters, Blanking Panels, Air Containment Curtains and CRAC Extension

After Before

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Step Five p

COMPLETE CONTAINMENT COMPLETE CONTAINMENT

• Supply air coming from the subfloor bubbles out like a water fountain

• Air spills in all four directions

• Three walls are needed to hold, or pool, the supply air so that its only direction is through the IT

equipmentq p

Air Containment Booth

Goal: Direct airflow through IT equipment

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Optimized CFD Ambient Room

Room

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The Results

Passive Air Flow and Thermal Management Passive Air Flow and Thermal Management

• Floor Plugs, Sub-Floor Disrupters, Blanking Panels, Air Curtains, CRAC Extensions and Air Containment Booth

Our model shows that with full

containment, i l di i l t d including isolated equipment, two CRAC units can be shut off

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CRACs: Cooling & Temperatures

Rack Statistics: The results of all 5 steps

g p

All racks are still between the 70°F and 80°F range

Name Airflow Return Temp

Supply Temp

Cooling

(Ton) Cooling (kW)

CRAC 1 13,500 73.5 53.9 25.4 89.5

CRAC 1_1 Turned off --- --- --- ---

CRAC 3 10,200 78.0 60.8 16.9 59.5

CRAC 1_2 Turned off --- --- --- ---

CRAC 3_1 10,200 78.0 56.6 21.1 80.4

Two 22 ton CRAC units have been shut off

Huge increase in cooling capacity of the three CRAC units

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Total Passive Thermal Design Total Passive Thermal Design

Air flow management at g racks, cabinets and cable management

Aisle containment Complete Thermal

solutions Thermal

Management

CFD Analysis S i

Services

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Thank you!