PASSIVE AIR FLOW MANAGEMENT IN THE Optimizing Network Performance through

DATA CENTER

BICSI Baltimore 2011

Lylette Macdonald, RCDDLegrand | Ortronics

Agenda:Discuss passive thermal management at the…Discuss passive thermal management at the…

Rack Level Aisle Level Facility Level

What is Layer ZeroTM?y• Solid foundation• Best practices in network design

Improved network performance, energy efficiency

Physical Infrastructure Is Critical to the Success of the NetworkSuccess 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

RACK LEVELThermal Management at the

Understanding Thermal ManagementManagement

• Thermal management is:• 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

Changing the Way You Look at Your NetworkLook 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 taligned through the infrastructure.

One basic best practice: adopt the rack as the basic building block for dataas the basic building block for data center density.

– Energy Efficient Data CenterSolutions and Best Practices,CISCOCISCO

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 environmentsAd 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

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 equipmentcooling for side vented equipment

Side rails remove the barriers to network equipment airflow

Cisco Nexus 7018in Server Rack

Open Rack Airflow Managementp g

Typical EIA relay rack with vertical cable management

The same EIA relay rack with the addition of airflow baffles

Thermal Management at the

AISLE LEVELThermal Management at the

Containment design lowers energy costs for coolingenergy costs for cooling

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

– Mark Monroe, Director of Sustainable ComputingDirector of Sustainable Computing Sun Microsystems

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

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

Enhance Energy Efficiencygy 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 equipmentC t li ith t dditi l f– Create cooling without additional fans

Air Control ComponentspFloor Mid-level

Top-of-rack

Thermal Management at the

FACILITY LEVEL

Types of CFD’syp

• Tracks the air pressure in the subfloor

• Tracks the air pressure in the subfloorUnder Floor

• Tracks the air movement in the ambient room

• Tracks the air movement in the ambient roomAbove Floor

• Tracks the air movement through the rack

• Tracks the air movement through the rackRack

• Tracks all of the above as one airflow envelope

• Tracks all of the above as one airflow envelopeFacility

Data Intensive

d• Factors to consider:– Rack thermal load data, including specific

dequipment data– Obstructions– AC characteristics

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

Good data in, good data out

The Power of CFD modelingg

Visualize Analyze PredictVisualize Analyze Predict

Visualize• Data center airflow is complicated due to the

i bl f h l l d d b h ITvariable 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 1can take the next step to analyze the wherefore and the whys.

1y

Analyzey• 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

22

Predict• How changes to the airflow will increase

li icooling capacity• How failure of each AC unit will impact the IT

equipment cooling• Energy savings due to optimized airflow gy g p

management

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Living Documentg• Accurate inventory of thermal load producing

iequipment• Regular update new IT inventory and its affect

on the cooling solution• Plan new installations such as high density g y

servers

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

Most Data Centers Are Too Cold

ASHRAE guidelines have just changedjust changed recommended operating temperatures in a data te pe atu es a datacenter

Reasons the cooling system may not be efficientbe efficient

Cold air pumped into raised floor not rising through perforated tilesperforated tiles

Mixing of hot and cold air through spaces in racks and cabinetscabinets

CRAC units pulling in cold air instead of hot

Too many obstacles for good airflow

CFD Services should address:

S bfl b l i Subfloor pressure balancing and cable cutout management

Elimination of cabinet l l l llevel cool air loss

Loss of cooling air from cold aisle areas

Baseline9000 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

gcold aisle and isolated equipment

is mixing with the cold supply air

Thermal Management applied in a

DATA CENTER

Baseline CFD Subfloor

Step OneStep 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

Optimized CFD Subfloorp

Baseline CFD Ambient Room

Baseline Room TemperatureTemperature

Step Two pPREVENT SUPPLY AIR FROM FLOWING

THROUGH THE EQUIPMENT RACKSTHROUGH THE EQUIPMENT RACKS

Blanking Panel

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

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

Step Threep

PARTITION HOT AND COLD AISLES ABOVEPARTITION HOT AND COLD AISLES ABOVE THE RACKS

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

Goal: Contain hot or cold air

Baseline Intake Airflow

Step Fourp

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 dropfunneling exhaust directly into the drop ceiling void

• Raise set point 10°F p

CRAC Extension

Goal: Increase CRAC unit efficiency

Optimized CFD Problem Areap

The Results

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

AfterBefore

Step Five p

COMPLETE CONTAINMENTCOMPLETE 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

Optimized CFD Ambient RoomRoom

The ResultsPassive Air Flow and Thermal ManagementPassive 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 dincluding isolated equipment, two CRAC units can be shut off

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 ReturnTemp

SupplyTemp

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 offHuge increase in cooling capacity of the three CRAC units

Total Passive Thermal DesignTotal Passive Thermal DesignAir flow

management at gracks, cabinets and cable management

Aisle containment Complete Thermalsolutions Thermal

Management

CFD Analysis S iServices

Thank you!