[GOOD READ] Data Cabinet Basics

7/23/2019 [GOOD READ] Data Cabinet Basics

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DATA CENTERCABINET DYNAMICSUNDERSTANDING SERVER CABINET

THERMAL, POWER AND CABLE

MANAGEMENT

BY

BRIAN MORDICK, RCDD

SENIOR PRODUCT MANAGER

HOFFMANTHERMAL MANAGEMENT

CABLEMANAGEMENT

POWER MANAGEMENT

MANAGEMENTSTRATEGIES FOR:



Summary:

Today’s IT professionals face many challenges in running an efcient data center, whether it is

maintaining current installations or planning for future applications. They must protect the productivity

of their company’s network end-to-end and research the latest technologies as networking

requirements evolve. To ensure the proper IT systems environment, it is essential to consider

thermal, power and cable management in today’s server cabinets.

IT professionals put signicant emphasis on protecting communications equipment from potential

outside threats. Meanwhile, increasing thermal densities, power shortages and uctuations, and

poor cable management may be compromising system operations or destroying the equipment from

the inside.

In a recent survey, data center managers indicated they are concerned about the following issues.

Data Center Cabinet Dynamics

THERMAL CABLE POWER

Top Concerns of Data Center Managers

Chart 1

Reference: Data Center User’s Group Conference, The Adaptive Data Center: Managing Dynamic TechnologiesUsed with permission




THERMAL CABLE POWER

2

Secur ing Your Network Against the Dangersof Overheating

IT professionals take all the necessary

precautions to ensure that computer networks

and communications equipment are secure

and protected. Locks, rewalls, passwords and

other protection protocols are in place—but an

invisible enemy lurks within and could wreak

havoc on the carefully congured and guarded

systems.

As equipment heats up, performance slows

and productivity drops. It can happen at any

time and can be directly attributed to heat

buildup in and around electronic equipment.

Many companies don’t realize that excessive

heat shortens the life of electronic equipment

and can even shut it down permanently. Heat

may be invisible, but its effects are devastating

and costly. According to the Uptime Institute,

for every 18 degrees Fahrenheit (10 degrees

Celsius) that internal cabinet temperatures

rise above normal room temperature, the life

expectancy of the enclosed electronics drops

by 50 percent.

Advances in technology allow equipmentto become faster and more compact, but

there are consequences: increased thermal

densities. Some industry executives predict

that at the current growth rate, thermal heat

densities could reach nuclear proportions

within a decade if unchecked. Understanding

how to temper those densities is becoming

increasingly critical to ensure system reliability

and availability.

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Year of First Produ ct ShipmentYear of First Product Anno uncement

Blade Servers’ Impact

Blade servers are the latest in high-density

network equipment. They use a common

chassis and provide slots for “blades” tobe installed. These new levels of power

density dramatically increase thermal

loads. A single blade server with all slots

lled and running at capacity can produce

more than 3 kilowatts of heat. Theoretically,

a cabinet lled with blade servers (seven

or eight chassis) can produce 21 to 24

kilowatts of heat.

Although blade servers represent less than

10 percent of overall server sales, they aregrowing rapidly and likely to become the

industry norm within the next few years.

This represents signicant challenges to

thermal and power management. “How

am I going to get that much power to my

servers, and how will I get rid of all the

heat?” is a common sentiment expressed

by most data center managers.



Understanding Server Cabinet

Thermal, Power, and Cable Management

3

Current Practices May Not Be Work ing

When it comes to protecting data center

servers, IT professionals should think inside

the box and select data cabinets that are

not only well built but also help manage heat

buildup. Thermal management is a growing

concern, because many existing data centers

weren’t built to handle the thermal densities of

next-generation blade servers and networking

equipment.

Many organizations believe the answer is

simple: Cool the ambient air to lower the inside

cabinet temperature. While this approach

seems logical, it is problematic. Issues still

present are:

• Continued hot spots and overheating.

• Massive increases in energy costs.

• Recirculation air ows are notaddressed.

• Using very cold air ows can cause

condensation, leading to corrosion,

equipment failure, poor or intermittent

contacts, thermal expansion or

contraction failures, etc.

The best way to measure the amount of

heat produced in a cabinet is to measure the

power being consumed. Every watt of power

consumed nearly equals every watt of heat

produced. The key to keeping equipment

cool is channeling or ducting cool air into the

equipment and providing a path for the heated

air to escape out of the cabinet.

Power Consumption Considerations Are

Signicant

Power management is equally as important

as thermal management. As power density

requirements continue to climb, data center

managers are increasingly asking, “How

do I get the power to and distributed within

the cabinet?” In addition, there is a direct

relationship between power used and heat

generated.

Power, dened as voltage x current, is expressed

in terms of watts (w) or kilowatts (kW) (1,000

watts). Watts cooling is also the expression

used when discussing cooling capacity.

The connection is simple: Power in = heat out.

Figure 1

This computer- generated image

illustrates heat buildup in the upper

portions of this data cabinet.

Figure 1

This computer- generated image

illustrates heat buildup in the upper

portions of this data cabinet.

For every 18 degrees Fahrenheit(10 degrees Celsius) that internalcabinet temperatures rise abovenormal room temperature, thelife expectancy of the enclosedelectron ics drops by 50 percent.

—Uptime Institute




THERMAL CABLE POWER

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POWER IN = HEAT OUTpower in = voltage x current (amps)Example: 208 vac x 30A (amps) = 6,240 watts or 6.24 kW.

The amount of power required provides a directrelationship to the amount of heat generated

and the cooling capacity required. For example,

power in = voltage x current (amps) e.g. 208

vac x 30A (amps) = 6,240 watts or 6.24 kW.

In the design stage, before the cabinet is

put into place and power is measured, the

amount of power required and the amount of

heat generated can be estimated by taking a

percentage of the “Name Plate” power that is

stated on the equipment. Network equipment

is required by UL and other agencies to list the

equipment’s power requirements. Since this

rating accounts for the maximum power that

can be consumed by the power supply, only a

percentage of this should be used. Typically,

power supplies are designed to provide manytimes the power output than the network

equipment actually needs. Using 50 to 75

percent of the “Name Plate” power provides

a good estimate for calculating the amount of

heat the cabinet will produce.

It should be noted that it takes more power to

cool than to heat. While network equipment

readily converts its power usage to heat, e.g.

5,000 watts of power in produces 5,000 watts

of heat, cooling systems do not. Five thousand

watts of cooling could require 10,000 watts or

more of power.

What causes the rapid increase in power

and thermal loads?

When a cabinet is lled with blade servers, the

average power consumption of that cabinet

can increase from 1,500 watts to more than

20,000 watts (20 kilowatts). This increase in

power and the resulting increase in heat impacta data centers’ capacity to service customers.

This level of power demand changes the way

power is distributed inside the cabinet. Where a

basic 15A power strip with multiple outlets was

required, a three-phase 208 vac capable of

more than 16.6 kilowatts of power provided by

a PDU (Power Distribution Unit) is now needed

to handle greater power demands.

The solution seems simple: ensure that the

data center is capable of providing 20 kilowatts

or more of redundant power and cooling

to every enclosure. While that may seem

easy, it’s not always economical, practical

or even technically possible because of up-

front infrastructure capital cost and ongoing

operational costs for the life of the data center.The capital cost to provide this level of thermal

and power service is typically beyond the reach

of many companies, because even though they

are dependent on their data centers and the

services they provide, companies are forced to

make compromises due to budget realities.

A Br ief Look at Thermal Basics

Network equipment requires a stream of cool

air to continually run via convection. Thereare only two components that a data center

manager can manipulate to dissipate the heat

generated inside the cabinet: the amount of

air and the data center temperatures. The

very best designed data center typically can

provide air temperatures around 55 degrees

Fahrenheit, thus a ∆T° (in °F) of about 45

degrees Fahrenheit.





5

As cooling strategies become more complex, theresulting increase in the number of components

and their potential failure can result in rapid

temperature rise in the cabinet in as little as

5 to 10 minutes. Choosing the best thermal

and power management solution is essential

to help facilitate optimal component speed and

processing power in your data center without

sacricing reliability and performance.

Cabinet Design’s Role in Heat Dispensation

Cabinets can be designed with features that

facilitate heat dispensation and be placed in

a data center to dene specic thermal zones

for air intake and exhaust to create maximum

cooling efciencies.

Hoffman has tested several cabinetcongurations to determine how cabinet design

and data center placement can maximize heat

dispensation and established best practices

for keeping electronic equipment cool and

reliable.

Passive Cooling versus Active Cooling

Passive cooling uses louvers, vents and

perforated panels, along with the equipments’

fans, to exchange ambient air. Active coolinguses cabinet venting fans to exhaust hot air

and can be used in conjunction with piped-in

chilled air.

Critical Formulas For Thermal Management

Watts (power) = voltage x current (amperes) = Watts (heat load)

Watts (thermal convection cooling) = .316 x CFM x ∆T° (in °F)

or

CFM = Watts (cooling) / .316 x ∆T° (in °F)

or

∆T° (in °F) = Watts (cooling) /(.316 x CFM)

This equation can be manipulated to solve any of the three variables: Watts (cooling),

CFM or ∆T° (in °F), and is invaluable in the design and operation of a data center.

CFM = cubic feet per minute (quantity of air and it s velocity)

∆T° (in °F) = Delta T (the difference between the coolest air (55°F) and the maximum

allowable temperature (95°F).

Example:

10 kW of heat load in a typical data center with a (30 ∆T°) will need 1,055 CFM

BTUs (Bri tish thermal uni ts) = Watts cool ing x 3.413

Example: 10 kW cool ing = 34,130 BTUs




THERMAL CABLE POWER

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Hot Aisle/Cold Ais le Data Center Layout

A hot aisle/cold aisle data center layout has

specic hot and cold areas. Computer room air

conditioners (CRAC) are placed strategically to

create cold aisles. The cabinets on both sides

of those aisles have network equipment installed

that draws the cold air through the cabinet fronts

and into its intakes. The equipment exhaust

exits through the cabinet rear, creating hot aislesthat alternate with the cold aisles. The hot air is

then re-circulated to the CRAC unit. This airow

management strategy addresses adverse

equipment airow, preventing equipment

exhaust from being drawn into other equipment

intakes. This type of data center layout has

been universally accepted and is being actively

deployed in most data centers.

Hot Aisle/Cold Aisle Conguration, Passive Cooling

When hot aisle/cold aisle data center cabinet positioning is

implemented and heat buildup is 1,500 to 2,000 watts, passive

cooling can be utilized. In this conguration, cold air is pulled

from the oor to cool equipment as it moves from the front to the

back of the cabinet. The resulting warm air is then exhausted

out the cabinet top and back.

Hot Aisle/Cold Aisle Conguration, Active Cooling

Hot aisle/cold aisle cabinet congurations in conjunction with

active cooling are the most efcient cooling solutions for

components with heat dispensation levels ranging from

4,000 to 6,000 watts . Cabinets that have a perforated front and

a rear fan door are the most efcient for this type of application.

Hot Aisle/Cold Aisle Conguration, Active Cooling with

Floor Ducting

Hot aisle/cold aisle cabinet congurations in conjunction with

active cooling plus oor ducting will help manage heat buildup

when heat dispensation levels reach 6,000 to 10,000 watts .

The most effective cabinets for these applications have a front

window door, a rear fan door and a oor-ducted base with ple-

num front.

Three types of hot aisle/cold aisle cabinet designs are:





7

Random Data Center Layout

The random data center layout is typically

associated with older or legacy data centers,

where the entire room is cooled with no specic

hot or cold area strategies. In many cases,

data center managers do not have the capital

to upgrade the data centers to more efcient

designs, but they still need to increase the

cabinets’ thermal density.

Layout Summary

Air-cooling continues to be the most economical

means of dissipating heat. All commercially

available servers continue to use airow to

dissipate heat out of the equipment (cold intake

air from the front while exhausting hot air out the

back). Careful consideration should be taken

to determine the best cabinet conguration for

your data center.

Random Conguration, Passive Cooling

When a data center has random cabinet positioning and a

relatively low heat dispensation volume of 1,000 to 2,000 watts,

passive cooling will manage heat buildup. Cabinets that have a

perforated front, rear and top perform the most efciently in this

type of application.

Random Conguration, Active Cooling

As heat loads increase to a range of 2,000 to 3,000 watts in

random cabinet positioning data centers, active cooling can be

employed. The cabinets used in this type of application have a

perforated front, a louvered lower-one-third rear door and a top

fan. Legacy data centers typically use this type of congura-

tion to increase thermal densities without incurring costly facility

reconstruction.

Two types of legacy systems are:




THERMAL CABLE POWER

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Data Center Design Considerations

When determining the placement of high-

density cabinets into a data center, there are

several practical and effective strategies.

Utilization of Load Spreading

The most popular solution for incorporating

high-density equipment into many of today’s

data centers is load spreading. When the

power required and heat

generated by the equipment

inside a cabinet exceeds the

cabinet’s cooling capacity,

installing the equipment

in multiple cabinets, or

spreading the load, more

evenly distributes the power

and cooling demands

between cabinets. Within

the data center many 1U

servers and blade servers do not need to beinstalled in the same cabinet and can be spread

out across multiple cabinets. Load spreading

can be a good option, because it may be less

costly to enlarge or expand a data center than

to add complex supplemental cooling systems.

A careful analysis of real estate, power,

technical labor force, connectivity and other

costs needs to be conducted in order to make

proper decisions.

It should be noted that spreading equipment

among multiple cabinets can result in a sizable

amount of unused vertical space within each

cabinet. The unused space must be lled with

blanking panels to prevent hot air recirculation,

which reduces cooling performance. Load

spreading can also cause data cabling issues.

Proper cable management techniques will be

discussed later in this paper.

The Borrowed Cooling Option

When borrowed cooling is utilized, cabinets

containing low heat producing equipment are

strategically placed throughout the data center

next to cabinets containing high heat generating

equipment. This enables the higher heat

load cabinets to use, or borrow, the adjacent

cabinet’s unused cooling capacity. This cooling

option can reliably and predictably enable

cabinets to be cooled to more than twice their

average design value.

Cabinet heat capacity

rules can be established

with compliance veried

through power consumption

monitoring. However, many

IT professionals nd that

this cooling method requires

them to enforce complex

rules, occupy more oor

space and limits them to about twice the design

power density.

Implications of Liquid Cooling

Another solution for removing excessive heat

loads from data center cabinets is liquid cooling.

Liquid cooling solutions are either water or

refrigerant based. Many IT professionals are

hesitant to use water in data centers because

of leakage. Also, moving cooling pipes, tubes

or hoses requires time and money, thus

making moves, adds and changes (MACs) a

challenge.

Liquid cooling systems operate similar to

a heat exchanger, but supply chilled liquid

instead of cold air, to the system. The cabinet

heat transfers to the liquid, which is then piped

out to be reconditioned (chilled back down).

The systems must be leakproof, reliable,

“ ...it may be less costly toenlarge or expand a datacenter than to add complexsupplemental coolingsystems. A careful analysisneeds to be conducted tomake proper decisions” .





9

expandable and exible enough to allow easyreconguration in a data center space.

The following should be considered before

installing a liquid cooling solution:

• Liquid supply lines and warm water

return lines need to be installed.

– Pipe runs must not interfere with

already installed connectivity or

power cables.

– Future exibility can be limited.

– Every threaded or welded tting

presents a potential leak; pipe

runs need to be reviewed for

condensation.

• Additional electrical circuits are

required.

• Multiple independent systems will

be needed to provide redundancy or

backup systems, which are required in

most data centers.

• Future MACs can be more costly.

In applications of extreme heat, when spreading

the load and increasing the size of the data

center aren’t possible, liquid cooling solutions

can be an alternative. However, facility design

considerations must be fully understood.

Challenges of a Dedicated High-Density Area

When power density exceeds 10 kilowatts per

cabinet, unpredictable airow is a problem. To

remedy this, the airow path between the cooling

system and the cabinet must be shortened.

Creating a special high-density row or zone in

a section of the data center, cooled with the

center’s CRAC, is a solution. This approach

is likely temporary though, due to data center

Thermal Management Best Practices:

• Avoid restricted, cascading and short

circuited airows.

• Install blanking panels in all unused rack

spaces.

• Neatly rout cables to prevent air restrictions.

• Take a holistic approach to the data center(raised oor, CRAC units, cabinets, etc.).

• Avoid the use of cable support arms and

slide outs that may restrict airows.

• Spread the load to the available spaces

(cabinets).

• Strategically locate low and high heat loaded

cabinets within the data center.

• Create special high heat zones within thedata center.

• Consider the addition of a supplemental

(liquid) cooling system.

• Increase the size of the data center (new

addition or building).

• Adopt hot aisle / cold aisle cabinet layout.

• Avoid large temperature swings – thermal

expansion and condensation issues.

• Avoid temperatures below the dew point

(condensation).

• Strategically place CRAC units to provide

airow to aisles.

• Position perforated tiles to uniformly provide

cold air to equipment aisle.




THERMAL CABLE POWER

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growth and change. Cabinet density must alsobe predictable or known in order to determine

power and cooling requirements.

Design Wrap-up

It is important to remember that a cabinet, no

matter what the design, cannot make up for

insufcient total cooling within the data center.

A cabinet using fans, deectors, blocking plates

or any other similar devices can never cool itself

below the surrounding ambient air temperature,however, it can improve the efciency of heat

movement in the data center by controlling

intake and exhaust airows. Increased heat

dissipation requires greater complexity and

integration of the entire data center such as

raised oor, CRAC, cabinets, etc.

Importance of Proper Cable Management

Deploying thermal and power management

solutions should not be viewed as the only waysto maintain an efcient data center. Checking

for cable performance is as important as

tending to overheated equipment or increased

power loads. To maintain the quality of vital

information exchanged in today’s data rooms,

IT professionals must properly manage cables

and cords.

As unsettling as it may be for IT professionals

to see a cluttered mass of cable spaghetti,

effective cable management is not just about

appearances.

Improper cable management can lead to

serious consequences:

• Nicks, stretching and twisting cable canaffect the signal quality and also the network

speed.

Employ Cable Management Best Practices

As the number of IT components continues to

increase inside a cabinet, so does the number of

power and data cables. The care and attention

given to cables during installation and ongoing

changes are the main factors in maintaining

high-quality network performance.

Consider the following checklist to ensure

proper cable management:

• Run cables overhead or below whenever

possible to provide easy access.

• Install proper cable management supports.

(Most manufacturers have several cable

management offerings.)

• Consolidate cable bundles with Velcro®

straps, using low to moderate pressure. This

can prevent cable damage associated with

traditional metal rings.

• Keep copper and ber-optic cables on

separate runs so the weight of the copper

does not impact the ber.

• Avoid kinks and sharp bends in cables by

using waterfall and cable spool devices.

Spools can be especially effective with ber

for maintaining proper bend requirements

and controlling slack.

• Make sure that when cables run through metal

openings there are protective grommets and

edging.

• Separate power, Data(copper)

and Data(ber)

from

each other.

“ ...effective cable management isnot just about appearances.”





11

• Cables in the rear of a cabinet can blockairow and increase the temperature inside a

cabinet.

• Sharp changes in direction can change theelectrical properties of the cable by changing

the cable size and twist rate.

Cross

Sectional

Area

Cable Fill Rate

40%

Cable Fill Rate

60%

Cable Fill Rate

80%

Cable Type (CAT) 5e 6 6a 5e 6 6a 5e 6 6a

Diameter Inches 0.22 0.28 0.35 0.22 0.28 0.35 0.22 0.28 0.35

PROLINE “PVCM”

50mm 6.220 65 40 26 98 61 39 131 81 52

100mm 12.920 136 84 54 204 126 81 272 168 107

X50mm 10.870 114 71 45 172 106 68 229 141 90

X100mm 22.960 242 149 95 363 224 143 483 298 191

PROLINE “ PVCMTD”

3.00 x 4.00 12.000 126 78 50 189 117 75 253 156 100

PROLINE “PRBTD*

50mm (1.91 x 4.00) 7.640 80 50 32 121 74 48 161 99 64

100mm (3.88 x 4.00) 15.520 163 101 65 245 151 97 327 202 129

PROLINE “ PRBF”

50mm (1.60 x 5.25) 8.400 88 55 35 133 82 52 177 109 70

100mm (3.57 x 5.25) 18.700 197 121 78 295 182 117 394 243 156

Tie Wraps

Tie Wrap 8” 2.400 N/A N/A N/A N/A N/A N/A 51 31 20

Tie Wrap 12” 6.000 N/A N/A N/A N/A N/A N/A 126 78 50

D-Ring

Large 9.440 99 61 39 149 92 59 199 123 79

Small 3.500 37 23 15 55 34 22 74 45 29

Cable Fill Rates




THERMAL CABLE POWER

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• Cable issues can increase the time requiredto trace a cable during a MAC in the cabinet

or rack.

Finding the Best Thermal, Power and Cable

Solution for Your Data Center

As new technologies arise and the demand for

more performance from computer equipment

in data centers increases, IT professionals

must constantly research best practices for

maintaining power consumption, high levels ofheat and an abundance of cables.

There is a full range of cabinet features anddesigns that can be combined with your facility’s

data center layout to effectively mitigate heat

generated by network equipment, power

consumption and effective cable management.

Thinking inside the box and nding the solutions

for these areas can help facilitate optimal

component speed and processing power

without sacricing reliability and performance.

For more information on thermal,

power and cable management, visitwww.hoffmanonline.com.

Brian Mordick is a Senior Product Manager at Hoffman, with special expertise in

datacom, thermal and seismic issues. While developing various types of enclosures

during the last 17 years, he’s incorporated innovation into new enclosure designs

and holds several patents. His engineering background and knowledge of the

Information Technology industry made him an integral part of the development of

the Data and Communication product platforms at Hoffman. Mordick is a

graduate of the University of Wisconsin – Stout, a member of the BICSI,

and Registered Communication Distribution Designer (RCDD). He has

frequently contributed to articles regarding enclosure trends and electronics

and is active in the industry as a public speaker. Recent presentations

include: Thermal Management, BICSI, July 2006; EMC, BICSI, May 2004;

Seismic Compatibility of Network Racks & Cabinets, BICSI, May 2002;

Thermal management of Network equipment, BICSI, Jan 2002; Data

Communications Racks and Cabinets, BICSI, Sept. 2001

About the Author

Brian L. Mordick, RCDD, Senior Product Manager, Hoffman


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Hoffman

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Anoka, Minnesota 55303-1745 U.S.A.

Phone: 763-421-2240

Fax: 763-422-2178

Customer Service: 763-422-2661

http://www.ehoffman.com

Canada

Hoffman

111 Grangeway Avenue, Suite 504

Scarborough, Ontario MIH 3E9

Phone: 416-289-2770

Fax: 416-289-2883

1-800-668-2500 (Canada only)

Mexico

Pentair Enclosures, S. de R. L. de C. V.

Federico T. de la Chica, No. 8 Piso-4A

Cd. Satelite, Naucalpan, Mexico C.P. 53100

Tel: (55) 5393-9005 ext. 222

Fax: (55) 5393-8827

For additional international locations see www.hoffmanonline.com/international

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