“Energy Conservation and the Electronically Communicated Fan”

• Theory

• Benefits

• Application

• A Typical Installation

Presented by: Ed Hegwood, LEED AP O+M

Data Center Energy Efficiency Is a Priority…

This year, mankind will create 1.2 trillion gigabytes (GB) of data, equivalent to

75 billion 16 GB iPods. That’s more than enough for every person on earth

to own 10 iPods.

Executive Summary:

The energy consumed by fans, pumps and other cooling components already

accounts for some 35-45% of the total energy consumption in the data center,

and some data predicts that energy costs will become the second highest cost

in 70% of the world’s data centers by 2012, trailing staff/personnel costs, but

well ahead of the cost of the IT hardware. It is now believed that in most data

centers, particularly those located in single-story industrial-type buildings,

electrical costs are already more than two to three times greater than real-

estate costs, and many existing data center buildings may be physically

incapable of providing the higher levels of power and cooling that are now

required.

Credits:

• EPA ENERGY STAR Data Center Energy Efficiency Initiatives

http://www.energystar.gov/index.cfm?c=prod_development.server_efficiency

• Lawrence Berkeley Lab Data Center Support’s, https://commons.lbl.gov/display/itdivision/SA+-

+Data+Center+Support

• EBSCO Sustainability Watch, http://ebscosustainability.files.wordpress.com/2010/06/data-center-

energy-efficiency.pdf http://www.emersonnetworkpower.com/en-

S/About/NewsRoom/NewsReleases/Pages/State-of-Data-Center-2011.aspx

Data Center Cooling System Retrofit Solutions Background

A US Environmental Protection Agency survey released in 2007

concluded that IT data centers consumed 61 billion kW of electricity at a

total cost of $4.5 billion. (2006)

As energy costs continue to rise, energy conservation has become a

top-of-mind issue for data center management.

The data center cooling system is a primary target for energy efficiency

improvements.

Energy usage by cooling systems—comprised of cooling and air

movement equipment— can account for up to 38 percent

($1,710,000,000.00) of data center energy consumption.

Imagine Fan Savings of 10% = $171,000,000.00 Savings

Retrofit for Efficiency Improvements for Legacy Data

Centers

What’s in it for You?

$ MONEY ! $

Level 3 DC -23 ea. Data Aire DA CRAC ←Customer Yellow = Inputs

Enter your total electricity cost ($/kWh)→ $0.075 Total Amps ↓ CFM For EC Fans→ 67 402,000

Enter the number of EC Fans needed (6,000 CFM Each @ .05")→ 67 50.61 Fan Utilization Factor 71.94% Voltage Voltage

Enter Cost per EC Fan to Retrofit Unit→ $2,732 Rated Fan Amps→ 19.6 Rated 480

Enter Motor Voltage→ 480 EC Fan CFM De-Rated Fan Amps 19.60 Actual→ 480

Enter % of Flow→ 60% 241,200 Actual Amps→ 14.1 Derate = 0.00%

Enter Number of CRAC/CRAH Units to be Retrofitted→ 23 Total Amps ↓ Corrected CFM 326,149

Existing Unit Total Fan Motor Current Amp Draw/ phase 14.1 324.30 CFM Correction→ 1.212

Enter Existing Unit Total Fan Motor POWER FACTOR → 0.85 CFM

Enter Existing Unit Total OEM Rated CFM → 11,700 Job Site CFM Alt Ft Correction

Existing Unit Fan Motor Utilization FACTOR 71.94% 234,628 4000 1.157

YOUR ESTIMATED ENERGY SAVINGS & PAYBACK kWh kW 4200 1.166

Annual Energy Spend Belt Drive FC Fan $150,390 2,005,198 228.90 4400 1.175

Annual Energy Spend EC FAN $27,359 364,788 41.64 4600 1.184

TOTAL ANNUAL SAVINGS $123,031 1,640,410 187.26 4800 1.193

TOTAL EC FAN UPGRADE COST $183,044.00 + TAXES 5000 1.202

EC FAN Maintenance COST Avoidance $4,600.00 $200/Unit 5200 1.212

ROI/ PAYBACK in Years 1.45 kW Saved 5400 1.222

Rebates @ $???./kW $74,905 187.26 5600 1.232

ROI/ PAYBACK with Rebates in Years 0.84 $400 < Rebates 5800 1.2426000 1.252

Fan Motor Heat Gain Reduction ( Increased Cooling to Floor) 622,167 BTUs-Cooling 6200 1.26

Total Capacity Made Available and returned to your Environment 273.69 Amps/phase Existing Retrofit 6400 1.268

Water Savings at Power Plant 623,356 Gallons / Year Fan W/kBTUs Fan W/kBTUs 6600 1.276

Carbon Dioxide Equivalent Avoided 2,460,615 Pounds / Year 69.86 12.71 6800 1.284

7000 1.292

W/CFM W/CFM

1.18 0.22

EC Fan Energy $ avings Calculator ©EE

Assumptions: 8760 Hour/Year Operation, 72 oF 35% RH. Energy Savings based on average EC fan modulation and

amp draw as identified

Disclaimer: Calculations are based on estimates and the assumptions shown above. While every precaution has been taken to ensure

accuracy and completeness, We assume no responsibility and disclaim all liability for damages resulting from use of this information or for

any errors or omissions.

$0

$20,000

$40,000

$60,000

$80,000

$100,000

$120,000

$140,000

$160,000

Annual Energy SpendBelt Drive FC Fan

Annual Energy SpendEC FAN

ENERGY COST COMPARISON

Airflow Efficiency

This metric characterizes overall airflow efficiency in terms of the total fan

power required per unit of airflow.

Total Fan Power (W) / Total Fan Airflow Cubic Feet per Minute (CFM)

1.25W/CFM (Standard) Exiting CRAC/CRAH Units

0.75 W/cfm (Good)

0.5 W/cfm (Better) with EC Fans

If cooling units are oversized, (most that we test are 10 to 40%) the fan

speed can be reduced.

The motor power varies with the cube of the motor speed.

Motor kw2 = Motor kw1 x (speed2/speed1)3

Example:

• A 10 percent reduction in fan speed results in an energy savings of 27%

• A 20% reduction in fan speed results in 49% energy savings

In order to prevent over-dehumidification, the water flow rate to the chilled

water coil should also be reduced by the same percent as the fan speed.

Why would a Data Center Increase Efficiency?

Utilities aim to increase monetary incentives

and decrease barriers, thereby:

o Decreasing the initial Investment

o Increasing the return on Investment (ROI)

o Vetting new Technologies

Utilities help Tip the Scales Toward Action

On Energy Efficiency Initiatives!

Recent Energy Meeting Information

Proposed ---

CALIFORNIA STATEWIDE UTILITIES CODES AND

STANDARDS PROGRAM

Data Center CASE Proposed prescriptive fan power limit

Title 24 2011 Data Center CASE: Stakeholder Meeting #2

California Statewide Utility Codes and Standards Program Mark Hydeman, PE, Principal Taylor Engineering, LLC mhydeman@taylor‐engineering.com 510‐263‐1543 September 16, 2011

Title 24 2011 CASE Website: http://www.h-m-g.com/T24/CASE.htm

CALIFORNIA STATEWIDE UTILITIES CODES AND STANDARDS

PROGRAM

Data Center CASE Proposed prescriptive fan power limit

Power Limit:

● Title 24 §144(c) has fan‐power limitations (in watts/cfm) based on built‐up

ducted overhead systems with terminal units ducted overhead systems with

terminal units. Computer rooms typically have less pressure drop and operate

longer hours

● Proposed fan power limit is 27 watts per kBtuh of net sensible cooling

capacity.

Based on 20°F ∆T, 2.5” total pressure, 55% fan efficiency and 90%

motor/drive efficiency. It can also be met at 3” total pressure and 65%

fan efficiency

A CRAC unit may be designed for 30 W/kBtuh but will operate at 20

W/kBtuh at peak load because it will not be running at full speed

CALIFORNIA STATEWIDE UTILITIES CODES AND STANDARDS

PROGRAM

Data Center CASE Fan Power Analysis Survey of Existing Projects

How It Works

The EC fan has a DC (direct current) motor operating off of an AC (alternating current

source), 230/460v, 3 phase, 60 Hz main supply with an integral rectifier.

The EC (electronically commutated) brushless motor has permanent magnets in the

rotor, which revolves around the outside of the motor.

The backward curved fan blades are attached to the rotor casing. A more traditional

DC motor uses brushes to switch the direction of the current in the stator (this is

known as commutation) so that the North magnetic pole of the stator windings repels

the North magnet in the rotor. Then, as the rotor revolves, the brushes switch current

direction to South to repel the South magnet. Thus, with the rotor revolution a rotating

magnetic field is generated. The EC motor behaves like a brushed DC motor as the

speed under load is proportional to the drive voltage and the developed torque

is in linear proportion to the current. The EC motor utilizes a ‘Hall Effect’ I.C.

switch to sense the position of the magnets in the rotor and then precisely times

the switching of the output transistors to control the direction of the current in

the stator windings (electronic commutation).

Adjustable fan speed is achieved by a 0-10v control signal. The EC fan motor uses the

0-10v signal to proportionally adjust the effective voltage at the stator windings The EC

motor has a sensing and feedback circuit to ensure that the correct speed is obtained.

Backward-curved blades use blades that curve against the

direction of the fan wheel's rotation. The blades are single

thickness with 9 to 16 blades inclined away from the

direction of rotation. Air leaves the impeller at a velocity less

than its tip speed. Relatively deep blades provide efficient

expansion with the blade passages. The backward

curvature mimics that of an airfoil cross section and

provides good operating efficiency with relatively

economical construction techniques. Backward-curved fans

are much more energy efficient than forward curved fans.

The EC Fan design moves the air in more of a straight line.

Forward-curved blades use blades that curve in the

direction of the fan wheel's rotation.

Efficiency is less than backward curved bladed

impellers. Has 24 to 64 shallow blades with both the

heel and tip curved forward. Air leaves the impeller at

velocities greater than the impeller tip speed. Tip speed

and primary energy transferred to the air is the result of

high impeller velocities and operates most efficiently at

lowest speed.

Replacing the existing forward curved fans with EC (electronically

commutated), brushless motors and backward curved fans.

Value added savings are the removal of belts. Traditional fans are belt-

driven which can absorb 5 to 15 per cent energy even when they are

correctly installed, plus the cost of replacement and regular servicing.

No belts also means no belt dust, thus removing a major concern in

maintaining the clean environment of datacenters.

A further advantage of using these alternative fans, is the vastly

improved airflow across the cooling coil. Most CRAC/AH unit existing

fans are positioned just under the cooling coil, which causes three

unnecessary issues:

1. They block part of the coil, reducing the surface area and its efficiency.

2. The airflow has to split on either side of the fan, and then turn 90°

before it can be distributed.

3. Air is distributed into the floor slab, causing turbulence and

resistance, which uses up energy, located much lower down, on or in the

floor of the CRAC/AH unit, thus removing the dead spots over the coil’s

surface.

Fan manufacturers across the globe print data along with their fans to show Air Handling

Manufacturer’s (OEM’s) how much air a given fan will move. The majority of these manufacturers test

their products using standards established by Air Moving and Control Association (AMCA)

publications.

When measuring air flow using a wind tunnel and unless otherwise noted by the manufacturer,

centrifugal fans in housings are tested under ideal conditions with unobstructed inlets and a new,

clean, straight length of outlet duct in accordance with AMCA Standard 21. When considering a real

world air handler, the AMCA 210 test will not replicate what the installing engineer or OEM design

engineer sees in the installed system because published data from these tests will never directly

match real world applications of fans in AHU’s.

This in an HVAC application the duct acts very much like a rifle barrel and allows for the volume of

air to take full advantage of the space and normalize its flow and pressure. However, in CRAC

design, blowers are usually bulk head mounted or mounted with very short discharge areas, this

has a negative effect on airflow and leads to a major loss in flow and like the AHU cabinet wall and

inlet or outlet design, the effect cannot be measured as a change in total static pressure.

Forward Curved Fan EC Fan

17”

Reduce

d AIR

FLOW

AREAS

Recirculation

Zones

22% Savings CRAC/CRAH

6 CRAC/CRAH units are working in the IT rooms of a data center, each equipped

with 3 E C fans.

With a duty cycle of 100%, up to 50 MWh of electricity can be saved. That

corresponds to about 30 tons of CO2 and every year !

EC Fan

Typical

Data Center CRAC unit

Fan Law (Cube Law):

The motor power varies with the cube of the motor speed.

Reduced Motor kW = Existing Motor kW x (speed2/speed1)3

*A 10 % reduction in fan speed results in 27% energy savings.

**A 20 % reduction in fan speed results in 49 % energy savings.

Total Units → 2 Total Total

2

New Fans @ 6000 CFM

ea.

EC Fans

Amps ea. → 4.20 EC Fan FC Fan

EC FAN Total Amps → 8.4 rpm Amps Amps

% Flow

Annual

Hours Annual Energy Use Annual Cost 2040 ↓ 14

100% 8760 49,774.43 $1,742.10 2040 8.40 Savings

100% 8760 49,774.43 $1,742.10 2040 8.40 ↓

95% 8760 42,675.35 $1,493.64 1938 7.20 14.26%

90% 8760 36,285.56 $1,269.99 1836 6.12 27.10%

85% 8760 30,567.72 $1,069.87 1734 5.16 38.59%

80% 8760 25,484.51 $891.96 1632 4.30 48.80%

75% 8760 20,998.59 $734.95 1530 3.54 57.81%

70% 8760 17,072.63 $597.54 1428 2.88 59.99%

65% 8760 13,669.30 $478.43 1326 2.31 62.33%

60% 8760 10,751.28 $376.29 1224 2.12 58.98%

55% 8760 11,359.70 $397.59 1122 1.92 55.43%

The Liebert CW, a chilled water-based computer room air handling

unit, uses the building chilled water supply as the cooling source. It

is available in up-flow and down-flow configurations and in cooling

capacities up to 400 kW.

Previously, only the largest down-flow models were available with

optional EC plug fans, but with this extension they are now available

in all down-flow models from 26-400 kW.

The Liebert DS, a refrigerant based direct expansion (DX) computer room air

conditioning unit, uses the industry leading Digital Scroll™ variable capacity

compressor technology as its primary method for cooling.

It is available in up-flow and down-flow configurations and in cooling

capacities up to 105 kW.

With this announcement all down-flow units are now available with optional

EC plug fans.

The use of the variable capacity compressors enables the fan speed to be

automatically adjusted during operation— based on the IT server demand —

down to 60 percent cubic feet per minute (CFM) without the coils freezing,

because of the control algorithms utilizing variable capacity compressors.

EC FAN Savings Points - EMERSON

• Energy Efficient EC fan savings up to 36%

Variable Fan Speed

Direct Air Path

Lower Energy Consumption

• 16300 CFM

• 8.6kW

Blower System “A” Blower System “B” Blower System “C”

• 16400 CFM

• 6.9kW

• 16400 CFM

• 5.5kW

Reliability

The DC motor is inherently more efficient

than AC motors and, therefore, operates at a

lower temperature putting less thermal

stress on windings and bearings, while also

reducing the amount of heat introduced

into the air stream (lessening the impact

on “total” vs. “net” capacity of the CRAC

unit).

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Efficiency The efficiency of the EC motor (typically > 90%) is higher than that of traditional asynchronous

AC motors (typically < 80%) and generates less heat, as there are no slip losses, less copper and

iron losses. The EC motor is also more efficient than alternative speed control methods including:

Inverter, AC frequency control, Triac voltage control, Multi-taped transformer voltage control (steps),

and Star/Delta switch (two step)0

No induced shaft currents that cause motor

bearing failures, pitting of a bearing race wall

(magnified) is shown, the result of inverter-induced

electrical discharges from the motor shaft

Advantages of the EC Fan

• No drive belts – reduced maintenance (no changing nor adjusting)

• No belt dust and therefore no contaminating of mission critical equipment, including

servers, disk drives, telecom switch gear, etc.

• Longer filter change intervals

• No power transmission losses through belts and pulleys

• Site adjustable air volume (fan speed) from local controller and therefore easy adaptation

to changing conditions

• Increased net cooling – reduced cooling load on refrigeration plant

• Integrated electronics – no need for secondary electronics e.g. inverters and filters

• Power factor is greater than 0.92 at full load due to integrated power factor controller – no

need for correction

• Soft start – without high inrush current – no belt slip or peak noise

• Fan direction always correct – not phase directional

• High efficiency is maintained at variable speeds / no efficiency penalty at reduced speeds

• Integral overload protection

• Backward curved aerodynamically optimized impeller

• Due to individual direct drive nature of EC fan, redundancy is built into each unit

containing multiple fans (greater allowable coil air volume range)

EC fan Install

completed in “live”

DATA CENTER

67 FORWARD CURVED FANS AND

MOTORS TO BE REPLACED WITH

EC MOTORS AND BACKWARD-

CURVED FANS

EC Motor Preparation Area

Motor Staging Area

Note shipping pallet w/3 fans

Tech removing old motors and wiring

Tech removing old motors and wiring

Tech. removing old fans, clearing area for install

Note: drop cloth on floor and organized tools

Old fans were palletized for

easy moving out of center

New EC fans ready for install

New EC fans in place and ready for control wiring

“C” Channel detail

Frame is made to fit. Fans sit inside frame and are screwed

down into c channel

“C” Channel detail

20T unit , fans installed and ready for control wiring

Pre-Project Measurements

6.30

8.15

5.94

7.98

8.27

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

CRAC Measured KW 10 day average

Avg. KW

CRAC Unit Number

1 4 8 13 10

Post-Project Measurements

1.77 1.85 1.80 1.73 1.86

0.00

1.00

2.00

3.00

4.00

5.00

6.00

7.00

8.00

9.00

10.00

CRAC Measured KW 10 day average

Avg. KW

CRAC Unit Number

1 4 8 13 10

KW Measurement Comparison

6.30

8.15

5.94

7.98

8.27

1.77 1.85 1.8 1.73 1.86

1.10

2.10

3.10

4.10

5.10

6.10

7.10

8.10

9.10

KW

Measu

rem

en

t

CRAC KW Measurement Comparison

Pre

Post

1 4 8 13 10

Actual KW Differences

CRAC UNIT NUMBER

1 4 8 13 20

PRE 6.30 8.15 5.94 7.89 8.27

POST 1.77 1.85 1.80 1.73 1.86

Difference 4.53 6.30 4.14 6.16 6.41 (KW)

This was a sampling of the overall project, 67 Motors were replaced.

The Liebert MC Condenser

EC Fan reduces annual condenser energy requirements

29% Savings on Air Cooled Condensers 6 fans work on one condenser.

At an average duty cycle of 75% this means an annual savings

potential of over 24 MWh.

This corresponds to approx. 14.4 tons of CO2 and every year.

ebm-papst, the world’s leading source for engineered air movement

solutions, provides a “total solution” approach to your cooling requirements

using our extensive in-house resources.

• Worldwide Revenue / Sales: Over 1 Billion

• 47 Sales and Distribution Groups Worldwide

• 15 Production Sites Worldwide

• 9,900 Employees Worldwide

• Ship Over 46 Million Products Annually

ASHRAE honored EBM with an award for the most innovative energy saving

product in the field of ventilation.

This award was presented by the ASHRAE President, Richard Rooley, at the

2004 AHR Expo in Anaheim, California.

In addition, EBM-Papst won the 2005 Cleanrooms Contamination Control

Technology Award, the “Air Movement Product of the Year” at the 2004 H &

V News Awards and “Environmental Product of the Year” at the Cooling

Industry Awards in the same year.

Advanced Green HVAC Training

at

Rocky Mountain Education

Center

Red Rocks Community College

What we do at

Rocky Mountain Education

Center

Red Rocks Community College

Train technicians to be

HVAC Energy Efficiency

Systems Specialists.

The HVAC Energy Efficiency

Systems Specialist effectively

frees the stranded energy and

money that exists in buildings

today.

ALL Training simulates field conditions

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EC Fans for RTU

EC Fans for CRACs

EC Fans for CRACs

Thank you for attending our Presentation

Harold R. Null Sr. Engineer

NTS Consulting Group, Inc.

Questions or Comments?