a practical guide to energy saving_energy appraisal brochure

7/31/2019 A Practical Guide to Energy Saving_Energy Appraisal Brochure

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Energy appraisal or lowering energy useand CO2 emissions

A practical guide to energy eiciencyusing AC drives and electric motors

Drives and motors


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Why saving energy is everyones responsibility

For more detailed advice, please contact your local ABB sales

oice directly or visit www.abb.com/energyeiciency to

view a video demonstration o the energy appraisal process.

*Drives and motors

Around the world there are many names and acronyms that

are used or electronic variable speed drives. These include

VSD (var iable speed drive), ASD (adjustable speed dr ive), VFD

(variable requency drive), AFD (adjustable requency drive),

requency converter, inverter and just drive.

The requency converter is an electronic device that convertsalternating current (AC) o one requency to alternating current

o another requency. ABB widely uses the word AC drive to

mean a requency converter. International standards, however,

are basically using the term requency converter.

Carrying out an energy appraisal o the motor-driven

applications across a plant or process can reveal

signiicant ways to reduce costs. The monetary savings

provided by an energy appraisal come rom lowering the

amount o electricity being consumed - hence lower utility

bills - and reducing carbon dioxide (CO2) emissions.

A dr ive* and electric motor* combination, when used to

control the speed o applications such as pumps and ans,

can reduce the energy bill by up to 70 percent with a payback

in less than 12 months. When it is considered that 65 percent

o the total electricity at industrial sites is consumed byelectric motors, the need or an eective energy appraisal is

even more apparent.

The indings o an energy appraisal, thereore, aects

everyone in an organisation, whether that is a maintenance

engineer, a process engineer, a acilities manager, a inancial

controller or a board director.

ABB has developed a very simple energy appra isal process

that it or one o its authorized channel partners, can carry out.

This guide describes the energy appraisal process; shows thebeneits o implementation; highlights the impact on real-lie

industrial applications; and demonstrates some o the key

drive and motor eatures that urther enhance energy savings.

2 Why saving energy is everyones responsibility l Energy appraisal or lowering energy use and CO2 emissions

An energy appraisal starts with a tour o the plant.


3/12Energy appraisal process l Energy appraisal or lowering energy use and CO2 emissions 3

Energy appraisal process

What makes a good energy appraisal?

ABB has devised a simple and methodical energy appraisal

process that presents end-users with hard, compelling acts

about the electricity they can save. It achieves this by rapidly

identiying some key applications that can beneit immediately

rom the use o drives and electric motors.

An energy appraisal is normally carr ied by an ABB engineer

or one o ABBs authorized local channel partners who can

identiy relevant applications that will generate energy saving

results. This identiication will help the end-user target their

investment so that it generates the highest possible savingsand delivers the best return on investment.

There are six steps to an e icient energy appra isal:

1. Outlining the scope o supply

2. Monitoring and data collection

3. Data analysis

4. Recommendations

5. Implementation

6. Veriication and ollow-up

Centriugal ans and pumps are typical variable torque applications to be considered.


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Six steps to an eicient energy appraisal

4 Six steps to an eicient energy appraisal l Energy appraisal or lowering energy use and CO2 emissions

1. Outlining the scope o supply

An ABB engineer or one o ABBs authorized channel partners

visits the end-user to get an understanding o their acility

including location o the applications, an inventory o motors,

any health and saety restrictions as well as anything unusual

that might aect the energy proile.

Energy appraisals are most suitable or processes with

variable torque applications that obey the cube law, running

continuously and where low is controlled by a mechanical

means such as valves or dampers. This is where the savings

rom a drive really start to look good compared to theinvestment cost.

Centriugal ans and pumps are typical variable torque

applications. The requirement or torque (and hence current)

increases with the square o the speed. The voltage again

varies in proportion to the speed, so power actually varies in

proportion to the cube o the speed. Hence, by reducing the

speed by a certain percentage, the power reduces by the

cube o the speed change. So 80 percent speed results in

(0.8)3 = 51 percent power.

Oten payback times o less than two years and sometimes

under one year, can be achieved.

Complete motor nameplate data is collated and each application may be photographed or easy recognition in the appraisal.

100

90

80

70

60

50

40

30

20

10

0

0 20 40 60 80 100

Powerrequired(%)

Flow (%)

Recirculation

Throt tling

Cyclic control

VSD

Pump

Saving potential


5/12Six steps to an eicient energy appraisal l Energy appraisal or lowering energy use and CO2 emissions 5

Selected applications may be monitored to determine electricity consumption.

During the energy appraisal priority is given to:

Variable torque applications, such as centriugal pumps and

ans, with priority to those which are operating with partial

low (i.e. valves, dampers). Saving potential up to

70 percent. Typical payback times o less than one year.

Variable torque applications with motor running at constant

nominal speed (ull fow) but where partial fow at lower

constant speed can be enough. Saving potential up to

30 percent and more. Typical payback time one to two years.

Continuously running old motors with incorrect power rating

(motors running sub-optimal point). Saving potential up to

5 - 8 percent. Typical payback time one to two years. Continuously running old motors with correct power rating

(poor motor eiciency). Saving potential: 1 5 percent.

Typical payback t ime two to three years.

Other standard applications (i.e. screw compressors,

mixers) that can be updated with drive control with speed

reduction. Saving potential up to 20 percent and more.

Typical payback t ime two to three years.

Other questions that may be asked include:

How old are the installed motors?

How eicient are the installed motors?

Are there pumps and ans that run or long times and/or

with variable loads?

Do you have motors that are too large or too small or the

process - check motor plate values?

What load variations does the process have?

What position are your low control devices (valves,

throttles, dampers) operating in or most o the time?

In many instances, answers to these typical questions may

not be readily available. But this does not restrict the energy

appraisal. ABBs expertise in motor-driven applicationsmeans it can easily assess the condition o the installed

base o motors or drives and make educated or calculated

assessments o what is needed.

ABB also engages with the plants process engineers to

determine the exact design criteria or the various processes.

This gives ABB a clearer understanding o how the process

is meant to operate and its critical design operating points,

thereby ensuring that the correct motor and/or drive

is selected.


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Six steps to an eicient energy appraisal

6 Six steps to an eicient energy appraisal l Energy appraisal or lowering energy use and CO2 emissions

2. Monitoring and data collection

During a walk around the acility, the engineer will spot typical

applications that may be running ineiciently. The engineer

will look not only at ixed speed motors but also any drives

currently used, to see i the application is running at

maximum eiciency.

The selected applications may be monitored in order to

accurately determine which applications are consuming

the most energy. I this stage is necessary then it may be

perormed over a seven-day period, to gain a complete

picture o the plants typical energy use.

3. Data analysis

Following the collection o the data, the indings are

analysed and potential savings identiied using dedicated

sotware. The indings are methodically presented, with

tables and graphs being created to help identiy where

savings are likely to arise. Among the data available includes

an estimation o present energy usage, areas o potential

savings, payback time i an investment is made in drives and/

or motors, carbon dioxide emission reduction, along with

many other key acts and analysis.

4. Recommendations

An action plan is prepared, usually compr ising an Execut ive

Summary and a detailed engineers report, highlighting

applications that can save the most.

The igures will normally be translated into monthly savings,

and there will be detailed recommendations or itting

particular drives or motors.

Oten the recommendations will show that drives can provide

excellent savings in particular applications. The report shows

the expected payback time on itting new equipment.

Monitoring may take place over several days.


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8/128 Reasons to consider an energy appraisal l Energy appraisal or lowering energy use and CO2 emissions

Reasons to consider an energy appraisal

As energy prices continue to luctuate and i rms are pressured

into reducing their carbon ootprint, there has never been a

better time or industry to consider the merits o drives and

high eiciency motors.

Surprisingly, negotiating better prices with existing energy

suppliers is oten cited as a preerred energy saving technique

ahead o installing drives and motors. Yet this makes little

sense when all suppliers are being orced to increase their

prices and are likely to continue to do so as uture energy

costs are orced upwards.

During an energy appraisal, ABBs engineers may also review

existing business operations and technology to identiy the

scope or improvements in energy eiciency and reduced CO2

emissions in such areas as:

Low-cost or no-cost investment opportunities in reducing

CO2

emissions

The scope or employing available technology, including

drives and electric motors or applications such as pumps,

ans and compressors

Availability o suitable energy loans and grants that may

apply to the organisations sector and speciic technologies

(depending on local knowledge)

Other beneits o an energy appraisal may also include:

Clearly identiied energy savings and CO2 emissions

reduction

Estimated payback times

Review o current preventive maintenance schemes

Following an energy appraisal, ABB oers advice on:

Replacing drive or motor components as part o a

preventive maintenance plan

Upgrading entire systems to the latest technology or to

extend the unctionality o existing drives and motors

Retroitting existing drives with modern technology

Recycling o all removed drives and motors to the latest

legislation

An action plan is prepared comprising engineers report and an Executive Report.


9/12Energy appraisal impact on real-lie industrial applications l Energy appraisal or lowering energy use and CO2 emissions 9

Steelworks

A large steelworks in northern Ita ly wanted to increase i ts

competitiveness through a signiicant reduction in the amount

o energy being used, which accounted or up to 30 percent

o its manuacturing costs.

Beore the eiciency goals were deined, technicians rom the

client and rom ABB worked together to analyze the installation

itsel. Ater considering return o investment (ROI) periods,

a series o drives were installed in the most critical points,

especially on the combustion air ans on the urnaces, which

previously had been regulated using choke dampers.

The installed motor base was also renewed, with an init ial

batch o 100 high eiciency low voltage motors replacing the

same number o standard eiciency motors.

Adding together the applications that have been installed, and

those that are planned or the uture, by its completion the project

expects to cut the energy being used by 3,000 MWh per year,

which could save up to $560,000 every year on its energy bill.

Summary

Energy saving About 2,300 MWh a yearCO2 reduction 1,288 tons/year

Segment and application Steel manuacturer, combustion

air ans

Salt plant

ABB equipment installed or just $32,000 is saving over

$32,000 a year at a UK salt plant. Replacing a single

oversized an motor with a smaller one equipped with speed

control, cut energy being used on one o the plants dryers by

over 60 percent.

Summary

Energy saving About 1,640 MWh/year

CO2 reduction 918 tons/year

Segment and application Food and beverage, ans

Cranes

Rapid, precise and eicient control o crane movements

reduces stresses on the system and the operator. In

modern container cranes, AC drives control all three

movement directions. Hoisting movement is most demanding

and a regenerative ABB AC drive gives energy savings

when braking.

Summary

Energy saving About 190 MWh/year


Segment and application Harbors, crane

Energy appraisal impact on real-lie industrial applications

Steelworks saves 2,300 MWh. Over $32,000 per year saved at a salt plant.


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Brass manuacturer

A brass manuacturer is saving $210,000 a year in energy

costs with ABB AC drives. An energy appraisal covering the

ume extraction ilter plant revealed signiicant savings on

iltration units, one with a 250 kW an and the other with three

132 kW ans.

Summary


CO2 reduction 1,500 tons/year

Segment and application Metal, ans

Plastics manuacturer

A plastic i lm manuacturer upgraded its 93 kW compressor

with ABB AC drives and saved 37% o its energy bill. Ater

sealing all leaks, a transducer was installed to monitor system

pressure. Improvements are expected to save $12,000 per

year or $375,000 over the installations lietime.

Summary



Segment and application Plastics and rubber, compressor

Brass manuacturer benefts rom energy appraisal. Fertilizer plant reduces electricity consumption.

Fertilizer plant

One o Europes leading producers o ertilizers and animal

eed phosphates upgraded ive process ans with ABB AC

motors and drives, replacing existing motors and mechanical

low control systems. Reduction in annual electricity

consumption is in excess o 4,000 MWh with annual energy

cost saving o some $210,000.

Summary



Segment and application Chemical, ans

Chemical plant

A chemical plant in China replaced its existing constant speed

acid pumps and ans control with 8 x ABB AC drives totalling

977.5 kW. The applications run about 8,000 hours a year and

the average energy saving is 37 percent lower, resulting in a

payback o about 6 months.

Summary



Segment and application Chemical, pumps and ans



11/12Energy appraisal impact on real-lie industrial applications l Energy appraisal or lowering energy use and CO2 emissions 11

Cooling towers

Cooling towers typically use banks o ans, each eeding

cooling cells. Within the cells, a an moves outside air through

a spray o water, allowing heat to dissipate. With variable

speed control, the energy saving can be 60 percent. With

100 kW total motor power and 4,000 h/year, this means:

Summary



Segment and application HVAC ans

Petrochemical plant

A reinery in Argentina replaced a steam turbine, which was

driving a blower, with an ABB AC drive and an induction

motor. The Energy Intensity Index (EII) improved by 10.5%

within one year.

Summary



Segment and application Petrochemical, blower

Cooling towers reduce CO2

by 112 tons/year. Mexican cement plant saves 5,300 MWh.

Sugar cane mill

A sugar plant in Honduras replaced ive steam turbines, which

were driving the cane mill, with ABB AC drives and induction

motors. The steam, produced by the steam turbines, can be

used to generate electricity which will eed the whole plant

and can even be sold to the grid.

Summary



Segment and application Sugar cane mill

Cement

A Mexican cement plant is saving 5,300 MWh annual ly since

replacing the existing damper an control o two 735 kW

ixed speed ID ans with ABB AC drives. Additional beneits

included improved productivity, which has boosted revenues

by about 574,000 per year, whilst giving a reduction in

maintenance by 97 percent. The payback time has been

estimated at six months.

Summary


CO2 reduction 3,650 tons/yearSegment and application ID ans



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Your ABB Partner

www.abb.com/energyeiciency

EnergyAppraisalbrochure/Feb

2010Notes:

We reserve the right to make technical

changes or modiy the contents o

this document without prior notice.

With regard to purchase orders, the

agreed particulars shall prevail. ABB

AG does not accept any responsibil ity

whatsoever or potential errors or

possible lack o inormation in this

document.

We reserve all rights in this documentand in the subject matter and

illustrations contained herein. Any

reproduction, disclosure to third parties

or utilization o its contents - in whole

or in part - is orbidden without prior

written consent o ABB AG.

Copyright 2010 ABB

All r ights reserved

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