Energy Audit Report of Kaliti Metal Product Factory

April 2014

Strategic Climate Institutions ProgrammeEnergy Efficiency Regulatory Framework Development and Implementation

Implementation AgencyEthiopian Electricity Agency (EEA)

Energy Audit Report of KalitiMetal Product Factory

Project Code 2013IB22

© The Energy and Resources Institute 2014

T E R I. 2014Energy Audit of Kaliti Metal product Factory, EthiopiaBangalore: The Energy and Resources Institute; 36 pp.[Project Report No. 2013IB22]

For more information

Industrial Energy (IE)T E R I Telephone +91 80 25356590-94Southern Regional Centre E-mail [email protected] t h Main Domlur II Stage Fax +91 80 25356589Bangalore – 560 071 Web www.teriin.orgIndia +91 •Bangalore (0) 80

Project Team

TERI Team

Mr. Ramesh DharmarajMr.Atulkumar Auti

EEA Team

Ato. Abdurazak MohammedAto. Kefelegn G/MichaelAto. Asemamu TadesseAto. Tsegaye Tilahun

Project Advisor

Mr. Girish SethiMr. G R Narasimha RaoMr. P.R.Dasgupta

Secretarial Assistance

Ms. S.Vijayalakshmi

Acknowledgements

We are thankful to the management for giving us the opportunity to be involved in this veryinteresting and challenging project. We would be happy to provide any further clarifications, ifrequired, to facilitate implementation of the recommendations.

We would like to thank the Kaliti Metal Product factory, Management and their team who havegiven full co-operation and support. They took keen interest and gave valuable inputs during thecourse of study.

We are also extremely thankful to the below management team for their nice hospitality,positive support and guidance and cooperation in undertaking this energy audit assignment.

Mr. Mutios Aselle - Chief Executive OfficerMr. Mekoya Kassa - Executive Officer

Table of contents

EXECUTIVE SUMMARY.......................................................................................................I

1.0 INTRODUCTION ................................................................................................................ 1

1.1 GENERAL DESCRIPTION ................................................................................................... 1

2.0 METHODOLOGY AND APPROACH FOR ENERGY AUDIT ............................................... 2

2.1 GENERAL DESCRIPTION ................................................................................................... 2

3.0 ENERGY CONSUMPTION PROFILE ................................................................................... 4

3.1 ENERGY DESCRIPTION ..................................................................................................... 4

3.2 ENERGY CONSUMPTION PROFILE ................................................................................... 4

3.1.1 Energy consumption ........................................................................................ 4

4.0 ELECTRICAL SYSTEMS ...................................................................................................... 6

4.1 GENERAL DESCRIPTION................................................................................................... 6

4.1.1 Plant description ............................................................................................... 6

4.1.2 Power capacitors ................................................................................................. 6

4.2 OBSERVATION & ANALYSIS ............................................................................................ 6

4.2.1 Electrical power measurements...................................................................... 6

4.2.2 Transformer No 1 system parameters ........................................................... 7

4.2.3 Transformer No 2 system parameters ........................................................... 8

4.2.4 MTN unit system parameters ......................................................................... 8

4.2.5 Transformer Load Management..................................................................... 9

4.2.6 LT Bus Voltage and Frequency....................................................................... 9

4.2.7 Distribution losses ............................................................................................ 9

4.2.8 Power factor management............................................................................... 9

4.2.9 DG system........................................................................................................ 10

4.2.10 Energy Monitoring System............................................................................ 10

4.2.11 Power quality ................................................................................................. 10

4.3 ENERGY CONSERVATION MEASURES............................................................................ 11

4.3.1 Rectification APFC control panel and additional kVAr banks ................ 11

5.0 COMPRESSED AIR SYSTEM ............................................................................................ 12

5.1 PLANT DESCRIPTION ..................................................................................................... 12

5.2 OBSERVATIONS, ANALYSIS AND FINDINGS ............................................................... 12

Energy Audit report of Kaliti Metal product, Ethiopia

5

5.2.1 Energy consumption pattern......................................................................... 12

5.2.2 Free air delivery (FAD) test ........................................................................... 13

5.2.3 Specific Energy Consumption of Air Compressor..................................... 13

5.2.4 Operation of Air Compressor ....................................................................... 14

5.2.5 Leakage (No Load) test .................................................................................. 14

5.3 ENERGY CONSERVATION PROPOSALS ......................................................................... 15

5.3.1 Optimization the compressed air by arresting the leakages..................... 16

5.3.2 Install variable frequency drive (VFD) for air compressor....................... 16

6.0 PUMPING SYSTEM ........................................................................................................... 18

6.1 GENERAL DESCRIPTION ................................................................................................. 18

6.2 OBSERVATION, ANALYSIS & FINDINGS ...................................................................... 18

6.2.1 Performance evaluation of Pump................................................................. 18

6.3 ENERGY CONSERVATION MEASURES............................................................................ 19

6.3.1 Resizing the discharge pipe of cooling water pump ................................. 19

7.0 LIGHTING SYSTEM.......................................................................................................... 21

7.1 GENERAL DESCRIPTION ................................................................................................. 21

8.0 SUMMARY OF ENERGY SAVING POTENTIAL ............................................................... 25

List of Tables

Table 2.1 Details of Instruments ...............................................................................................2

Table 3.1 Electricity consumption from Grid..........................................................................4

Table 3.2 Tariff Structure for ICS Industrial LV (Tariff 41)...................................................5

Table 3.3 Cost of energy.............................................................................................................5

Table 4.1 Loading Parameters of transformer no 1 Incomer Panel during working day.7

Table 4.2 Loading Parameters of MTN unit Incomer Panel during working day ............8

Table 4.3 Measured total harmonic distortion levels at transformer secondary level....10

Table 5.1 Design specification of screw air compressor......................................................12

Table 5.2 FAD test result of screw air compressor...............................................................13

Table 5.3 Specific energy consumption of the compressor.................................................13

Table 5.4 Operating pattern of the compressors ..................................................................14

Table 5.5 Leakage test of the compressed air line ................................................................14

Table 6.1 Design specifications of the water pump .............................................................18

Table 6.2 Performance evaluation of pump..........................................................................18

Table 7.1 Details of lighting fixture in the plant...................................................................21

List of Figures

Figure 2.1 Instruments used for energy audit study ...............................................................3

Figure 4.1 Single line diagram of the electrical system...........................................................6

Figure 4.2 Transformer No 1Normal working day trend.......................................................7

Figure 4.3 Transformer No 1Normal working day trend with different phases.................7

Figure 4.4 MTN unit working day trend...................................................................................8

Figure 4.5 Phase to Phase Voltage trend ...................................................................................9

Figure 4.6 Measured power factor at each feeder....................................................................9

Figure 4.7 Power factor recorded trend...................................................................................10

Figure 5.1 Load trend of screw air compressor......................................................................12

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List of Abbreviations

EEA : Ethiopia Electricity AgencyTERI : The Energy and Resources InstituteAPFC : Automatic power factor controllerHFO : Heavy Fuel Oil (Furnace oil)CFL : Compact Fluorescent LampCO : Carbon MonoxideCO2 : Carbon DioxideMT : Metric TonneEEPCo : Ethiopia Electric Power CooperationSEC : Specific Energy ConsumptionDG : Diesel GeneratorHT : High TensionLT : Low TensionPF : Power FactorMCC : Motor Control CenterPCC : Power Control CenterIEEE : Institute of Electrical and Electronic EngineersTHD : Total Harmonic DistortionECM : Energy Conservation MeasureEE : Energy EfficientCCR : Central Control RoomFTL : Fluorescent Tube LightGLS : General Lighting ServicesGHG : Green House GasHP : Horse PowerkW : Kilo WattkWh : Kilo Watt HourLtr : LitreKL : Kilo LitrekCal : Kilo caloriekg : Kio GramMVL : Mercury Vapour LampO&M : Operation and MaintenanceSCM : Standard Cubic MeterMU : Million UnitsSPP : Simple Payback PeriodTR : Tonnage of Refrigerationtpd : tonne per daytpy : tonne per yearVFD : Variable Frequency Drive

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Executive Summary

1.0 This section presents a brief summary of the results of the energy audit carried out atKaliti Metal Product Factory, Ethiopia. The study covered with a focus on energyconservation measures including performance assessment of vital energy consumingequipment.

2.0 A team of two consultants of TERI and four consultants of EEA were involved in theenergy audit study. The energy audit was mainly targeted at identifying practical,sustainable and economically viable energy saving opportunities in all sections of theplant, resulting from a detailed study and analyses of technical parameters. Theenergy audit involved using a wide range of sophisticated, portable, diagnostic andmeasuring instruments to generate refined data and facilitate in complex analyses togive a more reliable basis for evaluation of performance, energy saving measures andeconomic viability.

3.0 Electricity is the major energy source to the plant. The annual electrical energyconsumption of the plant during the year December 2012- November 2013 was849thousand kWh.

The major savings can be achieved with small investment.

Type ofRecommendations No. of recommendations

Annual costsaving

potential Birr.thousand

Cost ofImplementationBirr. thousand

Small investment,payback less than 1year

2 97 25

Medium investment,payback within 1 to3 years

4 83 142

High investment,payback above 3years

2 31 75

Total 8 211 242

The identified annual electrical energy saving potential of 245 thousand kWh works out to28.05% from the average annual electrical energy consumption of 849 thousand kWh. Thetotal annual energy cost saving potential is Birr 211 thousand.

Total budgetary implementation cost for the recommended proposals is estimated to be Birr242 thousand.


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4.0 During the study, there was continuous interaction with the plant personnel, all therecommendations have been thoroughly discussed with concerned section officialsand also at group meetings. There has been close involvement of senior officials,which ensured the necessary co-ordination required for the study.

5.0 A summary list of recommendations, saving potential and implementation costs aregiven below:

S. Energy ConservationMeasures

Annual Investment Simplepayback

period, inYears

No.Savings Potential

Energy / Value,thousand

kWhthousand

Birrthousand

BirrSHORT TERM MEASURES

Compressed air system1 It is recommended to arrest the

leakages and optimise ofcompressed air usages.

134 89 20 0.22

Pumping system2 Resizing the discharge pipe of

cooling water pump13 8 5 0.6

Sub-Total 147 97 25 0.26

MEDIUM TERM MEASURESElectrical System

3 Rectification APFC controlpanel and additional kVArbanks

0.2 55 100 1.8

Lighting4 Replacement of Mercury lamps

400W with Metal Halide lamps23 15 17 1.1

5 Replacement of Mercury lamps250W with Metal Halide lamps

5 3 5.6 1.7


23 10.4 19.2 1.9

Sub-Total 51.2 83.4 141.8 1.70

LONG TERM MEASURESCompressed air system

7 Install variable frequency drive(VFD) for air compressor

23 15 17 1.1

Lighting8 Replacement of existing FTL T8

lamps with FTL T5 in phasemanner

24 16 58 3.6

Sub-Total 47 31 75 2.42

Grand Total 245 211 242

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1.0 Introduction

1.1 General descriptionKaliti Metal Products Factory (KMPF) was established in 1968 with the objective ofproducing structural and furniture hollow sections, door and window frame profiles, EGAand ribbed sheets for roofing & wall cladding. The factory is located on the main road toDebrezeit, 20 Kms away from the center of Addis Ababa (capital). It occupies a total landarea of 99,400 square meters. The factory uses imported steel sheets in coils as its majorinput to produce standardized and job order metal products. The factory distributes its highquality and dependable products to the local market.

Kaliti Metal Product Factory invited EEA and TERI to carry out an energy audit, in themonth of February 2014. The energy audit was focussed to evaluate the existing energyconsumption levels and to identify the potential to reduce this consumption. The audit teaminvolved two TERI professionals and four EEA professionals to evaluate the scope forenergy efficiency.

The study focuses on improving energy use efficiency and identifying energy savingopportunities at the various equipment.

During the study, every attempt was made to understand the existing practices to developset of recommendations in the interest of:

Energy Saving (conservation)

The preliminary observations have been discussed with the operations personnel as well asthe management, both during the course of the study. This is primarily to ensure that thereis a proper dissemination of information, as well as to provide the right platform for sharingof ideas. The keen response and avid involvement of the management team for theimplementation has been extremely encouraging and heartening.

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2.0 Methodology and Approach for Energy Audit

2.1 General description

The audit covered an in-depth study of all the electrical equipment, Pumps, Compressed airsystems, Fans and blowers, Process equipment, etc. The energy audit covered an in-depthstudy of all the major energy consuming equipment / stages of manufacture. The auditinvolved carrying out various measurements and analysis covering all major energyconsuming sections, to realistically assess losses and potential for energy savings.

A wide array of latest, sophisticated, portable, diagnostic and measuring instruments wereused to support our energy audit and analyses. The audit study made use of variousportable instruments, for carrying out various measurements and analyses. The specializedinstruments that were used during the audit for various measurements their description isgiven in table 2.1.

Table 2.1 Details of Instruments

S No Description Functions1 Krykard ALM 32 Three phase power and harmonic analysers2 Krykard ALM 10 Single phase power and harmonic analysers3 Fluke-41B Power and harmonic analysers4 Anemometer Air flow measurements5 Multifunction kit RH%, Temperature, Pressure, flow6 Lux meter Illumination levels7 Ultrasonics flow meter Water flow measurements8 Thermography Thermal Imagers9 Thermo hunter Surface temperature measurements10 Gas analysers Oxygen, CO and CO2 measurements11 Temperature probe Temperature measurements12 Fyrite Kit Oxygen and Carbon di oxide percentage


3

Figure 2.1 Instruments used for energy audit study

During the audit, there was continuous interaction between the audit team and plantpersonnel to allow for possible concurrent implementation and to ensure that thesuggestions made are realistic, practical and implement able. Our team made regulardiscussions and final presentation to the management group on the findings andrecommendations, so that immediate action can be taken for implementation to the extentpossible.

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3.0 Energy Consumption Profile3.1 Energy Description

The detailed energy audit at Kaliti Metal Product Factory has been conducted to identify thepotential of energy savings. The plant major energy consumption is electricity. Energyconsumption parameters were measured and recorded for analysis during the study. Theenergy data of the plant for the last year was collected for analysis.

3.2 Energy Consumption Profile

3.1.1 Energy consumption

The month wise consumption electricity consumption from EEPCo from May-2012 to Nov-2013 is given in Appendix – 3/1. The summary of the electricity consumption is given intable 3.1

Table 3.1 Electricity consumption from Grid

Month Powerconsumption

Powercost

Powerfactor

Maximumdemand

Totalamount

UnitCharge

kWh Birr kVA Birr Birr/kWh

Jun-12 82500 47668.50 0.984 420 47722.07 0.578

Jul-12 49500 28601.10 0.426 420 42253.53 0.854

Aug-12 55500 32067.90 0.797 420 35067.44 0.632

Oct-12 51000 29467.80 0.728 435 34630.79 0.679

Dec-12 51000 29467.80 0.783 435 32997.71 0.647

Jan-13 34500 19934.10 0.821 450 22421.10 0.650

Feb-13 58500 33801.30 0.773 450 37759.90 0.645

Mar-13 67500 39001.50 0.756 450 43494.95 0.644

Apr-13 64500 37268.10 0.758 450 41690.11 0.646

May-13 76500 44201.70 0.743 450 49098.78 0.642

Jun-13 68139 39370.71 0.775 450 43276.06 0.635

Jul-13 69861 40365.69 0.800 450 43496.92 0.623

Aug-13 88500 51135.30 0.719 450 56751.64 0.641

Sep-13 94500 54602.10 0.724 450 60066.25 0.636

Oct-13 69000 39868.20 0.771 450 43891.77 0.636

Nov-13 106500 61535.70 0.599 450 70860.62 0.665

3.2.1 Electricity tariff and cost detailsThe plant has sanctioned contract demand of 2MVA at specified voltage of 400V. Electricitysupply from EEPCo is billed under the ICS Industrial low voltage (tariff 41). The tariffincludes several other components in addition to energy (kWh) consumed, namely;


5

The billing is based on two-part tariff structure:

Table 3.2 Tariff Structure for ICS Industrial LV (Tariff 41)

Particular Range BirrFrom To

Active energy 0 1000000000 0.5778

Service charges 0 1000000000 53.57

Power factor 0 1000000000 68.396

3.2.1.1 Unit cost of energy

The cost of electricity considered for techno-economic evaluation of the various proposals isgiven in table 3.3.

Table 3.3 Cost of energy

Electricity Birr 0.665 per kWh

kWh energy charges @ Birr. 0.5778 per kWh (units).

Service Charges @ Birr 53.57

Power factor charges @ Birr 68.396 (upto 0.9 power factor)

Details of the Tariff structure are given in Table 3.2.

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4.0 Electrical Systems

4.1 General Description4.1.1 Plant description

Kaliti Metal plant receives electricity from Ethiopian electricity Power Corporation throughsingle feeder of 15kV line. The 15kV supply is step down to 380V by two transformers anddistributed to the plant. The rating of distribution transformers at plant are 830kVA. Thedistribution transformer is situated in back yard of the plant.

The 1000kVA and 135kVA FG Wilson make DG set is installed near PCC room, which nowoperates during black out of the EEPCO.

The systematic Single line diagram of the electrical system is depicted in Figure 4.1.

Figure 4.1 Single line diagram of the electrical system

4.1.2 Power capacitors

The 600kVAr/440V LT capacitor banks are provided at Main Incomer at LT sub distributionPanel. The capacitor banks were installed in year 2004. The capacitors are de-rated thecapacity, due ageing factor.

4.2 Observation & Analysis4.2.1 Electrical power measurements

The electrical power measurement were carried out at the LT Side Incomer feedertransformer No 1 and transformer No 2, Air Compressor feeders and at eachsection/operating machines of Distribution board to monitor all the electrical parameterswas carried out in the LT main incoming panels using sophisticated portable power andharmonic analyser to monitor the power factor and the incoming supply voltage condition.


7

4.2.2 Transformer No 1 system parameters

The Power parameters of Transformer No 1 Incomer panel were measured at the LT level,parameters such as incoming voltage profile, variation in load current, kW, kVA, powerfactor with respect to time is given in Appendix – 4/1. The summary of the loadingparameters of the transformer No 1 Incomer feeder is given in table 4.1.

Table 4.1 Loading Parameters of transformer no 1 Incomer Panel during working day

Description V I kW kVA PF Hz %Uthd %Ithd

Minimum 371.2 2.7 4.2 7.3 0.65 49.92 0.3 1.7Average 386 106 50.4 70.8 0.69 49.99 1 9.7Maximum 406.6 321.4 142.9 205 0.97 50.07 3 14

The load on the Transformer No 1 Incomer varies around from 50.4kW ~ 143kW on workingday. The major loads on incomer are Air compressor, lighting, welding. The trend is given infigure 4.2 and at different phase is given in figure 4.3.

Figure 4.2 Transformer No 1Normal working day trend

Figure 4.3 Transformer No 1Normal working day trend with different phases

0.0010.0020.0030.0040.0050.0060.00

14:2

0:00

16:2

0:00

18:2

0:00

20:2

0:00

22:2

0:00

00:2

0:00

02:2

0:00

04:2

0:00

06:2

0:00

08:2

0:00

10:2

0:00

12:2

0:00

14:2

0:00

16:2

0:00

18:2

0:00

20:2

0:00

22:2

0:00

00:2

0:00

02:2

0:00

04:2

0:00

06:2

0:00

08:2

0:00

10:2

0:00

kW

Time

Trend of loading at different Phases

R Phase Y Phase B Phase

Electrical System

8

4.2.3 Transformer No 2 system parameters

The Power parameters of Transformer No 2 Incomer panel were measured at the LT level,parameters such as incoming voltage profile, variation in load current, kW, kVA, powerfactor with respect to time is given in Appendix – 4/2. The transformer No 2 is connected tofew lights and one slotting machine. It is recommended to dis connect the transformer No 2,and re connect the load to Transformer No 1.

4.2.4 MTN unit system parameters

The Power parameters of MTN unit Incomer panel were measured at the LT level,parameters such as incoming voltage profile, variation in load current, kW, kVA, powerfactor with respect to time is given in Appendix – 4/3. The summary of the loadingparameters of the MTN unit Incomer feeder is given in table 4.2.

Table 4.2 Loading Parameters of MTN unit Incomer Panel during working day

Description V I kW kVA PF Hz %Uthd %Ithd

Minimum 372 66 36.3 44 0.63 49.94 0.7 7.6Average 386 139 69.3 93 0.76 49.99 1.6 14.9Maximum 406 288 143 192 0.83 50.03 2.6 31.1

The load on the MTN unit Incomer varies around from 36.3kW ~ 143kW on working day.The major loads on incomer are drives and pumps. The trend is given in figure 4.4.

Figure 4.4 MTN unit working day trend


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4.2.5 Transformer Load Management

The plant has two numbers distribution transformer of which only one transformer loadedto less than optimal level and new shed transformer is not even loaded to 1% level.

4.2.6 LT Bus Voltage and Frequency

The LT voltage varied from 386.6 ~ 427.1V secondary side transformer, which has connectedto Off-load tap changer. The figure 4.5 gives the phase to phase voltage trend at the incomer.

Figure 4.5 Phase to Phase Voltage trend

The Observed grid Frequency varies between 49.92 ~ 50.03 Hz.

4.2.7 Distribution losses

The Building has made use of adequate sizes of cables from the main HT/LT PCC to varioussub feeder MCC panels. Suitable size of LT PVC/ XLPE cables of single/multiple runs (3 ½core armoured cables) ranging from 2.5 mm2 to 300mm2 have been used, to keep thevoltage drop and distribution losses to minimum.

4.2.8 Power factor management

The power factor measured at PCC level of varies between 0.65~ 0.973pf. The Detailsmeasured of the power factor at each feeder is given in Figure 4.6.

Figure 4.6 Measured power factor at each feeder

Electrical System

10

The capacitor banks are not connected at the motor loads /APFC bank is not activated. Therecorded power factor trend is given in figure 4.7.

Figure 4.7 Power factor recorded trend

4.2.9 DG system

The 1000kVA and 135kVA Perkins FG wilson make DG set is operated, during power failureof the grid. At present diesel consumption and number of hours operation are recorded, it isrecommended to recorded the kWh generation, after rectification kWh meter at DG set paneland Main incomer panel.

4.2.10 Energy Monitoring System

The energy meters to be provided for the main incomer and major loads or at PCC/MCCpanels. The management should plan to install energy meters to know section/unit wiseenergy consumption versus the Usage for typical periods/day/month. This will help inconversation energy consumption.

4.2.11 Power quality

During the study the total harmonic distortion (THD) of voltage and current were alsomonitored at the PCC, MCC levels as well as at load end. The main industry standard usedfor harmonics in power system is referred to IEEE – 519. Table 4.3 summarises the totalharmonic distortion as observed at the incomer level of feeders.

Table 4.3 Measured total harmonic distortion levels at transformer secondary level

Description % THD(V) % THD (I)

Incomer Feeder Avg 1.04 9.74

0.000

0.200

0.400

0.600

0.800

1.000

1.200Ju

n-12

Jul-1

2

Aug-

12

Sep-

12

Oct

-12

Nov

-12

Dec-

12

Jan-

13

Feb-

13

Mar

-13

Apr-

13

May

-13

Jun-

13

Jul-1

3

Aug-

13

Sep-

13

Oct

-13

Nov

-13

Pow

er fa

ctor

Month

Trend of Recorded power factor from Grid


11

As per IEEE-519, the % voltage distortion should be below 5.0%. Total harmonic distortionof current (%THD-I) should be below 15.0% and as observed from the analysis at the mainincomer at the Transformer, the % THD (V) and %THD (I) is well within the limits asspecified in IEEE- 519.

4.3 Energy conservation measuresBased on the observations/ findings during detailed energy audit conducted in the unit, thefollowing major energy conservation measures (ECMs) have been identified. The details aregiven below.

4.3.1 Rectification APFC control panel and additional kVAr banks

4.3.1.1 Background

At Present APFC panel is fault, with the capacitor bank (Non-functional), which leads toimproper/lower pf maintenance of the pf levels. During audit period, last twelve monthEEPCo is charged pf Penalty.

4.3.1.2 Recommendation

Rectification of the APFC control card, to maintain the optimal level of pf greater than 0.90level to avoid pf penal charges and reduction the distribution loss. It recommended to install2kVAr, 3kVAr capacitor banks and removed present higher kVAr banks.

4.3.2.3 Energy & Cost Saving

Annual Cost Savings (pf penalty) Birr 54610

Annual Energy Savings 250unitsAnnual total savings Birr54610Investment Cost Birr100000Payback Period 1.8years

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20.00

25.00

30.00

35.00

40.00

45.00

15:15

:0015

:21:00

15:27

:0015

:33:00

15:39

:0015

:45:00

15:51

:0015

:57:00

16:03

:0016

:09:00

16:15

:0016

:21:00

16:27

:0016

:33:00

16:39

:0016

:45:00

16:51

:0016

:57:00

17:03

:0017

:09:00

17:15

:0017

:21:00

17:27

:0017

:33:00

17:39

:0017

:45:00

17:51

:0017

:57:00

18:03

:0018

:09:00

18:15

:0018

:21:00

18:27

:0018

:33:00

18:39

:0018

:45:00

Pow

er c

onsu

mpt

ion,

kW

T i m e

Load trend of air compressor

5.0 Compressed Air System5.1 Plant descriptionThe plant has installed single screw type air compressor and reciprocating air compressor tomeet the instrument air demand of various sections. The Design specification of the screwair compressor is given in table 5.1.

Table 5.1 Design specification of screw air compressor

Description Unit Details

Make Worthington CreyssensacModel RLR 5000 BX2Type ScrewCapacity m3/hr 342

cfm 201Pressure kg/cm2 10Motor Power kW 37

The generated compressed air (instrumental) is passed through refrigerated air drier toreduce its moisture content. The Compressed air is used for cutting machine, press machine,un-coiler, ejector unit, painting, etc.

The reciprocating air compressor was in servicing, during the our audit period.

5.2 Observations, Analysis and Findings

5.2.1 Energy consumption pattern

The plant was operating screw compressor to meet the plant air compressor demand.During study period, logged power quality analyser to air compressor to understand the aircompressor cycles and same is graphically represented in figure 5.1.

Figure 5.1 Load trend of screw air compressor


13

The analysis was carried out for the air compressor cycles and calculated loading andunloading based on the logging. The loading and unloading of the air compressor wasaround 90% and 10% respectively.

5.2.2 Free air delivery (FAD) test

The Free air delivery (FAD) test can be conducted in two ways namely suction velocitymethod and pump up method. The procedure for the FAD test is given in Appendix -5/1.Suction velocity method was adopted in present case as the plant was in continuousoperation and the measured FAD figures are provided in table 5.2.

Table 5.2 FAD test result of screw air compressor

Description Unit Design Air compressor

Air flow rate m3/hr 342 354cfm 201 208

Percentage % 103%

The operating FAD of the screw compressor found to be satisfactory.

5.2.3 Specific Energy Consumption of Air Compressor

The specific energy consumption was evaluated for the compressor in use. The specificenergy consumption depends on the compressor type, capacity, stages and operatingpressure etc. The detail evaluation of specific energy consumption of the air compressor isgiven in table 5.3.

Table 5.3 Specific energy consumption of the compressor

Description Unit Air compressor

Air Flow rate m3/hr 354cfm 208

Loading Power kW 38.9Unloading power kW 9.1Specific power Consumption kW/cfm 0.187

Compressed Air System

14

The specific power consumption of air compressor is around 0.187 kW/cfm. The specificpower consumption of air compressors is found to be satisfactory.

5.2.4 Operation of Air Compressor

During the audit period, air compressor was unload at 7.5 kg/cm2 and load at 6.0 kg/cm2.The detail of operating pattern of the compressors is given in table 5.4.

Table 5.4 Operating pattern of the compressors

Description Unit Air comp

Loading pressure kg/cm2 6.0

Unloading pressure kg/cm2 7.5

Loading % 90%

Unloading % 10%

Loading power consumption kW 38.9

Unloading power consumption kW 9.1

The compressed air is mainly used for instrumentation purpose and pressure required atuser end is around 5~6 kg/cm2. The present compressed air requirement of the plant isaround 208cfm (354m3/hr).

5.2.5 Leakage (No Load) test

The leakage test for the compressed air was carried out during lunch time when plant wasnot in operation. The procedures for carrying out leakage test are given in Appendix – 5/2.The detail leakage test is given in table 5.5.

Table 5.5 Leakage test of the compressed air line

Description Unit Air Comp

Air Flow rate m3/hr 354Cfm 208

Loading Power kW 38.9Specific power Consumption kW/cfm 0.187Loading Time Sec 77Unloading Time Sec 58Loading % 57%Unloading % 43%Quantity of air leakage m3/hr 202

Cfm 118.8Energy Loss kW 22.2

From, the above table, it can be observed that compressed air leakage is around 118cfmwhich is 57% of total compressed air generation. The compressed air leakage of the plant ishigh as compare to acceptable leakage (5-10%) for metal processing industries.Also during leakage test, try to identified the location of compressed air leakages and it wasshown to the plant maintenance team. It is recommended to arrest the leakage of thecompressed air.


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5.3 Energy Conservation ProposalsBased on the observations/ findings during detailed energy audit conducted in the unit, thefollowing major energy conservation measures (ECMs) have been identified. The details aregiven below.

Compressed Air System

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5.3.1 Optimization the compressed air by arresting the leakages

5.3.1.1 Background

During leakage test, compressed air was not used in the plant and compressor operates atloading / unloading condition mainly because of leakages. Compressor was running 57%load and 33% unlading condition i.e. leakages is around 57%. The plant leakage is around118cfm and power loss is 22.2 kW.

In ideal condition means when there is no usage of compressed air in plant, compressor hasto run on unload condition. But in practically full leakages arresting is not possible. Formetal processing industries 5-10% leakages is acceptable.


It is recommended to arrest the leakages and optimise of compressed air usages.

5.3.1.3 Energy Saving

Present comp power consumption : 38.9 kWEstimated power saving : 17.5kW(After arresting leakages)Annual operating hours (24hrs x320 days) : 7680 hrAnnual energy saving : 134400 kWhAnnual Cost saving (@0.665 Birr/kWh) : Birr 89300Investment : Birr 20000Simple payback period : 0.22 year

5.3.2 Install variable frequency drive (VFD) for air compressor

5.3.2.1 Background

Plant has installed single screw compressors to meet the plant air compressor demand.Operating pressure of air compressor between 6.0 to 7.5 kg/cm2. Compressed air is mainlyused for instrumentation purpose and pressure required at user end is around 5~6 kg/cm2.The present compressed air generation is around 208cfm (354m3/hr) and leakage is around118cfm which is 57% of total compressed air generation. Actual compressed air requirementfor the plant is around 90cfm. After arresting compressed air leakages, loading of thecompressor will come down to 40-50% and compressor will run most of time in unload(idle) condition.


It is recommended to install variable frequency drive (VFD) for air compressor andcompressor speed will vary as per the compressed air requirement.


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5.3.2.3 Energy Saving

Present comp power consumption : 35.8kWhEstimated power saving : 3.6kWh(After installing VFD)Annual operating hours : 7680 hr(24 hrs and 320days)Annual energy saving : 26880kWhAnnual Cost saving (Birr 0.665/ kWh) : Birr 17800Investment : Birr 62000Simple payback period : 3.5 years

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6.0 Pumping system

6.1 General descriptionThe plant has installed two numbers of pumps to cater cooling water to various place suchas heat exchanger of coolant, DM water cooler, electrical panel cooling and strip wieldingmachine, etc. The design specification of pump is given in table 6.1.

Table 6.1 Design specifications of the water pump

Particular Cooling tower pumpFlow, m3/hr 7.5-30Head, m 20-24.5Motor power, kW 11

6.2 Observation, Analysis & Findings6.2.1 Performance evaluation of Pump

Two number of cooling water pumps (1R+1S) has been installed to circulate cooling water tovarious machines in the plant. Normally single pump was in operation. During the study,pumps flow rate, developed head and power consumption are measured. The water flowrate was measured using portable ultrasonic flow meter. The performance of the pumps is intable 6.2.

Table 6.2 Performance evaluation of pump

Particulars Unit Coolingwaterpump

Design parameters

Flow m3/hr 7.5-30

Head m 20-24.5

Motor power kW 11

Operating parameters

Flow m3/hr 5.0

Differential head m NP*

Power kW 8.5

Pump efficiency % -

NP*- Not Possible

Cooling water pump flow was around 5m3/hr which is less as compare to design flow.Provision was not available to connect pressure gauge due to that differential headmeasurement was not possible.


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It was observed that pipe size installed to supply cooling water to various place is notuniform. Pump discharge side water smaller size pipe has been installed and after that pipesize increased (2 inch). Throttling effect is happening due to the smaller size pipe atdischarge side of the pump and water flow rate is less. It is suggested to install bigger sizepipe at discharge of the cooling water pump.


6.3.1 Resizing the discharge pipe of cooling water pump

6.3.1.1 Background

Two number of cooling water pumps (1R+1S) has been installed to circulate cooling water tovarious machines in the plant. Normally single pump was in operation. Cooling water pumpflow was around 5m3/hr which is less as compare to design flow. It was observed that pipesize installed to supply cooling water to various place is not uniform. Pump discharge sidewater smaller size pipe has been installed and after that pipe size increased (2 inch).Throttling effect is happening due to the smaller size pipe at discharge side of the pump andwater flow rate is less. It is suggested to install bigger size pipe at discharge of the coolingwater pump.


It is recommended to install proper size of the pipe at discharge of cooling water pump.

Pumping System

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6.3.1.3 Energy Savings

Present power consumption of pump : 8.5kWRealizable Energy Savings : 1.7 kW(After changing pipe size)Operating hours (24hrs x 320dasys) : 7680 hrsAnnual Energy Savings : 13000 kWhAnnual Cost Savings (@ 0.665 birr/kWh) : Birr 8600Investment Cost : Birr 5000Simple Payback Period : 0.6 years

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7.0 Lighting System

7.1 General descriptionThe plant has installed/retrofit different types lamps, which are retrofit 44 years old lightingof GLS fixtures in the plant. The lighting fixtures used in the plant include fluorescent tubelamps (FTL) and GLS lamps, mercury lamps and sodium lamps. The plant is used forvarious lighting fixtures their description is given in table 7.1.

Table 7.1 Details of lighting fixture in the plant

Location Type oflamp

Wattage Quantity

Basic Manufacturing Shed MV 400 18

MV 125 30

FTL 40 33

Carpentry MV 400 2

FTL 40 25

Assembling Shed MV 125 1

FTL 40 42

Maintenance Shed MV 125 1

FTL 40 87

Storage area MV 400 1

Street light MV 250 7

7.2 Observation7.2.1 General observationDuring the study, the lighting fixtures used in the plant were counted and their workingcondition was assessed, most lighting illuminations level were inefficient in the critical areasof the plant.


7.3.1 Replacement of Mercury lamps 400W with Metal Halide lamps

7.3.1.1 BackgroundIt is observed that plant uses mercury vapour lamp for lighting in production area. Theexisting lamps consume 400W power and ballast consumes 15W power. The lumens perwatt of mercury vapour lamp are low and also the life is short. The total 21 fixtures arepresent in the plant.

Pumping System

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It is recommended to replace existing mercury vapour lamps by metal halide lamps.

Major benefits of metal halide fixtures over conventional MVL are as follows: Lamps are suitable for 220V and 240V. Uniform light output for wide range of supply voltages. A colour-rendering index of between 80 and 95. Less heat generation, hence load on ACs reduces. Higher lumen output per watt (around 85 lumens per watt)The total lighting load of the building is 8.4kW.

7.3.1.3 Energy savings

Particulars Unit Existing ProposedType of lamp - MVL 400W MHWattage of lamps W 400 250Design Lumen (Approx.) Lumen 20000 20000No. of lamps to be replaced No. 21 21Average Operating Hours per day Hours/Days 24 24Operating day /year No. 300 300Energy savings kWh/year 22,680Energy Cost Birr/kWh 0.665Energy cost savings Birr/ year 15,082Initial retrofitting cost / lamps Birr 800Initial investment cost Birr 16800Payback period Years 1.1

7.3.2 Replacement of existing FTL T8 lamps with FTL T5 in phasemanner

7.3.2.1 Background

Fluorescent tube lights of 36W FTLs with electro mechanical ballasts consume more energy.About 844 numbers such lamp fittings were found in different locations of the plant.


It is proposed to replace all 36W electro mechanical ballast FTLs with 28W FTLs havingelectronic ballasts. Electronic ballasts help in instantaneous starting of lamps and haveimproved regulation for varying input voltage. Major benefits of T5 fixtures overconventional T8 FTL are as follows:


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Uniform light output for wide range of supply voltages. Instant start and flicker free operation. Improves the power factor almost close to unity. Less heat generation, hence load on ACs reduces. Increased lamp life around 15000 hrs. Higher lumen output per watt (around 105 lumens per watt)


The envisaged annual energy saving potential is 18986kWh per year equivalent to amonetary saving of Birr 8354 per year. The investment requirement is Birr 92295 with asimple payback period of 11 years.

Particulars Unit Existing ProposedType of lamp - FTL-T8 FTL-T5Wattage of lamps W 36 28Design Lumen (Approx.) Lumen 3200 2900Watt loss per ballast W 12 2No. of lamps to be replaced No. 187 187Average Operating Hours per day Hours/Days 24 24Operating day /year No. 300 300Energy savings kWh/year 24235Energy Cost Birr/kWh 0.665Energy cost savings Birr year 16116Initial retrofitting cost / lamps Birr 315Initial investment cost Birr 58905Payback period Years 3.6

7.3.3 Replacement of Mercury lamps 250W with Metal Halide lamps

7.3.3.1 Background

It is observed that plant uses mercury vapour lamp for lighting in production area. Theexisting lamps consume 250W power and ballast consumes 15W power. The lumens perwatt of mercury vapour lamp are low and also the life is short. The total 7 fixtures arepresent in the plant.


It is recommended to replace existing mercury vapour lamps by metal halide lamps.Major benefits of metal halide fixtures over conventional MVL are as follows: Lamps are suitable for 220V and 240V. Uniform light output for wide range of supply voltages. A colour-rendering index of between 80 and 95. Less heat generation, hence load on ACs reduces. Higher lumen output per watt (around 85 lumens per watt)The total lighting load of the building is 1.75kW.

Pumping System

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Particulars Unit Existing ProposedType of lamp - MVL 250W MHWattage of lamps W 250 150Design Lumen (Approx.) Lumen 20000 20000No. of lamps to be replaced No. 7 7Average Operating Hours per day Hours/Days 24 24Operating day /year No. 300 300Energy savings kWh/year 5040Energy Cost Birr/kWh 0.665Energy cost savings Birr/ year 3352Initial retrofitting cost / lamps Birr 800Initial investment cost Birr 5600Payback period Years 1.7

7.3.4 Replacement of Mercury lamps 125W with Metal Halide lamps7.3.4.1 BackgroundIt is observed that plant uses mercury vapour lamp for lighting in production area. Theexisting lamps consume 125W power and ballast consumes 15W power. The lumens perwatt of mercury vapour lamp are low and also the life is short. The total 32 fixtures arepresent in the plant.


It is recommended to replace existing mercury vapour lamps by metal halide lamps.Major benefits of metal halide fixtures over conventional MVL are as follows: Lamps are suitable for 220V and 240V. Uniform light output for wide range of supply voltages. A colour-rendering index of between 80 and 95. Less heat generation, hence load on ACs reduces. Higher lumen output per watt (around 85 lumens per watt)The total lighting load of the building is 4.0kW.


Particulars Unit Existing ProposedType of lamp - MVL 125W MHWattage of lamps W 125 80Design Lumen (Approx.) Lumen 20000 20000No. of lamps to be replaced No. 32 32Average Operating Hours per day Hours/Days 24 24Operating day /year No. 300 300Energy savings kWh/year 22,680Energy Cost Birr/kWh 0.665Energy cost savings Birr/ year 10,368Initial retrofitting cost / lamps Birr 600Initial investment cost Birr 19200Payback period Years 1.9

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8.0 Summary of Energy Saving Potential

The detailed energy audit recommendations given in the report have identified an annualelectrical energy saving potential of 245 thousand kWh. The energy savings works out to beat 28.85 % of the average annual energy consumption (849 thousand kWh). The total energycost saving potential is Birr 211 thousand. The total cost of implementation for therecommended proposals is estimated to be Birr 242 thousand.

The details of various proposals are given below:

Short-term measures (simple payback period of less than 1 year)

Medium-term measures (simple payback period of 1 to 3 years)

Long – term measures (simple payback period of above 3 years)

The summary of the proposals is given in table 8.1.

Table 8.1 Summary of overall potential savings

S. Energy ConservationMeasures

Annual Investment Simplepayback

period, inYears

No.Savings Potential

Energy / Value,thousand

kWhthousand

Birrthousand

BirrSHORT TERM MEASURES

Compressed air system1 It is recommended to arrest the

leakages and optimise ofcompressed air usages.

134 89 20 0.22

Pumping system2 Resizing the discharge pipe of

cooling water pump13 8 5 0.6

Sub-Total 147 97 25 0.26

MEDIUM TERM MEASURESElectrical System

3 Rectification APFC controlpanel and additional kVArbanks

0.2 55 100 1.8

Lighting4 Replacement of Mercury lamps

400W with Metal Halide lamps23 15 17 1.1


5 3 5.6 1.7

Pumping System

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23 10.4 19.2 1.9

Sub-Total 51.2 83.4 141.8 1.70

LONG TERM MEASURESCompressed air system

7 Install variable frequency drive(VFD) for air compressor

23 15 17 1.1

Lighting8 Replacement of existing FTL T8

lamps with FTL T5 in phasemanner

24 16 58 3.6

Sub-Total 47 31 75 2.42

Grand Total 245 211 242

Energy Audit Report of Kaliti Metal Product Factory

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