Energy Audit Guidebook
2
Imprint
Publishedbythe
DeutscheGesellschaftfur
InternationaleZusammenarbeit(GIZ)GmbH
Registeredof�ices
BonnandEschborn,Germany
MOIT/GIZEnergySupportProgramme
Unit042A,4thFloor,CocoBuilding,
14ThuyKhue,TayHoDistrict,
Hanoi,Vietnam
T+842439412605
F+842439412606
www.giz.de/viet-nam
Asat
August2017
Text
EnergyConservationResearchandDevelopmentCenter
GIZisresponsibleforthecontentofthispublication.
Onbehalfofthe
GermanFederalMinistryforEconomicCooperationand
Development(BMZ)
3
TABLE OF CONTENT GENERAL 13
Objectives 13
Audiences 13
AssessmentofCurrentEnergyAuditing 13
CategoryorLevelofanEnergyAudit 14
REQUIREDCONTENTSFORENERGYAUDIT 16
1.AUDITPLANANDRESOURCE
1.1.Auditplan
1.2.Resources
161616
1.2.1.Humanresource 161.2.2.Technicalresource 17
2. AUDITMETHODOLYANDAPPROACH 182.1. Approach 18
2.1.1.Energybenchmarking 182.1.2.Energybalance 182.1.3.Proposeenergyconsumptionreductionsolutions 19
2.2. Auditmethodology 192.2.1.Auditpreparation 192.2.2.Datacollection 22
2.2.3.Dataanalysis 24
3. STANDARDAUDITREPORTTEMPLATE 33
3.1. Summary 333.2. Introduction 333.3. GeneralInformationoftheauditorganization 343.4. Descriptionofoperationprocess 343.5. Energydemand,supplyandconsumption 353.6. Economicandtechnicalconstraints 363.7. Energysavingmeasure 363.8. Conclusionandfutureplan 373.9. Annexes 37
4
PARTII.RECOMMENDATIONFORENERGYAUDITPRACTICES 39
39
39
41
1. MEASUREMENTDEVICES
1.1. Electricitymeasurement
1.2. Thermalmeasurementequipment
1.3. Pressure,velocityand�lowratemeasurementequipment 42
2. OVERALLENERGYCONSUMPTIONANDENERGYMANAGEMENTASSESSMENT 44
2.1. Generalinformation 442.2. Materialconsumptionandproductvolume 442.3. Powerandwaterconsumptiondata 442.4. Energyperformanceindicatorandbenchmarkingreferences 462.5. Energymanagementassessment 49
2.5.1.Objectives
2.5.2.Evaluationmethod
4949
3. COMMONENERGYCONSUMPTIONSYSTEMANALYSIS 543.1. Electricitysupplysystem
3.1.1.Introduction
3.1.2.Loadgraphandelectricalloadmanagement
3.1.3.Harmoniceffects
3.1.4.Datacollectionforelectricitysystem
Lightingsystem
3.2.1.Introduction
3.2.2.Energy�lowdiagramoflightingsystems
3.2.3.Energysavingsmeasureforlighting
3.2.4.Datacollection
Motor
3.3.1.Introduction
3.3.2.Energy�lowformotor
3.3.3.Theenergysavingmeasures
3.3.4.Datacollection
54
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60
61
63
65
65
3.2.
system
3.3.
65 66 71
3.4. Fans 723.4.1.Introduction 723.4.2.Energy�lowforfan 763.4.3.Energyef�iciencyforfan 773.4.4.Collectiontoolsforfansystem 78
3.5. Pump 803.5.1.Introduction
3.5.2.Energy�lowforpump
3.5.3.Energysavingsmeasures
3.5.4.Datacollection
Aircompressor
80 84
85 86
3.6. 883.6.1.Introduction 883.6.2.Energy�lowdiagram 923.6.3.Energysavingsmeasures 933.6.4.Datacollection 97
3.7. Airconditioningsystem 1023.7.1.Introduction 1023.7.2.Assessmentofairconditioning 1053.7.3.Energysavingsmeasures 1063.7.4.Datacollection 107
5
3.8. Industryrefrigerationsystem 1083.8.1.Introduction
3.8.2.Energy�low
3.8.3.Energysavingsmeasures
3.8.4.Datacollection
108 111 111 116
3.9. Boiler 1183.9.1.Introduction
3.9.2.Energy�low
3.9.3.Energysavingmeasures
3.9.4.Datacollection
118 125 125 135
3.10. Furnace 1363.10.1.Introduction
3.10.2.Heatlossesaffectingfurnaceperformance
3.10.3.Energysavingsmeasures
3.10.4.Datacollection
136140141144
4. SAFETYREQUIREMENTANDEQUIPMENT 1454.1. Electricalsafety 1454.2. Chemicalsafety 1464.3. Pressureequipmentsafety 1474.4. SafetyforworkingatHeights 148
APPENDIXES 149
REFERENCE 155
6
ABBREVIATIONS
ACB
ATS
BEE
BEP
CO2
COP
DB
AirCircuitBreaker
AutomaticTransferSwitch
BureauofEnergyEf�iciency,MinistryofPower,India
BestEf�iciencyPoint
CarbonDioxide
Coef�icientofPerformance
DistributionBoard
DepartmentofIndustryandTrade
Lawon
DoIT
EE&C EnergyEf�iciencyandConservation
EnMS EnergyManagementSystem
EnergyServiceProvider
ElectricityofVietnam
Fibre
ESP
EVN
FRP -reinforcedPlastic
GDE GeneralDirectorateofEnergy
GDP GrossDomesticProduct
GreenHouseGas
DeutscheGesellschaftfurInternationaleZusammenarbeit(GIZ)GmbH
GHG
GIZ
GCV GrossCaloricValue
HVAC Heating,VentilationandAirConditioning
IGA InvestmentGradeAudit
IndividualQuickFreezer
ModeledCaseCircuitBreaker
MinistryofIndustryandTrade
MainDistributionBoard
Speci�icEnergyConsumption
IQF
MCCB
MOIT
MSB
SEC
TOE TonofOilEquivalent
VFD VariableFrequencyDrive
VNEEP VietnamNationalEnergyEf�iciencyProgram
VSD VariableSpeedDrive
7
Listoftables
Table1.Energyauditlevels
Table2.Summaryofenergysavingpotentialandestimationofinvestmentcost
Table3.Thelistofdedicatedequipmentusedintheenergyaudit
Table4.Rawmaterialandmainproducts
Table5.Operatinghourperayearofenergyconsumptionareas/workshop
Table6.Electricitytariff(appliedfrom…)
Table7.Electricityconsumptionandelectricitycostsinmonthly(…)
Table8.Fuelconsumptionandcostsinmonthy(...)
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33
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92
Table9.Waterconsumptioninmonthly(…)
Table10.Energyconstrainsandstandards
Table11.Powerfactor
Table12.Energyconsumptionrateuntil2020s.
Table13.Energyconsumptionratefrom2021s–to2025s
Table14.Energyconsumptionrateforsteelindustryuntil2020s
Table15.Energyconsumptionrateforsteelindustryfrom2021sto2025s.
Table16.Energyconsumpationrateinchemistryindustry
Table17.Amatrixofenergymanagementevaluation
Table18.Assessmentresultsandimprovementact ions
Table19.Classi�icationoftransformers
Table20. Strategytomanagepeakload
Table21.Applicationsofcolorrenderinggroups
Table22.Luminousperformancecharacteristicsofcommonlyusedluminaries
Table23.EnergysavingbyusingLED
Table24.Energysavingcalculationtable
Table25.Ratedpower,numberandcurrentstatus
Table26.Lightingtransformer,ratedpowerandnumbers
Table27.Thebasicmotorloadtypes
Table28.Operatingcostestimationofselectedmotors
Table29.Standardef�iciencymotorvs.premiumef�iciencymotor
Table30.Motor
investmentcomparison
Table31.Correlationbetweentherotationspeed,�low,andpowercapacity
Table32.Motordatacollection
Table33.Ef�iciencyoftypesoffan
Table34. Fanspeedvs.�low
Table35.Fanspeedvs.powercapacity
Table36.Percentageofpowerconsumprionby�lowpercentage
Table37.Datacollectiontemplateforfan
Table38.Datacollectiontoolforpump
Table39.Relationshipbetweenpressureandpowerconsumption
Table40.Pressuredropfordifferentpipesize
Table41.Inletairtemperaturevs.Powersaving
8
Table42.Basedatabasetocompressorsystem
Table43.Currentcompressors
Table44.Componentsofcompressor
Table45.Tanksandreliefvalve
Table46.Mastercontrollersandairmaincharging
Table47.Distributionsystem,pipe,connections,anddistributionairline
Table48.Compressorroom
Table49.Airconditionatcompressorroom
Table50.Airrequirements(Operatingtime,pressuredemands)
Table51.Tableofeffectivemaintenanceforpowerconsumptionofthecompressor
Table52.Effectofvariationinevaporatortemperatureonthecompressorpowerconsumption
Table53.Effectofvariationincondensatetemperatureonthecompressorpowerconsumption
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153
154
measurements,openingsetc.
Table54.Propertiesofsaturatedwaterandsteam
Table55.AdvantageanddisadvantageofFiretubeboiler
Table56.Advantageanddisadvantageofwatertubeboiler
Table57.Advantageanddisadvantage ofwatertubeboilerwithsteamdrum
Table58.Boileref�iciencycalculation
Table59.Heatlossduetouninsulation
Table60.Heatlosscalculationduetouninsulation
Table61.Advantagesanddisadvantagesofsteamtrap –free�loat
Table62.Advantagesanddisadvantag esofsteamtrap–Invertedbucket
Table63.Advantagesanddisadvantagesofthermodynamicsteamtrap
Table64.AdvantagesandDisadvantagesofthermostaticsteamtrap –balancedpressure
Table65.Steamtrapselection
Table66.Classi�icationoffurnaces
Table67.Heatbalance
Table68.Measuringinstruments
Table69.Datacollectiontemplateforfurnaceperformance
Table70.Spreadsheetforenergysavingcalculation
Table71.Theelectricitypricesforenterprisesinrecentyears
Table72.TheconversionintoTOE, MGandemissionfactorsofsomeenergytypes
Table73.Theemissionfactorofsomecommonenergytypes
Table74.Metrologicalcontrolmeasuresandinstrumentinspectionintervals
9
Listof�igures
Figure1.Approachtoenergyaudits
Figure2.Energybalancetoindentifytheloss
Figure3.Exampleofregressionanalysisforelectricityconsumptionandproduction
Figure4.EPIforglassmelting
Figure5.Comparisonbetweenthemill
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andthebenchmarkandestimatedenergysavings
Figure6.Flowchartofadyingprocesswithenergyandmaterial�low
Figure7.Sankeydiagramfortheenergylossinsteamsystem
Figure8.Shareoftheenergyusers
Figure9.Energymanagementassessmentchart
Figure10.Thetransformerinpowersystem
Figure11.Maindistributionswitchboard
Figure12.Distributionboard
Figure13.Exampleofsinglelinediagramofelectricalsupply
Figure14.Adailyloadcurve
Figure15.Waveformsofharmonics
Figure16.Sankeydiagramoflightingsystem
Figure17.Daylightingwithpolycarbonatedsheet
Figure18.AtriumwithFRPdome
Figure19.LEDphaseandaroundlighting
Figure20.Squirrelcagerotormotor
Figure21.Woundrotormotor
Figure22.Costdistributionofmotor
Figure23.Ef�iciencyandfullloadpercent
Figure24.Ef�iciencyandrotatingspeedofsquirrelcagerotor
Figure25.Standardef�iciencymotorvs.premiumef�iciencymotor
Figure26.Performancecurveofpumpwith�lowcontrolvalve
Figure27.Loaddiagramofairconditioning
Figure28.Fanpowercalculation
Figure29.Calculationoffancapaciy
Figure30.Costdistributionoffan
Figure31.Sankeydiagramoffan
Figure32.Reducemotorspeedbydecreasingthepulleysize
Figure33.Calculatepumppower
Figure34.ParametersofPumpsystem
Figure35.PumpPerformanceCurve
Figure36.ParallelPumps&pumpscurve
Figure37.Pumpcontrolmethods
Figure38.ON-OFFcontrolforpump
Figure39.PerformancecurveofpumpwithVSD
Figure40.PowerRequirementsforvariouspumpingcontroloptions
Figure41.Costdistributionofpump
10
Figure42.SanSankeydiagramofpump 84
Figure43.Aircompressionsystemillustration 88
Figure44.Typeofaircompressors 88
Figure45.Effectofinlettemperatureandpowerconsumption 92
Figure46.Costdistributionofaircompressor 92
Figure47.Sankeydiagramforcompressedairsystem 93
Figure48.Energysavingspotentialforaircompressedsystem 93
Figure49.Effectofrelativehumidityandpowerconsumption 94
Figure50.Effectofsuctionpressureandpowerconsumption 94
Figure51.Heatrecovery 96
Figure52.Airconditionsystemtypes 102
Figure53.Air-cooledchiller 103
Figure54.Water-cooledchiller 103
Figure55.OperatingPrinciplesofairconditioner 104
Figure56.CalculationmethodofCOP 105
Figure57.HVACsystemdatacollection 105
Figure58.Glassproperties 106
Figure59.DetectheatsourcesinsideHVACspace 106
Figure60.Therefrigerationcycle 108
Figure61.Basictypesofcompressors 108
Figure62.Typicalheattransferloopinrefrigerationsystem 111
Figure63.DiagramofHeatRecoveryfromdischargeoutletfromcompressor 112
Figure64.Comparisonofpowerconsumptionbydifferentregulationmethods(screwcompressor)112
Figure65.Relationshipofthecondensationtemperatureandtheperformanceoftherefrigeration 113
temperature 114
Figure67.Steamphasediagram 119
Figure68.SimplediagramofTubeboiler 119
Figure69.Firetubeboiler 120
Figure70.Watertubeboiler 120
Figure71.Watertubeboilerwithsteamdrum 121
Figure72.Typicallossesfromcoal�iredboiler 123
Figure73.Sankeydiagramofboiler 125
Figure74.Heatrecovery�lowdiagram 127
Figure75.Waterpre-heaterandairdryer 128
Figure76.Typicalsteamtraps 129
Figure77.Functionsofsteamtraps 129
Figure78.Classi�icationofsteamtraps 129
Figure79.Mechanicalsteamtrap–Free�loat(source:TLV) 130
Figure80.Operatingprinciplesofmechanicalsteamtrap–Free�loat 130
Figure81.Mechanicalsteamtrap–invertedbucket(source:TLV) 131
Figure82.OperatingPrinciplesofmechanicalsteamtrap–Invertedbucket 131
Figure83.Thermodynamicsteamtrap(source:TLV) 132
Figure84.Operatingprinciplesofthermodynamicsteamtrap 132
Figure85.Thermostaticsteamtrap–Balancedpressure(source:TLV) 133
Figure66.Principleschematicoftworefrigerationsystemswiththedifferentofthecevaporator
11
Figure86.Operatingprinciplesofthermostaticsteamtrap-balancedpressure
Figure87Steamtrapoperation
Figure88.Ultrasonictesting
Figure89.Spira -tecmeasurement
Figure91.Typesoffurnaces
Figure92.Radiation factorforheat
Figure93.Blackbodyradiationatdifferenttemperature
Figure94.Heatlossfromtheceiling,sidewallandhearthoffurnace
Figure95.Heatlossedinafurnace
Figure96.GHSPictograms
Figure97.Exampleofpressureequipment (boiler)
Figure98.Workingatheight
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13
GENERAL
Objectives
Theguidebookisdevelopedtoinstructenergyauditorsandotherstakeholderstoassessandconduct
well-structured and effective energy audits in industrial facilities aswell as in commercial building.
Followingtopicsareconsidered:
· Frameworkoftheauditwhichwilldescribescopes,tasks,qualityrequirements,budget,timeframe,
kickoffmeeting,energyauditteametc.
· Asummaryoftheregulatoryrequirements,includingVietnameseStandardsonenergyef�iciencyof
industrialprocesssystem
· Collectingrequireddataandreviewing
· Conductingsiteinspectionandmeasurement
· Analyzingdata,interpretingand�indings
· Energyauditreportincludingpotentialenergysavingmeasures
Audiences
TargetedaudiencesoftheGuidebookare:
· EnergyAuditors
· Energyandfacilitymanagers
· EnergyManagementDepartmentofProvincial/CitylevelofDepartmentofIndustryandTrade(DOIT)
· MinistryofIndustryandTrade
· Lecturers
Energyauditors are assumed tohaveadequateknowledgeof energyandenergy systems.Thus, this
guidebookisdesignedtoprovideasystematicapproachinconductingauditinindustrial/commercial
facilities,which includesmethodologyandapproachesof anaudit and supporting toolsof checklist,
questionnaireanddataanalysisetc.
AssessmentofCurrentEnergyAuditing
EnergyAuditingcanbeseenasadiagnosticofthecurrentconditionsofafacilityregardingitsenergy
performanceandconsumption.Energyauditingde�inesviablemeasures toward the improvementof
energyef�iciencyorlowercostenergysourcealternatives.Overallobjectiveistosupporttheaudited
facilityinoutlineactionplantoimproveeitherhigherenergyef�iciencyorlowerenergycostandinsome
casesbothofthem.
InVietnam,energyauditingisneededtocompensatefortherisingenergyprices(especiallyelectricity),
reducemanufacturingcost,reducepollutantemission,andconservationofenergyresources.
TheLawNo.50/2010/QH12onEnergyEf�iciencyandConservation(EE&C)approvedon17June,2010is
akeymilestoneinthedevelopmentprocessofEE&Clegislationinthecountry.Accordinglyenergyauditis
mandatorytostate-ownedagenciesandintensiveenergyconsumingenterprises,whichannualenergy
consumptionisfrom1,000TOE–Industrialandfrom500TOE–Commercial.Theseenterprisesand
14
Table1.Energyauditlevels
Level1– PreliminaryAudit Level2– DetailedAudit
Objectives: Different energy systems (pump, fan,compressedair,steam,processheating,etc.)areassessedindetail
Provide energy saving measures withcostanalysisandprioritytobeinvested
Pros: Lowestcost
Overallassessment
Shorttime
Highcon�idence
Give a more accurate picture of theenergy performance and more speci�icrecommendationforimprovements
Cons: Lowcon�idence Highcost
Level 2 – EnergyAudit is preferred by the Law of EE&C, Degree 21/2011/ND-CP and the Circular
09/2012/BCTduetoitslevelofdetails.Thisguidebookonlyfocusesonlevel2energyaudit.
organizationshave todevelopaplan to conduct their energyaudits in accordancewith theexisting
regulationsandprocedurestoidentifyenergysavingopportunities.
Currently,therearemorethanthousandsofenergyauditswhichhasbeentakenplaceinVietnamin
variousindustrialsub-sectors.However,thequalityoftheseactivitiesseemsinadequate. Inaddition,
thereisnotechnicalguidebookindetailforenergyauditstostandardizeandensurethecomplianceofthe
auditactivitiestotheregulatedprocedure.
CategoryorLevelofanEnergyAudit
An Energy Audit is typically categorized based on the level of detail for investigation. Two level
categorizationisnormallyusedregardingthementionedaspects:
Quickassessmentofenergyconsumptionandenergyperformance
Provide action plan and focus points toLevel2–DetailedEnergyAudit
Can be used as guide toward detailedenergyaudit
16
PARTI.
REQUIREDCONTENTSFORENERGYAUDIT
1. AUDITPLANANDRESOURCE
Planningforauditandde�iningthenecessaryresourcesareimportantstepsthatshouldbeperformed
beforetheaudits.This�irstchapteroftheguidebookwillhelptheaudiencetounderstandtheimportance
ofplanningandwhataretheresourcesneededpriortoaudit.
1.1. Auditplan
Anauditplanoutlinesthestrategyandprocedureoftheaudit.Auditobjectiveshouldbede�inedclearly
beforetheauditplanning.
Theauditplanshouldprovidethefollowinginformation:
· Preparationstepsfortheaudit
· Auditprocedure,inwhichtimeoftheauditandthetimetableforeachstepshouldbede�inedclearly.
Theaudittimedependsontheorganization'sconditionsandstatus.Audittimecanbeshortenedifthe
auditplanningiswellestablished
· Responsibilitiesandtasksofeachauditteammembershouldbeclari�ied.
Audit resources consist of human resources, �inance resources, time resources, and available
measurementdevices.Safetyprocedureandequipmentshouldbewellprepared.Anauditplanisalsoa
vitalcommunicationstoolforensuringthattheauditwillbeconsistent,completeandeffectiveinitsuseof
resources.
Keystepsneedtobeplannedintheauditprocedureincluding:
· Preparepre-auditquestionnaire
· Preliminaryauditplan
· Audit check list preparation: Detailed daily work plan with timetable for on-site survey: work
description,area,supportrequiredfromauditedfacility(e.g.technician,technicalmanageretc.)
· Dataanalysisandreportwithtimetable.
Anauditplanmustbe�lexibleenoughtoaccommodateadjustmentstoallowforunexpectedinformation
and/orchangedconditions.Methodologytoimplementeachofthestepswillbedescribedinthepart2.
1.2. Resources
The necessary resources to implement energy auditare human and technical resources. These two
resoucesshouldbepreparedwelltoensurethequalityoftheaudit.
1.2.1. Humanresource
Energy audit is carried out by a certi�ied auditor including an energymanager in the company or
outsourcedtoexternalspecialists.
1.2.1.1. Auditors
Quali�ication
Theauditormustbeacompetentandprofessionalone,whoisfamiliarwithenergyauditingprocessand
techniques. Energy auditors can be accredited separately for electrical and thermal energy audits,
accordingtotheirquali�ications.Energyauditorsmustbeeitherelectrical,thermalorenergyrelated
engineerswithabove3yearsexperienceinenergy.
TherearecertainrequirementstobeanEnergyAuditors:
· Technical/Engineeringbackgroundispreferrede.g.bachelorofengineering
· Participateinatleasttwoenergyaudits
· Participateandpassthetrainingcourseofenergyauditor,hostedbyDirectorateofEnergy,Ministryof
IndustryandTrade.
Itemof#1and#2arenotregulatedinthecurrentlegaldocuments,however,thesearescreeningcriteria
tocandidateswhowanttoregisterintheitem#3.Certi�icateofenergyauditorisproofthatanenergy
auditorhasparticipatedinthetrainingcourseandpassedtheexam.
Certi�icate
Energyauditormustbecerti�iedbyMinistryofIndustryandTrade,byaninternationalorganizationwith
mutualrecognitionagreementsaccordingtotheCircular39/2011/TT-BCT.AccordingtocircularNo.
39/2011/TT-BCT,onlytheMinistryofIndustry&Tradeisauthorizedtoofferexamsandissueof�icial
certi�icationsforenergyauditorsandenergymanagers.Thesecerti�icationsaresignedbytheMinister
andareconsideredtobetheof�icialprofessionallicensesissuedbytheState.
Theenergyauditorsmustbetrainedonworksafetyandelectricalsafety.
Experience
Energyauditorshouldunderstandwelltheproductionprocessandhaveexperienceonthesame�ield
whichtheyareassignedtoperformtheaudit.
1.2.1.2. Energyauditteamleader
Energyauditteamleaderwillassignthetaskforteammembers.Heshouldhavethefollowingskills:
· Strongcommunicationandorganizationalskill
· Abilitytothinkcriticallyandattendtodetail
· Abilitytointeracteffectivelyandpositivelywithprospectivecustomers
· Apositiveattitudeandabilitytoworkwellinateamsetting
· Timemanagementskills
· Problemsolvingskills.
1.2.2. Technicalresource
Technicalresourcesincludeinstrumentationrequiredfordatacollection.Thetechnicalavailabilityfor
themeasurementshouldbeconsideredandthefeasibilityofdatacollectionshouldbeestimated.
Instrumentation could be available at the audited factories, or rented from other professional
organization.
17
18
Figure1.Approachtoenergyaudits
Energy
benchmarking
Energy
balance
Energy
consump�on reduc�on
2. AUDITMETHODOLOGYANDAPPROACH
2.1. Approach
Thenecessaryoutput informationorexpectation �indingsof theaudit shouldbeunderstoodclearly
beforetheaudit.Approachandmethodologyofenergyauditaredescribedbrie�lyinthischapter.
Approachis,inasystematicallyway,toproposeasuitableenergymanagementsolutionsapplyingin
energyconsumersandequipment.
The pathway solution is presented in the Figure 1, including three stages (1) benchmark energy
consumptionwithinthesectors,(2)establishandstudyenergybalanceand(3)�indoutsolutionsfor
energyconsumptionreductioninenergymanagementstrategy
2.1.1. Energybenchmarking
Energybenchmarkingisamethodtoevaluatetheenergyperformanceoftheauditplantbycomparing
withsomethingsimilar. “Somethingsimilar”mightbeinternal,likeperformanceatthesametimelast
year.Oritmightbeexternal,likeperformancecomparedtosimilarfacilitieselsewhere.
Energyperformanceindicatorisusedforcomparingthespeci�icenergyconsumptionoftheorganization
toenergybenchmarkinginthesameproductionlineorproducttypeinanindustry.
Through benchmarking, the key metrics for assessing performance are identi�ied, baselines are
established,andgoalsareset.Thisprocesshelpstoidentifythekeydriversofenergyuseandprovidesan
importantdiagnosticstoolforimprovingperformance.
Itisakeystepinidentifyingopportunitiestoincreasepro�itabilitybyloweringenergyandoperating
costs.
2.1.2. Energybalance
Energybalanceisananalyticalmethodtoprovideinformationofplant'senergyperformanceandthe
causeofloss.Oneoftheimplicationsoftheenergybalanceprincipleisthatwecanquantifyallenergy
inputs andbalance themagainst all energyoutputs. Lossof energy is identi�iedby energybalance
analysis.
Maintasksofenergyauditaretoinspect,surveyandanalysisofenergy�lows,balancingtheenergyinput
andoutputoftheoperation,de�ininglossinthe�low,andproposesolutionstoreducetheamountof
energyinputintothesystem.
Basedon theenergybalanceanalysis results,opportunities toreduceenergyconsumptionwouldbe
identi�ied.Methodologytostudyenergybalanceisexplainedinpart2.2.3.5.
2.1.3. Proposeenergyconsumptionreductionsolutions
Energyef�iciencyde�inedasthegoaltoreducetheamountofenergyrequiredtoproduceproductsand
services.Inotherwords,energyef�iciencyisdoingthesameamountofworkwhileusinglessenergy,
withoutcompromisingonthecomfortorqualitylevels.Forconvenienceofinterpretation,electricaland
thermalenergyhasbeenseparatelymentioned.
The electricity consumption investigation and thermal energy consumption investigation are good
startingpointsinthesearchofenergysavingopportunities.
Bybenchmarkinganalysisandenergybalancestudy,energylossesareidenti�ied,andthemeasuresfor
energyconsumptionreductionwillberecognizedbyminimizingthelosses.
2.2. Auditmethodology
Astep-by-stepmethodology,referredtoCircular09(AnnexIV)willbedescribedinChapter3.Anaudit
procedureusuallyconsistsofthreesteps:(1)preparation;(2)datacollection,(3)datainterpretationand
�indings,andwritingareport.
2.2.1. Auditpreparation
Thekeytoasuccessfulauditisproperauditpreparation.Inadequatepreparationmaycausedelaysin
reportsubmission,excessiveauditfees,penalties,non-compliancewithregulationsordebtcovenantsand
ultimately,embarrassment.
2.2.1.1. De�ineauditobjectiveandexpectationoutput
Theauditobjectivemayvaryfromoneorganizationtoanother.Anenergyauditisusuallyconductedto
· Understandhowenergyisusedwithintheorganization
· Findopportunitiesforimprovementandenergysaving
· Faiseenergyusingawarenessforemployees
· Provideabenchmark(referencepoint)formanagingenergyintheorganization
· Evaluatetheeffectivenessofanenergyef�iciencyprojectorprogram.
Figure2.Energybalancetoindentifytheloss
Energy
?Losses
UsefulEnergy
19
Theauditcanbecarriedouttomeettheneedtoreduceenergycosts,toparticipateinanenergyprogram
orberegulatedbythegovernment.
AccordingtotheDecree09/2012/TT-BCT,thekeyenergyusedorganizationsareresponsibletoestablish,
registerandreporttheirenegyconsumptionannually.Theyareregulatedtoconducttheenergyaudit
everythreeyears(Clause33,Ef�icientEnergyConsumptionandSavingsLaw).
Otherorganizationsaremotivatedtoperformtheenergyauditsandreporttheirenergyconsumption
regularly(Clause25,Decree21/2011/NĐ-CP).
2.2.1.2.Scopeofauditandfocus
Theauditteamshould:
· Identi�iesthesystemboundary
· Speci�iesthephysicalextentoftheauditbysettingthetermsoftheboundaryaroundtheaudited
energyconsumingsystem
· Identi�iesenergyinputsthatcrosstheboundarytobeaudited.
The audit scope depends on the audit objective, audit program, the available resources and the
organization'sdemand.
Basedon(1)Functionandtypeofindustry,(2)Depthtowhich�inalauditisneeded,and(3)Potentialand
magnitudeofcostreductiondesired,ascopeofauditcanbe:
· Theentireplant
· Thedepartment,productionline,orprocessstep,suchasthekilnorthepackagingplant
· Speci�ic(energy)equipmentsorresources,suchassteam,compressedair,motors,orfans.
Thefocusareaischosenbasedon:
· Sizeoftheplant
· Management'sareasofinterestorconcern
· Highenergy/resourceconsumptionorcosts
· Highpotentialenergysavingsarea
· Areasforwhichenergyef�iciencyauditsorprojecthavenotyetbeencarriedout
· Plansforconstructionorupgrading.
2.2.1.3.Setuptheauditteam
Number of required auditorswith speci�ic tasks should be determined. The factory's engineers and
technician could be invited to participate in energy audits for their knowledge and experience on
equipment,O&M,etc.
Auditorscouldbeinternalstaff(s)orexternalspecialists.
Auditteamleaderwithrequiredskillsshouldbeappointed,andshe/hewillorganizeandassignthetask
forteammemberswhenestablishingtheauditplan.
Ameetingfortheteammembersshouldbeorganizedbeforetheauditstartstohavebetterinteractionfor
theef�icientteamwork.
2.2.1.4.Timeandcostestimation
Thetimeandcostofenergyauditsishighlyvariabledependingon:
20
· Thesector
· Thesizeofthefacility
· Thequali�icationsoftheenergyauditorand/orauditing�irm
· Thetypeofaudit(buildings,processesortransportoracombination)
· Theaccuracyandcompletenessofinformationprovidedbytheclient;andthedetailprovidedbythe
expert.
Theenergycostincluding:
· Laborcostforauditorsandexternalprofessionalswhenneeded
· Rentalfeeformeasurementdevicesandotherfacilitiesifnotavailableatthefactory.
2.2.1.5.Preliminaryaudit
Thepreliminaryanalysishelpsprovidingageneralpictureoftheplantenergyuse,operation,andenergy
losses.
Theinitialwalk-throughvisitisfortheenergyauditteamtobecomefamiliarwiththefacilitytobeaudited.
Theauditteamcanobservetheexistingmeasurementinstrumentationontheequipmentandthedata
recorded,sothattheycandeterminewhatextrameasurementanddatacollectionarerequiredduringthe
audit.
Informationshouldbede�inedduringpreliminaryaudit:
· Layoutoftheorganizationtoplanwithtimeframe
· Operational status of the audited plant, operating characteristics of equipment, database of
productionandenergyconsumption.
· Loadinventoryandkeyenergyconsumingareatobesurveyedduringtheaudit
· Energy�low(input/output)ofthecommonload
· Measurementpoints,existinginstrumentationandadditionalmeteringrequired
· Whetheranymeterswillhavetobeinstalledpriortotheaudite.g.,powermeter,steam,oilorgas
meter.
Abriefmeeting–kickoffmeetingwithalldivisionheadsandpersonalconcernedcouldbeorganizedto
develop orientation awareness creation and build up the cooperation. The auditors can inquire for
commentsfromthefacilitystaffandcancollectreadily-availabledataduringthewalk-throughvisit.
Inthepreliminaryanalysis,a�lowchartcanbeconstructedthatshowstheenergy�lowsofthesystem
beingaudited.Anoverviewofunitoperations,importantprocesssteps,areasofmaterialandenergyuse,
andsourcesofwastegenerationshouldbepresentedinthis�lowchart.
The auditor should identify the various inputs and outputs at each process step. The preliminary
�lowchartisasimplebutdetailedinformationanddataabouttheinputandoutputstreamscanbeadded
laterafterthedetailedenergyaudit.
2.2.1.6.AuditChecklistPreparation
Audit checklist is designed to stimulate questions about energypractices. Audit checklist should be
preparedbeforeonsiteauditingforeachsections/utilities.Thechecklisthelpsgatheringtherightdata,
withtheappropriateamountofdetail,whichisakeycomponenttorealizethemaximumsavingsfroman
energyaudit.
21
Thechecklistshouldbearrangedaccordingtotheitineraryoftheaudit.Itineraryofdatacollectionisset
upbasedonthelayoutoftheorganizationwhichshouldbeobtainedduringthepreliminaryaudit.
Processfordatacollectioniscurrentlynon-standardized,andcrucialdatacanbeoverlookedorthelevelof
detailisinsuf�icientfortherequiredenergyand�inancialanalyses.Toaddresstheseissues,templatedata
collectionformshavebeencreated.Thepurposeofthesesampleformsistoassistenergyauditorscollect
datarequiredtocompletecomprehensiveenergyand�inancialanalysesofproposedmodi�icationstothe
organization.
In the following part, standardized templates of audit checklists of common load system will be
introduced.However,theactualchecklistortemplateshouldbemodi�iedafterthepreliminaryaudits
becauseactual load inventories,dataavailability, andoperation conditionsarevaried fromplants to
plants.
2.2.1.7. Measurementequipmentpreparation
Dependingonenergytypetobeaudited,alistofinstrumentationswillbede�inedandprepared.The
numberofmeasurementpointsaredeterminedbasedontheneedsandpracticalability.Amoredetailed
breakdownwillrequiremoremeasurements,measurementequipmentandexpertise.
The operating instruction for all Measurement equipment must be understood and staff should
familiarizethemselveswiththeinstrumentsandtheiroperationpriortoactualaudituse.
TheMeasurementequipmentshouldbecalibratedregularly.Listofcommonmeasurementequipmentis
describedinpart.II.
2.2.1.8. WorkSafetyPreparation
Auditorshavetoconductsurveysinlotofareasinfactoriesandbuildings,suchastransformerstations,
coldstorage,boilerarea,thewastewatertreatment,etc.Eachplaceispotentiallyharmfultoauditors.
Therefore,auditorsneedtotalktotheorganization'ssafetyof�icerstotakemeasurestosecuresuitable
work.
Auditorsshouldbetrainedorunderstandwellonworkplacesafetyandfullyequippedwithsafetybefore
enteringtheauditedsites.
Worksafetytrainingforauditorsshouldinclude:
· ElectricalSafety
· ChemicalSafety
· Boilerandpressurevesselsafety.
· Safetyatheight
WorksafetyrequirementandpracticesaredescribedmoredetailsinthepartII.
2.2.2. Datacollection
Datacollectionisanimportantstepinauditprocess.TheDatacollectionshouldbeenoughandaccurate
fortheanalysis,thereforethequantityandqualityofthedataisalwaysachallengetoauditors.Auditors
shouldknowwhichdatatheyneedtocollectandhowtoobtaintheaccuracyofthedata.
Somedataareavailableatthefacilityandcanbeprovidedthroughquestionnaireandinterviewsurvey.
Datawhicharenotavailablewillbeobtainedthroughmeasurementandcalculation.
2.2.2.1. Availabledatacollection
Energybillsalongwithothercurrentandhistoricalenergy-andproduction-relateddataandinformation
shouldbecollectedatthebeginningoftheauditprocess.
22
Thedatathatcanbecollectedatthebeginningofanenergyauditincludethefollowings:
· Generalinformationabouttheplant(yearofconstruction,ownershipstatus,renovations,typesof
products,operationschedule,operatinghours,scheduledshutdowns,etc.)
· Energybillsandinvoices(electricityandfuels)forthelast3years
· Monthlyproductiondataforthelast3years
· Possiblearchivedrecordswithmeasurementsfromexistingrecorders
· Architecturalandengineeringstructureoftheplantanditsequipment
· Statusofenergymanagementandalreadyimplementedenergy-savingmeasures
· Thetechnicalspeci�icationsoftheequipmentandproductionlinestobeaudited(inwhichcaseit
shouldbenotedthebuilding�loorarea,structure,directionandnumberofdevices)
· Operatingparameter(temperature,pressure,capacity,etc.)
· Operatingproceduresandequipmentrepairguidelines.
Acomprehensivequestionnairetemplateshouldbepreparedandsendtotheauditedplanttocollectthe
generalinformation.Otherinformationwouldbesurveyedduringthepreliminaryaudit,briefmeeting,
plant'sstaffinterviewandmoreinsuf�icientdetailsarecollectedduringtheaudit.
Achecklistshouldbepreparedinadvancetoensuredatasuf�iciencytobecollected.
2.2.2.2.Measurement
Energy audits require identi�ication and quanti�ication of energy necessitates measurements with
equipment.Auditorsshouldselecttheparameterstomeasureandpointstomeasureintheenergy�low.
Measurementequipmentshouldbeportable,durable,easytooperateandrelativelyinexpensive.
Theauditteamshouldde�inewhichinformationcouldbecollectedbyavailabledataandinformationthat
needed tobe collectedbymeasurement afterpreliminary audit.Additional equipment,which isnot
availableattheauditfacilityshouldbede�inedandpreparedbeforeaudit.
Basicmeasurementduringenergyauditmayincludethefollowing:
· Basicelectricalparametersinalternativeanddirectcurrentsystems-Voltage(V),Current(I),Power
factor,activepower(kW),reactivepower(kVAR)
· Energyconsumption(kWh),Frequency(Hz)
· Temperature
· Heat�low
· Airandgas�low,airvelocity
· Liquid�low
· Moisturecontent
· Relativehumidity
· Fluegasanalysis-CO ,O ,CO,SO ,NO2 2 x x
· Combustionef�iciency.
23
2.2.2.3.Instrumentinspectionrequirements
Inorder toperformdata collectioneffectively andaccurately, the instrument shall be inspectedand
calibrated.AccordingtotheCircularNo.23/2013/TT-BKHCNdatedSeptember26,2013oftheMinistryof
ScienceandTechnologyongroup2measuringinstruments,therearethreetypesofinspection:
· Initialinspectionisperformedbeforetheinstrumentisputintooperation
· Theperiodicinspectionmeansinspectionofthemeasuringinstrumentswhichareinoperation
· Theinspectionafterrepairmeansinspectionofthemeasuringinstrumentinoneofthefollowing
cases:
-Therepairedmeasuringinstrumentfailstosatisfytechnicalmetrologicalrequirements;
-Inspectioncerti�ications(inspectionseals,stamps,certi�icates)ofthemeasuringinstrumentislost
ordamaged,butitsstructureandmetrologicalcharacteristicsarenotchangedcomparedtothe
approvedtype;
-Theinspectionisnecessaryaccordingtotheconclusionofthecompetentauthorityorperson;
- Users of themeasuring instrument suspects that themeasuring instrument does not satisfy
technicalmetrologicalrequirementsandrequestsare-inspection.
Measuringinstruments,metrologicalcontrolmeasures,andmeasuringinstrumentinspectionintervals
arespeci�iedintheTable74.
2.2.3. Dataanalysis
Theinitialworkofenergyauditistoassessthecurrentoperationalstatusoftheequipment,establish
performanceindicatorsofrespondents.
Informationthatneededtobestudiedaftertheauditare:
· Energyconsumption
· Energycost
· Energydemand/supply(energy�low)
· Energydistributionandloss.
Afterdatacollectionandmeasurement,auditorsscreenandsynthesisthedataintoanalysisfactorsand
identifythevalue.Data�luctuationshouldbeanalyzed.
Energyperformanceofthewholeorganizationwouldbeanalyzedafterde�iningtheenergyconsumption
indicators,andbenchmarkinganalysis.To�indoutthelossandpotentialsavings,studyonenergy�low
shouldbeconductedonkeyenergyconsumptionareas.
Energysavingspotentialswillbeproposedafterdataanalysisandauditorshavetoproposetheproven
amountofsavingsorsavingpercentageforeachenergysavingssolutions.
ToolsfordataanalysisofcommonenergyconsumerwillbeintroducedinpartII.
2.2.3.1. Energybillanalysis
Energyauditorsshouldunderstandwelltheenergypricesystemandallenergycost,whichisimportantto
calculatetheamountofsavings.
Energybillsre�lecttheenergyconsumptionofthefactory.Byanalyzingmonthlyandannuallyenergybills,
auditorscanassesstheenergyconsumptionstatusofthefacility,trendofincreasingordecreasingin
energyconsumptionthroughoutthetime.
24
25
Figure3.Exampleofregressionanalysis forelectricityconsumptionandproduction
Energyperformanceindicator(EPI)=Energyconsumption(convertedtoMJ,KWhorTOE)
Productionvolume(mostlyintons)
Tabulating historical energy consumption records provides a summary of annual consumption at a
glance.
Utility and fuel supplier invoices also contain valuable information about consumption that can be
tabulated.Templatesfortabulating,graphingandanalyzinghistoricalenergyconsumptionandpurchase
datacouldbegeneratedwhennecessary.
Atheoreticalassessmentofspeci�icprocessesyieldsalinearrelationshipwhenplottingenergyagainst
production,producingastraightlineofthegeneralform
Y=mx+c
Linearregression,i.e.by�indingthebest�itofastraightlineusingtheleastsquaresmethodtotheplotof
energyconsumptionvs.production,couldhelptode�inethecaseofconsistentperformance,installed
improveorbreakdown.ExampleisillustratedinFigure3.
Thebaselineandthetargetoftheperformancecanbesetinconsistentperformancethatisunaffectedby
improvementsorbreakdowns.
2.2.3.2. Energyperformanceindicator
Energy Performance Indicators (EPI) are used to explain the status and effect of the management
externally.Themostpracticalandfrequentlyusedenergyperformanceindicatorisenergyintensityor
speci�icenergyconsumption(SEC),whichreferstoenergynecessaryforacertainproductionunit(ton,
piece,set,etc.)asshowninthefollowingformula.
Benchmarkingtheenergyintensivewithotherfactoriesorworkplacesinthesameindustryevaluatethe
possibilitytoimproveenergyef�iciencyortheachievementlevelofenergyconservationforafactory.
2.2.3.3.Energyef�iciencyanalysisbyhistoricaltrendandbenchmarking
Theenergyperformancewithintheplantsshouldbestudiedincludinghistoricalenergyconsumption
andtrendinthreerecentyears.
Energyintensityisoftenusedasindicatortoevaluatebywayofcomparisonwiththefollowings:
· Plannedvalue
·����Valueinthesameperiodofthepreviousyear
Elec
tric
ity
(kW
h)
180 000
160 000
140 000
120 000
100 000
80 000
60 000
40 000
20 000
0
0 50 100 150 200
Produc�on (tonnes)
26
Figure4.EPIforglassmelting
Figure5.Comparisonbetweenthemillandthebenchmarkandestimatedenergysavings
Source:EcoEnergy, 2008
· Otherfactoryorfacilitiesinthesameindustry
· Benchmarkbetweencompaniesanarea.
Historicaltrendofenergyconsumptioninthelastthreeyearswouldprovideapictureofenergy
practicesoftheplants,improvinginenergyef�iciencymaybeobservedshowingtheeffectivenessof
energymanagementapplication.
Anexampleofhistoricaltrendanalysisbasedonweeklydataofglassmeltingisillustratedinthe
Figure4.
ExistingregulatedEPI,orinternationalbestpracticesofthesimilarprocessorofthesameindustry
shouldbecollectedtoperformtheanalysis.
The gap inEPIbetweenexistenceplant and thebest practiceshelps to estimate energy savings
potentialfortheplant,asdemonstratedinFigure5.
Benchmarkingde�ineshigh-ef�iciencyequipmentinordertoidentifyandgivetheprioritytoimprove
low-ef�iciencyequipmentimmediately
EnergySaved
Range YourMill
ComparableBenchmark
EnergyGap
Gap A�erBest Prac�ces
Your Mill w’Best Prac�ces
27
Figure6.Flowchartofadying processwithenergyandmaterial�low
Energybalance,physicalbalancewouldbesetup forauditedobjects (blockdiagrama "blackbox");
operationalcharacteristicsofdevicesusingenergy.
Characteristicofkeyenergyconsumptionareaswouldbeidenti�ied,consistingof(butnotlimited)to:
· Thetypeandcharacteristicsoftheheatingboiler,andsteamsupplysystem
· The typeandcapacityof thecoolingsystem, the technical characteristics (refrigerationpressure,
temperature,�lowandtemperatureofcoolingwater,pressure,etc.)
· Type of air-conditioning systems, system components (pumps, fans, compressors, pipes, etc.),
operatingcharacteristics(�low,temperature,pressure,etc.)
· Thelevelofmobilizationofequipment,systemsandequipment
· The mechanism controlling the devices, system devices (controllers, devices Executive, sensors,
controllogic,etc.)
· Lightingequipmenttype,speci�icationandcontrolstructure
· Characteristicsoftheelectricitydistributionsystem.
Incaseofauditsofbuildings,auditorsneedtounderstand:
· Featuresofthebuilding
· Operating characteristicsof the system lifts, escalators (servicearea, typeofdrivemotor, control
system,etc.).
Comparisonsshouldbemadetoforkeyenergyconsumptionareasandequipmenttoidentifythelostand
savingpotentialsbyminimizingtheloss.Allcomparisonsincluded:
· BoilerEf�iciency,lossesinfuelcombustion
· Lossonheatsupplyingpipe(Pa/m)
· Theperformanceef�iciencyoftheengine(%)
2.2.3.4.Process�lowchartandkeyenergyconsumptionareaanalysis
The process �low chart of performing in the entire plant, line technology, key equipment, and
identifyingtheenergy�low,material�lowandproductin/outof"thebox"wouldbedrawn.Thekey
energyconsumptionareashouldbeidenti�iedinthe�lowchart.
Anexampleoftheprocess�lowchartispresentedinFigure6.
Yarn
Dyeing
process
Dyedyarn
Compressionair
Water
Steam
Rawmaterials
Wastewater
Condensate
Condensateandheatrecovery
28
· Theperformanceef�iciencyofthecoolingoperation
· Thecapacityofthesystemfanpower(kW/literofairsupply/sec)
· Theperformanceef�iciencyofthefan(%)
· PumpPerformanceef�iciency(%)
· Theperformanceef�iciencyofthecompressor(%)
· 2Lightingpowerdensity(W/m )
· Illuminanceofthelightingsystem(Lm/W)
· Lossoflightingcontrolsystems(W).
Forheatingsystems,ventilation,airconditioning(HVAC),wastedareacanbedeterminedfromthedata
recordkeepingontraf�icchangescorrespondingtochangesintemperatureandpressure.
Forpowersupplysystems,wasteareacanbedeterminedfromtherecordbookincurrent,voltage.
Intheabsenceoftherecordbook,themeasurementsaredonetodeterminetheequipment/system
devicesareworkinginef�iciently.
2.2.3.5.Energy�lowandenergybalance
Breakdownofenergyusebyareas/processes/functions….andidentifyingtheenergy�lowofeachpoint
areperformed.
Energybalanceisanalyzedandenergy�lowswouldbeidenti�iedintheformofSankeydiagramandpie
chart.
Sankeydiagram
TheSankeydiagramisan important tool in identifying inef�icienciesandpotential forsavingswhen
dealingwithresources.
Sankeydiagramrepresentsalltheprimaryenergy�lowsintofactory.Thewidthsofthebandsaredirectly
proportionaltoenergyproduction,utilizationandlosses.Theprimaryenergysourcesaregas,electricity
andcoal/oilandrepresentenergyinputsattheleft-handedsideoftheSankeydiagram.
TheSankeyshouldlooklikethepicturebelow–asteamsystemwithoutcondensaterecovery,nowaste
heatrecovery,allunitsinkg/day.
29
Figure7.Sankeydiagramfortheenergylossinsteamsystem
Figure8.Shareoftheenergyusers
100.0 72.0 66.3 60.3 51.3 41.0
6.0%
291 10.2%
5.8% 9.0% 500
281 441
28.0%
Fuel lossess (kg/day) 1,366 Total fuel lossess (kg/day)
2879/4879 (kg/day)
Example: using 2
ton/hr of steam, fuel
oil boiler with the
Fuel supply
Piechart
Piechartsshowingthedistributionoffuelsand�lowsgoingthroughtheselectedenergyconsumers.The
piechartscouldbeusedtopresent:
· Distributionoffuelspassingthroughthenode
· Distributionoftheenergycontentoftheincoming�lows
· Distributionoftheenergycontentoftheoutgoing�lows.
Water hea�ng23%
Cooking5%
Stand by5%
Ligh�ng11%
Other appliances24%
Hea�ng andcooling
20%
Refrigera�on12%
Heat transfer losses
Condensate lossesSteam leakage
Pipe heat losses
Boiler heat losses
Fuel flow 4,879 3,513 3,232 2,941 2,500 4,000 kg/day
- flue gas- radia�on- blow down, etc.
Usefulenergy
AreaBoilerheat
loss
Pipeheat
loss
Steam
leakage
Condensate
losses
Heat
transfer
losses
Losses>>> 28% 8% 9% 15% 20%
30
2.2.3.6.Energysavingopportunities
Thekeyenergyconsumptionareawouldbede�inedfromtheenergy�lowsdiagram(piechart)andthe
highsavingopportunitiesareawouldbeobservedfromtheSankeydiagramwherehighenergylossareas
areobserved.
Theauditteamshouldcomparetheoperationalcharacteristicsofthedevicewithdesigndataorwiththe
technicaldocumentationtodetectdifferences.Detectionareasareenergywastersandenergy-saving
potential.
2.2.3.7.Proposeenergysavingsolutions
Mostofthemeasuresaresimplegoodhousekeepingmeasureswhichcanbeimplementedimmediately.
Othermeasuresarelowcost(e.g.�ittingtimers,pipeinsulation,draughtproo�ing,etc.)andwillinvolve
someexpenditureand/orcontactingestates.
Energysavingsolutionsareclassi�iedintothreegroups:
Solutionswhichdonotrequireinvestmentcost
Includespracticalsolutionwithoutinvestmentcosts,doesnotaffectthenormaloperationofequipment/
technologyline:
· Changeproperlymanipulationofoperation
· Rationalizetheproductionline
· Arrangetidybuildingsandfacility
· Applysimplemeasures(airconditioningoff,turnoffthelights,stoppowertothedevicewhennotin
use,setthetemperatureofairconditioningintheroomproperly,etc.)
Solutionswithlowinvestmentcost
Includingsolutionswhichrequirelowinvestmentcosts,anddonotsigni�icantlydisrupttheoperationof
thedeviceorprocessline..Someexamplesare
· Installationofadditionaltimecontrollerstoon/offequipmentandopen/closedevicesintechnology
lines;
· Replacepower-savinglights;
· Equiponlinemeters,andmore...
Solutionswithhighinvestmentcost
Includessolutionswithhighinvestmentcosts,cansigni�icantlydisrupttheoperationofthedevice/line
technology
· Installationoftheinvertertothemotor
· Equipmentinstallationforpowerfactoradjustment
· Replacement,reconstructionofboiler
· Replacingthecoolers(chillers).
· Equipmentinstallationforwasteheatrecovery
Technicaland�inanceconstraintanalysisshouldbeperformedwhenproposingandanalyzingtheenergy
savingsolutions.Impracticalsolutionswithsigni�icantinvestmentcostshouldnotbeavoided.
Technicalfeasibilityanalysisshouldaddressthefollowingconditions
· Technologyavailability,space,skilledmanpower,reliability,service,etc.
· Theimpactofenergyef�iciencymeasureonsafety,quality,productionorprocess
· Themaintenancerequirementsandsparesavailability.
Economic feasibilitycanbeconductedbyusing thevarietymethodswhichareexplained in thenext
Section.
2.2.3.8.Financialandfeasibilityanalysis
Energysavingprojectsmustbecompetitivecomparedtootherprojectsbyincreaseofcostsavingsor
pro�itexpectations.
Financeanalysisisrequiredtodeterminetheappropriateinvestmentoptionsbycomparingtheoptionsto
achievetheobjectivesoftheorganization.
Theenergyef�iciencyprojectsinvolvingdifferenttypesofcosts.
Investmentcosts
Thescaleof the investment isavery important factor inthe�inancialevaluationofenergyef�iciency
projects.Thiscostareoftenexpressedinalargeamountofmoneyspendonprojectsbeingimplementedin
ayear.
Investmentcostsincludethefollowingcosts:
· Installationcosts(construction,installation)
· Equipmentexpenses
· Taxes,customsfees
· Thecostsofstafftraining
· Otherexpenses(Insurance,EngineeringandTransport).
Operationcost
Theoperatingcostsandmaintenanceassociatedwiththeoperationareanalyzed.Thedifferenttypesof
expensesincludinginoperationcostsinclude:
· Energyandrelatedcosts
· Laborcosts(salariesofoperatingpersonnelandmanagement,)
· Thecostofrepairsandmaintenance
· Otherexpenses(supplementarymaterial,administrativecosts,etc.).
Othercost
· Replacementcost:costtoremovethedeviceattheendoflifecycle
· Lost production due to stop productionwhile installing the equipment and put the system into
operation.
Pro�itscanbeearnedfromanenergyprojectmaybe
· Energysavings
· Incomefromthesaleofenergy
· Reducemaintenancecosts
31
· Incomefromimprovingquality
· Incomefromincreasedproductivity.
The�inancialcriteriatoevaluateproject
· Simplepaybacktime:
Thetimerequiredtorecovertheinvestmentfromcash�low.Thisisaquantitativemethodwhichiswidely
usedtoassessthecosteffectivenessofenergy-savinginvestments
Simplepayback=Costofinvestment/Netannualsavings
Whenapplyingthismethod,savingsafterpaybacktimeisnotcalculatedandthevariationinmoneyvalue
overtimeisnotconsidered.
· Rateofreturn(ROI)
ROI=(GainfromInvestment-CostofInvestment)/CostofInvestment
Description"annualbene�it" fromtheprojectcostasapercentageofcapital.Costcomparison isnot
considered.
· Netpresentvalue(NPV)
Allthesenetbene�itsaredepreciatedreturnatthelowestappealtodeterminetheequivalentpresent
value.
· Internalrateofreturn(IRR)
Thediscountrateatwhichthenetpresentvalueoftheaccruedbene�itsofaninvestmentequaltothe
investmentcosts.IftheIRRvalueishigher,projectismoreeffective.
· LifecycleanalysisForexample,considerthecomparisonoftraditional�luorescentlights(FL),spotlights,toCompact�luorescentlights(CFL)orlight-emittingdiode(LED)replaced.CFLlamplifeis5timeshigherthanhalogenlampandLEDlifespanatleast20timesmorethanhalogenlamps.
Thecalculationwilltakeintoaccountthelifecycletocomparetheoriginalequipmentandreplacement.
32
33
Table2.Summary ofenergysavingpotentialandestimationofinvestmentcost
No. Measures Energysavings ExpectedInvestment
(106VND)
Costsavings
(106VND/year)
PaybackPeriod(Year)Electricity
(kWh/year)
Fuel
(ton/year)
1
2
3
…
Total
3. STANDARDAUDITREPORTTEMPLATE
AuditreportformatshouldbestandardizedwiththecontentsregulatedbytheCircular09.Thischapter
recommendsastandardauditreporttemplate,consistingoftwomaincontents:
· Statusoftheorganizationincludingtheirgeneralinformation,descriptionproductionprocessand
energy�lows.Theenergyconsumptionstatus,annualEPI,andenergylossshouldbeincluded.
· Energysavingssolutionsconsistingof listofenergysavingsolutionsclassi�ied inthreegroupsas
mentioned in chapter2.Effectivenessof the energyaudit shouldbe evaluated in this report and
economicanalysisforeachenergysavingmeasuresshouldbereported.
Contentofthestandardauditreportshouldbeorganizedasbelow:
3.1. Summary
· Summaryofenergyconsumptionintheenterprise
· Summaryoftheenergysavingmeasureswithpriority
· Proposetheselectedmeasurestobeimplementedandinvested.
Thecontentshouldbesummarizedinthefollowingtable
3.2. Introduction
· Briefintroductionoftheauditorganization
· Objectiveandnecessaryoftheaudit
· Scopeoftheaudit
· Introductionoftheauditteam,andtheirtask
· Measurementmethodanddevice,listedinthetablebelow
34
Table3.Thelistofdedicatedequipmentusedintheenergyaudit
Table4.Rawmaterialandmainproducts
I Rawmaterialinyear…
Mainproductsinyear
Table5.Operatinghourperayearofenergyconsumptionareas/workshop
…
…
II
…
No. Name Code Quantity Origin
No. Item Unit Data
No. Area/Workshop Operationtime(hour/year)
3.3. GeneralInformationoftheauditorganization
· Developmenthistoryandtheirstatus
· Operationstructureandfrequencyofproduction,includingoperationhours
Therawmaterialandmainproductsisdescriptedbyfollowingtables:
3.4. Descriptionofoperationprocess
· Flow chart or black box description of the production process, including in/out �lows of energy,
materials,andwater
· Identifytheinef�iciencyenergyconsumersduringthesurvey
· Energysavingpotentials
35
Table6.Electricitytariff(appliedfrom…)
· Energydemandandconsumption
Table7.Electricityconsumptionandelectricitycostsinmonthly(…)
Table8.Fuelconsumptionandcostsinmonthly(…)
Amount(ton/yr)
Cost(103VND/yr)
Amount(ton/yr)
Cost(103VND/yr)
Amount(ton/yr)
Cost(103VND/yr)
Wholeyear
1
2
..
12
Fuel1 Fuel2 Fuel3 Totalcost(103VND/yr)
Monday–Saturday Sunday
Peakhours
(5hours)
Normalhours
(13hours)
Off-peakhours(6hours)
1
2
3
Tariff(VND/kWh)No. Item Appliedtime
3.5.Energydemand,supplyandconsumption
·Sourceofenergysupplyandcost,fuelcharacteristic
Normalhours
Peakhours
Off-peakhours
Total Normalhours
Peakhours
Off-peakhours
Wholeyear
Ratio(%)
1
…
12
Month Hourlyelectricconsumption(kWh) Electricitycost(VND)
36
· Waterdemandandconsumption
Table9.Waterconsumptioninmonthly(…)
Wholeyear
Table10.Energyconstrainsandstandards
1
2
…
12
Month Quantityofwater(m3) Watersource
Solidfuel
- Coal Kg
- Antracitecoal Kg
- Biomass(Wood/Ricehusk) m3
Liquidfuel
- DieselOilDO(ρ=0.86kg/dm3) Littre
- FuelOil(ρ=0.94kg/dm3) Kg
Gasfuel
- Natualgas–NG m3
- Liquidpetroliumgas–LPG Kg
Electricityconsumption MWh
Heatvalue/unit CO2emission
MJ/unit kWh Kg/MJ Kg/kWh
Energytypeandstandard Unit
3.6. Economicandtechnicalconstraints
· Energylossanalysis,andareawhichrequiredfurtheranalysis
· Technicalconstraintsbycomparingtheactualoperationstatuswithdesigncapacity
· Economicconstraints,costofenergy,andfuelandCO emissionconstraints2
· Theincreasingofenergycostandrequirementofenergysubstitutionshouldbeanalyzed
3.7. Energysavingmeasure
· Identifygroupofenergysavingmeasures,listofmeasuresineachgroupwithdetailsdescription
· Priorityofmeasurestobeimplemented
· Financialanalysisofselectedmeasures,amountofsavings,paybackperiodandenvironmental
aspectanalysis
· Conclusion and recommendations, proposing an energy management program for the
organization.
37
3.8. Conclusionandfutureplan
· Conclusionandrecommendationonenergyauditresult
· Proposedactionplanfortheenterprise:
-1-yearplan
-5-yearplan.
3.9. Annexes
· Primarydatatables:Summaryofproductionvolume,energy,etc.
· Actualloadpro�ile
· Energysavingcalculationsforproposedmeasuresmentionedintheenergyauditreport
· Energyprice
· Energytypeconversion
· Conversioncoef�icientofCO emission2
…
39
Watt-hourMeter:Usedtomeasurethepowerused on the line by time cycle. The meterincludes a small motor running at speedsproportionaltothepowerused.
Wattmeter:Usedtomeasuretheusepowerofanelectricaldevice.Portablewattmeterallowsdirectreadingofelectricitydemand.Limitworkof300kWs,650Vand600A.Wattmetercanbeusedforbothlineonephaseandthreephase
Ampere meter: Used to measure the electric current. Portableclamp type ampere meter is very popular and convenient in theenergyauditwhenafixedmeterisnotrequired
Voltmeter:Usedtomeasurethevoltagebetweentwopointsofthepowerlines.Mostoftheactualmeasuredvoltageisbelow600V.
KiloWatt(kW)
Apparentpower
Powerfactor
PARTI.
RECOMMENDATIONFORENERGYAUDITPRACTICES
1. MEASUREMENTDEVICES
1.1. Electricitymeasurement
Measuringinstrumentsmainlyforelectricityaspower,powerfactor,reactivepower,electricalcurrent,
voltage.Someinstrumentsaremeasuredbothharmonics.
Thedevicesaregettingtotheline,wheretheenginesareworkingwithouthavingtostopthemotor.Hand-
heldmeasuringdevicescanbeusedforinstantmeasurements.Otheradvancedinstrumentscombining
datacanbereadwithprintsinacertaintimeperiod.
40
PowerFactorMeter:Initialmeasuringdeviceforpowerfactoristhree-phase.Canmeasurethepowerfactorearlyof 1.0 to delay 1.0 and accept the current to 1500A at600V. This range includes themajor applications in thelightIndustry.
Power Analyzer: The system analysis one phase andthreephase,Volt,Amps,Watts,VARs,VA,W,HzkWh
Clampautomatictypeusedto(20A,200A&1000A)
Lightingsystemmeasurementequipment
Luxmeter:
Illumination ismeasured by luxmeter, consisting of a photovoltaic cellsensitivity to emission light, converted into electrical pulses and areformattedtolux.
Clamp-onPower
These devices are getting up to lines to measure theelectrical parameters of themotor, transformer and theelectricheatingwithoutstoppingoperation.
Usedtomeasureparameters:
•Voltage:150Vto600V,
•Current:200Ato1000A,
•Voltage/currentpeak
• Effectivepower / reactive / apparent (onephaseorthree-phase):30kWto1200kW,14combination
Type
•Loadfactor
•Thephaseangle
•Frequency
•Thesynchronouslevelofvoltage/current
41
Dust filter
1.2.Thermalmeasurementequipment
Combustionef�iciencymeasurement
Oxygenmeasurement,�luegastemperature.The
heatvalueofthecommonfuelsisloadedintothe
processortocalculatethecombustionef�iciency.
Relativehumiditymeter
Wetanddrybulbwith�iltrationcombinedwith
mercurythermometers.
Quantity:150gms
Temperature:-5°Cto50°Cor20°Fto120°F
Fyritetube
Useamanualpumptosuckthesmokeintothe
deviceprocessor.Thechemicalreactionchanges
theliquidvolumeofthevolumeofairexpress.
ThedifferentFyritetubescanusedtomeasure
theO andCO2 2
Fluegasanalyzer(ORSAT)
TubeisarrangedinsidethedevicetomeasurechemicalgasessuchasO ,CO,NO andSO .Thisdeviceis2 X X
importantimplicatedfortheboilersystem,incalculatingtheamountofexcessairinthe�luegasesand
lossesduetouncompletedburnout.
42
Infraredthermometers
Range:upto1000°C
Readingaccuracywithin±1%
Contactthermometer:
This is a thermocouple to measure the �lue gas
temperature, hot air, hot water, etc. by bringing the
probeintothe�low.
Forsurfacetemperatures,leaftypeprobeisusedwith
thesamedevice.
The thermometer is attached to the pipe, used to
measurethetemperaturebothhotandcoldwater,and
steam,.
1.3.Pressure,velocityand�lowratemeasurementequipment
Pitotubeandmanometer
Measurewindspeedintubes,pressuregaugeattached
tocalculatethe�lowproperties
43
Speedmeasurement
Inanypublicenergyauditing,rotationspeedmeasurement is
importantbecausespeedmayvaryduetopowerfrequency,load
andunderloadskating.
Contacttypespeedmeterismaybeusedinareasaccessible.
Stroboscopic device is non- direct contact type, sophisticated
andsafer.
Leakdetectiontools
Ultrasonicinstrumentcandetectleaksoncompressedairpiping
andothergasesthatareusuallydif�iculttodetectbyeye.
Measurewater�lowrate:
Contactless �low measuring device use the Doppler effect/
ultrasoundprinciples(UltraSonic).Thereisatransmitterand
receiver set lying opposite pipe. The meter directly displays
water�lowor�luidinsidethetube.
Airvelocitymeter
Airvelocitymeterisadeviceusedformeasuringtheairvelocity
withfanbladessensor.Largefanbladeisusedforlargesurface
areatoensuretheaccuracyofthemeasurement.
Measuringrange:+0.3to+20m/s
Accuracy:±(0.1m/s+1.5%measuringvalue)
Resolution:0.01m/s
44
2. OVERALLENERGYCONSUMPTIONANDENERGYMANAGEMENTASSESSMENT
2.1. Generalinformation
Generalinformationoftheorganizationshouldconsistof:
· Nameandaddress
· Contactperson
· Mainactivities
· Startingyearofoperation
· Productioncapacity(design,actual)
· Numberofemployees(managers,technical,production)
· Organizationchartandlayout(ifavailable).
2.2. Materialconsumptionandproductvolume
Informationiscollected:
· Materialtypesandproducts
· Productquantityofenterprisesinrecentyears
From collected data can be analyzed by changing product trends, and production capacity of the
enterprises.
2.3. Powerandwaterconsumptiondata
Monthlypowerandwaterconsumptioninayearandthelast3yearsshouldbecollected.Fromcurrent
statusofenergyconsumptionandproductionvolume,itispossibletoidentify.
· Energy consumption status of the company in last years. Thus, the energy consumption of the
companycanbepredicted.
· Thetypeandcostofenergyconsumption.Thecostsavingpotentialandgreenhousegasemissionin
case the company use a new type of energywith lower cost and greenhouse gas emission (e.g.
renewableenergy)
Therearemanydifferentenergytypescanbeconsumedbyenterpriseinclude:electricity,coal,DOoil,FO
oil,LGPandnaturalgas,biomass,steam…andwater.
Theunitoffuelconsumptiondatawouldbeconvertedtobeconsistentwhenanalyzingandreporting.
Energydataanalysis
Dependonfueltypes,itisnecessarytocollecttheircalorific value of fuel, especially coal and biomass. Coal
and biomass have their calorific value, that can vary widely according to fuel type, percentage of moisture, ash in
the fuel. Thus,inordertoanalyzethetotalactualenergyconsumptionofenterprises,orconverttoTOE
unitAuditorcanaskenterprisesorcoal/biomasssupplierprovidesampletestingresultsofthesefuels
thatenterprisesareusing Innecessarycases,bringingthosesamplestotestingcentertochecktheir.
calori�icvalue.
45
Ap:Activepower(kWh)
Aq:Reactivepower(kVArh)
Priceforreactivepower:
Tq:Priceforreactivepower
Tp:Priceforactivepower.
k:Off-setpricefactorduetousingexcessreactivepower.
Determinekinbelowtable.
T =T xk%q p
With natural gas (NG) or compressed natural gas (CNG): Due to limited pipeline or limited
distribution,thosefuelsonlyprovideforsomefactoriesatindustrialareassuchasBaRia-VungTau
andDongNaiprovince.CNGcanprovidetoHCM,DongNai,BinhDuongprovince…
PowersupplycantakefromnationalGridorproducedbytheenterprises(bybackupgeneration,
cogenerationsystems,solar…).Now,nationalGridisthemostpopular.Cogenerationsystemscanbe
foundinlargeenterprisesandcompanysuchas:sugar,paperindustry…Otherpowersupplycanbe
generatedbyrecoverheatofcementorsteelindustry.
For national Grid, electricity price is different, depends on business types, voltage supply and
accordingtothetimeofuseinaday(normalhour,off-peakhour,peakhour).Theelectricitypricefor
enterprisesinrecentyearsisintheTable71.
Moreover,accordingtoCircular15/2014/TT-BCT,May28th,2014,prescribedaboutpurchaseand
saleofreactivepower.Theelectricitybuyerhastransformerorwithouttransformer,buthasthe
maximumpowerutilizationregisteredinpurchaseagreementfrom40KWormoreandthepower
factorlessthan0.9,havetobuyreactivepower.Thepowerfactorcanbecalculatedonthebasisofdata
measuredbytheelectricitymeterinrecordingcyclemeter,byfollowingformula:
46
Table11.Powerfactor
Therefore,whencollectingdataonpowerconsumption,takecareaboutthepriceofreactivepower,that
enterprisesmustpay,ifany.
TheconversionintoTOE,MGandemissionfactorsofsomeenergytypesisintheTable72.
2.4. Energyperformanceindicatorandbenchmarkingreferences
MethodologyofEPIcalculationandbenchmarkapproachhavebeenintroducedinprevioussections.In
thissection,energyconsumptioninenterprisesandenergyrateinsomeindustriesinVietNamwillbe
presentedasareferencetool.
Fromdataonproductqualityandenergyconsumption,willhelpdetermineenergyconsumptionforeach2productunit,orconsumptionpowerperaream atbuilding,commercialcenter,servicecenter….So,we
compareenergyconsumptionrateofthesectorinthecountryandintheworld.
AtVietNam,someindustrieswereruledtheirenergyconsumptionratebyMinistryofindustryTrade
suchas:steel,cement,drinks(beerorbeverage),chemistry(rubber,fertilizerNPK,paintwater,solvent).
Hereisshortlistaboutenergyconsumptionrateinthesector/sub-sectors:
k(%) k(%)
From0,9andabove
0,89
0,88
0,87
0,86
0,85
0,84
0,83
0,82
0,81
0,8
0,79
0,78
0,77
0,76
0,76
0
1,12
2,27
3,45
4,65
5,88
7,14
8,43
9,76
11,11
12,50
13,92
15,38
16,88
18,42
20,00
0,74
0,73
0,72
0,71
0,7
0,69
0,68
0,67
0,66
0,65
0,64
0,63
0,62
0,61
0,6
below0,6
21,62
23,29
25,00
26,76
28,57
30,43
32,35
34,33
36,36
38,46
40,63
42,86
45,16
47,54
50,00
52,54
PowerfactorCosϕ PowerfactorCosϕ
47
· Circulars19/2016/TT-BCT,publishedin14/09/2016,prescribedpowerconsumptionrateinbeer
andbeverageindustry.
Table12.Energyconsumptionrateuntil2020s.
TT Industry Powerscale(millionlitre) Rate(MJ/hl)
1 Beer >100 140
20–100 215
<20 306
Producttype
2 Beverage Sodaorbothsodaornonsoda. 55
Nonsoda 111
Table13.Energyconsumptionratefrom2021s–to2025s
TT Industry Powerscale(millionlitre) Rate(MJ/hl)
1 Beer >100 129
20-100 196
<20 286
Producttype
2 Beverage Sodaorbothsodaornonsoda. 52
Nonsoda 107
· Circulars 20/2016/TT-BCT, published in 20/09/2016, prescribe energy consumption rate in
steelindustry:
Table14.Energyconsumptionrateforsteelindustryuntil2020s
TT Productphase Units Rate
1 Sinteringofironore
Productionofcastironbyblastfurnace
Productionofsteelbilletby
Productionofsteelbilletbyelectricarcfurnace
Productionofsteelbilletbyinductionfurnace
Hotrollingoflongsteelproducts
Coldrollingofsteel
MJ/tonne 2,350
2 MJ/tonne 14,000
3 (top-blown)converter MJ/tonne 150
4 MJ/tonne 2,600
5 MJ/tonne 2,600
6 MJ/tonne 1,650
7 plates MJ/tonne 1,600
48
Table15.Energyconsumptionrateforsteelindustryfrom2021sto2025s.
TT Productphase Units Rate
1 Sinteringofironore MJ/tonne 1,960
12,400
100
2,500
2,500
1,600
1,500
2 Ironmakingbyblastfurnace MJ/tonne
3 Productionofsteelbilletby(top-blown)converter MJ/tonne
4 Productionofsteelbilletbyelectricarcfurnace MJ/tonne
5 Productionofsteelbilletbyinductionfurnace MJ/tonne
6 Hotrollingoflongsteelproducts MJ/tonne
7 Coldrollingofsteelplates MJ/tonne
Table16.Energyconsumpationrateinchemistryindustry
TT Industry Powerscale Rate(kOE/tons)
1 Rubber Designedpowerbelow5,000tons/year 44
Designedpowerfrom5,000to10,000tons/year 36
Designedpowerabove10,000tons/year 28
2 FertilizerNPK Designedpowerbelow4,000tons/year 14.8
Designedpowerfrom4,000to9,000tons/year 16.8
Designedpowerabove9,000tons/year. 19.7
3 Paintwater all 12.1kOE/tons
4 Solvent all 17.7kOE/tons
Factorieswhichonlyproduce a single product, calculate their energy consumption intensiveby
dividingdeterminedtotalenergyconsumptionwithtotalproduction.
Forfactorieswhichproducesvaryproductsorwhenanalyzingenergyconsumptionateachstage,itis
necessarytomeasureenergyconsumptionforparticularproductionorbyproductionstage.Youcan
alsousemultivariateregressionmethodstoanalyze, inthiscase,theaccuracyofdataaffectsthe
purityoftheanalyticalresults.
· Circulars 02/2014/TT-BCT, published in 16/01/2014, prescribe energy consumption rate in
chemistryindustry
49
Table17.Amatrixofenergymanagementevaluation
Ranking Energypolicy Assessment
4 Have energy policy, action plan, periodical checking,topmanagementcommitmentintheenergymanagementimplementation.
3 Thereisaformalpolicybutnotopcommitment.
2 Thereisapolicy, butitisnotyetimplemented
1 Thereareunwrittensetofguidelines.
0 Noenergypolicy
2.5. Energymanagementassessment
2.5.1. Objectives
This toolhelps theauditor to identify theenergymanagement statusof theenterpriseandpropose
solutionstoimproveenergyef�iciencyviamanagementimprovement.
2.5.2. Evaluationmethod
Inassessingthestatusofenergymanagement,auditormayusedifferentmethods.Inthismanual,onlythe
PDCAcycle(Plan–Do-Check-Act)isintroduced.Thisapproachprovidestheauditoranoverviewofthe
company's energy management system, starting from leaders' commitments to the performance
implementationandevaluation,aswellasimprovementactivities.
Belowisatableofcriteriatoevaluatethecurrentstatusofenergymanagement.Therearesixcriteriato
evaluatethecurrentstatusofenergymanagement,whicharedesignedbasedonthePlan-Do-Check-Act
model,including:
· Criteria1:Energypolicy(Planning)
· Criteria2:Organization(Planning)
· Criteria3:Training(Do)
· Criteria4:Informationexchange(Do)
· Criteria5:Checkingandevaluation(Check)
· Criteria6:Investment(Act)
Eachcriterionwillbescoredintheratingcolumn,thescorerangeisfrom0to4,inwhich0correspondsto
thelowestmanagementleveland4isthehighest.
50
Ranking Energymanagement Assessment
4
3
2
1
0 Thereisnoonewhoisinchargeofenergymonitoring.
Ranking Training Assessment
4
3 There are regularly trainings, awareness and sensitization campaigns onenergysavingbutonlyinsidetheenterprise.
2 There are trainings, awareness and sensitization campaigns on energysavingintheenterprisebutnotregularly.
1 There are trainings, awareness and sensitization campaigns on energysavingbutnotof�icially.
0 Thereisnotraining,awarenessandsensitizationcampaigns.
Ranking Motivation Assessment
4 There is information channel and all staff can exploit in order toknowenergyconsumptionstatusandresultsofenergysavingactivities.
3 Thereisanenergyboardandthisboardisthechanneltointeractwithallmainenergyusersintheenterprise.Thisboardisledbytopleader intheenterprise.
2 Interactions between some main energy users/staff is conducted byboard/team,organizationinchargeofenergy(headoforganization)
1
0 Thereisnothing
Energy management is fully integrated into company management;
Thereisclearenergyconsumptionregulation.
There is energy manager; there is energy board with head of board is top
leader of the enterprise.
There are regularly trainings, awareness and sensitization campaigns on
energy saving inside the enterprise and outside (equipment suppliers,
services, customers…) systematically, officially. There are regularly training
courses on energy saving in the enterprise.
There are only unof�icial interactions between factory engineers or
betweentechnicaldepartmentstaffwithsomemainenergyusers/staff
There is energy manager; there is energy board with head of board is head of
department [1]. (not top leader of the enterprise)
There is energy manager; but not official, the authority is limited. There is no
energy board.
51
Ranking Informationsystem Assessment
4 There is comprehensive information system of recording, analyzing,targeting,planning,costbene�itanalysis,investmentplan.
3 There is information system of recording, analyzing, reporting energyconsumption though at local level but results of energy saving activities,informationofenergysavingarenotannouncedtoenergyusers
2 Thereismonitoring,analyzingofenergydatasystembutmainlybasedonbills and some calculated data, there is not much data from measuringinstrument; but the energy manager has important role of budgetingenergycostandenergyinvestment
1 There is energy report but notmuch analysis, data is based on bills. Allenergydataisusedforinternaltechnicaldepartment.
0 Thereisnothing.
Ranking Investmentpolicy Assessment
4 Detailed investment plan with particular cost/ bene�it ratio given highpriority.
3 There is detailed investment planwith particular cost/ bene�it ratio, butonlyconsideringenergysavinginvestmentasnothighpriorityone.
2 Thereisdetailedinvestmentallegeandplanbutonlyconsideringmeasureswithshortpaybackperiod.
1 Thereisdetailedinvestmentplanbutonlyconsideringmeasureswithlowinvestmentcost.
0 Thereisnotinvestmentplan.
Aftercompletingtheassessment,theresultscanbereportedinvariousforms,suchascolumncharts,line
charts,orspiderwebcharts,etc.The�igurebelowshowsasampleofassessmentresultsrepresentedin
linechartatanenterprise
52
Figure9.Energymanagementassessmentchart
0
1
2
3
4
Energy policy Organiza�on Training Informa�on exchange Checking and evalua�on Investment
ASESSMENT ON STATUS OF ENERGY MANAGEMENT
Fromtheresultsofevaluation/graphshowsomestrengthsandweaknessesinenergymanagementofthe
enterprises. Auditors need to raise recommendation in short term and long term. The short-term
recommendationaimedat improvingtheweaknessmanagement,andlong-termrecommendationto
helpimprovecomprehensivemanagementlevelofwholeenterprises.
Belowaresometypicalassessmentresultsandrecommendationsforenergymanagementimprovement.
53
Table18.Assessmentresultsandimprovementactions
Shape Picture Description Results Action
1.High
balance
Scoreof3or
moreforall
columns
Excellent
performance
Maintainthislevel
2.Low
balance
Scoreunder3
forallcolumns
Allaspectsinenergy
managementshould
beimprove
Commitmentfromthe
leader.Setupanenergy
managementstrategy.
Setgoals,actionplans&
checkingprocess
3.Uform Twoouter
columnswith
scoresof3or
more
Havecommitmenton
energyef�iciency.
Highexpectation,but
theteamperforms
poorly
4.Nform Thetwoouter
columnsaretoo
low
Nocommitment.Have
anenergyspecialist
toperform.The
middlecolumngood
resultiswasted
Commitmentfrom
leaders
5.Gutter Themiddle
columnislower
thantheouter
columns
Theweaknessofthis
columncanreduce
thesuccessofother
columns
Focusmoreonthe
weakaspect
6.Peak Themiddle
columnis
higherthanthe
outercolumns.
Theeffortofthis
columncanbewasted
bythestagnationof
othercolumns.
Focusmoreonthe
weakaspect
7.Unbalance Twoormore
columnsare
higherorlower
thanaverage
Themorethe
imbalance,theharder
toperform.
Focusonthelower
aspectsandtrytolift
themup
Setupanenergy
managementboard,
establishaformal
communicationchannel
withallemployees.Set
goals,actionplans&
checkingprocess.
54
Figure10.Thetransformerinpowersystem
Table19describestheclassi�icationoftransformers:
Table19.Classi�icationoftransformers
Criteria Types Comment
Inputvoltage
stepup Convertlowvoltagetohighvoltage
stepdown Converthighvoltagetolowvoltage
(populartransformer)
Operation
Powertransformer Located at distribution station to increase voltage andtransmitlargepower
Distributiontransformer
Located at sub-distribution station to transmit lowpower.
3. COMMONENERGYCONSUMPTIONSYSTEMANALYSIS
Thissectionwillpresenttechnicalguidelinesfordatacollectionandanalysisatkeyandcommonenergy
consumersinfactoriesandbuildings.
Briefexplanationandcalculationforeachsystemwillbeintroduced.Standarddatacollectiontemplate
willbesuggested.SomecalculationtoolstoaccrueherequireddatawillalsobeintroducedinthisSection.
Keyenergyconsumptionsystemincluding;
· Energysupplysystem
· Keyelectricityconsumptionsystem:motors,pump,fan,aircompressionsystem,refrigerationsystem,
airconditioningsystem
· Keythermalenergyconsumptionsystems:boiler,furnace,steamdistribution.
3.1. Electricitysupplysystem
3.1.1. Introduction
3.1.1.1. Componentsofelectricaldistributionsystem
Transformer
Atransformerisastaticelectricaldevice,whichtransformselectricalenergyfromonevoltagelevelto
anothervoltagelevel.
55
Measuringtransformer
Usedtomeasurevoltageandcurrentwithmeasurementdevices.
Locationofinstallation
Outdoor Locatedoutdooronconcreteorironshelf
Indoor Locatedindooronconcreteorironshelf
Numberofphases
3phases Inputandoutputarethreephases(R,Y,andB)withorwithoutneutralwire.
1phase Inputandoutputareonephase
Source:BEE,2004
Figure11.Maindistributionswitchboard Figure12.Distributionboard
Distributionboard
Distributionboardistheimportantpartofanelectricitysupplysystemandisusedtodivideanelectrical
powerfeedintosubsidiarycircuits.Moreover,itisalsoaplaceforinstallationandprotectionofcircuit
breakerandcontrollerdevices.Twotypesofdistributionboardaremaindistributionswitchboard(MSB)
anddistributionboard(DB)inelectricalsystem.
Maindistributionswitchboardisinstalledrightafterstepdowntransformer.Itsmainfunctionistoshut
down to protect electrical consumption systems. There aremany cabinets insideMSBwith speci�ic
functionssuchasstoringmainACB/MCCB,storingMCCB/MCBoutput,storingcompensatescapacitor,or
storingATSsources.
DBisusedinlowvoltagenetworksanditisinstalledafterMSB.Itisthesmallestelectricalcabinetand
supplyelectricityforequipmentsuchaspumps,motorsandetc.
3.1.1.2. Singlelinediagramofsupplypowersystems
Singlelinediagramisdesignedtoanalyseelectricalsystem.Itcanhelpauditorunderstandthedesignand
structureofelectricaldistributionsystem.Then,theauditorcanhavesurveyplanstomeasuresystems
logicallyandeffectively.
56
Figure13.Exampleofsinglelinediagramofelectricalsupply
Figure14.Adailyloadcurve
0
100
200
300
400
500
600
700
800
900
1000
9:4
0
10:
40
11:
40
12:
40
13:
40
14:
40
15:
40
16:
40
17
:40
18
:40
19:
40
20:
40
21:
40
22:
40
23:
40
0:4
0
1:4
0
2:4
0
3:4
0
4:4
0
5:4
0
6:4
0
7:4
0
8:4
0
9:4
0
cap
acit
y (K
W)
TimeMBA 1 MBA 2
3.1.2. Loadgraphandelectricalloadmanagement
3.1.2.1.Loadcurve
ALoadcurveshowstheloaddemandofaconsumerversustime.Ifpowerconsumptionisplottedfor24
hoursofaday,itiscalled“hourlyloadcurve”andifpowerconsumptionisplottedfordaysofamonth,itis
called“dailyloadcurve”.
57
Table20.Strategytomanagepeakload
Solution Perform
ShiftingNon-Criticaland
Non-ContinuousProcess
LoadstoOff-Peaktime
SheddingofNon-
EssentialLoadsduring
PeakTime
OperatingAir
Conditioningunits
duringoff-peaktimes
andutilizingcool
thermalstorage
InstallationofPower
FactorCorrection
Equipment
Source:EnergyEf�iciencyManagementAgency,2004
Themaximumdemandcanalsobereducedat theplant levelbyusing
capacitor banks and maintaining the optimum power factor. These
systemsswitchonandoffthecapacitorbankstomaintainthedesired.
Powerfactorofsystemandoptimizemaximumdemandthereby.
Rescheduling of large electric loads and equipment operations, in
different shifts can be planned and implemented to minimize the
simultaneous maximum demand. For this purpose, it is advisable to
prepare an operation �low chart and a process chart. Analyzing these
chartsandwithanintegratedapproach,itwouldbepossibletoreschedule
theoperationsandequipmentinsuchawayastoimprovetheloadfactor
whichreducesthemaximumdemand.
Whenthemaximumdemandtendstoreachapresetlimit,sheddingsome
ofnon-essentialloadstemporarilycanhelptoreduceit.Itispossibleto
install direct demand monitoring systems, which will switch off
nonessentialloadswhenapresetdemandisreached.Simplesystemsgive
alarms,andtheloadsareshedmanually.Sophisticatedmicroprocessor
controlled systems are also available, which provide automatic load
sheddingoptions.
It is possible to reduce themaximumdemand by building up storage
capacityofproducts/materials,water,chilledwater/hotwater,using
electricityduringoffpeakperiods.Offpeakhouroperationsalsohelpto
save energy due to favorable conditions such as lower ambient
temperatureetc.
3.1.3. Harmoniceffects
Harmoniccurrentsarecausedbynon-linearloadsconnectedtothedistributionsystem.Aloadissaidto
benon-linearwhenthecurrentdoesnothavethesamewaveformasthesupplyvoltage.The�lowof
harmonic currents through system impedances in turn creates voltage harmonics,whichdistort the
supplyvoltage.
Theharmonicscausessuchthebeloweffectsinpowersystems:
·����Overheatingofelectricaldistributionequipment,cables,transformers,standbygenerators,etc.
ALoadcurveisusedtopredicthigh/lowdemandofpartoffactory,entirefactory,oradistributionsystem,
etc.Italsoshowspeakpower,off-peakpowerandaveragepowerofthefactory.Basedonthatinformation,
theauditorwillproposetheproperenergysavingsolutions.
3.1.2.2.Loadmanagement
Atthemacrolevel,thepowerconsumptionandelectricaldemandincreaseduringcertaintimesinaday
andthentheywillleadtoshortfallincapacitytomeetdemand.Thebetterloadmanagementattheuser
endhelpstominimizepeakdemandsontheutilityinfrastructureandimprovetheutilizationofpower
factorycapacity.Thefollowingtablelistssometechniquestohelpbetterloadmanagement:
58
Figure15.Waveformsofharmonics
· Meteringerrors
· Increasedinternalenergylossesinequipment,causingcomponentfailureandshortenedlifespan
· Falsetrippingofcircuitbreakers
· Lowersystempowerfactor,resultinginpenaltiesonmonthlyutilitybills
Source:www.hersheyenergy.com
Therearemanyoptionstoattenuateharmonics:
· AddAlternatingCurrentorDirectCurrentchokes
· Usepassive�iltering
· Uselowharmonicsdrive.
3.1.4. Datacollection
Theenergyauditorneedstocollectthefollowingdataforelectricitysystem:
· Single-linediagramofelectricalsystems
· Alltransformersdataandtheirpowercapacity
· Totalpowerconsumptionandannualcost
· Operatingcapacity:max,min,average
· Powerfactor
· Thebalancebetweenelectricalphases
· Powerconsumptionofeachsystemorarea
· Electricityrate
ElectricityrateisregularlyupdatedatthewebsiteofVietnamElectricity(EVN).Asthedifferentoperating
timebetweenfactories,theaverageelectricityrateshouldbecalculatedasthefollowingformula:
For equipment with unstable operating time, the average electricity rate will be used to calculate
electricitycost inenergysavingmeasures.Forequipmentwithstableoperating time,electricityrate
shouldbeusedaccordingtospeci�icperiod.
TotalelectricitycostAverageelectricityrate=Totalelectricityconsumption
Fundamentalrd
3 Harmonicth
5 Harmonicth
7 Harmonic
Resultant
HarmonicsA
mp
litu
de
Time
59
Table21.Applicationsofcolorrenderinggroups
Colorrenderinggroups
CIEgeneralcolorrenderingIndex
(Ra)
Typicalapplication
1A Ra>90
1B 80<Ra<90
2 60<Ra<80 Wherevermoderatecolorrenderingisrequired
3 40<Ra<60 Wherevercolorrenderingisof littlesigni�icancebutmarkeddistortionofcolorisunacceptable
4 20<Ra<40
Source:BureauofEnergyEf�iciency,2005
3.2. Lightingsystem
3.2.1. Introduction
De�initionsandcommonlyusedterms
Lumen(lm):isthephotometricequivalentofthewatt,weightedtomatchtheeyeresponseofthe
“standardobserver”.1watt=683lumensat555nmwavelength.Oneluxisequaltoonelumenper
squaremeter.
Luminaire:consistingofalamporlampstogetherwiththepartsdesignedtodistributethelight,
positionandprotectthelamps,andconnectthelampstothepowersupply.
Lux:isthemetricunitofmeasureforilluminanceofasurface.Averagemaintainedilluminanceisthe
averageofluxlevelsmeasuredatvariouspointsinade�inedarea.Oneluxisequaltoonelumenper
squaremeter.
LuminousIntensityandFlux:Onelumenisequaltotheluminous�lux,whichfallsoneachsquare2meter(m )ofasphereonemeter(1m)inradiuswhena1-candelaisotropiclightsource(onethat
radiatesequally inalldirections) isat thecenterof thesphere.The luminous �luxemittedbyan
isotropiclightsourceofintensityIisgivenby:
Luminous�lux(lm)=4π×luminousintensity(cd)
TheInverseSquareLaw:Theintensityoflightperunitareaisinverselyproportionaltothesquareof
thedistancefromthesource(essentiallytheradius):
2E=I/d
WhereE=illuminance,I=luminousintensityandd=distance
Distanceismeasuredfromthetestpointtothe�irstluminoussurface-the�ilamentofaclearbulb,or
theglassenvelopeofafrostedbulb.
ColorTemperature(K):isthecolorappearanceofthelampitselfandthelightitproduces.
ColorRenderingIndex:Theabilityofalightsourcetorendercolorsofsurfacesaccuratelycanbe
convenientlyquanti�iedbythecolor-renderingindex.Thisindexisbasedontheaccuracywithwhich
asetoftestcolorsisreproducedbythelampofinterestrelativetoatestlamp,perfectagreement
beinggivenascoreof100.
Wherever accurate color rendering is required e.g. color printing
inspection
Wherever accurate color judgments are necessary or good color
renderingisrequiredforreasonsofappearancee.g.displaylighting
Wherever color rendering is of no importance at all andmarked
distortionofcolorisacceptable
60
Table22.Luminousperformancecharacteristicsofcommonlyusedluminaries
TypeofLamp Lm/Watt
Colorrenderingindex
Typicalapplication Life
Range Avg. (Hours)
Incandescent 8-18 14 Excellent Homes,restaurants,generallighting,emergencylighting
1,000
Fluorescentlamps
46-60 50 Good w.r.tcoating
Of�ices,shops,hospitals,homes
5,000
Compact�luorescentlamps(CFL)
40-70 60 Verygood Hotels,shops,homes,of�ices
8,000-10,000
High pressuremercury(HPMV)
44-57-57 50 Fair Generallightinginfactories,garages,carparking,�loodlighting
5,000
Halogenlamps 18-24 20 Excellent Display,�loodlighting,stadiumexhibitiongrounds,constructionareas
2,000-4,000
High pressuresodium(HPSV)SON
67-121 90 Fair Generallightinginfactories,warehouses,streetlighting
6,000-12,000
Low pressuresodium(LPSV)SOX
101-175
150 Poor Roadways,tunnels,canals,streetlighting
6,000-12,000,
Source:AsiaEnergyEf�iciency
Characteristicsandapplications
Auditorsshouldunderstandthelampcharacteristicandapplicationtoproposeenergysavingsolutionfor
lightingsystem.
Thefollowingtabledescribesperformancecharacteristicsofcommonlyusedluminaries.
3.2.2. Energy�lowdiagramoflightingsystemsThelampisonlypartofthelightingsystem.Theentirelightedspaceshouldbealsoconsideredpartofthe
system,sincemanyfactorssuchaswallcolor,re�lectivity,windowdesignandinteriorpartitionscanhave
justasgreataneffectontheamountoflightthatisdeliveredtothetaskpoint.Theend-useofalighting
systemcanbemeasuredasthelightlevelatthetaskpoint(usefulillumination).Adetailedenergyaudit
should consider the various energy losses occurring in lighting systems, as indicated in the Sankey
diagrambelow:
61
Figure16.Sankeydiagramoflightingsystem
Source:Enerteam
ThevariouslossesintheaboveSankeydiagramarelistedbelow:
· Electric-to-Light-ConversionLosses: lightoutput(lumens)of lightsourceperunitof inputpower
(watts)
· FixtureLosses:Lighttrappedwithin�ixture
· Roomlosses:Lightlostbeforeitreachestaskduetophysicalroomcharacteristics
· VisibilityLosses:Excesslightsuppliedtoovercomelightingqualityproblems
· Over-IlluminanceLosses:Excesslightsuppliedtoovercomepoorlightingdistributionorconsistency
· OveruseLosses:Lightingleftswitchedonwhennotrequired.
3.2.3.Energysavingsmeasureforlightingsystem
3.2.3.1.Usenaturaldaylighting
Someofmethodstoincorporatedaylightingare:
· Innovativedesignsarepossiblewhicheliminatetheglareofdaylightandblendwellto illuminate
buildings,industrialworkshopsandwarehouses
· A good design incorporating sky lights with Fibre-reinforced plastic (FRP) material along with
transparentortranslucentfalseceilingcanprovidegoodglarefreelighting;thefalseceilingwillalso
cutouttheheatcomeswithnaturallights
· Useof atriumwithFRPdome in thebasic architecture can eliminate theuseof electric lights in
passagesoftallbuildings
Naturallightfromwindowshouldalsobeused.However,itshouldbewelldesignedtoavoidglare.Light
shelvescanbeusedtoprovidenaturallightwithoutglare.
ElectricEnergy
Input
ElectrictoLight
ConversionLosses
Useful
illumination
Overuse
LossesOver
illuminance
LossesVisibility
Losses
Room
LossesFixture
Losses
62
Figure17.Daylightingwithpolycarbonatedsheets Figure18.AtriumwithFRPdome
3.2.3.2. De-lampingtoreduceexcesslighting
Theamountoflightbulbcanbereducedby:
· Reducingthemountingheightoflamps
· Providingef�icientluminairesandthende-lampinghasensuredthattheilluminanceishardlyaffected
· De-lampingatemptyspacewhereactiveworkisnotbeingperformedisalsoausefulconcept
· Tasklighting.
Anothermethodtoreducetheamountoflightbulbistoprovidetherequiredgoodilluminanceonlyinthe
actualsmallareawherethetaskisbeingperformed.Theconceptoftasklightingifsensiblyimplemented,
canreducethenumberofgenerallighting�ixtures,reducethewattageoflamps,saveconsiderableenergy
andprovidebetterilluminanceandalsoprovideaestheticallypleasingambience.
3.2.3.3.Timer,twilightswitchesandoccupancysensors
Automaticcontrolforswitchingoffunnecessarylightscanleadtogoodenergysavings:
· Twilightswitchescanbeusedtoswitchthelightingdependingonavailabilityofdaylight
· Electronicdimmerissuitablefordimmingincandescentlamps.Dimmingof�luorescenttubelightsis
possible, if there are operated with electronic ballasts; these can be dimmed using motorized
autotransformersorelectronicdimmers(suitablefordimming�luorescentlamp;presently,thesehave
tobeimported).
3.2.3.4.Lightingmaintenance
Lightlevelsdecreaseovertimebecauseofaginglampsanddirton�ixtures,lampsandroomsurfaces.The
followingbasicmaintenancesuggestionscanhelppreventthis:
· Clean�ixtures,lamps,andlensesevery6to24months
· Replacelensesiftheyappearyellow
· Cleanorrepaintsmallroomseveryyearandlargerroomsevery2to3years.Dirtcollectsonsurfaces,
whichreducestheamountoflighttheyre�lect.
3.2.3.5.Selectionofhighef�iciencylampsandluminaries
Currently,LEDtechnologyhasbeendevelopedwithhighluminousef�icacy, longeroperatinglife,and
lower production cost. LED are gradually replacing all current conventional lights, including high
pressurelampintraf�iclighting.SomeadvantagesofLEDarelistedasfollows:
·����Generatehigherilluminationthanotherlamps
·����Lesserheat
63
· Notcontaintoxicsubstancessuchas:mercury,lead,cadmiumandharmfulradiation .
Figure19.LEDphaseandaroundlighting
ThetablebelowdescribestheenergysavingofLED:
Table23.EnergysavingbyusingLED
Currentlamp Replacedwith %Energysaving
Tungstenhalogenlamps
Fluorescentlamp
Mixedmercurylamp
Highpressuremercury(HPMV)
Metalhalidelamps
Highpressuresodium(HPSV)
LED 75to83
62to73
80
72
64
64
Table24.Energysavingcalculationtable
Items Unit Currentlamps LED
Powercapacity(+ballast) W/unit
Thenumberhoursinaday Hr/day
Thenumberdaysinayear Day/year
Numberofluminaires
Powerconsumptioninayear kWh/year
Energysavinginayear kWh/year
Averageelectricitypriceinaday VND/kWh
Moneysavinginayear MillionVND
Luminairesprice MillionVND
Totalinvestment MillionVND
Paybacktime Year
64
1
2
3
Table26.Lightingtransformer,ratedpowerandnumbers
No. Factorylocation
Ratedpoweroflightingtransformer(kVA)
Number Voltage/Ampe/kW/
1
2
3
3.2.4.Datacollection
· Step1:Prepareequipmentchecklistforlightingsystemandtransformers:
Table25.Ratedpower,numberandcurrentstatus
No. Factorylocation Lightingtypeandballast
Ratedpower Number ShiftI/II/II
date
· Step2:useluxmetertomeasureluxatvariousplantlocations
· Step3:measureandrecordpowerconsumptionatdifferentinputssuchasdistributionboard,lighting
transformer
· Step4:comparethemeasuredvaluewith luxstandard.Usethevaluesasareferenceandidentify
locationsofunderlitandoverlitareas
· Step5:Analyzethefailureratesoflamps,ballastsandtheactuallifeexpectancylevelsfromthepast
data
· Step6:Basedoncarefulassessmentandevaluation,identifyimprovementoptions.
65
Figure20.Squirrelcagerotormotor
Advantagesofsquirrelcagerotormotoraresimpledesign,inexpensive,easytooperate,lowmaintenance
cost,andhighreliability.
Figure21.Woundrotormotor
Thefollowingtabledescribesthebasicmotorloadtypes:
Table27.Thebasicmotorloadtypes
Loadtypes Description Example
Constanttorque Outputenergychangesbuttorqueisunchanged. Conveyors,rotatingovens,
vacuumpump
Changedtorque Torqueisproportionaltothesquareofspeed Centrifugalpumps,fans
Fixedload Torqueisinverselyproportionaltospeed Machinetool
3.3.2.Energy�lowformotor
Operatingcostandinvestmentinamotorarepresentedinthefollowingpiechart:
3.3. Motor
3.3.1. Introduction
Electricmotorisadevicethatconsumeselectricityandconvertselectricalenergyintomechanicalenergy.
TwomostpopularelectricmotorsinVietnamaresquirrelcagerotorandwoundrotor.
66
Figure22.Costdistributionofmotor
Source:PECSME
Energy cost 83%
Maintainance cosst3%
Investment14%
Basedontheabovechart,energycostsaccountforover80%ofthetotallifecyclecostofmotor.Therefore,
optimizingutilizationwillsigni�icantlyreducetheoperatingcostsofthemotor.
3.3.3. Theenergysavingmeasures
Therearesomeenergysavingsolutionsformotorsystem:
· Optimizetheoperatingcapacityandensurethatthesystemisoperatingatthehighestef�iciency
· Reducethepartialloadoperatingtimeofmotor
· Optimizetheoperatingconditionsofequipment
· Selectingpropermotor
· Usinghighperformancemotor
· Usinginverterformotor.
Themethodsforenergysavingsolutionsarediscussedinthefollowingsections.
3.3.3.1.Motorselection
Underloadmotors:Choosingamotorwithagreatercapacitythandemandwillreducetheperformance
ef�iciencyoftheengine
Motorselectionshouldbebasedontheperformancegraphandpercentageoffullload.Motoref�iciency
canbecalculatedasfollows:
Motoref�iciency(%)=outputpower/inputpowerx100%
67
Figure23.Ef�iciencyandfullloadpercent
Source:AsiaEnergyEf�iciency
Theabove�igureshowsthatthemotoref�iciencyissigni�icantlyreducedwhenthemotoroperatesat30-
40%ratedpower(%fullloadmeasuredwhenthemotoroperates).
Atthesameratedpower,higherspeedmotorhashigheref�iciency.
Figure24.Ef�iciencyandrotatingspeedofsquirrelcagerotor
Source:PECSME
Example:Calculationbene�itwhenchoosingrightmotorforloaddemand7,5hp.Thecalculationresults
arepresentedinthebelowtable:
68
Fromabove calculation, choosing rightmotormatch loaddemand,we can savepower consumption
aswellasoperatingcosts.
3.3.3.2.High-Ef�iciencymotor
Bene�itsofhigh-ef�iciencymotorselection:
Highperformanceandmotorlifetime
Reducepowerconsumption,reduceoperatingcosts
Reducedaffectpowerquality,increasepowerfactor,stableload.
Figure25.Standardef�iciencymotorvs.premiumef�iciencymotor
Source:PECSME
Table28.Operatingcostestimationofselectedmotors
(1)Requiredpower
(2)Designpower
(3)FullLoadEf�iciency
(4)Loadfactor
(5)Diminishingef�iciency
(6)Operationalef�iciency
(7)Operatinghours
(8)Electricityprice
(9)Operationalpower
(10)Electricityconsumption
(11)Annualcost
(12)Differentofoperatingcost
Requirement
SelectedMeasure
Result
hp 7,5
(A) (B)
hp 15 10
% 86,3% 86,0% Basedoncatalogue
% 50% 75% (1)/(2)
% 98,0% 100% Basedon%loadandef�iciencychart
% 84,6% 86,0% (3)x(5)
hours/year 7.920 7.920 (byactuallyoperationalhours)
VND/kWh 1.671 1.671 (byaverageelectricityprice)
kW 6,62 6,51 (2)x0,746x(4)/(6)
kWh 52.395 51.526 (7)x(9)
VND 87.551.754 86.100.024 (8)x(10)
VND/year 1.451.730 (A)-(B)
100
95
90
85
80
75
1 5 10 50 100 200
Premium Efficiency
Standard Efficiency
Input power (hp)
Effici
ency
(%
)
69
Table29.Standardef�iciencymotorvs.premiumef�iciencymotor
Source:AsiaEnergyEf�iciency
Thefollowingillustrationcomparestheenergysavingsandannualcostsbetweenenergyef�iciency
motortrandstandardmotor:
Table30.Motorinvestmentcomparison
HP kW
5
7,5
10
15
20
25
30
40
50
60
75
100
125
150
200
3,7 38,3 87,3 344
494
614
811
1.025
1.230
448
647
780
1.042
1.268
1.542
5,5 85,2 89,5
7,5 86,0 89,4
11,0 86,3 90,4
15,0 88,3 92,0
18,5 89,3 92,5
22 89,5 92,6 1.494 1.824
30 90,3 93,1 1.932 2.340
37,5 91 93,4 2.487 2.881
45 91,7 94,0 3.734 4.284
55 91,6 94,1 4.773 5.520
75 92,1 94,7 5.756 6.775
100 92,0 94,7 7.425 9.531
120 93,0 95,0 9.031 11.123
150 93,8 95,4 10.927 13.369
Power Efficiency (%) Price ($)
104
153
166
231
243
312
330
408
394
550
747
1.019
2.106
2.092
2.442
4,6
4,8
3,8
4,5
4,0
3,5
3,3
3,0
2,6
2,4
2,7
2,6
2,9
2,1
1,7
Standardmotors
High efficiencymotors
DiffirentDiffirentHigh efficiencymotors
Standardmotors
Thecostsofhighef�iciencymotorsarehigherthanthoseofstandardmotors.Thepaybackperiodwill
be rapid due to reducing operating costs, particularly in new applications or end-of-lifemotor
replacements.However,replacingexistingmotorsthathavenotreachedtheendoftheirusefullife
withenergyef�icientmotorsmaynotalwaysbe�inanciallyfeasible.Therefore,thereplacementis
recommendedwhentheexistingmotorisfailed.
Requirement
Power hp
Operatinghoursinday hours/year
Fullloadfactor %
Avarageelectricityprice VND/kWh
High-ef�iciencymodelef�iciency %
Normalmodelef�iciency %
Differentosprice VND
Annualelectricitysavings kWh
Annualsavings VND 9.846.334 12.704.947 19.851.480
Simplepaybackperiod months 6,4 6,0 7,2
Selectedmeasure
Result
5.892 7.603 11.880
75
7.920
80
1.6711.671
7.920
80
50
7.920
80
1.671
30
94,1
91,6
11.952.000
93,4
91,0
6.304.000
92,6
89,5
5.280.000
70
Figure26.Performancecurveofpumpwith�lowcontrolvalve
Source:AsiaEnergyEf�iciency
VSDimprovesenergyef�iciencybybalancingtherotationspeedwithvariableload.
Af�initylawsdescribetherelationshipsbetweenspeed,�lowrateandpower:
Q:Flowrate,P:Power,N:rotationspeed
Table31.Correlationbetweentherotationspeed,�low,andpowercapacity
Accordingtotheabovetable,themotorwithratingof50HPisthebestchoicesinceitcansave7,603
kWh/yearwhichisequivalentto13millionVND/yearanditspaybackperiodisshortest.
3.3.3.3.Variablespeeddrive
Forpumpsandfans:thevalvesystemandtheventdoorsmustnotbefullyopenedduringoperationdueto
overcapacitydesignorduetothenecessarychangesaccordingtoproductionstatus.
Thereasonformotorspeedcontrol:
· Mechanicalpoweriscontrolledbycycleoron/offaccordingtooutputpowerrequirements
· Infanorpumpsystem,�luid�lowisadjustedbycontrolvalvesatinletandoutletwhilethemotoris
operatingata�ixedrate.Thiscontrolstrategywillaffecttothepumpcharacteristicscurve.Inthis
method, the �low is reduced, while power consumption does not change, so that the total head
increases.Thefollowing�igureshowshowthesystemcurvemovesupwardsandtotheleftwhena
dischargevalveishalfclosed
Somemotorsandactuatordevicesusemechanicalcouplingandgearboxtoadjustspeed.
Asmallreductioninspeedwillresultinaverylargereductioninpowerconsumption.Thebelowtable
showsthecorrelationbetweentherotationspeed,�low,andpowercapacityofthecentrifugemachine.
Rotationspeed Flow Powercapacity
100% 100% 100%
90% 90% 73%
80% 80% 50%
70% 70% 34%
FLOW RATE
HEA
D
Flow 2 Flow 1
System Curvewith Fully Open Valve
Head Drop AcrossHalf Open valve
System Curve with Half Open Valve
71
60% 60% 22%
50% 50% 13%
40% 40% 6%
30% 30% 3%
Source:PECSME
Figure27.Loaddiagramofairconditioning
VSDcontrollerisappliedwellinthefollowingcases:
· Flowvariationsrequirethecontrolvalveandby-passvalve
· Motorratingismuchlargerthanpowerrequirement
· Thesystemhason/offcyclecontroller.
3.3.3.4.Optimizemotoroperation
Examplebasedonloadcurve:Loaddiagramofcompressorandcoolingwaterpump.Weseethatthe
compressor works intermittently while cooling water pump works continuously. So, operating
systemdoesn'tworkoptimally.
3.3.4. Datacollection
Inordertoevaluatetheoperationofmotorsystem,thefollowinginformationneedtobecollected:
· Loaddiagram:actualcapacity,thedifferencebetweenactualcapacityanddesigncapacity,operating
time
· Operationcontrolstrategy
· Parametersaffectingtheoperationofsystem.
Thedatacollectiontableformotorscanbereferencedbelow:
Coolingwaterpumpcompressor2
time
Inputpower(kW)
72
Table32.Motordatacollection
No. 1 2 …
-Name
-Code
-Ratedpower(motor) kW/hp
-Ef�iciency(motor) %
-Ratedspeed rpm
-Primaryspeed rpm
-Secondaryspeed rpm
-Voltage V
-Current A
-Cosj
-Operatingpower kW
-Operatingtime Hour/year
-Control(aperturevalve,VSD)
-Notes
3.4. Fans
3.4.1. Introduction
Basedonoperationpressure,classi�icationoffans,blowers,compressorsareasbelow:
· Fans:operatewithpressurebelow1,4mH O2
· Blowers:operatewithpressurefrom1,4mH Oto14mH O2 2
· Compressors:operatewithpressureabove14mH O.2
Therearetwotypesofindustrialfan:
· Axialfan:High�low,lowpressure
· Centrifugalfan:low�low,highpressure(normally,Δp<2,04mH O).2
3.4.1.1.Fansystem
Fansystemincludesthefollowingmaincomponents:
· Motor
· Propeller
Valves,ventscontrol�low.
73
P:Powercapacity(kW)
ΔpPressuredifference(Pa):
Q:Flow(m3/s):
(hisef�iciency(<0,85).Higherdifferentialpressurehasloweref�iciency)
Fanef�iciency
Table33.Ef�iciencyoftypesoffan
Typesoffans Minimumperformance Maximumperformance
Centrifugalfanwithhollowblades. 75% 86%
Centrifugalfanwithconvexblades 50% 73%
Centrifugalfanwithstraightblades 50% 60%
AxialFans 60% 86%
Source:PECSME
h Comparetheoricalpowerconsumptionandactualpowerconsumptionatthesamepointfan
H transmission:transmission ef�iciency. Transmission systems by cogged raw-edged belt with power
capacity above 10kW has ef�iciency of at least 95%. Transmission losses can be ignored if it is
directtransmissionsystems.
Hmotor:motoref�iciency.Checkmanufacturercatalogue
Theoreticalfancapacityiscalculatedasthefollowingdiagram:
Động cơ
Cánh quạt
Van
Engine
Propeller
Valve
3.4.1.2.Flowcontrol
Methodsusedfor�lowcontrolinclude:
· Circulation:apartofairvelocityiscirculatedtothefaninlet
· Airinlet:usedformitigatingairvelocityintheairinletoroutlet
· Flowchange:themotorspeedis�ixed,butpropellerspeedischangedbyusingembrayage.
· Inverter:invertercontrolunitisusedforchangingmotorandfanspeed.
3.4.1.3.Basicinformation
h=h .h .hfan transmission motor
75
Figure29.Calculationoffancapaciy
Effectof�lowcontrolandsystemef�iciency:
Table34.Fanspeedvs.�low
Source:PECSME
Table35.Fanspeedvs.powercapacity
Source:PECSME
Table36.Percentageofpowerconsumprionby�lowpercentage
Source:PECSME
Fanspeed(round/minute) Flow(%)
800 55
900 62
1.000 69
1.100 76
1.200 83
1.450 100
Fanspeed(round/minute) Powercapacity(%rated)
800 17
900 24
1.000 33
1.100 44
1.200 57
1.450 100
Flow(%) Outputvents Inputvents Inverter
100 81 78 83
90 61 74 81
80 44 58 80
70 31 42 76
60 21 28 70
50 14 18 66
76
3.4.2.Energy�lowforfan
3.4.2.1.Costdistributionoffan
Operatingcostandinvestmentinafanarepresentedinthepiechart:
Figure30.Costdistributionoffan
Source:PECSME
Basedontheabovechart,wecanseeenergycostsaccountforover67%ofthetotallifecyclecostoffan.
Therefore,optimizingutilizationwillsigni�icantlyreducetheoperatingcostsofthefan.
Figure31.Sankeydiagramoffan
Source:Enerteam
AccordingtotheaboveSankeydiagram,theusefulenergyisonlyabout70%andtherestislossthrough
thevalves,leakages,piping,fanstructure…
EnergyConsumption;
87%
Investment;10%
Maintenance;3%
8.5% 36.0% 78.0%
8%
Useful power70%
4.5%
3.5%
2.5%
7%2.5%
2%
Power supply100%
Total losses: 30%
Loss due to transmissionand distribu�on
Loss through motor
Loss through driverLoss through fan
Loss through valves
Loss through pipingLoss through leakages
3.4.2.2.Sankeydiagramoffan
3.4.3. Energyef�iciencyforfan
3.4.3.1.Choosetherightfan
· Importantconsiderations:
-Noiselevel
-Rotatingspeed
-Air�lowcharacteristics
-Temperaturerange
-Operatingrange
-Spaceconstraintandsystemlayout
-Investmentcost/operationandoperatinglife.
· Avoidbuyingoversizedfan:
-Unabletooperateatthehighestef�iciency
-Riskofunstableoperation.
-Highnoiselevel.
3.4.3.2.Systemresistancereduction
Systemresistancewillreducefanef�iciency:
· Checkperiodically
· Checkafterrepairingsystem
· Reduceelbowsandremovedeadlegsofpipingsystem.
3.4.3.3.OperateclosetoBEP
· BestEf�iciencyPoint(BEP)
· Usuallyclosetoratedcapacity
· DeviationfromtheBEPwillresultinincreasedlossandinef�iciency.
3.4.3.4.Frequentmaintenance
· Inspectfancomponentsperiodically
· Lubricateandreplacebearingifnecessary
· Motorrepairorreplacementifnecessary
· Fancleaning.
3.4.3.5.Controlthefanair�low
· Pulleychange:reducedrivepulleysize->Reducespeedandenergyconsumption.
77
78
Figure32.Reducemotorspeedbydecreasingthepulleysize
Source:Enerteam
· VSDs:reducespeedofmotortomeetreduced�lowrequirements
-Classi�ication:mechanicaltype,electricaltype.
-Advantage:
o Mostimprovedandef�icient�lowcontrol
o Speedisadjustedinacontinuousrange.
o Highoperatingef�iciency.
-Disadvantage:highinvestmentcosts.
3.4.3.6. Operatingmultipleparallelfans(insteadonehighpowerfan)
-Advantage:
o Highef�iciencywithlargeloadrange
o Avoidoff-motorrisk
o Cheaperandbetterpropertiesthanonelargefan
o Combinedwithother�lowcontroller.
-Disadvantage:onlysuitableforsystemthathaslowresistance.
3.4.3.7. Operatingmultipleserialfans
-Advantage:
o Theaveragepressureof�luidpipeislower
o Lowernoise
o Lowerrequirementsforstructureandauxiliaryequipment
o Suitableforsystemthathaslongpipe,highresistance.
-Disadvantage:notsuitableforsystemthathaslowresistance.
3.4.4. Datacollection
Datacollectionforfansystem:
· Designparametersoffan,motor,andduct:
79
Table37.Datacollectiontemplateforfan
Order 1 2 3
-Name
-code
-Flowtype
-rated�low
-Ef�iciency(pump,fan)
m3/h
%
-Inletpressure bar(Kg/cm2)
-Outletpressure bar(Kg/cm2)
-Flowspeed m/s
-Pipesize mm
-Designed�low m3/h
-Operatingtime Hour/year
-Control(aperturevalve,VSD)
-Notes
-Ratedpower,maximum�low
-Controlscheme,open/closemodeofvents.
· Operatingpowerofmotors:
-Averageelectricalpower(kW)
-DCmotororACmotor
· Motorspeedandfanspeed.
· Collecttechnicalinformation,speci�icationsheets,characteristiccurve,and�lowdiagrams.
Measurementmethod:
· Electricalpowermeasurement
· Mechanicaldevicessuchas:anemometer,Pitottubes,temperatureindicator,pressuregauge.
80
3.5.1.3.Basicinformation
· Pumppower:
P–Power(kW)
H-statichead(m)
Q-�lowrate(m3/s)
r-Density(kg/m3),
h:Pumpef�iciency(0.7–0.85)
Pumpcapacityisshownasthefollowingdiagram:
3.5. Pump
3.5.1. Introduction
3.5.1.1. Pumpclassi�ication:
· Volumetricpump:low�low,highpressure(piston,gear,screw,roto)
· Bladepump:high�low,lowpressure(centrifugal,axialdirection).
3.5.1.2. Pumpsystemsinclude:
· Motors
· Pumps
· Valves
Pipingsystem
p.Q.HP=102.h
81
Figure33. Calculatepumppower
Source:PECSME
· Statichead(H,m):includesthedifferenceofhydrostaticpressure,highdifference,andresistanceon
thepipeline.
Figure34.ParametersofPumpsystem
RequirementpowerpumpStatichead
Flowrate
Theoricalrequirementpower
82
· Identifythepumpoperatingpoint:intersectionbetweenpumpcurvesandsystemcurves.
Figure35.PumpPerformanceCurve
· Pumpsinparalleloperation
Figure36.ParallelPumps&pumpscurve
- Staticheadofsystemisequaltoeachstaticheadofpump.
H=H1=H2
- Flowrateofsystemisequaltototal�lowrate.
Q =Q +QT 1 2
3.5.1.4.Control�lowrate
Methodof�lowratecontrolforpumpisillustratedbelow:
Figure37.Pumpcontrolmethods
A(Operatingpoint)
(n)Pumpcurves
Systemcurves
Ƞ
QA
HA
H
Q
Ƞmax
Pumpef�iciency
·Adjustingpipecharacteristicsbyvalves(keeppumpcharacteristics)
-Throttlevalvereducessystempressure,changesthesystemcharacteristics,andreducespump
ef�iciency(A)
-Circulation:thisisnotenergysavingstrategy(B).
83
Figure38.ON-OFFcontrolforpump
Figure39.PerformancecurveofpumpwithVSD
· Comparepumppowerconsumptionbetween�lowcontrolstrategies.
Figure40.PowerRequirementsforvariouspumpingcontroloptions
·Adjustingpumpcharacteristicsbyvalves(keeppipecharacteristics)(C,D)
·� � �UseVSDformotor:adjusttheelectricalfrequencyofpowersuppliedtoamotortochangethe
motor'srotationalspeed.
Fromtheabovegraph,withthesamepump�low,thepowerconsumptionpercentageintheVSDControl
solution(redline)islowerthanthatinValvecontrolsolution.
· Closedloopcontrol:
-Flowcanvaryfrom20%to100%ofmotorspeed
84
Figure41.Costdistributionofpump
Figure42.Sankeydiagramofpump
Energy cost 83%
Maintainance3%
Investment14%
8%
4.5%
3.5%
2.5%
7%2.5%
2%
· ThepumpisdesignedclosetotheBEPat100%�low
-OperationclosetoBEPpoint
· Flowcontrolforhighstaticpressuresystem
-The�lowrateshouldnotbeadjustedinthewholeoperationrange
-Usemultiplepumpstomeetthe�lowchangedemand.
3.5.2. Energy�lowforpump
3.5.2.1. Costdistributionofpump
Operatingcostandinvestmentofapumparepresentedinthefollowingpiechart:
Source:Enerteam
AccordingtotheaboveSankeydiagram,theusefulenergyisonlyabout70%andtherestislossthrough
thevalves,leakages,piping,pumpstructure…
Source:PECSME
Basedontheabovechart,wecanseeenergycostsaccountforover80%ofthetotallifecyclecostofpump.
Therefore,optimizingutilizationwillsigni�icantlyreducetheoperatingcostsofthepump.
3.5.2.2. Sankeydiagramofpump
Loss due to transmissionand distribu�on
Loss through motor
Useful power70%
Loss through driverLoss through pump
Loss through valves
Loss through pipingLoss through leakages
Total losses: 30%
Power supply100%
85
3.5.3. Energysavingsmeasures
3.5.3.1. Selecttherightpump
Thereasonofoversizedpumpfairlycommon:
· Ensuretheoperationhasamplecapacity
· Duetolimitedavailabilityfromsupplier
· Usesparepumpwithoutthepropersizeintheinventory.
Thepumpisaffectedwhentheselectedpumpisoversized
· Controlledwithdifferentmethodssuchasthrottlevalveorby-passline
· Increasetheheadduetofriction
· Thesystemcurvewillbeshiftedtotheleft
· Reducepumpef�iciency.
Solutionforpumpsinstock:
· UseVSDormultispeeddrives.
· Lowerrotatingspeed
· Trimtheimpeller.
3.5.3.2. Useadjustmentthe�lowrate
· Speedadjustmentoveracontinuousrange
· Reducepowerconsumption
· Twotypesofsystems:
-Mechanical:�luidcouplings,adjustablebelts
-ElectricalVFD:variablefrequencydrives(VFDs).
3.5.3.3. Installpumpsinparalleltochangeload
· Installofmultiplepumps:stopsomeofthemwhenlowload
· Systemcurvedoesnotchangebyrunningpumpsinparallel
· Thetotal�lowrateofparallelpumpsissmallerthanthesumofthe�lowratesofdifferentpumps.
· Tomatchthepumpwiththesamecharacteristics
3.5.3.4. Eliminate�lowcontrolvalve.
Effectsofcontrolvalve:
· Thepowerconsumptionisnotreducedasthetotalheadincreases
· Vibrationandcorrosionincreasemaintenancecostsandreducepump'slifetime.
3.5.3.5. Eliminateby-passcontrol
· Dischargepartisdividedintotwoseparatepipes:
-Onepipedeliversthe�luidtothedeliverypoint
-Thesecondpipereturnsthe�luidtothesource.
Energywastageisduetopartof�luidcirculatedunnecessarilybypump.
86
3.5.3.6.Start/stopcontrolofpump.
· Stoppumpwhennotneeded
· Pumpatnon-peakhours.
3.5.3.7.Impellertrimming
· Changingtheimpellerdiametergiveschangeintheimpeller'svelocity
· Notes:
-Cannotbeusedwherevarying�lowpatternexist
-Donottrimmorethan25%oforiginalimpellersize
-Trimdiameterallsides
-Changingimpellerismoreexpensive.
3.5.3.8.Completingthepumpsystem
Minimizestaticheadbythefollowingmethods:
· Uselargediameterpipe
· Uselongcurvebendratherthansharp-edgedbend.
3.5.4. Datacollection
Stepstoevaluatethepumpef�iciency
· Themeasurementtools:3phasespowermeter,pressuregaugemeter,andultrasonic�lowmeters
· Datacollection:nameplate,speci�icationsheet,pumpcurve,andprocess�lowsystem
· Measurementsteps:
-Measureinputpowerofmotorby3phasespowermeter
-Measurepressureatsuctionandpushingofpump
-Measurepressureandtemperatureattheinputandoutputofpump
· Measure�lowrate.If�lowrateisnotpossiblymeasured,itcanbeestimatedfromthepumpcurve
-Sitediscussionwithoperatorsandplantengineers
- Checkthrottlevalveandcontrolvalvesinentirepipingsystem.Ifitwasthrottled,measuring
pressureatitsinputoroutput
-Checkby-passlineofsystem
-Estimateoperatingtimeofpumpsandequipment.
87
-Ef�iciency %
-Inletpressure bar(Kg/cm2)
-Outletpressure bar(Kg/cm2)
-Flowspeed m/s
-Diameter mm
-Actual�lowrate m3/h
-Operatingtime Hour/year
-Controlmethod(aperturevalve,VSD)
-Notes
Table38.Datacollectiontoolforpump
Items 1 2 3
-Name
-Code
-Flowtype
-Flowrate
m3/h
88
Figure43.Aircompressionsystemillustration
Figure44.Typeofaircompressors
· Reciprocatingcompressor:
Typeofcompressor
DynamicPositive
displacement
Poston Screw Lobe Vane Centrifugal Axial
Atypicalcompressedairsystemcomponentsandnetwork
· Aircompressor
· Filter
· Intermediatecooling
· Compressorcooling
· Dryer
· Dehumidi�ier
· Tank.
3.6.1.1.Classi�icationofaircompressors:
3.6. Aircompressor
3.6.1. Introduction
Compressed air systems are commonly used inmost industries such as packaging systems, product
transfer,industrialhygiene,garmentprocessing,agriculturalproductsprocessing,heavyindustry,etc.
Themaincomponentsoftheaircompressorsystem:
89
P =suctionpressure1
P =dischargepressure2
· PowerN(kW):
R=Individualgasconstant(286.7J/kg.K).
T1=absoluteinitialtemperatureofgas(K).
m=mass�low(kg/s)
n=ratioofspeci�icheats
-Advantage:
o Highcapacity
o Highpressureratios
o Simpletooperate/repair.
-Disadvantage:
o lowcompressionratio
o Lowef�iciency
o Thelargesize,noise,highvibration
o Irregular�low.
· Screwaircompressor:
-Advantage:
o Highcompressionratio(max=25)
o Highfullloadef�iciency
o Lowcostoperating.
-Disadvantage:
o Expensive
o Morecomplexandgoodmaintenanceisveryimportant.
3.6.1.2.Compressionratio
Compressionratio
Thehigherthepressure,thelargerthepowerconsumption.Therelationshipbetweenthepressure
andpowerconsumptionisdescribedinthefollowingtable.
90
Table39.Relationshipbetweenpressureandpowerconsumption
Pressure Powerconsumption
3 2.08
4 2.73
5 3.06
6 3.71
7 4.11
Source:PECSME
· CapacityQ(m3tc/s)(at00C,1,013bar)
V=tankvolume(m3)
µ-airmassofonekmol(µ=29kg/kmol)
Dt-CompressortimefromP1toP2(s)
Ta,Pa–TemperatureandPressureatsuction(K),(Pa)
Tb,Pb–TemperatureandPressureatdischarge(K),(Pa)
3.6.1.3.Compressoref�iciency
· Isothermalef�iciency
Isothermal ef�iciency = isothermal power/ actual measured input power
Isothermalpower(kW)=
2P =absoluteinletpressure(kg/cm )1
3Q =freeairdelivered(m /hr)1
r=compressionratio.
· Volumetricef�iciency
Compressordisplacement=ΠxD2/4xLxSxχxn
D=cylinderbore,m
L=cylinderstroke,m
S=compressorRPM
x=1,forsingleacting,and2fordoubleactingcylinders
n=numberofcylinders
The calculation of isothermal power does not include power needed to overcome friction and
generallygivesanef�iciencythatislowerthanadiabaticef�iciency.Thereportedvalueofef�iciencyis
normallytheisothermalef�iciency.Thisisanimportantconsiderationwhenselectioncompressors
basedonreportedvaluesofef�iciency.
91
3.6.1.4.Typicalpressuredropincompressedairpipelinefordifferentpipesize
Thefollowingtabledescribestheenergylossofpipingwithdifferentdiameters:
Table40.Pressuredropfordifferentpipesize
PipeNominalBore
(mm)
Pressuredrop(bar)per100meters
Equivalentpowerloss
(kW)
40
50
65
80
100
1.80
0.65
0.22
0.04
0.02
9.5
3.4
1.2
0.2
0.1
Source:PECSME
3.6.1.5. Airleakage
· Consequence
-Wasting20to30percentofacompressor'soutput
-Pressuredropinsystem.
· Commonairleakagearea:
-Couplings,hoses,tubes,and�ittings
-Pressureregulators
-Opencondensatetrapsandshut-offvalves
-Pipejoints,disconnects,andthreadsealants.
· Thesystemleakageiscalculatedasfollows:
%leakage=(Tx100)/(T+t)
T–on-loadtime(s)
t–off-loadtime(s)
Goodmanagementsystemshasairleakageratelessthan10%
· Systemleakage
3Systemleakage(m /s)=QxT/(T+t)
3Q-actualcapacity(m /s)
3.6.1.6. Inletairtemperatureandpowerconsumption
Effectofinletairtemperatureonpowerconsumptionisdescribedinthebelowtable:
Forpracticalpurposes,themosteffectiveguideincomparingcompressoref�icienciesisspeci�icpower
consumptionkW/volume�lowrate,fordifferentcompressorsthatwouldprovideidenticalduty.
92
Table41.Inletairtemperaturevs.Powersaving
Source:PECSME
Every50Criseinletairtemperatureresultsinahigherenergyconsumptionby1.5%toachieveequivalent
output.
Figure45.Effectofinlettemperatureandpowerconsumption
Source:PECSME
3.6.2.Energy�lowdiagram
· Costdistributionofaircompressor
Figure46.Costdistributionofaircompressor
Source:UNIDO
· Sankeydiagram
Energycost75%
Investment15%
Maintenace10%
Inlettemperature
10,5 +1,4
15,5 0,0
21,1 -1,3
26,6 -2,5
32,2 -4,0
37,7 -5,0
43,3 -5,8
Powersaving(%)
93
Aircompressorsystemusuallyhaslowenergyef�iciency.Thepowerrangeofindustrialaircompressoris
from5toover50,000hp,but70to90percentofconsumedenergyislost.
Figure47.Sankeydiagramforcompressedairsystem
Source:VNEEP
Figure48.Energysavingspotentialforaircompressedsystem
Source:UNIDO
Power supply
100%
8%
Useful power10%
Loss through leakages
4%
5%
32%5%
16%
20%
3.6.3. Energysavingsmeasures
Theenergysavingsachievedwhenimplementingenergysavingsolutionsforthecompressorsystemare
showninthe�igurebelow:
3.6.3.1. Locationofaircompressor
Elevationof air compressorand thequalityof air: the altitudeof aplacehas adirect impacton the
volumetricef�iciencyandhigheraltitudeconsumesmorepower.
Loss due totransmission and
Loss through motor
Loss through driver
Loss through compressing air
Loss through storage tanks
Loss through piping and valves
Improving air
compressed
treatment
1% Orther
1%
Air trap
3%
New air compressor
2%
Improving air
compressed
distribution
2%
Installing inverter for
air compressor
6%
Reducing setting
presure
6%
Controlling air
compressor
7%
Reducing leakage
32%
Reducing compressed
air abuse
14%
Improving air
compressor
enficiency
14%
Heat recovery
12%
94
3.6.3.2.Airintake
· Preventaircontaminationfrommoisture,dust
Figure49.Effectofrelativehumidityandpowerconsumption
Figure50.Effectofsuctionpressureandpowerconsumption
Source:PECSME
Accordingtoabovegraph,thepowerconsumptionincreasesasthesuctionpressuredecreases.
Source:PECSME
· 0Maintaininletairatlowtemperature4 Criseininletairtemperatureresultsinahigherenergy
consumptionby1%
· Locatetheinletpipeofcompressoroutsidetheroomorbuildingsothattheinletairtemperature
canbekeptataminimum.
3.6.3.3.Thepressuredropinair�ilter
· Installtheair�ilteratthecoollocation
· Thepressuredropacrosstheintakeair�iltershouldbekeptataminimum.
Forevery250mmWCpressuredropincreaseacrossatthesuctionpathduetochoked�ilters,the
compressorpowerconsumptionincreasesbyabout2%.
100
98
96
100806040200
Po
we
r co
nsu
mp
�o
n (
%)
Rela�ve humidity (%)
Suctionpressure(mmH2O)
Powerconsumption
110
108
106
104
102
100
0-200-400-600-800-1000
95
3.6.3.4.Inter-coolersandAfter-coolers
· Theinletairtemperaturesatsubsequentstagesarehigherthanthenormallevelsresultinginhigher
powerconsumption
· Intercoolers:Heatexchangerstoremovetheheatofcompressionbetweenthestages
· After-coolersareinstalledafterthe�inalstageofcompressiontoreducetheairtemperature
· Useofcoolingwateratlowertemperaturereducesspeci�icpowerconsumption.
3.6.3.5.Pressuresetting
· Athigherdeliverypressures:compressorconsumesmorepowerforthesamecapacity,thevolumetric
ef�iciencyofacompressorislower.
· Reducingdeliverypressure
- Operatingacompressorat100PSIGinsteadof120PSIG,forinstance,requires10percentless
energyaswellasreducingtheleakagerate
-Areductioninthedeliverypressureby1barinacompressorwouldreducethepowerconsumption
by6–10%.
· Compressormodulationbyoptimumpressuresettings
-Ifallcompressorsaresimilar:onlyonecompressorhandlestheloadvariation,whereastheothers
operatemoreorlessatfullload
-Ifcompressorsareofdifferentsizes,thepressureswitchshouldbesetsuchthatonlythesmallest
compressorisallowedtomodulate(varyin�lowrate)
-Ifdifferenttypesofcompressorsareoperatedtogether:Thecompressorwithlowestnoloadpower
mustbemodulated.
· Segregatinghighandlowpressurerequirements:Usinglowpressureandhigh-pressureairseparately
andfeedtorespectivedemands.
· Minimumpressuredropindistributionline:
-Pressuredrop:thereductioninairpressurefromthecompressordischargetotheactualpoint-of-
use
-Aproperlydesignedsystemshouldhaveapressurelossofmuchlessthan10%ofthecompressor's
dischargepressure
-Usealoopsystemtoreducepressuredrop.
3.6.3.6.Minimizingleakage
· Useanultrasonicleakdetector
· Tighteningaconnectionandajoints
· Replacefaultyequipment.
3.6.3.7. Condensateremoval
· Watervaporiscondensedwhencompressor'safter-coolerreducesthedischargeairtemperature
· Installcondensateseparator-traptoremovethiscondensation.
3.6.3.8. Controlledusage
· Don't'suseforlow-pressureapplicationssuchasagitation,pneumaticconveyingorcombustionair
· Useablowerthatisdesignedforlowerpressureoperation.
96
Figure51.Heatrecovery
Source:UNIDO
3.6.3.9.Maintenance
· Lubrication:Inspectperiodically(checkoilleveldailyandchangeoil�iltermonthly)
· AirFilters:checkedandreplacedregularly
· CondensateTraps:Ensuretodrainanyaccumulated�luidandcompressedairisnotleaked.
· AirDryers:checkandreplacepre-�ilterordeliquescentdryers.
3.6.3.10.HeatRecovery
Average85%ofinputenergyisusedtoprovideheat.Heatrecoverydependson:
· Heatdemandoffactory
· Thecompatibilitybetweentheoperationandtheheatdemand
· Distancefromcompressorstationtouser/distributioncompressorpipeline.
· Temperature.
Theapplicationcanrecoverheatfromcompressorsuchas:
· Buildingservices:hotwater,heating
· Process:dryingandheating
· Preheatforboiler:intakewater,air.
Total electrical powerconsump�on 100%
Drive motor 9%
Fluid cooler 72%
Radiated heat loss of thecompressor package 2%
Heat in thecompressed air 4%
A�er cooler 15%
Approx. 95% forheat recovery
97
3.6.4.Datacollection
Table42.Basedatabasetocompressorsystem
Items 1 2 …
Compressortype
HasVSD?
No.ofcompressorstage
Ratedpower
Compressorcapacity
Intakepressure
Operatingpressure(Load-Unload)
Loadtime
Unloadtime
Loadpower
Unloadpower
Intakeairtemperature
Ambienttemperature
CondensateremovalType
Leakagepercent
kW
Nm3/min.
bar
bar
s
s
kW
kW
0C
0C
%
98
Table43.Currentcompressors
No.
Man
ufacturer/type
Model/
CoolingSystem
Compressor
Fluid
Rated
Motor
Power
Typeof
Control
(dual)
FAD
(m3)
Running/Load
Hours
Load
/Unload
PressureSettings
PowerConsumption
Load
/Unload
(kW)
1
/
/
/
/
/
2
/
/
/
/
/
3
/
/
/
/
/
Table44.Componentsofcompressor
Componen
t
Example:
FlowController,Conden
sateM
anagem
ent,
Dryer,D
rain,Filter
Man
ufacturer
Model
Cap
acity
3(m
)
Dew
Point
Tem
perature
(°C)
Rem
ark
99
Table45Tanksandreliefvalve
Tan
k1:V
olume:(m
3)
MWP:
(bar)
PressureGau
ge
Drain
(selectap
propriatetypebelow)
ReliefValve
SetPressure
ReliefValve
RatedCap
acity
(m3)
Yes
No
Auto
Man
ual
Both
Tan
k2:volume:(m
3)
MWP:
(bar)
PressureGau
ge
Drain
(selectap
propriatetypebelow)
ReliefValve
SetPressure
ReliefValve
RatedCap
acity
(m3)
Yes
No
Auto
Man
ual
Both
Table46.M
astercontrollersandairm
aincharging
MasterController
Man
ufacturer
Model
TypeofControl
(cascade,pressureban
d)
AirM
ain
ChargingSystem
Yes
No
Yes
No
PipeSize(in/m
m)
100
Table47.D
istributionsystem,pipe,connections,anddistributionairline
DistributionAirLine
DropPipe-Connections
System
Diameter
Material
Total
Len
gth
Connections
Doespipeextend
outside?
Number
of
Connections
Diameter
Dropsfromtopof
header?
Yes
N
o
Yes
N
o
Table48.Compressorroomm
easurements,open
ings
etc.
PowerSupply
(V)
(Hz)
(phase)
PowerCosts$/k
W-hr.
CoolingSystem
WaterInletTem
p.(°C)
WaterPressure[psig]
WaterCosts$/p
erliter
CompressorRoom
LxW
xH(m
)x(m
)x(m
)
NumberofInletOpen
ings:
CoolingAirExh
aust:Yes
No
HeatRecovery:Yes
N
o
101
Table49.A
irconditionatcompressorroom
Ambienttemp.
Elevationabovesea
level
Relativehumidity
RoomhasHeating
Roomhascooling
Qualityofintakeair
Min
(°C)
Max
(°C)
Curren
t
(°C)
(Avg.%
)(M
ax.%
)
(m)
Yes
No
Yes
No
Processofneigh
boringfacilities:
Table50.A
irrequirem
ents(Operatingtim
e,pressuredem
ands)
No.ofoperatinghours
Day
Ca1
Ca2
Ca3
Weekend
Ca1
Ca2
Ca3
Hr/day
Hr/day
Day
/week
Day
/week
Averagem
3/shift
Averm
3/ca
Theminim
umpressurereq
uired
atuser.
Curren
tpressureof
system
Doairsystemsturn
onduringunload
time
Averagecapacity.
m3duringunload
time
Req
uired
compressorquality
PressureDP
(oC)
Particle
(micron)
Oil
(mg/m
3)
Yes
No
Dep
endonseason:
102
Windowtype Splittype
Multi-splittypeCabinet
Figure52.Airconditionsystemtypes
3.7. Airconditioningsystem
3.7.1. Introduction
Airconditioningistheprocessusedtocontrolorimproveaircondition(temperature,humidity)ina
certainspace.
Thechoiceofwhichairconditionersystemtousedependsuponanumberoffactorsincludinghowlarge
theareaistobecooled,thetotalheatgeneratedinsidetheenclosedarea,etc.AnHVACdesignerwould
consideralltherelatedparametersandsuggestthesystemmostsuitableforyourspace.
3.7.1.1. Unitaryairconditionsystem
Unitaryairconditionsystemonlyadjustsairconditioninnarrowplace,suchasprivateroom,smallrooms.
Unitaryairconditionsystemhasfourcommontypes:
· Windowtype
· Splittype
· Multi-splittype
· Cabinet.
103
Figure53.Air-cooledchiller
Figure54.Water-cooledchiller
3.7.1.2.Centralairconditioningsystem
Centralairconditioningisusedforcoolingbigbuildings,of�ices,hotels,gyms,etc.Ifthewholebuildingis
tobeairconditioned,HVACengineers �ind thatputting individualunits ineachof therooms isvery
expensive making this a better option. A central air conditioning system is comprised of a huge
compressorthathasthecapacitytoproducehundredsoftonsofairconditioning.
104
Therefrigerationcycleisshownasbelow:
Figure55.OperatingPrinciplesofairconditioner
Source:BEE,2004
· 1-2:Compression:Thesuperheatedvapourentersthecompressorwhereitspressureisraised.The
temperaturealsoincreases
· 2-3:Condensation:Thehighpressuresuperheatedgasturnedbackintoliquidinthecondenser.The
refrigerantliquidissub-cooled
· 3-4Expansion:Thehigh-pressuresub-cooledliquidpassesthroughtheexpansiondevice,whichboth
reducesitspressureandcontrolsthe�lowintotheevaporator
· 4-1Evaporator:Lowpressureliquidabsorbsheatfromitssurrounding,changesitsstatefromaliquid
tolowpressuregas.
105
3.7.2.Assessmentofairconditioning
3.7.2.1.Coef�icientofperformance:
· The theoretical coef�icient of performance (Carnot), (COPcarnot a standard measure of refrigeration
ef�iciencyofanidealrefrigerationsystem):
Te:Evaporatortemperature
Tc:Condensertemperature
· ActualCOP:
Qeva=coolingeffect
Wc=powerinputtocompressor.
h1,h2,h3,h4=enthalpiesofrefrigerantatstates1,2,3,4.
Figure56.CalculationmethodofCOP
Figure57.HVACsystemdatacollection
COP=UsefulCooling(Qeva)/Power(P)
3.7.2.2. Assessactualcoolingperformancecooling:
· CollectinformationaboutHVACsystems(HVACtype,designcapacity,refrigerant,designCOP...)
· Collectoperating information(inletpressure,outletpressure,evaporationtemperature,condense
temperature,electricalconsumption).Datacanbecollectedthroughthescreenmonitorormeasured
byhandinstruments.
COP=(h -h )/(h -h )1 4 2 1
COPCarnot
ToCOP=T -Tk o
1PIC=COP
106
Figure58.Glassproperties
· Keepdoorsorwindowsclosed
3.7.3.2.Limitinternalheatsourcesinsidetheconditionedspace
Heatsourcescomefromthepowerconsumptiondevices:lighting,motors,orcooking…
Thedeterminationofheatsourcescanbedetectedbytheinfraredinstrument.
Figure59.DetectheatsourcesinsideHVACspace
· CalculatetheoreticalcoolingcapacityandCOP.Eachrefrigeranthasparticularthermodynamic
parameters.
3.7.3. Energysavingsmeasures
HVACsystemconsumesalotofenergyinbuildingorfactory.Therefore,therearemanyopportunitiesfor
energysaving.Somemethodsarelistedbelow:
3.7.3.1. Preventheatpenetrationfromoutside
Preventheatpenetrationfromoutsidebyusingdoublelayersofglassandre�lectiveglasslamination.
Whentheheatsourceisidenti�ied,removethemfromconditionedspacetoreducewasteenergy.
3.7.3.3.Maintaintheheatexchanger
Maintenance helps the air conditioner to operate ef�iciently. According to the below table, effective
maintenanceistheimportantkeyforoptimizedpowerconsumption:
107
Table51.Tableofeffectivemaintenanceforpowerconsumptionofthecompressor
Condition Evaporationtemp(oC)
Condensationtemp(oC)
Refrigerationcapacity(tons)
Speci�icpower
consumption(kW/ton)
Increasein
kW/ton(%)
Normal 7.2 40.5 17.0 0.69
Dirtycondenser 7.2 46.1 15.6 0.84 20.4
Dirtyevaporator 1.7 40.5 13.8 0.82 18.3
Dirtycondenserandevaporator 1.7 46.1 12.7 0.96 38.7
Source:AsiaEnergyEf�iciency
3.7.3.4.MatchingCapacitytoSystemLoad
During part-load operation, the evaporator temperature rises and the condenser temperature falls,
effectivelyincreasingtheCOP.Butatthesametime,deviationfromthedesignoperationpointandthefact
thatmechanicallossesformagreaterproportionofthetotalpowernegatetheeffectofimprovedCOP,
resulting in lower part- load ef�iciency. Therefore, consideration of part-load operation is important,
becausemostrefrigerationapplicationshavevaryingloads.
3.7.4. Datacollection
· CollectinformationaboutHVACsystems
-HVACtype
-Designcapacity
-Refrigerant
-DesignCOP...
· Collectoperatinginformation:
-Inletpressure,Outletpressure
-Evaporationtemperature
-Condensetemperature,
-Electricalconsumption
Datacanbecollectedthroughthescreenmonitorormeasuredbyhandinstruments.
108
Figure60.Therefrigerationcycle
Figure61.Basictypesofcompressors
Source:AsiaEnergyEf�iciency
3.8.1.2.Characteristicsofrefrigerationsystem
Thereare4maincomponentsinrefrigerationsystem:compressor,condenser,expansiondevice,and
evaporator.Therefrigerationcycleofrefrigerationsystemissimilartotheoneofairconditioning
system.Pleaserefertosection3.7formoredetails.
Themost commonly types of compressors in industrial refrigeration systems are reciprocating
compressor,screwcompressor,pistoncompressor,andcentrifugalcompressor.
The power consumption of compressor is almost 70% of the total power consumption of the
refrigeration system.Therefore, properdesign is thekey to reduce thepower consumptionand
improveitsef�iciencyofarefrigerationsystem.
3.8. Industryrefrigerationsystem
3.8.1. Introduction
3.8.1.1. Overviewofrefrigerationsystem
Therefrigerationsystemisusedtocooltheairoraproduct.Inordertomaintainthetemperatureofcool
air,theinputworkisrequiredtoremoveheatfromacoolareaandtransfertowarmarea.
Screw compressor
Scroll compressor
Piston compressor
Centrifugal compressor
HighTemperatureReservoir
LowTemperatureReservoir
HeatRejected
WorkInput
HeatAbsorbed
109
SpiralFreezer StraightFreezer ImpingementFreezer
·ContactFreezer&Air-BlastFreezeraredesignedtofreezeamountsofgoods,forinstancefoodproduction.
ContactFreezer Air-BlastFreezer
· ColdStorageisusedtostorefrozenfoodsproducts.
ColdStorage
· Icemachines:BlockIceMachineandFlakeIceMachine
3.8.1.3.Applicationofrefrigerationsystem
The industry refrigeration system is commonly used in the central air conditioning of building,
refrigerators,chilledwaterplants,etc.
Somecommonapplicationsare:
· IndividualQuickFreezer(IQF):which isusedto freezeproducts individuallyratherthan ina
group.Thespeedoftheconveyorcanbeadjustedtomeetactualdemand
110
BlockIceMachine FlakeIceMachine
Q(kW)=m*Cp*(ti–t0)
m:mass�lowrateofcoolant,kg/s.
Cp:coolantspeci�icheatinkJ/kg0C
ti:inlettemperatureofcoolanttoevaporator,0C.
t0:outlettemperatureofcoolantfromevaporator,0C.
COPCarnot=Te/(Tc-Te)
Teisevaporatortemperatureand
Tcisthecondensertemperature
Thespeci�icpowerconsumptionkW/TRisausefulindicatoroftheperformanceofarefrigeration
system.BymeasuringtherefrigerationdutyperformedinTRandthekWinputs,kW/TRisusedasan
energyperformanceindicator.
Inacentralizedchilledwatersystem,apartfromthecompressorunit,powerisalsoconsumedbythe
chilledwater(secondary)coolantpump,thecondenserwaterpump(forheatrejectiontocooling
tower)andthefaninthecoolingtower.Effectively,theoverallenergyconsumptionwouldbethesum
ofpowerconsumptionof:
-CompressorkW
-ChilledwaterpumpkW
-CondenserwaterpumpkW
-CoolingtowerfankW,forinduced/forceddrafttowers
-EvaporatorkW.
·���Coef�icientofPerformance
ThisequationalsoindicatesahigherCOP isachievedwithhigherevaporatortemperaturesandlowerCarnot
condensertemperatures.ButCOP isonlyaratiooftemperatures,anddoesnottakeintoaccounttheCarnot
typeofcompressor.HencetheCOPnormallyusedinindustryiscalculatedasfollows:
3.8.1.4. Basicdata
Thebasicparametersofarefrigerationsystem,whichneedtobecollectedaretheload,temperatureand
refrigerationtime. If theoperatingparametersofarefrigerationsystemarenotavailable, thedesign
parameterscanbeusedforassessment.
·���CoolingCapacity
Coolingeffect(kW)COP=Powerinputtocompressor(kW)+auxiliaries(kWe)
111
3.8.2.Energy�low
Thefollowing�iguredescribestherefrigerationcycleofindustrialrefrigerationsystem:
Figure62. Typicalheattransferloopinrefrigerationsystem
PistonCompressor ScrewCompressor
· TheInstallationofVSDforthecompressorswithvariableloadswouldreducethepowerconsumption
ofcompressorbutitalsoreducesthecompressoref�iciency
· Avoidpart-loadoperation:twocompressorsoperatingat60%offullloadconsumelesspowerthana
compressoroperatingat100%fullloadandacompressoroperatingat20%offullload.
· 0The temperature of coolant in piston compressor is usually greater than 100 C. Therefore, heat
exchangercanbeinstalledtoremovetheheatfromcoolantandusethisheatforprocess
Source:Enerteam
3.8.3. Energysavingsmeasures
3.8.3.1. Compressor
In order to generate energy savings the factory could consider either to replace the low ef�iciency
compressorwiththehighef�iciencycompressorortoinstallVSDforthecompressor.
· Replacingapistoncompressorwithscrewcompressor
Requiredenergy1.94kWh/RT
21% 8.3% 54% 8.3% 8.3%
Air condi�oner
112
Figure63.DiagramofHeatRecoveryfromdischargeoutletfromcompressor
Figure64.Comparisonofpowerconsumptionbydifferentregulationmethods(screwcompressor)
Accordingtothe�igureabove,highlightsthefact,powerconsumptionisstillrelativelyhigheventhough
thecapacityisreducedby50%usingaslidevalvecontrol.Thiscanbeavoidedbyusingapropercontrol
system.
Foraneworupdatedrefrigerationcompressor,thecontrolsystemsolutioncanberelevantunderthefollowingcircumstances:
· Theexistingsystemisoldandequippedwitholdcontrolsystem.
· Therefrigerationsystemhaschangedfromitsoriginaldesign(multiunits)
· Loadsoroperationpatternshavechanged.
· VSDhasbeeninstalledforsomeofthecompressors
· Therefrigerationplantconsistsofdifferenttypeand/orsizesofcompressors
· Thereisnofunctioningcompressorcontrolsystem.
· oReducecondensertemperature:the5.5 Creductionofcondensertemperaturewillreduce20-25%of
powerconsumption
· Applythecontrolsystemfortherefrigerationcompressor.
Operatingcompressorat thepartial loador improperlywillreducetheef�iciencyoftherefrigeration
system. It is obvious when the refrigeration system has multiple compressors or the demand of
refrigerationvarious.Theef�iciencyofascrewcompressorcanbereducedby30%whenitoperatesat
partialloadasillustratedinthefollowing�igure.
113
Figure65.Relationshipofthecondensationtemperatureandtheperformanceoftherefrigeration
h
1
2 3
4
h3,4 h1 h2
6
5
h6
7
P2,3,6
P7,5
P1,4
Lgp
h5
T1
T1’
T1
’ > T
1
3.8.3.2.Optimizetheevaporator
0Theinletpressureofacompressorisimportantforpowerconsumptionofrefrigerationsystem.A1 C
raiseinevaporatortemperaturecansavealmost3%ofthepowerconsumed.
Itisgenerallyobservedthattheevaporatorpressuresaremuchtoolowcomparedtotherequiredcooling
temperatureofanindustrialrefrigerationinVietnamThisiscausedbyanumberofreasons:
· Toosmallevaporators
· Plateheatexchangersarenotused(drums/spiralsoroldandpoortechnology)
· Moist(ice)hasbuiltupontheevaporator.
According to the above �igure, when the evaporation temperature rises, the required inputwork is
reduced(h –h <h –h )andthecoolingeffectisincreased(h –h <h –h ). Therefore,theCOPofthe6 5 2 1 1 4 5 7
refrigerationsystemwillbeincreased.TheCOPisverydependentontheevaporationtemperature.
Inpractice,thismeansthatifthetemperaturedifferenceofthetwomediumsatthecoolestpointisgreater
than2ºC(seebelow),thereisroomforimprovementssince2ºCdelta-Tistheoptimaldesign.
114
Figure66.Principleschematicoftworefrigerationsystemswiththedifferentofthecevaporatortemperature
Source:LCTU(MOIT)
Table52.Effectofvariationinevaporatortemperatureonthecompressorpowerconsumption
Evaporatortemperature(oC)
Refrigerationcapacity*(ton)
Speci�icpowerconsumption
IncreaseinkW/ton(%)
5,0 67,58
56,07
45,98
37,20
23,12
0,81
0,94
1,08
1,25
1,67
0,0 16,0
33,0
54,0
106,0
-5,0
-10,0
-20,0
oNote:*Condensatetemperatureat40 C
Source:AsiaEnergyEf�iciency
Inordertoimprovetheef�iciencyoftheevaporator,therearesomerequirements:
· Performperiodicmaintenanceforevaporator.Removeobstaclesonairfan.
· Inspecttheexpansiondevice.
· Replacethemanualvalvewithautomationvalve.
· Determinetheproperheattransferareasaswellasrationalizethetemperaturerequirementtohighest
possiblevalue.
3.8.3.3. Optimizethecondenser
oThe condensation temperature is also as important as the evaporation temperature. A 1 C raise in
condensationtemperatureconsumesadditional3%ofthepowerconsumptionofarefrigerationsystem.
Thecondensationtemperatureanditscorrespondingpressureofanyrefrigerantaredependentonthe
heattransferarea,theeffectivenessofheatexchangeandthetypeofcoolingchosen.Therequirementsto
improveef�iciencyofcondenseraresimilartotheonesofevaporator.Thebelowtableillustratestheeffect
ofvariationincondensertemperatureonthecompressorpowerconsumption.
Theonlydifferenceisthesizeoftheevaporator.Byincreasingthesizeoftheevaporatorthetemperatureincreasefrom-10ºC(leftpartof�igure)to-7ºC(rightpartof�igure),whichsavesmuchas9%ofthepowerconsumptionofthecompressor.
The table below illustrates the effect of the evaporator temperature on the compressor power
consumption:
115
Table53.:Effectofvariationincondensatetemperatureonthecompressorpowerconsumption
ItisgenerallyobservedthatcondenserpressuresofindustrialrefrigerationinVietnamistoohigh,whichiscausedbyanumberofreasons:
· Poorlymaintained(fouled)condensers
· Airinthecondensers
· Toosmallcondensers
· Inef�icientoperationofthecondensers.
Thesavingpotentialforthismeasureishighduetoin�luenceonallcoolingdevicesconnectedtothe
condenser.Ifallcondensersarechangedorremoveditispossibletosave5to15%ofthetotalelectricity
usedforrefrigeration.Investmentsinsuchmeasureswillhavemediumtohighpayback-periods
However, ifthemeasureis introducedatthesametimeasmorerefrigerationcapacityis introduced,
investmentsandpaybackperiodfortheextrasizeofthecondensermightbelow.
3.8.3.4. IQFFreezer
TheenergysavingcouldbeobtainedforIQFsystembythefollowingmeasures
· oBy Increasing theevaporationpressurewhilemaintain the required temperaturea5.5 Craise in
evaporatortemperaturecansave20-25%ofthepowerconsumed.
· Pre-cooltheproductbeforetheyarefrozen
· Use2-stageIQFfreezer
EnergylossintheIQFfreezerincludes:
· Lossesduetopoorinsulation
· Lossesduetomechanicalfrictionofthefanorthemotorofconveyor
· Lossthroughopeningsintherefrigerationsystem.
3.8.3.5. Contactfreezerandairblastfreezer
Theenergysavingcouldbeobtainedbythefollowingmeasures
· Ensurethefreezerisfullwithproducts
· InstalltheVariableFrequencyDrive(VFD)toslowevaporatorfansforlowdemands
· Pre-cooltheproductbeforetransferringintofreezer.
EnergylossintheAirBlastFreezerincludes:
· Lossduetopoorinsulation
· Lossduetoauxiliarydevicesinthefreezer.
3.8.3.6. Coldstorage
Energysavingcouldbeobtainedforcoldstoragesbyimplementingthebelowmeasures
· Closethedoorimmediatelyaftergoinginandgoingout.Installautomaticdoorcloser
116
· Ensuretheinsulationofstorageisstillgoodinservice.
· Keepmonitoringtheinsidetemperatureandoutsidetemperatureofstorage.
3.8.3.7. Flakeicemachine
Energysavingcouldbeobtainedfor�lakeicemachinesbyimplementingthebelowmeasures
· Operateatnon-peakschedule
· Pre-coolthewaterbeforetransferringintomachine
· Wellinsulated.
3.8.4. Datacollection
Inordertoassesstheperformanceoftherefrigerationsystem,atemplateofdatacollectiontoaudita
refrigerationsystemisproposedasbelow:
Sectionno. Refrigerationcompressor Unit Machinereference
1 2
3
4
1 Make
Type
Capacity(ofcooling)
2
3
TR
4
Chiller:
A No.oftubes ..
B Dia.oftubes m
C
Totalheattransferarea
m²
D
Chilledwater�low
m³/h
E
Chilledwatertemp.difference
⁰C
5 Condenser
A
No.oftubes
B
Dia.oftubes
C
Totalheattransferarea
m²
D
Condenserwater�low
m³/h
E Condenserwatertemp.difference ⁰C
6
Chilledwaterpump
A
Nos
..
B
Capacity
m³/h
C
Headdeveloped
mWC
D Ratedpower kW
E
Ratedef�iciency
%
7
Condenserwaterpump
A
Nos
..
B Capacity m³/h
C
Headdeveloped
mWC
D
Ratedpower
kW
E
Ratedef�iciency
%
8 Coolingtower
A Nos ..
B Coolingcapacity kCal/h
C Airvolume m³/h
D Ratedpowerfan
Inletcoolingwatertemp.
Outletcoolingwatertemp.
Ambientemp.
kW
E ⁰C
F ⁰C
G ⁰C
117
118
Table54.Propertiesofsaturatedwaterandsteam
Pressure Temperature Speci�icenthalpyofevaporation Volumedrysat.
Bar kPa oC Water
(kJ/kg)
Latentheat
(kJ/kg)
Saturatedsteam
(kJ/kg)
m3/kg
0
0.5
1.0
1.5
2.0
3.0
4.0
5.0
6.0
7.0
10.0
14.0
0
50
100
150
200
300
400
500
600
700
1000
1400
100
112
120
128
134
144
152
159
165
170
184
198
419
468
506
536
562
605
641
671
697
721
782
845
2257
2226
2201
2181
2163
2133
2108
2086
2066
2048
2000
1947
2676
2694
2702
2717
2725
2738
2749
2757
2763
2769
2782
2792
1.673
1.149
0.880
0.714
0.603
0.461
0.374
0.315
0.272
0.240
0.177
0.132
3.9. Boiler
3.9.1. Introduction
3.9.1.1. Steam
Steam is the commonmedium to transfer heat to a process. Usually it is produced by boilers and
distributedthroughdistributionsteamsystem.Advantagesofsteamare:
· Lowrisk
· Inexpensive
· Highheattransfercoef�icient
· Easytodistribute
· Easytocontrol.
Inordertodeterminethestateoftheheattransfer�luid(steam)threesystemsparameters: areusedto
de�inethestateofwater:Pressure,Temperature,Speci�icvolume.
Steamtable:
119
Figure67.Steamphasediagram
Figure68.SimplediagramofTubeboiler
Boilerexamples
FireTubeBoiler
Source:AsiaEnergyEf�iciency
Theabove�iguredescribestherelationshipbetweentheenthalpyandthetemperatureofwaterandsteam
atdifferentpressures.Theliquidregionorwaterregionisontheleftsideofsaturatedliquidlineandthe
superheatedregionorsuperheatedsteamregionisontherightsideofsaturatedvaporline.Thesaturated
vaporlineandsaturatedliquidlineintersectatthecriticalpointandcreateanenvelopeoftwophase
regions.
ThelineABCDdescribesthephasechangeofwaterattheconstantpressure.Initially,Waterisheatedfrom
subcooledliquidtemperature(pointA)tosaturationtemperature(pointB).Iffurtherheatcontinuestobe
added,liquidwaterwillbeconvertedgraduallyfromsaturatedliquid(pointB)tosaturatedvapor(point
C)atconstantsaturationtemperatureuntilitreaches100%vapor.Ifheatisstillheated,thesaturated
vapor(pointC)willbeconverted tosuperheatedvapor(pointC–pointD).The temperaturewillbe
increasedduringconvertingtosuperheatedsteam.
3.9.1.2. Boilerintroduction
Aboilerisanequipmentthattransfersheatenergyfromthecombustionoffuelstowaterinorderto
convertwatertosteam.Aboilerproducessteamatvariouspressurestosupplyfordifferentdemands.
steamoutlet
waterinlet
flueairandfuelinlet
combus�onchamber
watertubes
Enthalpy
Superheatregion
Two phase regionTe
mp
erat
ure
Liquidregion
Lines ofconstantpressure
Cri�calpoint
Saturatedvapour line
Saturatedliquid line
120
Figure69.Firetubeboiler
Table55.AdvantageanddisadvantageofFiretubeboiler
Advantages Disadvantages
Usedforsmallscale
Easytooperateandmaintain
Inexpensive
Requiretimeto�illwater
Requirelongertimetoincreasepressure
Steammightcontainwater
· Watertubeboiler:
Figure70.Watertubeboiler
Table56.Advantageanddisadvantageofwatertubeboiler
Advantages Disadvantages
Higherthermalef�iciency
Abletoproducesuperheatedsteam
Customizabledesign
Morecomplexconstruction
Complexcontrolsystemsrequired
· Watertubeboilerwithsteamdrum:
121
Figure71.Watertubeboilerwithsteamdrum
Table57.Advantageanddisadvantageofwatertubeboilerwithsteamdrum
Advantage Disadvantage
- Suitableforallfuels
- Highparameters(capacity,pressure,
abilitytoproducesuperheatedsteam).
- Goodcirculation.
- Bendedpipe:abletoself-expand.
-Bulkysize
-Longinstallationtime
-Highcapitalinvestment
-Highwaterqualityrequirements
-Complexoperation(blowdownat
multiplepositions)
-Dif�icultcleaningofpipesurface
Costofgeneratingsteamfromboilercanbeestimatedbythefollowingformula:
Sc (VND/kg) =)(
)'''(
GCVD
Rhh
´´
-
h
h’’:enthalpyofsteam(kcal/kg)
h’:enthalpyofboilerfeedwater(kcal/kg)
h:boileref�iciency(%)
R:fuelcost(VND/lit)
D:density(kg/lit)
GCV:GrossCalori�icValue(kcal/kg)
122
3.9.1.3.Boileref�iciencyevaluation
Boileref�iciencycanbeevaluatedbydatacollectionandcalculationasdecribedbelow:
· Boileref�iciencyiscalculateddirectlybyfollowingformula:
Q(kg/hr):Steamgeneratedperhour
hs(kcal/kg):Enthalpyofsaturatedsteam
hw(kcal/kg):Enthalpyoffeedwater
m(kg/hr):fuelusedperhour
GCV(kcal/kgoffuel):Grosscalori�icvalueoffuel
Example:
Steamgenerated:2.5ton/hr
QuantityofDieselFO :180liters/hour(density:0.95kg/liter)
Feedwatertemperature :850C
GCVofDieselFO:9.800kCal/kg
Enthalpyofsteamat8kg/cm2:666kCal/kg(saturatedsteam)
Enthalpyoffeedwater:85kCal/kg
Boileref�iciency:
%67,86100980095,0180
)85666(2500=´
´´
-´
Advantages Disadvantage
Fewrequiredparameters
Quickcalculation
Fewrequiredinstruments
Unabletode�inespeci�iclosses
Heatlossesdueto:
q1(%) :Dry�luegas
q2(%) :Hydrogeninfuelburnt
q3(%) :Moistureinfuel
q4(%) :Moistureinair
q5(%) :Unburntfuelin�lyash
q6(%) :Unburntfuelinbottomash
q7(%) :Radiationandotherunaccountedlosses.
Theheatlossthroughtheboilerisdeterminedbytheboilerheatbalance
BoilerEf�iciency=100%-(q +q +q +q +q +q +q )1 2 3 4 5 6 7
· Theboileref�iciencycanbecalculatedbyindirectmethod.Thismethodologyrequiresdataofthe
principlelosses:
Qx(hg-hf)Boileref�iciency= x100
qxGCV
123
Figure72.Typicallossesfromcoal�iredboiler
Source:AsiaEnergyEf�iciency
ThefollowingExceltemplateshowsanexampleofboileref�iciencybyusinganindirectmethod(including
formulas):
Heatlossduetodry�luegas
Heatlossduetosteamin�luegas
Heatlossduetomoistureinfuel
Heatlossduetomoistureinair
Heatlossduetounburntsinresidue
Heatlossduetoradiation&other
unaccountedloss
HeatinSteam
100,0%
Fuel
BOILER
12,7%
8,1%
1,7%
0,3%
2,4%
1,0%
73,8%
124
Table58.Boileref�iciencycalculation
# Parameter Unit
1 AbsoluteAnalysis Coal DieselFO
Carbon
Hydro
Oxy
Sulphur
Nitrogen
Moisture
Ash
% 46.15 82.7
% 3.06 10.9
% 10.21 0.5
% 0 3.5
% 1.58 0.4
% 7.2 0.1
% 31.8 0.1
2 GCVoffuel KCal/kg 4400 9856
3 O2 in�luegas % 9 7.8
4 CO2 in�luegas % 8.5 9.9
5 �luegastemperature(T )f0C 180.4 181
6 Ambienttemperature(T )a0C 31 31
7 Moistureinair Kg/kgdrygas 0.018 0.018
8 Ashcontent % 10 0
9 GCVofash KCal/kg 800 0
ExcessAir(EA)
(O2x100)/(21–O2)
TheoreticalAirRequirement(TAR)
[11.43xC+{34,5x(H2 –O2 /8)}+4,32xS]/100
Actualairsupplied(AAS)
{1+EA/100}xtheoreticalair
InputK
%heatlossduetoevaporationofwaterformedduetoH2
infuel
[9xH2{584+0,45(Tf –Ta )}]/GCVoffuel
%heatlossduetoevaporationofmoisturepresentinfuel
[Mx{584+0,45x(Tf –T)}]/GCVoffuel
%heatlossduetomoisturepresentinair
{AASxHumidityFactorx0,45(Tf –Ta)x100}/GCVfuel
%heatlossduetounburntfuelinash
{ashx(100–burntfuelinash)xGCVofash/100}/GCV
fuel18 heatlossduetoradiationandotheraccountedloss % 2.00 2.00
19 Totalloss % 24.05 17.24
20 Ef�iciency%
75.95 82.76
Value
6.48
0.01
10%
11.42
75
11kg/kgoffuel 5.89
10.3112
kg/kgoffuel
0.65
0.26
0.00
59
13.34
21.23
8.48
%
%
17
%
4.08
1.07
0.28
5.20
%
%
16
15
14
%heatlossduetodry�luegas
{kx(T –T )}/%CO2f a
Wherek
=0,65forcoal
=0,56forDiesel
=0,40forNaturalGas
13
125
Figure73.Sankeydiagramofboiler
Source:AsiaEnergyEf�iciency
3.9.3.Energysavingmeasures
3.9.3.1.Insulateheatedpipingsystemandusers
Heat losswilloccur if thepipingsystemandequipmentarenotwell insulated.Theamountofheat
lossisdescribedinthefollowingtables:
Table59.Heatlossduetouninsulation
Source:Enerteam
3.9.2.Energy�low
Sankeydiagram
ThefollowingSankeydiagramillustrateshowtheinputenergyfromthefuelistransformedintothesteam
energyandenergyloss�lows.Majorlossesarestackgaslosses,blowdownlosses,andlossesbyunburnt
fuelinstackandash.
56
67
78
89
100
111
125
139
153
167
180
194
W/m
Pipesize
15mm
20mm
25mm
32mm
40mm
50mm
65mm
80mm
100mm
150mm
54
68
83
99
116
134
159
184
210
241
274
309
65
82
100
120
140
164
191
224
255
292
329
372
79
100
122
146
169
198
233
272
312
357
408
461
103
122
149
179
208
241
285
333
382
437
494
566
108
136
166
205
234
271
285
333
382
437
494
566
132
168
203
246
285
334
394
458
528
602
676
758
155
198
241
289
337
392
464
540
623
713
808
909
188
236
298
346
400
469
555
622
747
838
959
1080
233
296
360
434
501
598
698
815
939
1093
1190
1303
324
410
500
601
696
816
969
1133
1305
1492
1660
1852
Temperature
difference
steamtoairOC
StoichiometricExcess AirUn burnt
Convec�on &Radia�on
BlowDown
Ash and Un-burntparts of Fuel in Ash
FUEL INPUT Stack Gas
STEAM OUTPUT
126
Table60.Heatlosscalculationduetouninsulation
Lengthofpiping 32 m
Heatloss 16,032 W
Steampressure 5 bar
Productioninformation Operatingtime 7,920 hr/year
Costofsteamgeneration 516,250 VND/ton
Equivalentsteamloss 20.94 kg/hr
Wastemoney 85,609,121 VND/year
Steamtemperature
Outerdiameter
Innerdiamete
Heattransfercoef�icient
Insulationtemperature
Heattransfercoef�icient
Unwantedheatloss
150.90C
100 mm
90 mm
50 W/m.C
500C
0.051 W/m.C
100 W/m
Insulation+B12:F41thickness 19 mm
Heatlossof1mpiping
REQUIREDINSULATIONTHICKNESS
Piping
Insulation
3.9.3.2. Installeconomizerstorecoverheatforfeed-waterpreheating
A�luegasofboilerisusuallydischargedathightemperature.Therefore,recoveringheatfrom�luegasto
preheatthefeedwaterisabene�icialenergysavingmeasure.Anadditionaleconomizerisanessential
equipmentforthismeasure.
501 W/m
128
Moreover,theeconomizerisalsousedtodrytheair.
Figure75.Waterpre-heaterandairdryer
3.9.3.3.Optimizetheoperatingconditions
Theboileroperatingconditionsshouldbeoptimizedtoreducetheenergyloss,someproposedmeasures
are
· Controllingproperlytheamountratiooffuel/airwillmaintainthehighef�iciencyofcombustion
process
· Evaluatethesizeofboiler
· Automaticblowdowncontrol
· Installvariablespeedcontrolforairsupplyandexhaustfans.
3.9.3.4.UpgradeandReplacetheboiler
Anotheroptiontobene�itfromenergysavingistheupgradeorreplaceoftheboiler.Followingmeasures
arepossible:
· Installcombustionanalyzerforcontinuousmonitoring
· Recoverheatfrom�luegas
· Replacethelowef�iciencyboiler
· Replacefossilfuel�iredboilersbybiomass�iredboilers
129
Figure76.Typicalsteamtraps
Figure77.Functionsofsteamtraps
Classi�icationofsteamtraps:
Figure78.Classi�icationofsteamtraps
3.9.3.5. Installsteamtraptorecovercondensate
Asteamtraphasthefollowingmainfunctions:
· Dischargethecondensate
· Preventsteamloss
· Removeair.
MechanicalUse difference in
density between steamand condensate
Thermosta�cSense temperature
change of condensate
ThermodynamicSteam (flash) - velocity
difference
Trap types
Dischargecondensate
Func�on ofsteam traps
Prevent steamloss
Dischargeincondensable
gases
130
Mechanicalsteamtrap–Free�loat
· Structure:
Figure79.Mechanicalsteamtrap–Free�loat(source:TLV)
· OperatingPrinciples
Figure80.Operatingprinciplesofmechanicalsteamtrap–Free�loat
Table61.Advantagesanddisadvantagesofsteamtrap–free�loat
Advantages: Disadvantages:
-Continuouslydischargecondensateatsteamtemperature.
-Canhandleheavyorlightcondensate
-Largecapacity
-Resistanttowaterhammer
- Whenthetrapiscool,X-elementcontractsandAirVentValveopenstodischargeinitialair.After
coldcondensateentersthetrap,the�loatofsteamtrapwillrisetoallowdischargeofcondensate
fromori�ice.BothairandcondensatearealsodischargedfromAirventvalve
-Afterinitialairandcoldcondensatehavebeendischarged,hotcondensateheatstheX-elementand
closesAirVentValveinordertoavoidsteamloss.Atthistime,thecondensatecontinuestobe
dischargedthroughori�ice
-Ascondensatestops�lowingintothetrapandthesteamoccupiestheuppersection,the�loatwill
closetheori�iceandX-elementisalsoclosed.Therefore,thetrapiscompletelysealedtoprevent
steamleakage.
Trapsoperatingonhighdifferentialpressuresneedtohavesmallerori�ices
131
Mechanicalsteamtrap–invertedbucket
Structure:
Figure81.Mechanicalsteamtrap–invertedbucket(source:TLV)
· OperatingPrinciples
Figure82.OperatingPrinciplesofmechanicalsteamtrap–Invertedbucket
Table62.Advantagesanddisadvantagesofsteamtrap–Invertedbucket
Advantages Disadvantages
-Withstandhighpressures
Goodtolerancetowaterhammerconditions
Dischargeairveryslowly
Steammightbelostthroughdischargeportifthe
traploseswatersea
- Thetrapbodyisinitiallyfullofwaterfromlastoperationandthebucketisstillsettleddown.The
condensateispushedoutthroughtheopendischargeport
-Whentheair/steamleaksthroughventholeslowlyandthebucketrisesuptoclosethedischarge
port
-Trapiscloseduntilthesteaminsidethebucketiscondensedortheoutsidecondensate�lowsinto
thebucket.Thedischargevalvewillbepulledoff
-Accumulatedcondensateisreleasedandthecycleisrepeated.
132
ThermodynamicSteamTrap
· Structure
Figure83.Thermodynamicsteamtrap(source:TLV)
· Operatingprinciples
Figure84.Operatingprinciplesofthermodynamicsteamtrap
Table63.Advantagesanddisadvantagesofthermodynamicsteamtrap
Advantages Disadvantages
-Compact,simple,andlightweight
Largecondensatecapacity
Installhorizontallyorvertically
Removalcondensatealsocarriessteam
Lowef�iciency
Thedischargeofthetrapcanbenoisy
- On start-up, incoming pressure raises the disc, and cool condensate plus air is immediately
dischargedfromtheinnerringunderthedisc
- Thecondensatein�lowpushingopendisccausesthepressuredropandreleases�lashsteamwith
highvelocity.Thishighvelocitycreatesalowpressureareaunderthedisc,drawingittowardsits
seat
- Atthesametime,the�lashsteampressurebuildsupinsidethechamberabovethedisc,forcingit
downagainsttheincomingcondensateuntilitseatsontheinnerandouterrings.Atthispoint,the
�lashsteamistrappedintheupperchamber,andthepressureabovethediscequalsthepressure
beingappliedtotheundersideofthediscfromtheinnerring
-Eventuallythetrappedpressureintheupperchamberfallsasthe�lashsteamcondenses.Thediscis
raisedbythenowhighercondensatepressureandthecyclerepeats.
133
Thermostaticsteamtrap–Balancedpressure
· Structure:
Figure85.Thermostaticsteamtrap–Balancedpressure(source:TLV)
· OperatingPrinciples
Figure86.Operatingprinciplesofthermostaticsteamtrap–balancedpressure
Table64.Advantagesanddisadvantagesofthermostaticsteamtrap–balancedpressure
Advantages: Disadvantages
Compact,simple,andlightweight
Simplemaintenance
Largecapacity
Valve is not opened until the condensatetemperatureisbelowsteamtemperature.
Ascondensatepassesthroughthebalancedpressuresteamtrap,heatistransferredtotheliquidin
thecapsule.The liquidvaporisesbeforesteamreaches the trap.Thevapourpressurewithin the
capsule causes it to expand and the valve shuts. Heat loss from the trap then cools the water
surroundingthecapsule,thevapourcondensesandthecapsulecontracts,openingthevalveand
releasingcondensateuntilsteamapproachesagainandthecyclerepeats.
134
Steamtrapselectionnotices:
Table65 Steamtrapselection
Application Feature Suitabletrap
Steampiping Smallcapacity
Frequentchangeinpressure
Lowpressure–highpressure
Thermodynamic
Mechanical:�loat
Equipment
Reboiler
Heater
Dryer
Heatexchanger
Instrumentation Highreliability Thermodynamic
Thermostatic
Normaloperation Steamleakage
Figure87.Steamtrapoperation
Largecapacity
Variationinpressureandtemperatureis
undesirable
Ef�iciencyoftheequipmentisaproblem
Mechanical:�loat,bucket,
invertedbucket
· Temperaturetesting
-Useinfraredguns,surfacepyrometers,ortemperaturetapestomeasuretemperature
- Thesteamtrapoperateswellifthedifferencetemperaturebetweenthesteamandcondensateis
small.
· Ultrasonictesting:Usetheultrasonicleakdetectortodetermineifthetrapisfunctioningproperly
Twotypesoffailures:
· Failedinopenposition:steamlossincreasestheproductioncost
· Failedinclosedposition:waterhammercausesdamagetoequipment.
Therearefourwaystocheckforleaks,andcheckforsteamtraps
Visualtesting:Thismethodallowsustoobservetheoperationofsteamtrapwhenproductionisrunning.
Disadvantage:thesightglassneedsmaintenance,whichmightcauseincreasingproductioncost.
135
Figure88.Ultrasonictesting
· LeakdetectionbyusingSpira-tecequipment.
Figure89.Spira-tecmeasurement
SLDSSpira-tecmonitoringequipmentisusedtodetectifthereisleakofanysteamtrapduringitsoperation.
3.9.4.Datacollection
Necessaryparametersforboileref�iciencycalculation:
· Ultimateanalysisoffuel(%C,%H2,%O2,%S,moisturecontent,ashcontent)
· Fluegastemperature
· Ambienttemperature
· Humidityofair
· %O2or%CO2in�luegas
· GCVoffuel
· GCVofash
· Blowdownwater.
· Fueltemperature.
Touchsensor
Meter
Ampli�icationand�ilter
Headphone
136
Figure90.Typesoffurnaces
3.10. Furnace
3.10.1.Introduction
Afurnaceisanequipmentusedtomeltmetalsforcastingortoheatmaterialstochangetheirshape(e.g.
rolling,forging)orproperties(heattreatment).
3.10.1.1.Mainfurnacecomponents
· Heatingsystem:fuel�iredorelectricalheatingtype
-Fuel�ired:heatisproducedbyburninganappropriatemixtureofairandfuel
-Electricfurnace:heatisproducedbyresistance,inductionorarc.
· Refractory:preventheatlosstothesurrounding.Itshouldalsobechemicallyinerttotheprocess
· Loading–unloadingsystem:thematerial issuppliedandtakenoutof thefurnacethrougha
loadingandunloadingsystem.Energylossesoffurnacemightoccurduringsystemoperation
· Heatexchanger:useswasteheattopreheattheairandmaterialwhichisloadedinthefurnaceor
usedinexternalapplications
· Instrumentationandcontrol:thisincludessensorsandcontrollerstocontrolseveralprocesses
likefuelsupply,currentsupply,exhaust–gasanalysis,loadingandunloadingofmaterialetc.
Exhaust gas flue
Burner
Furnace chamber
Dischargedoor
Charge door Stock Hearth
137
3.10.1.2.Classi�ication
Table66.Classi�icationoffurnaces
Classi�icationmethod Types
Typeoffuelused Oil
Gas
Coal
Modeofchargingmaterials Batch
Periodical(Forging,re-rolling,pot)
Continuous(pusher,walkingbeam,walkingheart)
Modeofheattransfer Radiation
Convection
Modeofwasteheatrecovery recuperative
Regenerative
Heatinstock(Q)canbecalculatedwiththisequation:Q = m × Cp × (t2 − t1)
Q=quantityofheatinstockinkCal.
m=massofthestockinkg.
Cp=speci�icheatofstockinkCal/kg.0C
t2=�inaltemperatureofstockin0C
t1=initialtemperatureofthestockbeforeitentersthefurnacein0C
m=weightof�luegas(air+fuel)
Cp=speci�icheatof�luegas
rT=temperaturedifference
GCV=grosscalori�icvalueoffuel,kCal/kg.
3.10.1.3.Energyperformanceassessmentoffurnaces
Theef�iciencyofafurnaceincreaseswhenthepercentageofheatwhichistransferredtothestockorload
insidethefurnaceincreases.Theef�iciencyofthefurnacecanbecalculatedintwoways:
· Directmethod
Theef�iciencyofafurnacecanbedeterminedbymeasuringtheamountheatabsorbedbythestockand
dividingthisbythetotalamountoffuelconsumed.
· Indirectmethod
Furnaceef�iciencycanalsobecalculatedaftersubtractingsensibleheatlossin�luegas,heatlossdueto
moisture in �lue gas, heat lossdue toopenings in furnace, heat loss through furnace skin andother
unaccountedlossesfromtheinputtothefurnace.
- Heatlossin�luegas:
HeatinstockThermalef�iciencyofthefurnace=Heatinthefuelconsumed
138
- Heatlossfrommoistureinfuel:
m=%moistureofin1kgoffueloil
Tfg=�luegastemperature,0C.
Tamb=ambienttemperature,0C
- Heatlossduetohydrogeninfuel:
H2=%ofH2in1kgoffueloil.
- Heatlossduetoopeninginfurnace:
Thefactorofradiationthroughopeningsandtheblackbodyradiationfactorcanbeobtainedfromstandard
graphsasshownin�iguresbellows.
Figure91.Radiationfactorforheat
Source:BEE,2005
Figure92.Blackbodyradiationatdifferenttemperature
Source:BBE, 2005
139
- Heatlossthroughfurnaceskin:todeterminetheheatlossthroughthefurnaceskin,�irsttheheat
lossthroughtheroofandsidewallsandthroughotherareasmustbecalculatedseparately .
Figure93.Heatlossfromtheceiling,sidewallandhearthoffurnace
Source:BEE,2005
-Heatlossthroughroof/ceilingandsidewalls(=heatandsoakingzone).
Theaveragesurfacetemperaturet isestimatedfromdatapointsofpracticalmeasurementst
0 2Heatlossatt C(referto�igure39),kCal/m hr.st
2Totalareaofheating+soakingzone,m
0 2 2Sototalheatlossthroughfurnaceroof/ceilingis:Heatlossatt CkCal/m hr.xAream ,kCal/hr.st
-Heatlossfromareaotherthanheatingandsoakingzone.
Theaveragesurfacetemperaturet isestimatedfromdatapointsofpracticalmeasurementst
0 2Heatlossatt C(referto�igure39),kCal/m hr.ost
2Totalarea,m .
0 2 2Sototalheatlossthroughotherareasis:Heatlossatt CkCal/m hr.xAream ,kCal/hr.ost
The%heatlossthroughfurnaceskinis:
-UnaccountedLoss
Theselossescompriseofheatstorageloss,lossoffurnacegasesaroundchargingdoorandopening,heat
lossbyincompletecombustion,lossofheatbyconductionthroughhearth,lossduetoformationofscales.
Addingallofheatlossesabovegivethetotallossestoconstructaheatbalancefortypicalfurnace.
TemperatureofExternalSurfaceofFurnace(degC)
140
Figure94.Heatlossedinafurnace
Source:AsiaEnergyEf�iciency
Thesefurnaceheatlossesinclude:
· Fluegaslosses:partofheatremainsinthecombustiongasesinsidethefurnace
· Loss frommoisture in fuel: fuel usually contains somemoisture and some of the heat issued to
evaporatethemoistureinsidethefurnace
· Lossduetohydrogeninfuelwhichresultsintheformationofwater
· Lossthroughopeningsinthefurnace:radiationlossoccurswhenthereareopeningsinthefurnace
enclosureandtheselossescanbesigni�icant.Asecondlossisthroughairin�iltration
· Furnaceskin/surface losses:while temperatures inside their furnacearehigh,heat is conducted
throughtheroof,�loorandwallsandemittedtotheambientaironceitreachesthefurnaceskinor
surface.
Otherlosses:thereareseveralotherwaysinwhichheatislostfromafurnace,althoughquantifyingthese
isoftendif�icult.Someoftheseinclude:
· Storedheatlosses:whenfurnaceisstartedthefurnacestructureandinsulationisalsoheated,andthis
heatonlyleavesthestructureagainwhenthefurnaceshutsdown
· Coolingmedialosses:waterandairareusedtocooldownequipment,rolls,bearingandrolls,butheat
islossbecausethesemediaabsorbheat
· Incomplete combustion losses: heat is lost if combustion is incomplete because unburnt fuel or
particleshaveabsorbedheatbutthisheathasnotbeenputtouse
· Lossduetoformationofscales.
3.10.2.Heatlossesaffectingfurnaceperformance
Thetotalheatinputisprovidedintheformoffuelorpower.Thedesiredoutputistheheatsuppliedfor
heatingthematerialorprocess.Otherheatoutputsinthefurnacesareundesirableheatlosses.
Theenergy�lowisdepictedinthe�igurebelow:
141
Table67 Heatbalance
Heatinput Heatloss
Item kCal/kg % Item kCal/kg %
Combustionheatoffuel Fluegasloss
Electricity Moistureinfuelloss
Hydrogeninfuelloss
Coolingwaterloss
Heatlossduetoopening
Heatlossduetofurnaceskin
Heatlossin�luegas
Total
3.10.3.Energysavingsmeasures
Thegoalofanenergyauditoristominimizeheatlossandoptimizetheperformance.Potentialenergy
savingsareasinfurnacesarelistedbelow:
3.10.3.1.Completecombustionwithminimumexcessair
Tocompletecombustionoffuelwithminimumamountofair,itisnecessarytocontrol
· Airin�iltration
· Maintainpressureofcombustionair
· Fuelquality
· Excessairmonitoring
· Equippedanautomaticoxygen(air)/fuelratiocontroller.
3.10.3.2.Properheatdistribution
Afurnaceshouldbedesignedtoensurethatwithinagiventimethestockisheateduniformlytoadesired
temperaturewithminimumamountoffuel.
Whereburnersareusedto�irethefurnace,thefollowingshouldbeensuredforproperheatdistribution
· The�lameshouldnottouchorbeobstructedbyanysolidobject
· The�lameofdifferentburnersshouldstayclearofeachother
· Theburner�lamehasatendencytotravelfreelyinthecombustionspacejustabovethematerial.For
thisreason,theaxisoftheburnerinsmallfurnacesisneverplacedparalleltothehearthbutalwaysat
anupwardangle,butthe�lameshouldnothittheroof
· Insmallfurnacesusingoil,aburnerwithalong�lamewithagoldenyellowcolorimprovesuniform
heating.Butthe�lameshouldnotbetoolong,becauseheatislossofthe�lamereachesthechimneyor
thefurnacedoors
· Maintainingcleansurfacebyusingasootblower
· Completecombustionofcarbononradiantsurface
· Keepingheatexchangersclean
· Selectandlocateburnersandfanseffectively.
142
3.10.3.3.Wasteheatrecoveryfromfurnace�luegases
Wasteheatin�luegasescanberecoveredforpreheatingofthecharge,preheatingofcombustionair
orforotherprocesses.
· Chargepre-heating:
Whenrawmaterialsarepreheatedbyexhaustgasesbeforebeingplacedinaheatingfurnace,the
amountoffuelnecessarytoheattheminthefurnaceisreduced.
· Preheatingofcombustionair:
Theenergycontainedintheexhaustgasescanberecycledtopreheatthecombustionair.Sincethe
volume of combustion air increaseswhen it is preheated, it is necessary to consider thiswhen
modifyingairductdiametersandblowers.Itshouldbenotedthatpreheatingofcombustiongases
fromhighdensityoilswithahighsulphurcontent,couldcausecloggingwithdustorsulphidesand
corrosion.
· Utilizingwasteheatasaheatsourceforotherprocesses:
Thewasteheatcanbeusedtoproducesteamorhotwater.Sometimesexhaustgasheatcanbeusedfor
heatingpurposesinotherequipmentsuchastank,reactor,etc.
3.10.3.4.Minimizingfurnaceskinlosses
Thereareseveralwaystominimizeheatlossthroughthefurnaceskin:
· Choosingtheappropriaterefractorymaterials
· Increasingthewallthickness
· Installinginsulatingbricks
· Planningoperatingtimesoffurnaces.
3.10.3.5.Preventheatlossthroughopenings
Thereareseveralwaystominimizeheatlossthroughopening:
· Keeptheopeningassmallaspossibleandsealthem
· Openingthefurnacedoorslessfrequentandfortheshortesttimeperiodaspossible
· Checkairleakagefrequently.
3.10.3.6.Controloffurnacedraft
Ifnegativepressuresexistinsidethefurnace,aircanin�iltratethroughcracksandopeningsandaffect
theairfuelratiocontrol.Thisinturncancausemetaltonotreachthedesiredtemperatureornon-
uniformtemperatures.Toavoidthis, installingfurnacepressurecontrollershelpmaintaininside
positivefurnacepressure.
3.10.3.7.Operationattheoptimumfurnacetemperature
Itisimportanttooperatethefurnaceatitsoptimumtemperature.Operatingtemperaturesofvarious
furnacesaregivenintablebelow.Operatingattoohightemperaturescausesheat loss,excessive
oxidation,decarbonizationandstressonrefractories.Automaticcontrolofthefurnacetemperature
ispreferredtoavoidhumanerror.
143
Slabreheatingfurnaces 12000C
Rollingmillfurnaces 12000C
Barfurnaceforsheetmill 8000C
Bogietypeannealingfurnaces 6500C-7500C
3.10.3.8.Optimumcapacityutilization
Oneofthevitalfactorsaffectingef�iciencyisload.Thisincludestheamountofmaterialplacedinthe
furnace,thearrangementinsidethefurnaceandtheresidencetimeinsidethefurnace.
3.10.3.9.Optimumload
Ifthefurnaceisunderloaded,theproportionoftotalheatavailablethatwillbetakenupbyloadissmaller,
resultinginaloweref�iciency.Overloadingcanleadtotheloadnotheatedtorighttemperaturewithina
givenperiodoftime.
Thereisaparticularloadatwhichthefurnacewilloperateatmaximumthermalef�iciency,wherethe
amountoffuelperkgofmaterialislowest.
3.10.3.10.Optimumarrangementoftheload
Theloadingofmaterialsonthefurnacehearthshouldbearrangedsothat:
· Itreceivesthemaximumofradiationfromthehotsurfacesoftheheatingchambersand�lames
· Hotgasesareef�iciencycirculatedaroundtheheatreceivingsurfacesofthematerials.
3.10.3.11.Optimumresidencetimeoftheload
Fuelconsumptioniskeptataminimumandproductqualityisbestiftheloadonlyremainsinsidethe
furnaceuntil ithas therequiredphysicalandmetallurgicalproperties.Excessiveresidence timewill
increaseoxidationof thematerial surface,which can result in rejectionofproducts.Temperature is
increasedtomakeupforshorterresidencetime.Thehighertheworkingtemperature,thehigheristhe
lossperunitoftime.
Optimumutilizationoffurnacecanbeplannedatdesignstage,byselectingthesizeandtypethatmatches
theproductionschedule.
3.10.3.12.Useofceramiccoatings(highemissivitycoating)
Ceramiccoatinginthefurnacechamberpromotesrapidandef�icienttransferofheat,uniformheating
andextendedlifeofrefractories.Theemissivityofconventionalrefractoriesdecreaseswithincreasein
temperaturewhereas for ceramic coatings it increases slightly. Thisoutstandingpropertyhasbeen
exploitedbyusingceramiccoatinginhotfaceinsulation.Ceramiccoatingishighemissivitycoatinganda0havealonglifeattemperaturesupto1350 C.
3.10.3.13.Selectionofrefractories
Theselectionofrefractoriesaimstomaximizetheperformanceofthefurnace.Furnacemanufacturersor
usersshouldconsiderthefollowingpointsintheselectionofarefractory:
· Typeoffurnace
· Typeofmetalcharge
· Presenceofslag
· Areaofapplication
· Workingtemperature
· Extentofabrasionandimpact
144
Table68.Measuringinstruments
· Structuralloadofthefurnace
· Stressduetotemperaturegradientinthestructuresandtemperature�luctuations
· Chemicalcompatibilitytothefurnaceenvironment
· Heattransferandfuelconservation
· Costconsiderations.
3.10.4.Datacollection
3.10.4.1.Checklist
It isdif�icult tomakeachecklistofgeneraloptions for furnaces,becauseoptions to improveenergy
ef�iciencyvarybetweendifferenttypesoffurnaces.Butthemainoptionsthatareapplicabletomost
furnacesare:
· Checkagainstin�iltrationofair:usedoorsoraircurtains
· MonitorO ,CO ,COandcontrolexcessairtotheoptimumlevel2 2
· Improveburnerdesign,combustioncontrolandinstrumentation
· Ensurethatthefurnacecombustionchamberisunderslightpositivepressure
· Useceramic�ibersinthecaseofbatchoperations
· Matchtheloadtothefurnacecapacity
· Retro�itwithheatrecoverydevice
· Investigatecycletimesandreduce
· Providetemperaturecontrollers
· Ensurethat�lamedoesnottouchthestock.
3.10.4.2.Measuringinstrumentsforfurnace
No. Parameterstobemeasured LocationofMeasurement
Instrumentrequired
Value
1 Operatingtemperature Soakingzonesidewall Measuretemperature
oC
2 Measuretemperature
oC
3 Ambienttemperature(tamb) Aroundfurnace Measuretemperature andhumidity
oC,%RH
4 Fluegasanalyzer Measure the �luegas
5 Surfacefurnace Measuretemperature
oC
6 Average surface temperatureof areaotherthanheatingandsoakingzone
Surfaceothers Measuretemperature
oC
Averagesurfacetemperatureofheatingandsoakingzone
Exit�luegastemperatureafterpreheat(T )fg
Fluegasexitfromfurnace-chimney
Fluegasexitfromfurnace-chimney
OC,%ofOxygen,CO,CO2
145
3.10.4.3.Datacollectiontemplate
Table69.Datacollectiontemplateforfurnaceperformance
Items
Name
Model:
Fueltypes
Designedcapacity
Heatingzone
FuelLoadingdoor
Wallthickness
Coolingwater�lowrate(ifany)
Unit
tons/hr
m2
m2
mm
M3/hr
Measurement 1 2 3 1 2 3 1 2 3 1 2 3
Ambienttemperature OC
Operatingtemperature OC
Airtemperature OC
Surfacefurnacetemperature OC
Oxygen %
CO ppm
CO2 %
Note
4. SAFETYREQUIREMENTANDEQUIPMENT
Energyauditrequiresauditorstosurveyinmanyareasofthefactoryandbuildingssuchastransformers,
refrigerationsystem,boilers,wastewatertreatmentareas,etc.Eachareahasitsownrisksastheexposure
tospeci�ichazardscouldcauseseriousinjuries,ordiseases.Safetymanagersorsafetyspecialistsare
responsibleforensuringsafetyperformanceintheplant.Therefore,theenergyauditorneedstodiscuss
withthesestaffstode�inetheappropriatesafeworkpractices.Moreover,energyauditorsshouldbeaware
ofthebelowsafetyconcerns.
4.1. Electricalsafety
Electricityplaysanimportantroleinindustrialandresidentialenvironments,butitalsohashazardous
potentials.Electricitycancausemanyseriousaccidentsifitssafetystandardsarenotcomplied.Whenthe
electricpassesthroughbody,itcancausebraindamage,burns,pleurisyandorgansdamage.Themajor
task of energy auditor is to evaluate the ef�iciency of a lot of electrical equipment such asmotors,
transformers,andelectricitydistributionsystem.Therefore,theauditorhastobeawareoftheelectrical
safety.
Electricalaccidentscanoccurduetoelectricshocksorarc�lashes.Topreventelectricalaccidents,the
auditorshouldunderstandtheelectricalsystemdiagramsandde�inethehighvoltageareas.Then,the
auditor should discuss with managers to de�ine the appropriate safe work practices. The personal
protective equipment (PPE) should complywith the Vietnamese standards (TCVN) or international
standards.
Somepersonalprotectiveequipmentforworksrelatedtoelectricityarelistedasfollows:
146
Figure95.GHSPictograms
· Clothing shall be made of arc-rated �lame-resistant materials, have electrically non-conductive
properties,andhavelongsleevesandlongpants
· Hard hat has to comply with the International Safety Equipment Association Z89.1 Class E or
equivalentstandards
· Safetyglasseswithnon-conductivesideshields
· Safetyglovesorboots
· Sinceelectricalaccidentscanresultinhazardousnoiselevels,thehearingprotectionisrequired.
Somelegaldocumentsrelatedtoelectricitysafety:
· Degree 14/2014/NĐ-CP - Stipulating in detail the implementation of electricity law regarding
electricitysafety
· Circular31/2014/TT-BCT-Stipulatingcertaindetailsofelectricalsafety.
· Circular 39/2013 / TT-BLDTBXH promulgates national technical regulations on labor safety for
insulationshoeorboot.
4.2. Chemicalsafety
Theenergyauditorisnotrequiredtousechemicals,buttheymayenterareaswheretherearedangerous
chemicalsarehandled. Identi�icationofdangerouschemicalsby theirnamesandstructuresrequires
advancedknowledgeofchemicalsandlong-termtraining.However,theauditorscanrecognizethedanger
ofchemicalsfromitslabelinordertochooseanappropriatePPEwhenenteringhazardousareas.
Dependingupontheactualconditionsinafactory,thenecessaryPPEforchemicalsafetyareshownas
follows:
147
Imperviousgloves
Safetymasks
Safetyshoes
Figure96.Exampleofpressureequipment(boiler)
The common cause of exploded pressure equipment accident is operation under the overpressure
condition.Energysavingmeasuresshouldconsidernotonlytheef�iciencyofequipmentbutalsosafety
conditions. In order to satisfy both requirements, energy auditor needs to evaluate the drawing,
speci�icationsheet,inspectionsheet,andoperatingprocedurerelatedtoprocessequipment.Collecting
thedatafromthosedocumentsandcomparingdatawiththerequirementsoflocalregulations(TCVN,
QCVN…)or international standards (ISO,ASME…)will helpenergyauditor tode�ine theappropriate
operatingconditions.Moreover,theauditorcouldconsultatechnicalspecialistorequipmentsupplierfor
moreinformation.
Somelegaldocumentsrelatedtopressureequipmentsafety:
·� � �TCVN8366:2010-NationalTechnicalRegulationof pressure vessels-Requirementof design and
manufacture
PPE Purpose
Safetyglasseswithsideshields
Protecteyesfromsplashingchemicalssuchassolvents,toxicgases,etc.
Source:GlobalHarmonizedSystem
Somelegaldocumentsrelatedtoelectricitysafety:
· Circular04/2012/TT-BCT-Regulationsontheclassi�icationandlabellingofchemicals
· Circular20/2013/TT-BCT–Stipulatingtheplanandmeasuresforpreventionandresponseagainst
chemicalincidentsinindustry.
4.3. Pressureequipmentsafety
Pressureequipmentisusedtoconducthydraulicprocesses,thermalprocesses,chemicalprocesses,orto
storematerialsatthepressuregreaterthanatmosphericpressure.Accordingtothelocalregulations,the
equipmentwiththedesignpressureof0.7barisconsideredaspressureequipment.Forexample,boiler,
chillersystem,andcompressorsarethecommonpressureequipment.Energyauditorshouldpropose
theenergysavingmeasuressuchaschangingtheoperatingconditionsaswellasprocedures.Therefore,
understandingthesafetyparametersofpressureequipmentwillbene�itenergyauditorstoproposethe
appropriateenergysavingmeasures.
Protectagainstskinexposuretochemicalshazardwhenhandscontacttochemicalequipment
Protectagainstexposuretoair-bonedustorchemicalparticlesandprotectagainstnuisanceodorsfromsolventvapors
Protectagainstskinexposureinworklocationswhereliquidcontactwiththefeetislikely.
148
Figure98.Workingatheight
· QCVN01:2008/BLĐTBXH-NationalTechnicalregulationonsafeworkofsteamboilerandpressure
· 50/2015/TT-BLĐTBXH–Nationaltechnicalregulationonsafeworkofrefrigeratingsystem.
4.4. SafetyforworkingatHeights
Theenergyauditorsometimeshastoclimbuptheroofofbuildingorgouptothehighelevationtocollect
equipmentdata.Thereby,afallhazardexistsduetoanunintendedlossofbodybalancewhileworkingin
heights.ThereSomesafetymeasurescanreducethefallhazard:
· The�irstapproachshouldbetoreviewactivitiesrequireworkingatheightandtolookfortheother
alternativestocarryouttheworksuchasundertakingtheworkatgroundlevel
· Iffallhazardscan'tbecompletelyeliminated,installationofstairs,guardrails,barriers,andtravel
restrictionsystemscanleadtofallpreventionworkenvironment
·����Asalastlineofprotectionagainstfallfromheight,itisessentialtousefall-arrestingequipmentsuchas
harness,lanyards,shockabsorbers,lifelines,anchoragesetc.
Somelegaldocumentsrelatedtoworkingatheights:
· QCVN23:2014/BLDTBXH:Nationaltechnicalregulationofpersonalfall-arrestsystems
· TCVN7802:2007:Personalfallarrestsystems
· TCVN8207:2009:Personalequipmentforprotectionagainstfalls.
Inthesedocuments,somecommonissuesrelatedtosafetyforenergyauditarementioned.Toevaluate
exactlythesafetyforeachauditor, thefactoryhastoprovideanddiscussequipmentandproduction
processwiththeauditor.Thesafetymanagerorsafetyspecialistofafactoryneedstoprovideequipment
informationandinformaboutthehazardssothattheenergyauditorgets theappropriatesafework
practices.Moreover, it isnecessary toregularlyprovide trainingcoursesonOccupationalSafetyand
Health(OSH)forauditorsattrainingcentreswhichhavethepermitoftheMinistryofLabour-Invalids
andSocialAffairs.
149
APPENDIXES
Table70.Spreadsheetforenergysavingcalculation
Energysavingspreadsheetsaredividedintomanysheets,eachofwhich introduceaspeci�ictopicrelatedtoenergyef�iciency,including:
1. Electricitybill:foranalysis&calculationofelectricityconsumption,cost,powerfactor,...
2. Hourlyloadgraphs:todrawloadgraphsbasedonthepowerconsumptionrecordsperhour
3. Hourlyloadgraphs:todrawloadgraphsbasedonthepowerconsumptionrecordsperminute
4. Reactivepowercompensation:Supportsthecalculationofpowerfactor,compensationfactor,andreactivepowercapacitytobeused
5. Loadconversion:Supportsloadconversioncalculationssimply
6. Incandescentandcompactlamps:Supportscomputationalcomparisonsbetweenthesetwolamps
7. Ferromagnetic ballast & electronic ballast: supports the computational comparisonbetweentheuseof�luorescentlampswithdifferenttypesofballasts
8. Motorselection:supportstheevaluationofmotoref�iciencyperformance
9. HighEf�iciencyMotors:Comparetheef�iciencyofhighef�iciencymotors
10. VS-VSDmotor: Evaluate the result of the conversion fromVSmotors to themotorswithVSD
11. Pump-inverter:evaluatetheef�iciencyofthepumpsystemusinginverter
12. PumpEf�iciency:toassessandcalculatepumpef�iciency
13. BoilerEf�iciency–Directmethod:supportsthecalculationofboileref�iciencybydirectmethod
14. Boiler Ef�iciency – Indirect method: supports the calculation of boiler ef�iciency byindirectmethod
15. Insulation:Supportscalculationofpipeheatlossesandinsulationthickness
16. SteamLeaks:SupportssteamLeakageassessment
17. Chilleref�iciency
18. Coolingtower:Ef�iciencyofcoolingtower
19. OtherAppendix
150
Table71.T
heelectricitypricesforen
terprisesinrecentyears
Item
s01/0
1/2
007
01/0
3/2
009
01/0
3/2
010
01/0
3/2
011
20/1
2/2
011
01/0
7/2
012
22/1
2/2
012
01/0
8/2
013
01/0
6/2
014
Electricprice
forpro
duction
Above110kV.
a)Norm
alhour
785
898
1043
646
1862
1102
683
1970
1158
718
2074
1217
754
2177
1277
792
2284
b)Off-peakhour
425
496
c)Peakhour
1590
1758
From2
2k
Vto110
kV
a)Norm
alhour
815
445
1645
870
475
1755
920
510
1830
955
540
1900
935
518
1825
986
556
1885
1023
589
1938
1068
1128
710
2049
1164
727
2119
1216
767
2185
1184
746
2156
1225
773
2224
1278
814
2306
1243
783
2263
1286
812
2335
1339
854
2421
1305
822
2376
1350
852
2449
1406
897
2542
b)Off-peakhour
670
c)Peakhour
1937
From6kVto22kV
a)Norm
alhour
860
1093
b)Off-peakhour
480
683
c)Peakhour
1715
1999
Below6kV
a)Norm
alhour
895
1139
b)Off-peakhour
505
708
c)Peakhour
1775
2061
835
455
1690
1267
785
2263
16/0
3/2
015
1
1.1
1388
869
2459
1.2
1405
902
2556
1453
934
2637
1518
983
2735
1.3
1.4
1283
815
2354
1328
845
2429
1388
890
2520
151
2Electricityprice
forbusinessandservice
2.1
Above110kV.
a)Norm
alhour
1410
1540
1648
1713
1808
1909
2004
2104
2007
2125
1185
3699
b)Off-peakhour
770
835
902
968
1022
1088
1142
1199
1132
c)Peakhour
2615
2830
2943
2955
3117
3279
3442
3607
3470
2.2
From2
2k
Vto110
kV
a)Norm
alhour
1510
885
2715
1580
915
2855
1650
960
2940
1727
995
3100
1766
1037
3028
1846
1065
3193
1838
1939
2046
2148
2255
2158
2287
b)Off-peakhour
1093
1153
1225
1286
1350
1283
1347
c)Peakhour
3067
3226
3388
3557
3731
3591
3829
2.3
From6kVto22kV
a)Norm
alhour
1863
1965
2074
2177
2285
2188
2320
b)Off-peakhour
1142
1205
1279
1343
1410
1343
1412
c)Peakhour
3193
3369
3539
3715
3900
3742
3991
Note: -
Norm
alhour:from4h00–9h30;11h30–17h00;20h00–22h00fromMondaytoSaturdayandfrom4h00–22h00inSunday.
- Peakhour:from9h30–11h30andfrom17h00–20h00fromMondaytoSaturday.
- Off-peakhour:from22h00–4h00allofdayinaweek.
Electricitypricesforotherbusiness,organizations,pleasevisitEVNwebsite(
)toknow
moreinform
ation.
http
://w
ww
.evn
.com
.vn/
152
Table72.TheconversionintoTOE,MJandemissionfactorsofsomeenergytypes
Energytypes Units Energyconsumption(**)
(MJ/Unit)
TOEequivalent(*)
Emissionfactors(tonsCO2/unit)
Electricity
Cokecoal
Anthracitecoal1,2
Anthracitecoal3,4
Anthracitecoal5,6
DOoil
kWh
Tons
Tons
Tons
3.6
31,402.5
29,309.0
25,122.0
20,935.0
0.0001543
0.70-0.75
0.70
0.60
0.50
1.02
0.88
0.99
0.94
1.09
0.9
1.05
0.83
1.05
0.0006612
3.36
2.88
2.47
2.06
3.16
2.73
3.21
3.05
2.88
2.11
3.05
2.41
3.08
Tons
Tons 42,707.4
1.000litre 36,845.6
FOoil tons 41,451.3
1.000litre 39,357.8
LPG tons 45,638.3
Naturalgas(NG) 1000m3 37,683.0
Gasoline tons 43,963.5
1.000litre 34,752.1
JetFuel tons 43,963.5
Note:
(*)TOEcoef�icientsprescribedinOf�icialdispatchNo.3505/BCT-MOST,April19,2011
(**)Energy conversion coef�icient is calculated based on 1 TOE = 41,870 MJ by IPCC
((http://www.ipcc.ch/ipccreports/sres/emission/index.php?idp=167).Thisvalueisforreferenceonly,
recommendsusingresultsofcalori�icvalueistheactualfuel
153
Table73.Theemissionfactorofsomecommonenergytypes
Energytypes
(*)Electricitygrid
Cokecoal
Anthracitecoal
Value
0.6612
0.1070
0.0983
0.0741
0.0774
0.0631
0.0561
0.0693
0.070
0.112
0.100
Units
kgCO /kWh2
kgCO /MJ2
kgCO2/MJ
DO oil kgCO2/MJ
FOoil kgCO2/MJ
LPG kgCO2/MJ
NG kgCO2/MJ
Gasoline kgCO2/MJ
JetFuel kgCO2/MJ
Woodandwoodwaste kgCO2/MJ
Othersbiomass kgCO2/MJ
Source:IPCCguidelinesforNationalGreenhouseGasInventories”issuedin2006
Note:
(*)EmissionfactorofVNelectricitygridisissuedannuallybytheBureauofMeteorology,Hydrologyand
ClimateChange,MinistryofNaturalResourcesandEnvironment.
( )http://www.noccop.org.vn/modules.php?name=Airvariable_ldoc&menuid=33
WithCO emissionfactorforotherenergytypes,knowmoreatIPCCwebsite.2
( ).https://www.ipcc.ch/meetings/session25/doc4a4b/vol2.pdf
From the information on energy consumption and CO emission factor corresponding energy/ fuel2
consumptioncanbeconvertedCO emissionfactorofenergyconsumption(seeconversiontoolinexcel2
�ile).
154
- x - -
x x x x
x x x x
x x x x
x x x x
x x x x
- x x x
- x x x
- x x x
- x x -
x x x
- x x x
- x x x
- x x x
- x x x
- x x x
x x x x
x x x x
- x x x
Table74.Metrologicalcontrolmeasuresandinstrumentinspectionintervals
No. Measuringinstrument Metrologicalcontrolmeasures Inspectioninterval
Type
approval
Inspection
Once Periodi-cally
Afterrepair
(1) (2) (3) (4) (5) (6) (7)
Lengthmeasurements
1 Measuringtape
Volumeand�lowmeasurement
2 Mechanicalresidentialwatermeter 60months
3 Electronicresidentialwatermeter 36months
4 Oilandgasmeter 12months
5 LPGmeter x
6 Industrialair�lowmeter 12months
7 Commonvolumemeter 24months
Pressuremeasurement
8 Springmanometer 12months
9 Electronicmanometer 12months
Temperaturemeasurement
10 Macroscale electronic contact medicalthermometer
06months
11 In-earmedicalinfraredthermometer 12months
Physical-chemicalmeasurement
12 Seedmoisturemeter
Hydrometer
12months
13 24months
14 Vehicleexhaustgastester 12months
15 Equipment for measuring concentration ofSO2,CO2,CO,NOx inair
12months
16 Equipment for measuring pH, dissolvedoxygen, electrical conductance, wateropacity,totaldissolvedsolidsinwater
12months
Electricity&EMFmeasurement
17 1-phaseACelectricitymeter 60months
18 3-phaseACelectricitymeter 24months
Opticalmeasurement
19 Illuminancemeter 12months
Source:CircularNo.23/2013/TT-BKHCNdatedSeptember26,2013
Where:-“x”indicatesmandatorytasks;
-“-”indicatesoptionaltasks.
155
REFERENCE Date Content
LawNo.50/2010/QH12
17/6/2010 ECONOMICALANDEFFICIENTUSEOFENERGY
DecreeNo.21/2011/NĐ-CP
29/3/2011 DETAILING THE LAW ON ECONOMICAL AND EFFICIENTUSE OF ENERGY AND MEASURES FOR ITSIMPLEMENTATION
CircularNo.09/2012/TT-BCT
20/4/2012 PROVIDING FOR ELABORATION OF PLANS, REPORT ONIMPLEMENTATION OF PLANS ON ECONOMICAL ANDEFFICIENT ENERGY USE; IMPLEMENTATION OF ENERGYAUDIT
CircularNo.23/2013/TT-BKHCN
26/9/2013 GROUP2MEASURINGINSTRUMENTS
CircularNo.02/2014/TT-BCT
16/1/2014 Prescribedenergyconsumptionrateinchemistryindustry
CircularNo.19/2016/TT-BCT
14/9/2016 Prescribedenergyconsumptionrateinbeerandbeverageindustry
CircularNo.20/2016/TT-BCT
20/9/2016 PrescribedenergyconsumptionrateinSteelindustry
MoIT/GIZ Energy Support Progamme
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