building energy auditing - department of energy energy audit training... · dme building energy...
TRANSCRIPT
1
DEPARTMENT OF MINERALS AND ENERGYDME-Danida Capacity Building in Energy Efficiency & Renewable Energy
Building Energy Auditing
Energy Assessment andSavings OpportunityIdentification
DEPARTMENT OF MINERALS AND ENERGYDME-Danida Capacity Building in Energy Efficiency & Renewable Energy
Module 1: A Context forBuilding Energy Audits
Energy Efficiency in SouthAfrican Buildings
DEPARTMENT OF MINERALS AND ENERGYDME-Danida Capacity Building in Energy Efficiency & Renewable Energy
Module 2: Basic Principles ofEnergy
Understanding how energyworks in buildings
2
DME Building Energy Audit Course 4
DEPARTMENT ofMINERALS and ENERGY
Learning objectives
Define energy in its various forms and energy relatedproperties;Use the correct units for energy and power, and convertfrom one unit to another as needed;Determine the properties of steam and moist air;Describe the mechanisms by which heat is transferred;Explain the effect of insulation on heat transfer, and themeans by which radiative heat transfer is controlled.
DME Building Energy Audit Course 5
DEPARTMENT ofMINERALS and ENERGY
Energy in its variousforms
Chemical – in fuelsThermal – sensibleand latentMechanicalElectrical
Energy Equivalents
1000 joules (J) 1 kilojoule (kJ)
1 kilowatt-hour (kWh) 3,600,000 J or 3.6 MJ
DME Building Energy Audit Course 6
DEPARTMENT ofMINERALS and ENERGY
Basic electricity
VoltageThis is what pushes electricity through a circuit - the
“driving force”
Units are Volts (V)
CurrentThis is what is pushed through by the voltage - the
“flow”
Units are Amperes (A) (“Amps”, for short)
3
DME Building Energy Audit Course 7
DEPARTMENT ofMINERALS and ENERGY
Electrical power
When voltage and current work together todo something useful - such as turn a motoror light a lamp
Units are Watts1000 Watts = 1 kilowatt (kW)1 horsepower (HP) = 746 Watts
DME Building Energy Audit Course 8
DEPARTMENT ofMINERALS and ENERGY
AC/DC
220 volts DC vs. time
220
0 1/50 sec
310
220
0
-310
220 volts RMS
DME Building Energy Audit Course 9
DEPARTMENT ofMINERALS and ENERGY
Calculating power
Watts = Volts x Amps x Power FactorVA = Volts x Amps
Power factor (PF) indicates how well thecurrent and voltage are working together
Incandescent Lamps 100%Large Motors 80-90%Small Motors 60-75%
4
DME Building Energy Audit Course 10
DEPARTMENT ofMINERALS and ENERGY
Power Factor - laggingcurrent
310
220
0
-310
310
220
0
-310
DME Building Energy Audit Course 11
DEPARTMENT ofMINERALS and ENERGY
Why should I care aboutpower factor?
Utilities may bill for Volts x Amps (kVA) or apply asurcharge for PF below a set value
Note that kVA is always greater than or equal tokW
Increased line currentsLow PF may suggest lightly loaded motorsFacilitates interpretation of electrical profiles
DME Building Energy Audit Course 12
DEPARTMENT ofMINERALS and ENERGY
Power factor correction
Add capacitanceAt service entranceIn distribution systemAt point of use – e.g. on motors
5
DME Building Energy Audit Course 13
DEPARTMENT ofMINERALS and ENERGY
Power and energy
Power = How Fast(Demand)
Energy = How Much(Consumption)
Energy = Power x TimeUnits are kilowatt-hours (kWh)
DME Building Energy Audit Course 14
DEPARTMENT ofMINERALS and ENERGY
What is efficiency?
Electric HeatIncandescent Lamp
MotorsPumps/Fan
Air Compressor
100% Elec - Heat10-20% Elec - Light
50-95% Elec - Power20-60% Elec - Flow
5-15% Elec - Air
Output Input
Efficiency = x 100%
Device Efficiency Input - Output
DME Building Energy Audit Course 15
DEPARTMENT ofMINERALS and ENERGY
Thermal energy units
Unit of thermal energy is a Joule (J)Typically use MJ or GJ.
1 Joule per second = 1 Watt1 kWh = 3.6 MJ (0.0036 GJ)1 boiler HP = 9,810 Watts
6
DME Building Energy Audit Course 16
DEPARTMENT ofMINERALS and ENERGY
Other useful units
1 kWh = 3413 BTU1 Ton of refrigeration
= 12,000 BTU/Hr= 3.6 kW
DME Building Energy Audit Course 17
DEPARTMENT ofMINERALS and ENERGY
Sensible and latentheat
0EC for Water
100EC for Water at Sea Level Steam Only
Water & Steam
Ice & W aterIce
Heat Removed Heat Added
0% Steam Quality100% Steam Quality
Latent HeatLatent Heat SensibleHea t
SensibleHea t
SensibleHea t
DME Building Energy Audit Course 18
DEPARTMENT ofMINERALS and ENERGY
Humid air -psychrometry
7
DME Building Energy Audit Course 19
DEPARTMENT ofMINERALS and ENERGY
“Quality” of heat - aquestion of usefulness
Required Temperature: 60ECRequired Energy: 16,800 kJ
250 litres @ 100EC84,000 kJ
1000 litres @ 40EC84,000 kJ
100 litres@ 20EC
Which will do thejob?
The 100 litres willbe heated byimmersing its
container in one ofthe larger
containers.
DME Building Energy Audit Course 20
DEPARTMENT ofMINERALS and ENERGY
Large Body @ 20EC
Small Body@ 60EC
Conduction
Radiation
ForcedConvection Convection
Air &Surrounding
@ 20EC
Heat transfermechanisms
DME Building Energy Audit Course 21
DEPARTMENT ofMINERALS and ENERGY
Thermal resistance ofinsulation
R = thickness/thermal conductivity
8
DME Building Energy Audit Course 22
DEPARTMENT ofMINERALS and ENERGY
Controlling heat loss -insulation
Types:FibrousCellularGranular
Forms:Rigid boardFlexible sheetFlexible blanketsCement
DME Building Energy Audit Course 23
DEPARTMENT ofMINERALS and ENERGY
Protective coverings
Weather barrierVapour retarderMechanical protectionFire and corrosion resistanceAppearance coverings and finishesHygienic coverings
DME Building Energy Audit Course 24
DEPARTMENT ofMINERALS and ENERGY
Radiation heat loss
Radiation from a hotbody to a cold bodyDepends onε, the emissivity ofthe surfaceThe temperaturedifferenceThe radiating area
Controlled byselecting low-emissivity materials
q = ε σ (Th4 - Tc
4) A
9
DME Building Energy Audit Course 25
DEPARTMENT ofMINERALS and ENERGY
Heat flow calculations
Conduction:Q = U x A x (T2 - T1)
Air flow:Q = V x (T2 - T1) x 1.232
Humid air:Q = V x (H2 - H1) x 3.012
In liquids:Q = M x (T2 - T1) x C x1000
Pipe heat loss:Q = F x L
Refrigeration:Q = COP x Power toCompressor (kW)
Steam leaks:Q = M x h / 3600
DEPARTMENT OF MINERALS AND ENERGYDME-Danida Capacity Building in Energy Efficiency & Renewable Energy
Module 3: Overview ofBuilding Energy Audits
A Systematic Approach toEnergy Auditing
DME Building Energy Audit Course 27
DEPARTMENT ofMINERALS and ENERGY
Learning objectives
Describe the theoretical framework for abuilding audit;Identify the information that should be collectedand analysed before the site visit;Develop a building audit plan and schedule;Identify the steps involved in conducting abuilding audit.
10
DME Building Energy Audit Course 28
DEPARTMENT ofMINERALS and ENERGY
What is energyauditing?
“An energy audit is developing an understanding of the specific energy using patterns of a particular facility.”
Carl E. Salas, P.E.
“An energy audit is developing an understanding of the specific energy using patterns of a particular facility.”
Carl E. Salas, P.E.
DME Building Energy Audit Course 29
DEPARTMENT ofMINERALS and ENERGY
How is energymanagement done?
Purchase energysupplies at thelowest possibleprice.Manage energy useat peak efficiency.Utilize the mostappropriatetechnology.
DME Building Energy Audit Course 30
DEPARTMENT ofMINERALS and ENERGY
Managing Technology
No cost -housekeepingmeasuresLow cost - sometechnology, lots ofpeople inputHigh cost - capitalinvestment
11
DME Building Energy Audit Course 31
DEPARTMENT ofMINERALS and ENERGY
Energy consumingsystems in buildings
Organization /Site
Building B
Department BDepartment A Department C
System BSystem A System C
Equipment A
Building A
Department ...
System _System _
Equip...Equip...Equip...Equip...Equip...Equipment CEquipment B
DME Building Energy Audit Course 32
DEPARTMENT ofMINERALS and ENERGY
A basis for the energy audit. . . what comes in, goes out
Oil or Natural Gas
Energy Inflow
Boiler Stack Loss
Exhaust
Warm Fluid to DrainDoor Heat Loss
Wall Heat Loss
WindowHeat Loss
Ventilation
Process Exhaust
Electricity
Energy Inflow
SolarEnergy Inflow
Energy System Boundary
DME Building Energy Audit Course 33
DEPARTMENT ofMINERALS and ENERGY
Two levels of audit
Preliminary AuditHigh level assessmentAssesses merits ofdoing detailed auditIdentifies areas offocus for detailedauditIncludes walk-throughand preliminary dataanalysis
Detailed AuditGreater detail inassessment of specificareasIdentifies specificEMOs
12
DME Building Energy Audit Course 34
DEPARTMENT ofMINERALS and ENERGY
DME’s Audit Process
DME Building Energy Audit Course 35
DEPARTMENT ofMINERALS and ENERGY
Pre-site inspection datarequirements
Historical energy and water consumption and billingsdata for at least 12 months, preferably multi-year;Basic building configuration information, including atleast conditioned floor area;Building schedule and occupancy data;Breakdown of building uses by area (i.e. general office,computer facilities, library, cafeteria, etc.);Any other energy assessment data that may beavailable, including demand profiles, equipmentinventories, etc.Degree-day information applicable to the buildinglocation.
DME Building Energy Audit Course 36
DEPARTMENT ofMINERALS and ENERGY
Preliminary dataanalysis
Organise historical dataWhat are the patternsand trends?Calculate theEnergy/DemandIntensityCorrelate consumptionwith weather/occupancy
13
DME Building Energy Audit Course 37
DEPARTMENT ofMINERALS and ENERGY
Preliminary Audit
Purposethe need for or meritsof a detailed audit,based on performanceindices:
consumption index
demand index
Stepshistorical analysiscollect building datademand profilewalk-throughtariff analysis
MJ/m2/year
VAaverage/m2/month
DME Building Energy Audit Course 38
DEPARTMENT ofMINERALS and ENERGY
Preliminary auditfindings
Building performanceindicesDemand profileanalysisPotential savingsopportunitiesConfirmation of tariff
DME Building Energy Audit Course 39
DEPARTMENT ofMINERALS and ENERGY
Detailed audit
Purposeidentify specificmeasures to reduceconsumption, demand,cost
Stepsexamine site drawingsprepare load inventoryassess demand profileassess all energy loadareasprovide baselinecriterionassess tariff changeopportunity
14
DME Building Energy Audit Course 40
DEPARTMENT ofMINERALS and ENERGY
Auditing – the “bigpicture”
How and where energy enters the facility,department, system or piece ofequipment;Where it goes and how it is used;Any variances between inputs and uses;How it can be used more effectively orefficiently.
DME Building Energy Audit Course 41
DEPARTMENT ofMINERALS and ENERGY
Ten StepsPreliminary Client Meeting and
Historical Data Analysis1. Conduct a Walk-through
Inspection2. Analyze Energy Consumption
and Costs3. Compare Energy Performance4. Establish the Audit Mandate5. Establish the Audit Scope6. Profile Energy Use Patterns7. Inventory Energy Use8. Identify Energy Management
Opportunities9. Assess the Benefits10.Report for Action
Initial ClientMeeting
(1) PreliminaryWalk-through
Historical DataAnalysis
(2) AnalyseEnergy
Consumption &Costs
(3) ComparativeAnalysis
Preliminary Audit
(4) DetermineAudit Mandate
(5) Define AuditScope
Audit Plan
(1) Detailed Walk-throughs
(6) AnalyseEnergy Use
Patterns
(7) InventoryEnergy Use
(8) Identify EMOs
EMOA ssessment
Required
(9) Assess theBenefits
(10) Audit Reportf or Action
Engineering Study
Engineering Report
Detailed Audit
EMOs
EMOs
EMOsEMOs
EMOs
EMOs
DetailedAssessment
DME Building Energy Audit Course 42
DEPARTMENT ofMINERALS and ENERGY
Planning for the audit
Audit mandate and scopeDates and places where the audit is to be conductedDetails of the organizational and functional units to beaudited and contactsIdentification of the energy audit elements that are ofhigh priorityExpected time and duration for major audit activitiesIdentification of audit team membersAudit report content and format, expected date of issueand distribution.
15
DME Building Energy Audit Course 43
DEPARTMENT ofMINERALS and ENERGY
Coordination with O&M personneland building occupants
Review the purposes, scope and plan of the audit –change as neededDescribe audit methodologiesDefine communication linksConfirm availability of resources and facilitiesConfirm schedule of meetings with management groupInform about site health, safety and emergencyproceduresAnswer questions - create comfort level with the auditpurposes and outcomes.
DME Building Energy Audit Course 44
DEPARTMENT ofMINERALS and ENERGY
Step 1: the walk-through
Where energy isbeing wasted;Where repair ormaintenance work isneeded;Where capitalinvestment may beneeded to improveenergy efficiency.
(1) PreliminaryWalk-through
Historical DataAnalysis
(2) AnalyseEnergy
Consumption &Costs
DME Building Energy Audit Course 45
DEPARTMENT ofMINERALS and ENERGY
Step 2: Analyse energyconsumption and costs
Understand the tariffsAssess the trendsCorrelate to independentvariables (e.g. weather,occupancy, schedule)Unit energy costIncremental energy cost– what does the next unitconsumed, or the firstunit saved cost
(1) PreliminaryWalk-through
(2) AnalyseEnergy
Consumption &Costs
(3) ComparativeAnalysis
16
DME Building Energy Audit Course 46
DEPARTMENT ofMINERALS and ENERGY
Step 3: Comparativeanalysis
Two kinds ofcomparison:
Internal - period toperiod, site to site;External - tostandards ofperformanceestablished in thebuildings sector.
(1) PreliminaryWalk-through
(2) AnalyseEnergy
Consumption &Costs
(3) ComparativeAnalysis
DME Building Energy Audit Course 47
DEPARTMENT ofMINERALS and ENERGY
Data analysis
Energy density:MJ/m2/year
Demand density:VAaverage/m2/month
Correlation withweather - HDD andCDD
DME Building Energy Audit Course 48
DEPARTMENT ofMINERALS and ENERGY
Performance indices
Consumption
Demand
MJ/m2/year
VAaverage/m2/month
17
DME Building Energy Audit Course 49
DEPARTMENT ofMINERALS and ENERGY
Energy use drivers
ClimateFacility size & AgeSchedulesEquipment typeBuilding designProcessesOrganisational cultureBehaviour
DME Building Energy Audit Course 50
DEPARTMENT ofMINERALS and ENERGY
Types of comparisons
External benchmarksInternal benchmarks
multiple facilitiesHistorical consumptionTrends and patterns
DME Building Energy Audit Course 51
DEPARTMENT ofMINERALS and ENERGY
Benchmarking is…
A methodology to improve energyperformanceComparison of energy performance to a“standard”Investigation of the differences betweenexisting and “standard” practicesDriving action to improve practices
18
DME Building Energy Audit Course 52
DEPARTMENT ofMINERALS and ENERGY
Selected benchmarks
Demand intensityVA/m2
relates to size/number of electricity consumers
Electric energy intensitykWhE/m2
relates to size/number/duration of electricity use
Cooling or heating energy intensitykWhC/m2 or kWhH/m2
Total energy intensitykWhT/m2 = kWh(C or H)/m2 + kWhE/m2
DME Building Energy Audit Course 53
DEPARTMENT ofMINERALS and ENERGY
Best practices
Proven solutions for improvingperformanceExternal sources:
Industry / sector case studiesSurvey / study groups
Internal sources:Individuals/groupsBest historical performance
DME Building Energy Audit Course 54
DEPARTMENT ofMINERALS and ENERGY
“This facility is different from those benchmarks!”
Investigate thedifferencesThe opportunitieslie in thedifferences
19
DME Building Energy Audit Course 55
DEPARTMENT ofMINERALS and ENERGY
Step 4: Define the auditmandate
Clarification of thegoals and objectivesof the audit, and thekey constraints thatwill apply to actionson itsrecommendations
(4) DetermineAudit Mandate
(5) Define AuditScope
Audit Plan
DME Building Energy Audit Course 56
DEPARTMENT ofMINERALS and ENERGY
Step 5: Define the auditscope
Specification ofThe physical extent ofthe auditThe energy inputs andoutputsThe sub-systems to beassessed
(4) DetermineAudit Mandate
(5) Define AuditScope
Audit Plan
DME Building Energy Audit Course 57
DEPARTMENT ofMINERALS and ENERGY
Step 6: Profile energyconsumption
Electrical demand profile:Time pattern ofconsumptionSystem sizingDemand reductionopportunitiesPower factor correction?Loads on when they don’tneed to be?
(1) Detailed Walk-throughs
(6) AnalyseEnergy Use
Patterns
(7) InventoryEnergy Use
EMOs
EMOs
EMOs
20
DME Building Energy Audit Course 58
DEPARTMENT ofMINERALS and ENERGY
Step 7: Inventoryenergy loads
Electrical load inventory:How much and how fast?Where?
Thermal load inventory:An energy flow diagram
(6) AnalyseEnergy Use
Patterns
(7) InventoryEnergy Use
(8) Identify EMOs
EMOs
EMOs
DME Building Energy Audit Course 59
DEPARTMENT ofMINERALS and ENERGY
Step 8: Identify EMOs
STEP 1 - Match usageto requirementSTEP 2 - Maximisesystem efficienciesSTEP 3 - Optimise theenergy supply
Begin the search for opportunitieswhere the energy is the most
expensive – at the point of end use!
(7) InventoryEnergy Use
(8) Identify EMOs
EMOAssessment
Required
EMOs
DME Building Energy Audit Course 60
DEPARTMENT ofMINERALS and ENERGY
Step 9: Assess the costsand benefits
What benefits shouldbe taken into accountWhat costs should beincluded in theanalysisWhat economicindicators should beused
EMOAssessment
Required
(9) Assess theBenefits
(10) Audit Reportfor Action
21
DME Building Energy Audit Course 61
DEPARTMENT ofMINERALS and ENERGY
Costs and benefits
Benefitsdirect energy savingsindirect energysavingscomfort/productivityincreasesoperating andmaintenance costreductionsenvironmental impactreduction
Costsdirect implementationcostsdirect energy costsindirect energy costsO&M cost increase
DME Building Energy Audit Course 62
DEPARTMENT ofMINERALS and ENERGY
Step 10: Report forimplementation
Provide a clearaccount of the factsupon which yourrecommendations aremadeInterest those whoread the report inacting upon thoserecommendations
EMOAssessment
Required
(9) Assess theBenefits
(10) Audit Reportfor Action
DEPARTMENT OF MINERALS AND ENERGYDME-Danida Capacity Building in Energy Efficiency & Renewable Energy
Module 4: HistoricalEnergy Assessment
Understanding the patternsof energy use
22
DME Building Energy Audit Course 64
DEPARTMENT ofMINERALS and ENERGY
Learning objectives
Identify data sources for the assessment of thebuilding’s energy performanceDescribe the instrumentation used for energyauditsAnalyse the energy tariffs that apply to thebuildingCorrelate energy consumption to buildingoperational parameters and weather
DME Building Energy Audit Course 65
DEPARTMENT ofMINERALS and ENERGY
Analyzing performancerequires energy data
0 200 400 600 800 10000
40
80
120
160
200
240
280
320
Weather ( HDD )
Energy (GJ)Gas Energy vs. Weather
ABC Facility for 1999
GJ = 0.395 x HDD + 12 [ R-sq = 0.91 ]
$0
$10,000
$20,000
$30,000
$40,000
JanFeb
MarApr
MayJun
JulAug
SepOct
NovDec
On-Peak Energy Off-Peak Energy Demand
Energy Cost Demand Cost
Electricity Cost Breakdown for 1999ABC Facility
DME Building Energy Audit Course 66
DEPARTMENT ofMINERALS and ENERGY
Data requirements
Historical energyconsumption dataMetered energyconsumptionBuilding configurationWeather dataEnergy system nameplatedatamechanical, electrical,architectural plans andspecifications
building automationsystem (BAS)documentationmaintenance logskey plans (floor plans)contact information forbuilding operationalpersonnel or servicecontractors
23
DME Building Energy Audit Course 67
DEPARTMENT ofMINERALS and ENERGY
Instrumentation forauditing
Electric Power MeterCombustion AnalyzerDigital ThermometerInfrared ThermometerPsychrometer (HumidityMeasurement)Air Flow MeasurementDevicesTachometerUltrasonic Leak Detector
Other useful items:A cameraBinoculars and a smallflashlightDuct tape & Tie WrapsMulti- screw driver, adjustablewrench and pliersTape measureBucket and stopwatchSafety Glasses, Gloves & EarPlugsCaution tape
DME Building Energy Audit Course 68
DEPARTMENT ofMINERALS and ENERGY
Hand-held wattmeter
DME Building Energy Audit Course 69
DEPARTMENT ofMINERALS and ENERGY
Single-phaseconnections
24
DME Building Energy Audit Course 70
DEPARTMENT ofMINERALS and ENERGY
3-phase digital powermeter
DME Building Energy Audit Course 71
DEPARTMENT ofMINERALS and ENERGY
Combustion analysis
Fuel - carbon - hydrogen - sulpher
Combustion Air (TC) - oxygen - nitrogen
Heat (75- 85%)
Combustion
Flue Gas (TS) - CO2 - nitrogen, NOx - water - excess air - SOx - VOC - CO
DME Building Energy Audit Course 72
DEPARTMENT ofMINERALS and ENERGY
Light levelmeasurement
Table 5.14RECOMMENDED ILLUMINANCE LEVELS,
POWER DENSITIES AND SURFACE REFLECTANCESPower Den-
sityReflectances % Area and Task Illuminance
W/m2 Ceiling Walls Floor
Offices - accounting - drafting
-general
750 - 950750 - 950540 - 700
252518
70 - 80 40 - 60 20 - 40
Corridors 210 5.5 Lobbies 320 9
Cafeterias and Kit-chens
320 - 50014
70 - 80 40 - 80 20 - 40
Lecture Rooms 540 - 700 18 70 - 80 40 - 60 20 - 40 Toilet Areas 320 9 Laboratories 750 - 950 25 70 - 80 40 - 80 20 - 40
Production - general 750 - 950 25 Warehouses 320 9 Roadways 50 2
Parking 50 2
25
DME Building Energy Audit Course 73
DEPARTMENT ofMINERALS and ENERGY
Temperaturemeasurement
DME Building Energy Audit Course 74
DEPARTMENT ofMINERALS and ENERGY
Humidity measurement
DME Building Energy Audit Course 75
DEPARTMENT ofMINERALS and ENERGY
Static pressure
26
DME Building Energy Audit Course 76
DEPARTMENT ofMINERALS and ENERGY
Leak detection - ventilationand compressed air
DME Building Energy Audit Course 77
DEPARTMENT ofMINERALS and ENERGY
Check your speed -digital tachometer
DME Building Energy Audit Course 78
DEPARTMENT ofMINERALS and ENERGY
An electricity tariff
AdministrativechargeDemand chargeper kVA
May be time of use– on-peak/off-peak
Energy charge perkWh
27
DME Building Energy Audit Course 79
DEPARTMENT ofMINERALS and ENERGY
Analysing theelectricity billings
Electricity Consumption Data Location:
[ C:\Project Files\Audit Manual\Spreadsheets\[Electricity Cost.xls]Electicity Consumption Data ]
Billing Metered Metered Power Billed Energy Daily Load Demand Energy Adjust Sub TotalDate kVA kW Factor kW kWh Days kWh Factor Cost Cost (+/-) Total Cost
01/01/99 1,800.0 1,800.0 1,006,703 30 33,557 78% $21,250 $50,365 ($11,147) $71,615 $64,70102/01/99 1,900.0 1,900.0 1,206,383 31 38,916 85% $22,750 $56,441 ($13,204) $79,191 $70,60703/01/99 1,400.0 1,400.0 842,286 28 30,082 90% $15,250 $42,144 ($9,263) $57,394 $51,50104/01/99 1,850.0 1,850.0 1,102,176 31 35,554 80% $22,000 $53,315 ($12,132) $75,315 $67,60605/01/99 1,870.0 1,870.0 1,213,021 30 40,434 90% $22,300 $56,641 ($13,252) $78,941 $70,28706/01/99 2,200.0 2,200.0 1,339,599 31 43,213 82% $27,250 $60,438 ($14,716) $87,688 $78,08007/01/99 1,560.0 1,560.0 850,195 30 28,340 76% $17,650 $42,540 ($9,438) $60,190 $54,30408/01/99 1,570.0 1,570.0 948,747 31 30,605 81% $17,800 $47,467 ($10,429) $65,267 $58,67709/01/99 1,950.0 1,950.0 1,213,798 31 39,155 84% $23,500 $56,664 ($13,308) $80,164 $71,53610/01/99 2,300.0 2,300.0 1,373,054 30 45,768 83% $28,750 $61,442 ($15,111) $90,192 $80,33711/01/99 2,100.0 2,100.0 1,347,059 31 43,454 86% $25,750 $60,662 ($14,731) $86,412 $76,69912/01/99 2,400.0 2,400.0 1,024,475 30 34,149 59% $30,250 $50,984 ($11,685) $81,234 $74,418
Totals/Max 2,400.0 2,400.0 13,467,496 364 $274,500 $639,104 ($148,415) $913,604 $818,752
ABC Facility
$0$20,000$40,000$60,000$80,000
$100,000
Jan-
99
Feb-
99
Mar
-99
Apr-9
9
May
-99
Jun-
99
Jul-9
9
Aug-
99
Sep-
99
Oct
-99
Nov
-99
Dec
-99
Cost
($)
Energy Cost Demand Cost
Monthly Demand (kW)
0.0
500.0
1,000.0
1,500.0
2,000.0
2,500.0
3,000.0
Daily Energy (kWh/day)
0
10,00020,000
30,000
40,00050,000
Jan-
99
Feb-
99
Mar
-99
Apr-9
9
May
-99
Jun-
99
Jul-9
9
Aug-
99
Sep-
99
Oct
-99
Nov-
99
Dec
-99
9
Monthly Load Factor (%)
78%85% 90%
80%90%
82%76%
81% 84% 83% 86%
59%
0%
20%
40%
60%
80%
100%
DME Building Energy Audit Course 80
DEPARTMENT ofMINERALS and ENERGY
Load factor
100#24
(%) xperiodindaysxdayperhrxkWPeak
periodinusedkWhFactorLoad =
Monthly Load Factor (%)
78%85% 90%
80%90%
82%76%
81% 84% 83% 86%
59%
0%
20%
40%
60%
80%
100%
Low load factorsmean excessivedemand for ashort duration -and higher thannecessary cost.
DME Building Energy Audit Course 81
DEPARTMENT ofMINERALS and ENERGY
Graphical analysis ofhistorical energy use
Building "A"Gas Space Heat & Gas Domestic Hot Water, Electric A/C
02,0004,0006,0008,000
10,00012,00014,00016,000
Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec
Equi
vale
nt k
Wh
Monthly Electricity Consumption Monthly Gas Consumption
Building "B"Electric Space Heat, Electric A/C, Gas Domestic Hot Water
02,0004,0006,0008,000
10,00012,00014,00016,00018,000
Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec
Equi
vale
nt k
Wh
Monthly Electricity Consumption Monthly Gas Consumption
Building "C"Gas Space Heat & Domestic Hot Water, no A/C
0
2,000
4,000
6,000
8,000
10,000
12,000
Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec
Equi
vale
nt k
Wh
Monthly Electricity Consumption Monthly Gas Consumption
Building "D"Gas Space Heat & Process Heat, 2 Week August Shutdown
0
2,000
4,000
6,000
8,000
10,000
12,000
Jan Feb Mar Apr May June July Aug Sept Oct Nov Dec
Equi
vale
nt k
Wh
Monthly Electricity Consumption Monthly Gas Consumption
28
DME Building Energy Audit Course 82
DEPARTMENT ofMINERALS and ENERGY
Calculating degree-days
DME Building Energy Audit Course 83
DEPARTMENT ofMINERALS and ENERGY
Correlation of energyconsumption to degree-days
DEPARTMENT OF MINERALS AND ENERGYDME-Danida Capacity Building in Energy Efficiency & Renewable Energy
Module 5: EnergyAssessment - DemandAnalysis
Understanding the timepatterns of energy use
29
DME Building Energy Audit Course 85
DEPARTMENT ofMINERALS and ENERGY
Learning objectives
Obtain an electrical demand profile,interpret it, and identify possible EMOs;Identify opportunities for power factorcorrection.
DME Building Energy Audit Course 86
DEPARTMENT ofMINERALS and ENERGY
Hourly Demand Profile
Hour of the Day1
23
45
67
89
1011
1213
1415
1617
1819
2021
2223
240
20
40
60
80
100
120
140
DME Building Energy Audit Course 87
DEPARTMENT ofMINERALS and ENERGY
An ElectricalFingerprint
800
1000
1200
1400
1600
1800
2000
Kilo
wat
ts
Time of Day (00:00 - 24:00)
Peak Day Demand Profile15 minute demand interval
30
DME Building Energy Audit Course 88
DEPARTMENT ofMINERALS and ENERGY
Patterns Revealed
Peak DemandNight LoadStart-UpShut-DownWeather Effects
Loads that CycleInteractionsOccupancy EffectsProduction EffectsProblem Areas
DME Building Energy Audit Course 89
DEPARTMENT ofMINERALS and ENERGY
Analyzing the Profile
Requires facility operational knowledgeMark scheduled events on the profileCorrelate events with:
Demand increase, decrease, cycling, peaks
Reconcile with demand on utility billsInvestigate unknown patterns
“There’s always a savings opportunity in anew demand profile”
DME Building Energy Audit Course 90
DEPARTMENT ofMINERALS and ENERGY
Obtaining a DemandProfile
Periodic utility meter readingsRecording clip-on ammeter measurementsBasic recording power meterMulti-channel recording power metersA Facility energy management or SCADAsystemA dedicated monitoring system
31
DME Building Energy Audit Course 91
DEPARTMENT ofMINERALS and ENERGY
Obtaining a demandprofile
DC
AC
START STOP OFFON
CHART POWER
L1
L2
L3
CLIP-ON AMMETER
RECORDER
3 phase power fromsingle phasemeasurement:
kVA = Amps xVolts x 1.73 ÷ 1000
DME Building Energy Audit Course 92
DEPARTMENT ofMINERALS and ENERGY
3 phase measurement
DME Building Energy Audit Course 93
DEPARTMENT ofMINERALS and ENERGY
Daily or monthly
400
600 800
1000 1200
1400 1600
1800 2000
kilo
wat
ts
Day of the Month
Monthly Demand Profile15 minute demand interval
32
DME Building Energy Audit Course 94
DEPARTMENT ofMINERALS and ENERGY
Meter response
Loaddisconnected
Loadconnected
DME Building Energy Audit Course 95
DEPARTMENT ofMINERALS and ENERGY
What the demand metersees
20
15
10
5
0
DME Building Energy Audit Course 96
DEPARTMENT ofMINERALS and ENERGY
Savings opportunities
Scheduling – reduce startup peaksInfrequent demand peaks – avoidableShift on-peak to off-peak usage patternEquipment loading – consider sequencing
33
DME Building Energy Audit Course 97
DEPARTMENT ofMINERALS and ENERGY
Peak demand control
Eliminate accidental peaks Shift activity “off-peak” Peak demand warning for staff Interlock equipment Load shedding system Use generator to “clip” the peak
DME Building Energy Audit Course 98
DEPARTMENT ofMINERALS and ENERGY
Power factor correction
Correct power factor – on peakat service entrancein the distribution systemat the point of use power factor
DME Building Energy Audit Course 99
DEPARTMENT ofMINERALS and ENERGY
Analyse this!
34
DEPARTMENT OF MINERALS AND ENERGYDME-Danida Capacity Building in Energy Efficiency & Renewable Energy
Module 6: EnergyAssessment - Load Inventory
Understanding whereenergy is used
DME Building Energy Audit Course 101
DEPARTMENT ofMINERALS and ENERGY
Learning objectives
Create an energy load inventory, andreconcile it to consumption data
DME Building Energy Audit Course 102
DEPARTMENT ofMINERALS and ENERGY
Analyse the loadinventory
Where is electricity used?How much - i.e. consumptionHow fast - i.e. demand
35
DME Building Energy Audit Course 103
DEPARTMENT ofMINERALS and ENERGY
Lights40.0%
A/C40.0%
Plug Power20.0%
Demand
Lights50.0%
A/C15.0%
Plug Power35.0%
Energy
Why inventory?
Focus your effortsEstablish a basis for savings calculations
DME Building Energy Audit Course 104
DEPARTMENT ofMINERALS and ENERGY
Inventory calculations
Item Units Formula
Quantity (a number)
Unit Load kW
Total kW kW Quantity. x Unit Load.
Hrs/Period hours
kWh/Period kWh Total kW x Hrs/Period Diversity Factor (Div’ty Factor) 0 - 100%
Peak kW kW kW x Diversity Factor
DME Building Energy Audit Course 105
DEPARTMENT ofMINERALS and ENERGY
Demand breakdown
Demand Breakdown
Lighting50%
Motors25%
Other25%
Demand Breakdown
Lighting50%
Motors25%
Other25%
36
DME Building Energy Audit Course 106
DEPARTMENT ofMINERALS and ENERGY
Peak demandbreakdown
Peak Demand Breakdown
Lighting45%
Motors27%
Other28%
Peak Demand Breakdown
Lighting45%
Motors27%
Other28%
DME Building Energy Audit Course 107
DEPARTMENT ofMINERALS and ENERGY
Energy breakdown
Energy Breakdown
Lighting52%Motors
35%
Other13%
Energy Breakdown
Lighting52%Motors
35%
Other13%
DME Building Energy Audit Course 108
DEPARTMENT ofMINERALS and ENERGY
Sample inventory
Loads QtyUnit KW
Total KW
DiversityFactor
PeakKW Hours KWH
Fluorescent F96 4 0.165 0.66 1 0.7 300 198Incandescent 100 w 24 0.1 2.4 0.9 2.2 100 240400w MH Lights 21 0.465 9.765 1 9.8 420 4,101Compressor.(60HP) 1 50 50 1 50.0 400 20,000Pump (20 HP) 1 16 16 0.75 12.0 400 6,400Micro-Wave 1 0.75 0.75 0.1 0.1 2 2Coffee Machine 2 1.5 3 1 3.0 200 600
Total 83 77.7 31,541
37
DME Building Energy Audit Course 109
DEPARTMENT ofMINERALS and ENERGY
Energy flow diagram
Oil or Na tural Gas
Energy Inflow
Boiler Stack L oss
Exhaust
W arm F lu id to DrainDoor Heat Loss
W all Heat Loss
W indo wHeat Loss
Ventilat ion
Process Exhaust
Electric ity
Energ y Inflow
SolarEnergy Inflow
E nergy S ystem B oundary
DME Building Energy Audit Course 110
DEPARTMENT ofMINERALS and ENERGY
Thermal energyinventory
Energy Flow Type Example Equipment/Functions
Conduction Wall, windows Building structure.
Air Flow - Sensible General exhaust Exhaust and makeup air systems,combustion air intake.
Air Flow - Latent Dryer exhaust Laundry exhaust, pool ventilation,process drying equipment exhaust.
Hot or Cold Fluid Warm water to drain.Domestic hot water, process hot water,process cooling water, water cooled aircompressors.
Pipe Heat Loss Steam pipeline. Steam pipes, hot water pipes, any hotpipe.
Tank Heat Loss Hot fluid tank. Storage and holding tanks.Refrigeration systemoutput heat Cold storage. Coolers, freezers, process cooling, air
conditioning.
Steam Leaks and Vents Steam vent Boiler plant, distribution system,steam appliance.
DEPARTMENT OF MINERALS AND ENERGYDME-Danida Capacity Building in Energy Efficiency & Renewable Energy
Module 7: EnergyAssessment - EMOs
Finding energymanagement opportunities
38
DME Building Energy Audit Course 112
DEPARTMENT ofMINERALS and ENERGY
Learning objectives
Systematically identify EMOs;Describe the factors that need to beconsidered in assessing costs andbenefits.
DME Building Energy Audit Course 113
DEPARTMENT ofMINERALS and ENERGY
Finding opportunities:Start at the end-use
1st Analyze Present Usage
2nd Identify and Quantify the Savings Opportunities
Meter
End-Use
DME Building Energy Audit Course 114
DEPARTMENT ofMINERALS and ENERGY
Start at point of end-use
PipingNetwork
DistributionSystem
Motor
Bearings
Pump
FlowControlValve
Utility Meter
End-Use HeatExchanger
Other HeatExchanger
39
DME Building Energy Audit Course 115
DEPARTMENT ofMINERALS and ENERGY
Component efficiencies
PipingNetwork
60%
DistributionSystem
96%
Motor85%
Bearings98%
Pump60%
FlowControlValve70%
Utility Meter 100%
End-Use HeatExchanger
Other HeatExchanger
DME Building Energy Audit Course 116
DEPARTMENT ofMINERALS and ENERGY
System efficiency
Distribution
Meter Motor Pump
ValvePiping
Bearing
Energy In
Energy Out
Only 20%
DME Building Energy Audit Course 117
DEPARTMENT ofMINERALS and ENERGY
Component and systemefficiencies
20%Overall60%Piping70%Valve60%Pump98%Bearing85%Motor96%Distribution
100%MeterTypical EfficiencyComponent
40
DME Building Energy Audit Course 118
DEPARTMENT ofMINERALS and ENERGY
Three simple steps
Start with a valid needWaste-loss analysis
i.e. match and maximize
Optimize the supply
DME Building Energy Audit Course 119
DEPARTMENT ofMINERALS and ENERGY
Why this order?
End-use actions influence all other partsof the system – do this firstLower cost actions are operational – atend-useHigher cost actions are technological –higher efficiency componentsEnd-use determines supply requirement
DME Building Energy Audit Course 120
DEPARTMENT ofMINERALS and ENERGY
Match the requirement
Setback temperaturesTurn-off lights in unoccupied areasProvide task—rather than general — lightingAvoid dampers / throttling – match flows by:
Resizing the fan/pumpInstalling a variable speed drive on fan/pump motor
Provide ventilation on demand
41
DME Building Energy Audit Course 121
DEPARTMENT ofMINERALS and ENERGY
Maximise efficiencies
Reduce ventilation duct flowrestrictionsClean air filters regularlyKeep heat exchange surfacescleanUse a higher efficacy light sourceInstall a high efficiency motor
DME Building Energy Audit Course 122
DEPARTMENT ofMINERALS and ENERGY
Assessing the costsand benefits
Benefits:direct energy savingsindirect energy savingscomfort/productivityincreasesoperating and maintenancecost reductionsenvironmental impactreductionO&M savings
Costs:direct implementationcostsdirect energy costsindirect energy costsO&M cost increase
DME Building Energy Audit Course 123
DEPARTMENT ofMINERALS and ENERGY
More about savingsEnergy Savings: energy saved x incremental energy rateDemand Savings: kVA saved x incremental demand rateThermal Fuel Savings: Fuel Energy Saved = Point of Use Energy Saved÷ Heating Plant Efficiency
Fuel Cost Saved = Fuel Energy Saved x Incremental Cost of Fuel ÷Energy Content of Fuel
Indirect electrical savingse.g. reduced A/C loads due to more efficient lighting:
A/C kWh Saved = Lighting kWh saved ÷ COPLess re-lamping labour and lamp cost from switching to a longer-lifelamp typeIncrease in employee productivity from converting to a higher quality,higher efficiency fixture type.
42
DME Building Energy Audit Course 124
DEPARTMENT ofMINERALS and ENERGY
More about costs
Initial cost of implementing the retrofitDecrease in lamp life - increased re-lamping costs
Decrease in lamp life due to increase in switching
Any increase in maintenance costs such as higher costlamps and ballastsHigher cost of repairs or lower life of any replacementenergy-efficient equipmentIndirect energy costs:
Increase in heating costs due to more efficient or switchedlighting
DEPARTMENT OF MINERALS AND ENERGYDME-Danida Capacity Building in Energy Efficiency & Renewable Energy
Module 8: Energy Efficiencyin Building Electrical Systems
Electrical energymanagement opportunities
DME Building Energy Audit Course 126
DEPARTMENT ofMINERALS and ENERGY
Learning objectives
Describe building performance standardsIdentify and assess energy efficiencyopportunities for lighting systems;miscellaneous plug loads; motors, drives,fans and pumps.
43
DME Building Energy Audit Course 127
DEPARTMENT ofMINERALS and ENERGY
Building performancestandards - SAEDES®
Intended to:Minimise ODS useMinimise GHGemissionConserve non-renewable energyresourcesOptimise buildingperformance toachieve the economicbenefits
Provisions:Minimum demand andenergy efficiency ofnew buildingsBuilding performanceparametersClimate dataApplication of otherstandardsDetailed technicalcriteria
DME Building Energy Audit Course 128
DEPARTMENT ofMINERALS and ENERGY
SAEDES performancestandards
Area
Lux
W/m2 General Office Space Computer Rooms & Drafting Areas Public Areas (Foyer & Corridors) Stairs Kitchen Toilets Car Park Plant Rooms Retail
400 600
200 - 400 50 - 100 200-300
100 50 - 100
100 - 200 400 - 800
17 26
7 - 17 3 - 5
10 - 16 5
3 - 5 5 - 10 8 - 25
DME Building Energy Audit Course 129
DEPARTMENT ofMINERALS and ENERGY
. . . And climate data
SI Units (EC)
City
Latitude
Longitude
Elev (m)
HDD
CDD
Win. Des. 99%
Summer
DB 2,5%
WB 2,5%
CapeTown/ D F Malan
33,97S
18,60E
46
936
2474
22
72
53
Johannesburg
26,13S
28,23E
1694
1066
2362
13
65
51
Pretoria
25,73S
28,18E
1330
639
3,238
14
69
51
44
DME Building Energy Audit Course 130
DEPARTMENT ofMINERALS and ENERGY
SABS 0400-1990 –ventilation rates
Minimum Air Requirement, l/s (per person except
where noted)
Occupancy Smoking Non-smoking
Educational Buildings Classrooms Laboratories
Libraries
- - -
7,5 7,5 6,5
Shops Malls, arcades, warehouses
Sales floors, showrooms, dressing rooms
7,5 7,5
7,5 7,5
Garages Parking garages
Ticket kiosks
per m2 floor area 7,5 5,0
per m2 floor area 7,5 5,0
Libraries General
Bookstock
- -
6,5 3,5
Offices General
Meeting and waiting spaces Conference and board rooms
Cleaner’s rooms
7,5 7,5
10,0 1,0
5,0 5,0 5,0 1,0
DME Building Energy Audit Course 131
DEPARTMENT ofMINERALS and ENERGY
The building as an energysystem
What are theinteractions?
Heat from lightsHumidityreduction by ACIncreased freshair requirementfrom reductionof infiltrationOthers?
DME Building Energy Audit Course 132
DEPARTMENT ofMINERALS and ENERGY
Other impacts of energyreduction
Power quality – introduction ofharmonics?Indoor air quality – changes withventilation/infiltration ratesGreenhouse gas emissions – CO2 emissionreduction has monetary value
45
DME Building Energy Audit Course 133
DEPARTMENT ofMINERALS and ENERGY
Lighting system
Ceiling Fixture
Lamps (light source)Ballast
Lens or Diffuser
Floor
Switch
Work SurfaceThe Requirement
Walls
DME Building Energy Audit Course 134
DEPARTMENT ofMINERALS and ENERGY
Lighting considerations
Minimise operating time Ensure appropriate levels and quality Maximise efficiency of delivery Maximise the source efficiency
Lamp efficiency = efficacy
DME Building Energy Audit Course 135
DEPARTMENT ofMINERALS and ENERGY
Lighting quality
Illumination level Uniformity Absence of glare Colour temperature Colour rendition index (CRI)
46
DME Building Energy Audit Course 136
DEPARTMENT ofMINERALS and ENERGY
Colour renderingindex (CRI)
Light Source CRI RenderingIncandescent lamps 97 ExcellentFL, full spectrum 7500 94 ExcellentFL, cool white deluxe 87 ExcellentCompact Fluorescent 82 ExcellentFL, Warm White deluxe 73 GoodMH (400 W clear) 65 GoodHPS (250 W deluxe) 65 GoodFl, Cool White 62 GoodFL, Warm White 52 FairMV (phosphor-coated) 43 PoorHPS (400 W diffuse coated) 32 PoorMV (clear) 22 PoorLow Pressure Sodium --- Impossible
DME Building Energy Audit Course 137
DEPARTMENT ofMINERALS and ENERGY
Light source efficacy
Lamp Type Lumens/Watt Incandescent 10 - 18 Mercury Vapour 20 - 50 Fluorescent 40 - 100 Metal Halide 60 - 100 High Pressure Sodium 60 - 120 Low Pressure Sodium 90 - 200
DME Building Energy Audit Course 138
DEPARTMENT ofMINERALS and ENERGY
Some questions
Are lights on when the space is unoccupied?Are lights on in an area served by daylight?Is lighting switched from breakers?Is there sufficient and convenient switchingavailable?Is the level of light appropriate for the task athand?Is regular maintenance performed?
47
DME Building Energy Audit Course 139
DEPARTMENT ofMINERALS and ENERGY
Summary of lightingopportunities
Lower Cost – match the requirement Better switching - more switches & levels Occupancy sensors & timers Reduce overall level & use task lights
Higher Cost – improve the efficiency Upgrade to a more efficient fixture Use a more effective fixture layout Use a more efficient light source
DME Building Energy Audit Course 140
DEPARTMENT ofMINERALS and ENERGY
EMOs for lighting
Switch off unnecessary lightsRemove redundant fixturesDelampingRelampingModifications or replacement
Remove or replace fixture lensesRetrofit the existing lighting system with a moreefficient systemReplace inefficient ballasts
Clean light fixtures, lamp reflectors and roomsurfaces
DME Building Energy Audit Course 141
DEPARTMENT ofMINERALS and ENERGY
Plug loads
Plug loads add upTurn them offSelect high efficiencymodels
48
DME Building Energy Audit Course 142
DEPARTMENT ofMINERALS and ENERGY
Electric motors
First, reduceunnecessary useEnsure properoperating conditionsProvide goodmaintenanceConsider an energyefficient motor
The motor is not the end-use; consider what is beingdriven.
DME Building Energy Audit Course 143
DEPARTMENT ofMINERALS and ENERGY
Imbalance =Inefficiency!
0
20
40
60
80
100
0 2 4 6 8 10
Voltage Imbalance (%)
Incr
ease
in L
osse
s (%
)
DME Building Energy Audit Course 144
DEPARTMENT ofMINERALS and ENERGY
Match the motor to theload
Motor Loading
Effi
cien
cy (%
)
0% 25% 50% 75% 100%
0%
25%
5
0%
75%
10
0%
49
DME Building Energy Audit Course 145
DEPARTMENT ofMINERALS and ENERGY
Operating conditions
Leading cause of motor failure is heat 10% temperature increase = ½ life Clean air vents Balance voltages Avoid too many starts
DME Building Energy Audit Course 146
DEPARTMENT ofMINERALS and ENERGY
Motor rewinding
Could reduce efficiency by 5%Depends upon rewind shopSpecify motor iron core test after rewindIt is realistic to expect minimal reductionin efficiency after a rewind
DME Building Energy Audit Course 147
DEPARTMENT ofMINERALS and ENERGY
Energy efficient motors
Loading (%) 100% Load 75% Load 50% LoadHP Type Eff'y P.F. Eff'y P.F. Eff'y P.F.11
EEStd
84.072.0
80.578.0
84.072.0
74.070.0
81.568.0
62.058.0
1010
EEStd
90.284.0
88.085.5
90.284.0
85.080.5
90.281.5
77.075.0
5050
EEStd
92.891.7
84.584.0
93.091.7
81.081.
91.790.2
73.071.5
100100
EEStd
93.591.7
91.583.5
94.091.7
91.080.5
93.890.2
87.073.0
200200
EEStd
94.893.0
90.588.5
95.093.0
88.586.5
94.691.7
83.080.0
50
DME Building Energy Audit Course 148
DEPARTMENT ofMINERALS and ENERGY
Watch your speed!
Energy efficient motors tend to havehigher rated/operating speeds.
1-3% higher rated speeds.
When driving a centrifugal load:A 1% speed increase = 3.5% power increase.
DME Building Energy Audit Course 149
DEPARTMENT ofMINERALS and ENERGY
Fans & pumps
Comprise significantload in buildingsTypically oversizedMisapplication iscommonProper flow controlcan yield largesavings
DME Building Energy Audit Course 150
DEPARTMENT ofMINERALS and ENERGY
Assessing fans &pumps
Match the need - make sure thefan/pump size matches the need for flowEnsure that the pump or fan is operatingat close to optimal conditions - if notreconsider the pump/fan selectionReduce resistance to flow in thedistribution systems - flow resistance,fittings, pipe/duct sizing
51
DME Building Energy Audit Course 151
DEPARTMENT ofMINERALS and ENERGY
Powerful laws
Q2
Q1
'N2
N1
P2
P1
'N2
N1
2 kW2
kW1
'N2
N1
3
Affinity laws for centrifugal fans and pumps.
N = speed, Q = flow, P = pressure, kW = power
DME Building Energy Audit Course 152
DEPARTMENT ofMINERALS and ENERGY
Efficiency optimisation
Capacity (litres/sec)
Head -Capacity
Efficiency
MaximumEfficiency atthis Point
SimilarCurve for
Fans
DME Building Energy Audit Course 153
DEPARTMENT ofMINERALS and ENERGY
Fan/Pump savingsstrategy
MaximizeEfficiency
Technological Operational
Match theRequirement
2
1
4
3Apply avariablespeed drive
Maintain &operate atbest point.
Turn it offor reducevolume.
Replacepump ormotor.
52
DME Building Energy Audit Course 154
DEPARTMENT ofMINERALS and ENERGY
Assessment questions
Is the fan/pump being throttled at thedischarge?Is the fan/pump doing a meaningful job?Is the fan/pump correctly sized?Check fan/pump curves; is fan/pumpoperating efficiently?Does the requirement for air/liquid vary?
DME Building Energy Audit Course 155
DEPARTMENT ofMINERALS and ENERGY
More fan/pumpquestions
Can the fan/pump be slowed down?Can the system head be reduced,ducts/pipes cleaned?Is the fan/pump excessively noisy, hot orvibrating?Are there leaks in the air distributionsystem?Is the fan being throttled at the inlet?
DME Building Energy Audit Course 156
DEPARTMENT ofMINERALS and ENERGY
Fan/pump EMOs
Clean and balance air distribution systemsCheck overall fan/pump sizing andefficiencyEliminate air flow reduction with dampers,fluid flow control with valvesUse a booster fan/pumpReduce fan/pump speed
53
DME Building Energy Audit Course 157
DEPARTMENT ofMINERALS and ENERGY
The advantage ofvariable speed
0
20
15
5
25
10
40% 60% 80% 100% FLOW
VariableSpeedMethod
ThrottlingMethod
PowerSaving!
HP
DEPARTMENT OF MINERALS AND ENERGYDME-Danida Capacity Building in Energy Efficiency & Renewable Energy
Module 9: Energy Efficiencyin Building Thermal Systems
Thermal energymanagement opportunities
DME Building Energy Audit Course 159
DEPARTMENT ofMINERALS and ENERGY
Learning objectives
Assess the heating and cooling load of abuilding;Identify and assess energy efficiencyopportunities for building envelope; HVACsystems including boilers, steam and hotwater distribution systems, air distributionsystems; and the application of buildingcontrol systems.
54
DME Building Energy Audit Course 160
DEPARTMENT ofMINERALS and ENERGY
Heating/cooling loads andthe “comfort zone”
DME Building Energy Audit Course 161
DEPARTMENT ofMINERALS and ENERGY
Heat loss and gain – basicrelationship
Q U A T T= × × −( )2 1
Q = Heat loss rate (W)U = 1 / R-value = Heat transfercoefficient (W/m2.oC)A = Surface area (m2)T2 = Indoor Temperature (oC)T1 = Outdoor Temperature (oC)
DME Building Energy Audit Course 162
DEPARTMENT ofMINERALS and ENERGY
Insulation EMOs – reduceheat loss/gain
Maintenance:Repair damagedinsulationRepair damagedcoverings and finishesMaintain safetyrequirements
Low-cost:Insulate non-insulatedpipes & fittingsInsulate non-insulatedvesselsAdd insulation toreach therecommended level
55
DME Building Energy Audit Course 163
DEPARTMENT ofMINERALS and ENERGY
Insulation EMOs
Retrofit:Upgrade existinginsulation levelsReview economicthickness requirementLimited budgetupgrade
New construction:High R materialsBuilding orientationHigh efficiency glazingWindow shadesFloor plans
DME Building Energy Audit Course 164
DEPARTMENT ofMINERALS and ENERGY
Infiltration/ExfiltrationEMOs
Caulk all cracksCaulk around all pipes,louvers, or other openings thatpenetrate the building skinRepair windowsWeatherstrip exterior doorsand windowsCover window air conditionersduring off seasonsInstall revolving doors,vestibule and automatic doorclosers
Q F T TA= × × −1232 2 1. ( )
DME Building Energy Audit Course 165
DEPARTMENT ofMINERALS and ENERGY
Solar gain – radiationheat load
30° South Latitude Total(Wh/day)
Time of Day 6 7 8 9 10 11 12 13 14 15 16 17 18 S 131 115 71 56 56 56 56 56 56 56 71 115 131 1,024SE 417 552 516 385 218 75 56 56 56 56 48 40 20 2,493E 429 619 639 568 389 175 56 56 56 56 48 40 20 3,148
NE 167 298 357 357 290 175 67 56 56 56 48 40 20 1,985Dec N 20 40 48 56 60 75 83 75 60 56 48 40 20 679
NW 20 40 48 56 56 56 67 175 290 357 357 298 167 1,985W 20 40 48 56 56 56 56 175 389 568 639 619 429 3,148
SW 20 40 48 56 56 56 56 75 218 385 516 552 417 2,493Hor 75 242 520 715 861 953 993 953 861 715 520 242 75 7,726S 87 79 56 52 56 56 56 56 56 52 56 79 87 826SE 369 520 488 353 183 64 56 56 56 52 48 36 16 2,295E 397 615 651 576 393 175 56 56 56 52 48 36 16 3,124
Jan NE 167 326 397 397 330 210 87 56 56 52 48 36 16 2,176& N 16 36 48 56 79 107 119 107 79 56 48 36 16 802
Nov NW 16 36 48 52 56 56 56 210 330 397 397 326 167 2,144W 16 36 48 52 56 56 56 175 393 576 651 615 397 3,124
SW 16 36 48 52 56 56 56 64 183 353 488 520 369 2,295Hor 60 262 488 699 850 937 977 937 850 699 488 262 60 7,567S 22 30 41 48 48 52 52 52 48 48 41 30 22 534SE 204 401 371 245 100 52 52 52 48 48 41 30 7 1,651E 245 545 612 549 378 171 52 52 48 48 41 30 7 2,779
Feb NE 137 364 471 479 416 304 145 56 48 48 41 30 7 2,545& N 7 30 48 100 174 215 234 215 174 100 48 30 7 1,384
Oct NW 7 30 41 48 48 56 145 304 416 479 471 364 137 2,545W 7 30 41 48 48 52 52 171 378 549 612 545 245 2,779
SW 7 30 41 48 48 52 52 52 100 245 371 401 204 1,651Hor 22 174 397 597 742 835 872 835 742 597 397 174 22 6,408S 0 19 37 45 48 52 52 52 48 45 37 19 0 453SE 0 275 334 148 56 52 52 52 48 45 37 19 0 1,117E 0 460 586 534 382 178 52 52 48 45 37 19 0 2,393
Mar NE 0 364 486 564 523 419 249 93 48 45 37 19 0 2846
30° South Latitude Total(Wh/day)
Time of Day 6 7 8 9 10 11 12 13 14 15 16 17 18 S 131 115 71 56 56 56 56 56 56 56 71 115 131 1,024SE 417 552 516 385 218 75 56 56 56 56 48 40 20 2,493E 429 619 639 568 389 175 56 56 56 56 48 40 20 3,148
NE 167 298 357 357 290 175 67 56 56 56 48 40 20 1,985Dec N 20 40 48 56 60 75 83 75 60 56 48 40 20 679
NW 20 40 48 56 56 56 67 175 290 357 357 298 167 1,985W 20 40 48 56 56 56 56 175 389 568 639 619 429 3,148
SW 20 40 48 56 56 56 56 75 218 385 516 552 417 2,493Hor 75 242 520 715 861 953 993 953 861 715 520 242 75 7,726S 87 79 56 52 56 56 56 56 56 52 56 79 87 826SE 369 520 488 353 183 64 56 56 56 52 48 36 16 2,295E 397 615 651 576 393 175 56 56 56 52 48 36 16 3,124
Jan NE 167 326 397 397 330 210 87 56 56 52 48 36 16 2,176& N 16 36 48 56 79 107 119 107 79 56 48 36 16 802
Nov NW 16 36 48 52 56 56 56 210 330 397 397 326 167 2,144W 16 36 48 52 56 56 56 175 393 576 651 615 397 3,124
SW 16 36 48 52 56 56 56 64 183 353 488 520 369 2,295Hor 60 262 488 699 850 937 977 937 850 699 488 262 60 7,567S 22 30 41 48 48 52 52 52 48 48 41 30 22 534SE 204 401 371 245 100 52 52 52 48 48 41 30 7 1,651E 245 545 612 549 378 171 52 52 48 48 41 30 7 2,779
Feb NE 137 364 471 479 416 304 145 56 48 48 41 30 7 2,545& N 7 30 48 100 174 215 234 215 174 100 48 30 7 1,384
Oct NW 7 30 41 48 48 56 145 304 416 479 471 364 137 2,545W 7 30 41 48 48 52 52 171 378 549 612 545 245 2,779
SW 7 30 41 48 48 52 52 52 100 245 371 401 204 1,651Hor 22 174 397 597 742 835 872 835 742 597 397 174 22 6,408S 0 19 37 45 48 52 52 52 48 45 37 19 0 453SE 0 275 334 148 56 52 52 52 48 45 37 19 0 1,117E 0 460 586 534 382 178 52 52 48 45 37 19 0 2,393
Mar NE 0 364 486 564 523 419 249 93 48 45 37 19 0 2846
56
DME Building Energy Audit Course 166
DEPARTMENT ofMINERALS and ENERGY
Reduce solar gain . . .
In new construction:Glass area and typeBuilding orientation in new constructionOverhangs and shading
In existing buildings:Exterior shading (awnings)Interior shading and blindsRe-glazing (maybe)
DME Building Energy Audit Course 167
DEPARTMENT ofMINERALS and ENERGY
Summary of heat loadEMOs
Reduce heat loss/gainby:
Conduction - add insulationConvection - minimize airinfiltrationand radiation - replace orimprove windows, useshading
Strategy:eliminate waste - ensurebuilding need is exactlymet by the energy system;maximize efficiency –select best technology,improve operational andmaintenance practices;optimize energy supply -select most economicalenergy source, utilisewaste heat
DME Building Energy Audit Course 168
DEPARTMENT ofMINERALS and ENERGY
Reduce heating energy
Maintain the indoor temperature as low as possibleUse most economical level of insulationEnsure vapour barrier is installed and in good repairUse double or triple glazing for windowsReorganise activities inside the building - separate thebuilding into zones based on specific heating and coolingrequirementsDon’t heat unoccupied areas
57
DME Building Energy Audit Course 169
DEPARTMENT ofMINERALS and ENERGY
Reduce cooling energy
Maintain the indoor temperature as high aspossibleUse insulation to reduce heat gain in summerUse double or triple glazing or low-E glass forwindowsReorganize activities inside the building - thedesired configuration is opposite that requiredfor reducing heat lossDon’t cool unoccupied areas
DME Building Energy Audit Course 170
DEPARTMENT ofMINERALS and ENERGY
Energy efficient HVAC
Intake (make-up)AirFlow
“Waste Heat”Exhaust Air Flow
Outside (lower)Temperature
Inside (higher)Temperature
(B) Internal Heat Gain Exhaust
(A) CooledVentilation
Exhaust&
Intake
BoilerFuel
ChillerElectricity
DME Building Energy Audit Course 171
DEPARTMENT ofMINERALS and ENERGY
Causes of inefficiency
Over/underheating/cooling - set-point or temperaturecontrolOver ventilationSimultaneousheating/coolingInadequate controlsfor range ofconditions
Increased heating orcooling due toinfiltrationStratificationPoor equipmentmaintenanceIncorrect system typeor sizingLack of coordinationin central control
58
DME Building Energy Audit Course 172
DEPARTMENT ofMINERALS and ENERGY
Finding HVAC EMOs -some questions
Temperature and ventilation requirements ofthe conditioned space - match of systemcapacity to these needsContainment of contaminants from otherbuilding areasWhat is the accuracy of temperature andhumidity control - more accurate controls?Does the HVAC load vary daily and seasonally -does the system have capacity control toaccommodate these swings?
DME Building Energy Audit Course 173
DEPARTMENT ofMINERALS and ENERGY
. . . more questions
Is there a preventative maintenanceprogram for the HVAC systems?Are controls calibrated regularly?Was the existing system designed for thepresent purpose or conditions?Are there more efficient systems for ourapplication?
DME Building Energy Audit Course 174
DEPARTMENT ofMINERALS and ENERGY
EMOs checklist -ventilation
Shut down ventilation/exhaust systems when notrequiredMaintain dampers to reduce outside air leakage whennot requiredUse correct ventilation/exhaust rates for application &occupancyUtilise systems to destratify ceiling airMinimise the Use of local exhaust
59
DME Building Energy Audit Course 175
DEPARTMENT ofMINERALS and ENERGY
EMOs checklist - spaceconditioning
Control temperature and humidity according to comfortzoneMinimize solar gainsRaise thermostats during unoccupied hours during thecooling season, lower during heating seasonAdjust space temperatures in unoccupied or storageareasEnsure automatic controls are operating correctly andare calibrated regularlyUse enthalpy control on HVAC systemsUse filters to remove odours
DME Building Energy Audit Course 176
DEPARTMENT ofMINERALS and ENERGY
Boiler plant systems
UsefulHeat
Air
Flue Gas
Fuel
100xEnergyFuelEnergyUsefulEfficiencyBoiler =
DME Building Energy Audit Course 177
DEPARTMENT ofMINERALS and ENERGY
Hot water boiler plant
HOT WATER BOILER
CONTROL PANEL
T
BREECHING
T
PT
THWR
DHW HEATER
DCW
DHWT
T
HWS T T ZONE
��T
C
M
1
2
3
45
7
8
9
10
11
13
OPTIONALDHW HEATER
6
BURNER
12
60
DME Building Energy Audit Course 178
DEPARTMENT ofMINERALS and ENERGY
Fuel combustion
Fuel - carbon - hydrogen - sulpher
Combustion Air - oxygen - nitrogen
Heat (75- 85%)
Combustion
Flue Gas - CO2, CO - nitrogen, NOx - water - excess air - SOx - VOC
DME Building Energy Audit Course 179
DEPARTMENT ofMINERALS and ENERGY
Losses from boilersystems
Combustion by-products – depends on the air-fuel mixtureHeat in the flue gas – depends on the amountof excess combustion air and effectiveness ofheat exchangeBlow-down – hot water removed from theboiler to control accumulation of solidsSkin Loss – heat escaping from the boilerenclosure
DME Building Energy Audit Course 180
DEPARTMENT ofMINERALS and ENERGY
Combustion efficiencymeasurement
Flue gas & combustion airtemperatureFlue gas constituents
O2 (indicates CO2 and excessair)CONOx, SOx, etc
Draft and differentialpressureEfficiency is calculated fromflue heat loss
61
DME Building Energy Audit Course 181
DEPARTMENT ofMINERALS and ENERGY
Measuring combustionefficiency
Equipment required:Combustion analyzerOr, minimally O2,temperature sensorand efficiency tables
Access required:¼” to 3/8” hole influe close to last heatexchange
DME Building Energy Audit Course 182
DEPARTMENT ofMINERALS and ENERGY
Boiler plant EMOs
Adjust fuel/air ratioEnsure boiler temperature set point is OKClean heat transfer surfacesStaging/control of multiple unitsOff cycle heat loss reductionBurner alignment/adjustmentBoiler/pipe insulation
DME Building Energy Audit Course 183
DEPARTMENT ofMINERALS and ENERGY
More boiler plant EMOsRelocate combustion air intake to usewaste heatReplace inefficient unitsRight-size boilersSmaller boiler for summer loadsHeat recovery on larger boilers
Reduction of loss is first consideration
62
DME Building Energy Audit Course 184
DEPARTMENT ofMINERALS and ENERGY
. . . And more EMOs
Reduce blowdown rate, by managingwater treatment.
Reduction from 10% to 5% saves about 1%of fuel
Reduce steam pressureLower flue, radiation, and leak losses
Reduce venting/leaks if possible
DME Building Energy Audit Course 185
DEPARTMENT ofMINERALS and ENERGY
Heat recoveryopportunities
Use economizer to heat make-up waterCombustion air pre-heaterFlue gas condenserBlow down heat recoveryRecover de-aerator steam
DME Building Energy Audit Course 186
DEPARTMENT ofMINERALS and ENERGY
Savings example
Preheat combustionair with heat frompower house ceilingCombustion air 20oCto 40oCBoiler efficiencyimprovement of 1.1%
63
DME Building Energy Audit Course 187
DEPARTMENT ofMINERALS and ENERGY
Assessment of boilerplant
DME Building Energy Audit Course 188
DEPARTMENT ofMINERALS and ENERGY
Steam distribution
Heating Appliance
Kitchen
Steam Trap
Steam Trap
Steam Trap
Main Steam Line
Condensate Return Line
Steam From Boiler
Condensate to Boiler
Drain
Valve Steam Fitting
DME Building Energy Audit Course 189
DEPARTMENT ofMINERALS and ENERGY
Assessment of steamdistribution Analyze Steam
Distribution
SteamPressure
Pipe Size
Above userrequirement-
reduce pressure
IncreaseCapacityof Piping
SteamTrapping
FutureExpansion
Excessive Loss -consider smaller
pipes
Survey fordamage incorrect,type position, size.
Repair / replace
CondensateReturned?
CheckInsulation
HeatRecovery Send to Drain
Upgradeor
Replace
Finish
Returned toBoiler?
UsedLocally?
Too High
Undersize
Poor
Correct
No,Uncontaminated
Matched
O.K
Oversize No
Yes
No
YesYes
No,Contaminated
Maximum Return
No
Yes
Yes
No
In-adequate
O.K.
Send to Drain
64
DME Building Energy Audit Course 190
DEPARTMENT ofMINERALS and ENERGY
Losses in distributionsystems
Steam leaksExcessive pressure drop in steam lines inundersized linesExcessive standby losses due to oversized linesSteam lost due to failure of steam trapsCondensate sent to drain rather than returnedHeat loss from un-insulated pipes valves andfittings
DME Building Energy Audit Course 191
DEPARTMENT ofMINERALS and ENERGY
Losses in domestic hotwater
Leaking faucets/valvesAppropriate temperaturesShut down recirculation duringunoccupied periodsFlow restricting devicesInsulation of equipment
TanksRecirculation lines
DME Building Energy Audit Course 192
DEPARTMENT ofMINERALS and ENERGY
Insulation opportunities
Repair damaged insulationInsulate non-insulated pipes and vesselsInsulate valves and flangesPaint/wrap tank/pipe surfaces with low-E/aluminum paint/foilAdd/Upgrade insulation up to theeconomical thickness
65
DME Building Energy Audit Course 193
DEPARTMENT ofMINERALS and ENERGY
Cooling plant
PowerRequired
HigherTemperature
LowerTemperature
Condenser
Evaporator
DME Building Energy Audit Course 194
DEPARTMENT ofMINERALS and ENERGY
Refrigeration EMOs -some questions
Are the condensing devicesclean and well maintained?Are the evaporator devicesclean and well maintained?How is defrostingaccomplished on freezer units?Are inlet refrigerant linesinsulated properly?Are controls operatingproperly (small and largeunits)?Is there a regular maintenanceprogram for the refrigerationsystems?
Do condensers and coolingtowers have adequate coolair?Does simultaneous heatingand cooling occur?Can evaporator temperaturebe increased?Can condenser temperature bereduced?Are the compressor crankcaseheaters off during the warmermonths of the year?
DME Building Energy Audit Course 195
DEPARTMENT ofMINERALS and ENERGY
Refrigeration EMOs - morequestions for the experts
Is the refrigeration unit appropriate to the load?How do the refrigeration systems handle partload conditions?Has the heat load within refrigerated spacesbeen minimised?Can thermal storage avoid peak demand causedby refrigeration systems?
66
DME Building Energy Audit Course 196
DEPARTMENT ofMINERALS and ENERGY
Minimize temperaturelift
Match the requirementSetup space temperatures
Clean heat exchange surfacesReduce condenser temperature
Look at cool air supply
Increase evaporator temperatureChilled water reset
DME Building Energy Audit Course 197
DEPARTMENT ofMINERALS and ENERGY
Reduce the cooling load
Building insulationWindow solar radiation controlReduce infiltration
especially warm moist air
Refrigerant line insulation
DME Building Energy Audit Course 198
DEPARTMENT ofMINERALS and ENERGY
Maintenance &monitoring
Use the sight glassto check condition ofrefrigerant
Lubricationleading cause offailure
Log operatingconditions
67
DME Building Energy Audit Course 199
DEPARTMENT ofMINERALS and ENERGY
Higher costopportunities
Avoid head pressurecontrol
Save 20-40%
Avoid hot gas bypass35-40% power inbypass
Compressor upgradeHigher efficiency orvariable speed
DME Building Energy Audit Course 200
DEPARTMENT ofMINERALS and ENERGY
Match the requirement
What are the requirements?Temperature, RH, illumination, ventilation
What energy is being consumed?What energy should be consumed?Why is there a difference?
Eliminate waste
DME Building Energy Audit Course 201
DEPARTMENT ofMINERALS and ENERGY
Maximize efficiency
How do operation and maintenance practicesimpact energy use?
SchedulesTemperaturesDamper conditionHeat exchanger fouling
Is more efficient technology available?LightingBoilers & chillersControls
68
DME Building Energy Audit Course 202
DEPARTMENT ofMINERALS and ENERGY
Chiller efficiency
Note: ton of refrigeration = 12 000 Btu/hr
Electric Chiller New ChillerkW/ton
ExistingkW/ton
Reciprocating .78 to .85 .90-1.2 or higherScrew .62 to .75 .75-.85 or higherCentrifugal High .50 to .62 NA
Moderate .63 to .70 .70-.80 or higher
DME Building Energy Audit Course 203
DEPARTMENT ofMINERALS and ENERGY
Efficiency in airdistribution systems
Match the need - ensure that neither too littlenor too much air is supplied to a given areaEliminate waste - clean filters to prevent highback pressuresClean ventilation ducts to eliminate theadditional flow resistance caused by dirtdepositsOptimise efficiency by using fan speedcontrol to regulate air flow rather than dampers
DME Building Energy Audit Course 204
DEPARTMENT ofMINERALS and ENERGY
Waste heat recovery
����������
Intake (make-up)Air Flow
Outside (lower)Temperature
Inside (higher)Temperature�����������������
�����������������
(B) Internal Heat Gain Exhaust
Heat Direct from Fuel
(A) HeatedVentilation
BoilerThis is a
recoverableenergy flow.
“Waste Heat”Exhaust Air Flow
Hot Flue Gases
Hot Waterto Drain
This is arecoverableenergy flow.
This is arecoverableenergy flow.
FuelEnergy In
69
DME Building Energy Audit Course 205
DEPARTMENT ofMINERALS and ENERGY
Match the source touse
What waste heat sources are available?What quantity of heat is available?At what temperature is the heat available?
Where can the heat be used?How much energy is required and at whattemperature?What is the time coincidence between wasteand use?At what location is the heat required?
What is the practical recovery rate - whatportion of the waste heat may be used?
DME Building Energy Audit Course 206
DEPARTMENT ofMINERALS and ENERGY
Simple heat exchange
A
B
C
D
TEM PER ATURE
D ISTAN CE
D
C
B
A
DME Building Energy Audit Course 207
DEPARTMENT ofMINERALS and ENERGY
Heat recovery methods
DirectFrom one outflow to another inflowFrom higher to lower temperatureRate depends upon approach temperature
IndirectFrom one energy form to anotherTypically requires outside energy input
70
DME Building Energy Audit Course 208
DEPARTMENT ofMINERALS and ENERGY
Direct heat recovery
Regime Exchanger Typical Use
Cross Flow Commercial Air Exchange
Rotary Flue Gas Heat Recovery Gas - Gas
Regenerative High Temp. / Low Volume Exhaust
Shell & Tube Process Water, Oil Coolers
Spiral High Pressure Cooling
Plate & Frame Dairy, Process Water Liquid - Liquid
Heliflow Oil Coolers Recovery Boiler Furnace , Engine Exhaust
Evaporative Water Cooling, Humidification, Exhaust Gas Scrubber Gas - Liquid
Air Cooling Oil Cooler, Space Heating
DME Building Energy Audit Course 209
DEPARTMENT ofMINERALS and ENERGY
Gas to gas
HOT EXHAUST AIR
COOLED EXHAUST AIR
COLD FRESH AIR
HEATED FRESH AIR
CROSS - FLOWHEAT EXCHANGER
HOT EXHAUST AIR
COOLED EXHAUST AIR
COLD FRESH AIR
WARM FRESH AIR
ROTARY HEAT EXCHANGER
DME Building Energy Audit Course 210
DEPARTMENT ofMINERALS and ENERGY
Liquid to liquid
HEAD
SHELL
TUBE BUNDLE
TUBE & SHELL HEAT EXCHANGER
HOT FLUID
COLD FLUID
INLET
OUTLET
WARMER FLUID
COOLER FLUID
PLATES PLATE & FRAME HEAT EXCHANGER
INLET
OUTLET
SEALS
TRANSITION PIECES
COMPRESSION ROD
SPACERS
SEPARATE
71
DME Building Energy Audit Course 211
DEPARTMENT ofMINERALS and ENERGY
Gas to liquid
HOT GAS INLET
SPRAY WATER
SPRAY NOZZLES
WARM (136 F) WATER
SATURATED (COOL) GAS
DIRECT CONTACT HEAT EXCHANGER
AIRFAN / MOTOR
WARM AIRHOT LIQUID
COOLER LIQUID
AIR COOLED HEAT EXCHANGER
DME Building Energy Audit Course 212
DEPARTMENT ofMINERALS and ENERGY
Indirect heat recovery
Regime Exchanger Typical Use
Heat Pump Space Heating, Hot Water Production
Absorption Chiller Water Chilling, Space Heating
Flash Tank Boiler Blow down Mechanical
Vapour Recompression
Brewing, Sugar Processing
Thermal - Thermal
Combustion of Waste Gases Sewage Treatment, Foundries
Expansion Turbine Chemical Plants Thermal -
Mechanical / Electrical Rankine Cycle High Temperature Waste Gas
DME Building Energy Audit Course 213
DEPARTMENT ofMINERALS and ENERGY
Heat pump
EVAPORATOR(HEAT INPUT FROM COLD SOURCE)
CONDENSER(HEAT LOST TO HOT SOURCE)
COMPRESSOR EXPANSION VALVE
Requires Electricity
72
DME Building Energy Audit Course 214
DEPARTMENT ofMINERALS and ENERGY
Flash tank
HIGH PRESSURELIQUID FLOW
LOW PRESSURE VAPOUR
LOW PRESSURE LIQUID
Creates steam from a hot high pressure liquid.
DME Building Energy Audit Course 215
DEPARTMENT ofMINERALS and ENERGY
Compressed airsystems
Compressed air isexpensive - typicalefficiency is 5% to20%
Hole Diameter Air Leakage @ 600 kPa(87 psi) (Gauge)
1 mm 1 l/s
3 mm 10 l/s5 mm 26.7 l/s10 mm 105.7 l/s
DME Building Energy Audit Course 216
DEPARTMENT ofMINERALS and ENERGY
Compressed air EMOs -some questions
Are you supplying leaks in distribution system/end use?Is the supply pressure higher than required to overcomepipe loss?Can you reduce the requirement for air?Can compressor inlet pressure be raised?Can compressor inlet temperature be dropped?Is compressor drive system efficient?Do screw compressors have proper capacity control?Is storage capacity large enough?
73
DME Building Energy Audit Course 217
DEPARTMENT ofMINERALS and ENERGY
Compressed air EMOs
Reduce leaks in air distribution system and at point ofuseReduce compressed air system pressureReduce compressed air requirementsEnsure low inlet restrictions (clean air filter)Reduce inlet air temperature (relocate the intake)Provide sequencing control of air compressorsUse screw compressors with capacity controlConsider two stage compression with cooling
DME Building Energy Audit Course 218
DEPARTMENT ofMINERALS and ENERGY
Building controlsystems
Threecomponents
sensorscontrollerscontrol devices Controller
Sensor
Control Device Process
Set Point
Feedback
Controlled
Variable
DME Building Energy Audit Course 219
DEPARTMENT ofMINERALS and ENERGY
HVAC control loop
74
DME Building Energy Audit Course 220
DEPARTMENT ofMINERALS and ENERGY
Efficiency through control -4 principles
Run equipment only when neededSequence Heating and CoolingProvide only the heating or coolingrequiredSupply heating and cooling from the mostefficient source
DME Building Energy Audit Course 221
DEPARTMENT ofMINERALS and ENERGY
Control applications
Programmed Start/StopOptimised Start/StopDuty cyclingDemand controlTemperaturesetback/setupAlarms/monitoringEnergy monitoringOptimised ventilation
Optimisation of supply airtemperatureSupply water optimisationChiller/boiler optimisationOther control options
Interior and exteriorlightingDomestic hot watertemperatureCistern flow optimisation
DEPARTMENT OF MINERALS AND ENERGYDME-Danida Capacity Building in Energy Efficiency & Renewable Energy
Module 10: Assessing theBusiness Case
Analysing the costs andbenefits
75
DME Building Energy Audit Course 223
DEPARTMENT ofMINERALS and ENERGY
Learning objectives
Do preliminary assessment of proposedenergy management investments
DME Building Energy Audit Course 224
DEPARTMENT ofMINERALS and ENERGY
Objectives ofinvestment appraisal
Which investments makethe best use of availablemoney?Ensure optimum benefitsfrom investmentMinimise the riskA basis for subsequentperformance analysis
DME Building Energy Audit Course 225
DEPARTMENT ofMINERALS and ENERGY
Investment Criteria
Simple Payback
Return on Investment(ROI) and Internal Rateof Return (IRR)
Net Present Value (NPV)and Cash Flow
( ) SavingsAnnualCostCapital
yearsSPP =
Lifeojectx
CostojectEstimatedCostojectEstimatedojectofLifeForSavingsEnergyTotal
ROIPr
100Pr
Pr)Pr( −=
nixPVFV )1( +=
orni
FVPV)1(
=
76
DME Building Energy Audit Course 226
DEPARTMENT ofMINERALS and ENERGY
Simple payback period
Quick and easy wayof assessing financialmerits of measuresDoes not account for:
cost of moneyanything after paybackperiod
( )SavingsAnnualCostCapital
yearsSPP =
DME Building Energy Audit Course 227
DEPARTMENT ofMINERALS and ENERGY
Cash flow analysis
0 5 0 5 10 15 Project Life (years) Project Life (years) Project A Project B
Capital costsAnnual cash flows
TaxesAsset depreciation
Intermittent cashflows
Costs
Savings
DME Building Energy Audit Course 228
DEPARTMENT ofMINERALS and ENERGY
Cash flow table
Table 7.1: Cash Flow Table for Purchase of new BoilerCapital Expenditure R100,000
Expected Savings R48,000
90% on delivery/commissioning, and 10%performance guarantee due at one year.Half in first year, full amount in all remaining years.
(Values in R’000)Year 0 1 2 3 4 5Costs (90.0) (10.0) 0 0 0 0Savings 0 24.0 48.0 48.0 48.0 48.0Net cash flow (90.0) 14.0 48.0 48.0 48.0 48.0Net Project Value (90.0) (76.0) (28.0) 20.0 68.0 116.0
5 year average ROI = 116 / 100 x 100/5 = 23.2%Lifeoject
xCostojectEstimated
CostojectEstimatedojectofLifeForSavingsEnergyTotalROIPr
100Pr
Pr)Pr( −=
77
DME Building Energy Audit Course 229
DEPARTMENT ofMINERALS and ENERGY
Time value of money -discount factors
Discount Factors 1/(1 + i)n Year (n) 0 1 2 3 4 5 Discount Factor 6% 1 0.942 0.888 0.840 0.792 0.747 10% 1 0.909 0.826 0.751 0.683 0.620 20% 1 0.833 0.694 0.579 0.482 0.402 30% 1 0.769 0.591 0.456 0.350 0.270 40% 1 0.714 0.510 0.364 0.260 0.186 45% 1 0.690 0.476 0.328 0.226 0.156 50% 1 0.666 0.444 0.297 0.198 0.132
niFVPV
)1( +=
DME Building Energy Audit Course 230
DEPARTMENT ofMINERALS and ENERGY
Net present value
Table 7.3: NPV CalculationYear 0 1 2 3 4 5Net cash flow (R000s) (90.0) 14.0 48.0 48.0 48.0 48.0The discounted cash flow at 10% can be found as follows:
Year 0Year 1Year 2Year 3Year 4Year 5
1 x (90.0)0.909 x 14.00.826 x 48.00.751 x 48.00.683 x 48.00.620 x 48.0
= (90.0)= 12.73= 39.65= 36.05= 32.78= 29.76
NPV = the sum of all these values = 60.97 (compare to net project value = 116.0)
DME Building Energy Audit Course 231
DEPARTMENT ofMINERALS and ENERGY
Internal Rate of Return
year net cash flow Discount NPV IRR0 -90000 10% R61,048.67 30.37%1 14000 20% R25,216.052 48000 25% R11,885.443 48000 30% R753.504 48000 31% -R1,250.475 48000 35% -R8,627.04
ExcelSpreadsheet
78
DME Building Energy Audit Course 232
DEPARTMENT ofMINERALS and ENERGY
Payback and IRR
DME Building Energy Audit Course 233
DEPARTMENT ofMINERALS and ENERGY
Risk and sensitivityanalysis scenarios
Pessimistice.g. much higherinterest rates
RealisticBest guess
Optimistice.g. much higherenergy costs
DEPARTMENT OF MINERALS AND ENERGYDME-Danida Capacity Building in Energy Efficiency & Renewable Energy
Module 11: Reporting forImplementation
Getting action on the auditrecommendations
79
DME Building Energy Audit Course 235
DEPARTMENT ofMINERALS and ENERGY
Learning objectives
Prepare complete and effective energyaudit reports
DME Building Energy Audit Course 236
DEPARTMENT ofMINERALS and ENERGY
Writing good auditreports
Know your readerUse simple, direct language
Use an action-oriented style in the active (rather than passive)voiceAvoid technical jargon
Ensure that your report is grammatically correctPresent information graphicallyMake your recommendations clearExplain your assumptionsBe accurate and consistent
DME Building Energy Audit Course 237
DEPARTMENT ofMINERALS and ENERGY
A report template
Executive SummarySummary information onkey audit findingsThe recommended EMOsThe implementation cost,savings, and paybackAny special informationrelated to implementation
Technical Sectiondetails of your auditfindingsAudit mandate, scope, andmethodologyFacility description andobservationsAssumptions andcalculationsAudit recommendationsAppendices