energy conservation energy management. role of an energy manager assess assess current energy demand...
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Energy ConservationEnergy Conservation
Energy Energy ManagementManagement
Role of an energy managerRole of an energy manager
AssessAssess Current energy demandCurrent energy demand Energy auditEnergy audit
AnalyseAnalyse Energy requirementsEnergy requirements
AdviseAdvise On technical improvementsOn technical improvements
AdvertiseAdvertise Ways to save energyWays to save energy
AccountAccount For energy consumptionFor energy consumption
Assess energy demandAssess energy demand
Keep recordsKeep records ConsumptionConsumption Time of readingsTime of readings TemperatureTemperature Other factors affecting demandOther factors affecting demand
Weekday/weekendWeekday/weekend Special eventsSpecial events
Frequency of readingsFrequency of readings WeeklyWeekly DailyDaily
Energy AuditEnergy Audit
Feasibility studyFeasibility study Establish and quantify energy flows into and within a Establish and quantify energy flows into and within a
building or organisationbuilding or organisation AimAim
Identify viable and cost effective energy saving Identify viable and cost effective energy saving measuresmeasures
Enhance operating efficiency and reduce Enhance operating efficiency and reduce maintenance costsmaintenance costs
Establish a baseline energy consumptionEstablish a baseline energy consumption ProcessProcess
Collect data from energy invoices and metersCollect data from energy invoices and meters Surveys of plant, equipment and buildingsSurveys of plant, equipment and buildings Collect information from managers and other staffCollect information from managers and other staff
Auditing processAuditing process
Identify energy management Identify energy management opportunitiesopportunities
Can be ‘no cost’ or ‘low cost’ measuresCan be ‘no cost’ or ‘low cost’ measures Change an energy tariffChange an energy tariff Change an energy supplierChange an energy supplier Reschedule production activities Reschedule production activities
• Preferential tariffsPreferential tariffs Adjust existing controls to match requirementsAdjust existing controls to match requirements Implement ‘good housekeeping’ policiesImplement ‘good housekeeping’ policies Invest in small capital itemsInvest in small capital items
• Thermostats & time switchesThermostats & time switches
Who does energy audits?Who does energy audits?
Can be undertaken internally – energy managerCan be undertaken internally – energy manager Specialist energy consultantsSpecialist energy consultants Energy service companiesEnergy service companies
Performance contractsPerformance contracts Guarantee organisations energy cost savings in Guarantee organisations energy cost savings in
return for a feereturn for a fee Main interest is in installing and managing their Main interest is in installing and managing their
recommended plantrecommended plant May arrange finance of projectsMay arrange finance of projects Vested interestVested interest
Why is energy wasted?Why is energy wasted?
Poorly designed buildings and Poorly designed buildings and installationsinstallations Insufficient insulationInsufficient insulation Undersized ventilation ductsUndersized ventilation ducts
Inadequate control systemsInadequate control systems Poor control settingsPoor control settings Inefficient plant operationInefficient plant operation
Out of date technologyOut of date technology Poor maintenancePoor maintenance
Poor operating and working Poor operating and working practicespractices
Different types of energy auditDifferent types of energy audit
According to level of detail and depth of According to level of detail and depth of analysisanalysis
Preliminary Preliminary TargetedTargeted ComprehensiveComprehensive
Preliminary auditPreliminary audit
How much energy is being consumedHow much energy is being consumed What type of energyWhat type of energy Performance of facility compared with Performance of facility compared with
similar facilitiessimilar facilities Characteristic performance of buildingCharacteristic performance of building
Preliminary energy auditPreliminary energy audit
Identification of potential areas of energy Identification of potential areas of energy savingsaving
Financial energy auditsFinancial energy audits
Collect data Collect data Establish quantity and cost of each form of Establish quantity and cost of each form of
energyenergy Data from energy invoices and meters for Data from energy invoices and meters for
previous yearprevious year Analyse dataAnalyse data Present dataPresent data Establish priorities Establish priorities Make recommendationsMake recommendations
Targeted energy auditTargeted energy audit
Provide data and analysis on specific Provide data and analysis on specific targeted projectstargeted projects e.g. heating of one building or lightinge.g. heating of one building or lighting
Detailed survey of target areaDetailed survey of target area Analysis of energy flows and costsAnalysis of energy flows and costs Recommendations for actionRecommendations for action
Comprehensive energy auditsComprehensive energy audits
Similar to preliminary audits but in far Similar to preliminary audits but in far more detailmore detail
Detailed data on energy flows into Detailed data on energy flows into and within organisation or facilityand within organisation or facility Often requires use of sub-metering to Often requires use of sub-metering to
accurately determine component energy accurately determine component energy flowsflows
Or estimate energy useOr estimate energy use (Plant power output (kWh)/efficiency of (Plant power output (kWh)/efficiency of
plant) *operating hours per yearplant) *operating hours per year Use of thermal imaging Use of thermal imaging May use complex energy simulation May use complex energy simulation
softwaresoftware Detailed energy survey Detailed energy survey Energy project implementation plansEnergy project implementation plans
Collect dataCollect data Build up picture of pattern of energy consumption and Build up picture of pattern of energy consumption and
cost from energy invoicescost from energy invoices All invoices for relevant time periodAll invoices for relevant time period Delivery notes for oil, solid fuel, LPGDelivery notes for oil, solid fuel, LPG Identify estimated meter readings – check with previous yearsIdentify estimated meter readings – check with previous years Inadequate/unavailable invoices – contact utility company/fuel Inadequate/unavailable invoices – contact utility company/fuel
suppliersupplier Collect geographic data Collect geographic data
Location, altitude, orientationLocation, altitude, orientation Weather data, degree day dataWeather data, degree day data
Manufacturing data (if appropriate)Manufacturing data (if appropriate) Production output Production output
Check data for anomaliesCheck data for anomalies Small building using more energy than larger oneSmall building using more energy than larger one High energy use at night when unoccupiedHigh energy use at night when unoccupied
Understanding invoices: electricityUnderstanding invoices: electricity
Date of meter readingDate of meter reading Monthly standing chargeMonthly standing charge Present and previous meter readingPresent and previous meter reading
Daytime – peak rateDaytime – peak rate Night time – off-peak rateNight time – off-peak rate
Charges for each rateCharges for each rate Some tariffs have a higher unit charge for first 1000 kWhSome tariffs have a higher unit charge for first 1000 kWh
Monthly maximum demand charge Monthly maximum demand charge For every kW of the peak power demand during the monthFor every kW of the peak power demand during the month Penalise users make heavy demands during peak periodsPenalise users make heavy demands during peak periods
Supply capacity – annual maximum demandSupply capacity – annual maximum demand Monthly chargeMonthly charge
Total cost + VATTotal cost + VAT
Gas invoicesGas invoices
Much less complicated than electricityMuch less complicated than electricity Date of meter reading or estimateDate of meter reading or estimate Calorific value of gasCalorific value of gas Present and previous meter readingsPresent and previous meter readings Amount of gas used Amount of gas used
ftft33, kWh or therms, kWh or therms Unit price per kWhUnit price per kWh Standing chargeStanding charge
Monthly or quarterlyMonthly or quarterly Total cost + VATTotal cost + VAT
Other fuelsOther fuels
Fuel oilFuel oil Measured by volumeMeasured by volume
• Varies with temperature corrected to standard condition of Varies with temperature corrected to standard condition of 15.515.500CC
Date of deliveryDate of delivery Unit cost per standard litreUnit cost per standard litre Calorific value (?)Calorific value (?) Total cost + VATTotal cost + VAT
Solid fuelSolid fuel Weight deliveredWeight delivered Date of deliveryDate of delivery Total cost + VATTotal cost + VAT No calorific valueNo calorific value
Analysing energy recordsAnalysing energy records
Key variablesKey variables HeatingHeating
External temperature - dominantExternal temperature - dominant Wind speed )Wind speed ) Humidity ) <=10% variationHumidity ) <=10% variation Solar gain )Solar gain )
LightingLighting Hours of darknessHours of darkness
Data analysisData analysis
Many different ways of analysing dataMany different ways of analysing data Annual energy consumption Annual energy consumption Analysis of heating requirementsAnalysis of heating requirements
Degree day method Degree day method Mean temperature methodMean temperature method Cumulative deviation methodCumulative deviation method (Details in Keith’s lecture notes)(Details in Keith’s lecture notes)
Normalised performance indicators (NPI) Normalised performance indicators (NPI) (Beggs, 2002)(Beggs, 2002)
Time dependent energy analysisTime dependent energy analysis Linear regression analysisLinear regression analysis CUSUM – cumulative sum deviation methodCUSUM – cumulative sum deviation method
Annual energy consumptionAnnual energy consumption
Simplest analysisSimplest analysis Assess overall energy performance of buildingAssess overall energy performance of building
Produces a percentage breakdown of annual energy Produces a percentage breakdown of annual energy consumption and cost dataconsumption and cost data
Convert all energy consumption data into standard units (kWh) Convert all energy consumption data into standard units (kWh) • Standard conversion factors & gross calorific valuesStandard conversion factors & gross calorific values
Percentage breakdowns of total consumption and cost of each Percentage breakdowns of total consumption and cost of each energy typeenergy type
Present dataPresent data• Total annual energy consumptionTotal annual energy consumption• CostCost• Percentage breakdown of each fuel typePercentage breakdown of each fuel type• Historical trendsHistorical trends
Analysis of heating requirementsAnalysis of heating requirements
Degree day methodDegree day method QuickerQuicker Oil & coal heating difficult – general estimates Oil & coal heating difficult – general estimates
of consumptionof consumption Mean temperature methodMean temperature method
More accurateMore accurate Plot mean consumption against mean Plot mean consumption against mean
external temperatureexternal temperature
Degree day methodDegree day method
Two component partsTwo component parts Temperature relatedTemperature related Independent of temperatureIndependent of temperature
• Hot water & cooking if by gasHot water & cooking if by gas E = W + H*degree days*86400E = W + H*degree days*86400
• Where E is total energy consumedWhere E is total energy consumed• W energy for hot water + cooking (gas)W energy for hot water + cooking (gas)
W approx constant for given house – 7-10 GJ/quarterW approx constant for given house – 7-10 GJ/quarter
• H is heat loss rate for the homeH is heat loss rate for the home Two unknowns W & H, Two unknowns W & H, Know degree days & energy consumptionKnow degree days & energy consumption Estimate heat loss & steady energy requirementEstimate heat loss & steady energy requirement
Degree day method - exampleDegree day method - example
Energy consumption 2 successive quartersEnergy consumption 2 successive quarters 31.76 & 18.80 GJ31.76 & 18.80 GJ
Corresponding degree daysCorresponding degree days 1100 and 5001100 and 500
E = W + H * degree days*86400 E = W + H * degree days*86400 1100 * H * 86400 + W = 31.76 (1)1100 * H * 86400 + W = 31.76 (1)
500 * H * 86400 + W = 18.80 (2)500 * H * 86400 + W = 18.80 (2)Simultaneous equations (subtract 2 from 1)Simultaneous equations (subtract 2 from 1)
H = H = (31.76 – 18.80)(31.76 – 18.80) * 10 * 1099 = 250 Watts = 250 Watts (1100-500)*86400(1100-500)*86400Substitute for H in either equation to get WSubstitute for H in either equation to get W
W = 31.76 * 10W = 31.76 * 109 9 - 1100 * 250 * 86400- 1100 * 250 * 86400 = 8 * 10= 8 * 1099 = 8GJ = 8GJ
H - heat loss
W - hot water
Degree day method Degree day method
Once H & W have been calculatedOnce H & W have been calculated Performance for subsequent quarters can Performance for subsequent quarters can
be estimatedbe estimated If degree days for 3If degree days for 3rdrd quarter = 400 quarter = 400
Consumption predicted to be Consumption predicted to be 400 * 250 * 86400 + 8 * 400 * 250 * 86400 + 8 * 101099 = 16.64 GJ = 16.64 GJ
If actual consumption is 17.5 GJ then If actual consumption is 17.5 GJ then energy has been wastedenergy has been wasted
Mean temperature method Mean temperature method (non electrical heating)(non electrical heating)
Plot the mean consumption over a specific period Plot the mean consumption over a specific period against mean external temperatureagainst mean external temperature
For 1 week or 1 day - less time than previous methodFor 1 week or 1 day - less time than previous method
Analysis of lighting Analysis of lighting (non-electrically heated house)(non-electrically heated house)
Lighting varies throughout Lighting varies throughout the year with hours of the year with hours of darknessdarkness
Need to assess a realistic Need to assess a realistic time for lightingtime for lighting
There is constant load (A) There is constant load (A) from appliances and from appliances and refrigeration use and an refrigeration use and an increasing amount from increasing amount from lighting.lighting.
Increase in lighting hours Increase in lighting hours is used to obtain L & A in is used to obtain L & A in same way for H & W in same way for H & W in heating example heating example
Analysis of heating & lighting in an Analysis of heating & lighting in an electrically heated houseelectrically heated house
More complex as both H & L are unknownMore complex as both H & L are unknown Combine A & W to give overall appliance + hot water Combine A & W to give overall appliance + hot water
load (A)load (A) E = (degree days * H + lighting hours * L) * 86400 + AE = (degree days * H + lighting hours * L) * 86400 + A
Where E = energy consumptionWhere E = energy consumption H = heat loss rateH = heat loss rate L = lighting (units of L are Watts per hour)L = lighting (units of L are Watts per hour) A = appliance + hot waterA = appliance + hot water
3 unknowns – H, L & A3 unknowns – H, L & A If we have data for 3 quarters If we have data for 3 quarters Estimate values for H, L & A by solving 3 simultaneous Estimate values for H, L & A by solving 3 simultaneous
equationsequations If appliance load is known calculation is easierIf appliance load is known calculation is easier
Cumulative deviation methodCumulative deviation method
1.1. No energy conservation No energy conservation – horizontal line– horizontal line
2.2. Winter following Winter following improved insulationimproved insulation
3.3. Summer – no savings – Summer – no savings – heat conservation onlyheat conservation only
4.4. Winter – parallel to 2Winter – parallel to 25.5. Summer - improved Summer - improved
management of hot management of hot waterwater
6.6. Should be (4) + (5) but Should be (4) + (5) but less - energy less - energy conservation conservation performance is reducedperformance is reduced
Normalised Performance Indicators (NPIs)Normalised Performance Indicators (NPIs) Provides an indication of the energy performance of a buildingProvides an indication of the energy performance of a building Compares actual annual energy consumption and costs with those Compares actual annual energy consumption and costs with those
achieved by buildings of a similar type and functionachieved by buildings of a similar type and function ProblemsProblems
Buildings may be different sizesBuildings may be different sizes Locations may have different climatesLocations may have different climates Locations may have different levels of exposureLocations may have different levels of exposure Maybe different operating hoursMaybe different operating hours
Correct the building energy consumption data Correct the building energy consumption data allow for variables such as occupancy and weather.allow for variables such as occupancy and weather.
NPIs developed to address these problems. Used toNPIs developed to address these problems. Used to compare with other buildings of a similar type and functioncompare with other buildings of a similar type and function compare with standard energy benchmark for different building typescompare with standard energy benchmark for different building types
BenchmarksBenchmarks Many countries have national energy benchmarks for different types of Many countries have national energy benchmarks for different types of
buildingsbuildings Usually kWh/m2 of floor area (volume)Usually kWh/m2 of floor area (volume) Provide guidance, not absolute values to achieveProvide guidance, not absolute values to achieve
How to calculate NPIsHow to calculate NPIs Establish total building energy use in standard unitsEstablish total building energy use in standard units Calculate the annual energy use for space heatingCalculate the annual energy use for space heating
Sub-metering, or analytical techniquesSub-metering, or analytical techniques Correct space heating energy data for climate & exposureCorrect space heating energy data for climate & exposure
Weather coefficient = std annual heating degree days/ annual heating Weather coefficient = std annual heating degree days/ annual heating degree days experienced by buildingdegree days experienced by building
Exposure coefficientsExposure coefficients• Sheltered (city centre) = 1.1Sheltered (city centre) = 1.1• Normal (urban/rural) = 1.0Normal (urban/rural) = 1.0• Exposed (coastal/hilly site) = 0.9Exposed (coastal/hilly site) = 0.9
Non-heating energy consumption + corrected space heating = non-Non-heating energy consumption + corrected space heating = non-time corrected energy consumptiontime corrected energy consumption
To calculate normalised annual energy consumption need to correct To calculate normalised annual energy consumption need to correct for ‘hours of use’ for ‘hours of use’
non-time corrected energy consumption * coefficient non-time corrected energy consumption * coefficient Hours of use coefficient = std annual hours of use/actual annual hours Hours of use coefficient = std annual hours of use/actual annual hours
of useof use NPI = normalised annual energy consumption/building floor areaNPI = normalised annual energy consumption/building floor area
Energy SurveysEnergy Surveys
Integral part of energy auditIntegral part of energy audit Helps to understand energy flows within a Helps to understand energy flows within a
facility/buildingfacility/building Helps to identify energy wastageHelps to identify energy wastage Can be comprehensive or targetedCan be comprehensive or targeted ObjectivesObjectives
Determine energy performance of facility/building or specific Determine energy performance of facility/building or specific plant/equipmentplant/equipment
Identify and quantify the principal energy flows & energy cost Identify and quantify the principal energy flows & energy cost savingssavings
Produce costed recommendations to achieve energy cost Produce costed recommendations to achieve energy cost savingssavings
Make recommendations on future energy management of Make recommendations on future energy management of facility facility
What to include in an energy surveyWhat to include in an energy survey
Management and operation characteristics Management and operation characteristics of a facility or organisationof a facility or organisation
Energy supply to an organisations various Energy supply to an organisations various facilities facilities
Energy use within an organisations Energy use within an organisations facilitiesfacilities
The plant and equipment within a facilityThe plant and equipment within a facility The fabric of the organisation’s buildingsThe fabric of the organisation’s buildings
Management and operating characteristicsManagement and operating characteristics
Management cultureManagement culture Can have considerable influence on energy Can have considerable influence on energy
consumptionconsumption Determine management structure and Determine management structure and
practices relating to energy procurement practices relating to energy procurement and consumptionand consumption
Identify cost centresIdentify cost centres• Are the managers accountable for operating Are the managers accountable for operating
costs also responsible for energy consumption?costs also responsible for energy consumption? Maintenance proceduresMaintenance procedures
• Frequency and qualityFrequency and quality• Identify new maintenance measures to improve Identify new maintenance measures to improve
energy efficiencyenergy efficiency
Operating practices: data collectionOperating practices: data collection
Use of particular space or buildingUse of particular space or building Mechanical/electrical services in buildingMechanical/electrical services in building Number & type of occupants e.g. stationary or Number & type of occupants e.g. stationary or
activeactive Occupancy patternsOccupancy patterns Environmental conditionsEnvironmental conditions
Air temp, humidity, lightingAir temp, humidity, lighting Operating practices of plant/equipmentOperating practices of plant/equipment Identify where actual practices deviate from that Identify where actual practices deviate from that
stated by managementstated by management Overheated rooms, open windows, computers left onOverheated rooms, open windows, computers left on
Energy SupplyEnergy Supply
Identify tariffs and supply contracts of organisationIdentify tariffs and supply contracts of organisation Ensure organisation is using correct electricity tariff Ensure organisation is using correct electricity tariff
to suite its load profileto suite its load profile Calculate load profileCalculate load profile
Regular meter readings – include daytime, night time & Regular meter readings – include daytime, night time & weekendsweekends
For large electrical loadsFor large electrical loads• Need to be more accurateNeed to be more accurate
• Measure every 30 mins, use portable meters if necessaryMeasure every 30 mins, use portable meters if necessary Investigate large peaks in loadInvestigate large peaks in load
Plant and equipmentPlant and equipment Survey major items of plant and equipment to determine their Survey major items of plant and equipment to determine their
operating efficiencyoperating efficiency Include pipe distribution networksInclude pipe distribution networks
BoilersBoilers ‘‘tune’ to minimise flue gas heat losstune’ to minimise flue gas heat loss Identify if flue gas heat recovery is feasibleIdentify if flue gas heat recovery is feasible
RefrigerationRefrigeration Check efficiencyCheck efficiency Opening practicesOpening practices Is heat recovery feasibleIs heat recovery feasible
PipeworkPipework Insulation & leaksInsulation & leaks
Planned replacement of old plantPlanned replacement of old plant
Building fabricBuilding fabric Identify using U values areas of greatest heat lossIdentify using U values areas of greatest heat loss Thermal imagingThermal imaging Excess ventilation – open doorsExcess ventilation – open doors
Energy management: recommendationsEnergy management: recommendations
Recommendations will relate to cost of fuel – more interested in Recommendations will relate to cost of fuel – more interested in saving money than energy/carbonsaving money than energy/carbon
TechnicalTechnical Insulation, draft exclusion, thermostatic radiator valves, heating controlInsulation, draft exclusion, thermostatic radiator valves, heating control Low energy lighting, efficient refrigerationLow energy lighting, efficient refrigeration Power factor correctionsPower factor corrections Relocation of switches, movement sensorsRelocation of switches, movement sensors
Energy managementEnergy management Checking performanceChecking performance Record keepingRecord keeping
FinancialFinancial Make sub-sections responsible for their own energy budgetMake sub-sections responsible for their own energy budget ‘‘Carrots’ for those who save energyCarrots’ for those who save energy
Other factorsOther factors Change patterns of workingChange patterns of working Working practicesWorking practices Use of spaceUse of space