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Calibrated Modeling: How Well DoesMy Building Perform? Presented by Eveline Killian, CEM

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Learning Objectives By the end of this program, participants will be able to: Understand the value of energy models Understand the value of calibrated modeling for:  existing building savings potential  adjustments to future building designs  determine impact of interactive effects Understand the process of calibrating an energy model

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Presentation Overview What Is A Calibrated Model? Building A Model Common Challenges Results and ConclusionsAttribution for lightbulb photo: Randy Joy and Co. 3

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Calibrated Modeling Using M&V What Is A Calibrated Model?Attribution for lightbulb photo: Randy Joy and Co. 4

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Definition of Energy ModelingAn evaluation of the energy use ofa building through simulation,accounting for the many energyrelated components 5

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Modeling Components• construction, orientation, location• HVAC, lighting, controls• occupancy levels and schedules• plug loads and internal energy uses (such as refrigeration or process loads) 6

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Uses for Modeling• Energy impacts of alternative designs• LEED credits• Efficiency program incentives Typical issues Does not incorporate final design changes Actual usage of differs from original intent 7

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Definition of “Calibrated” ModelingAn energy analysis using an energymodel calibrated to utility dataand/or end-use metering.Specifications from the International PerformanceMeasurement and Verification Protocol (IPMVP)Option D: Calibrated Simulation 8

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Why Use Calibrated Modeling? Increases accuracy and credibility of energy savings claims Conveys an accurate representation of measure interactive effects Provides feedback on effectiveness of measures 9

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Uses for Calibrated Modeling LEED EAc5.1 M&V Credit and Verification Energy Efficiency Programs and Impact Evaluations Demand Resource Certification Retrocommissioning (RCx)/Troubleshooting Performance Contracting / Energy Service Companies (ESCO) Building Feedback – is the building performing as expected? Energy Audits/Benchmarking/Assessments 10

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Alternatives to Calibrated Modeling Retrofit Isolation (IPMVP Option B)  Submetering of components and subsystems  Approved for LEED verification Whole Facility Analysis (IPMVP Option C)  Utility data analysis of whole building  No modeling  Not approved for LEED verification Mathematical formulas and spreadsheets  Not calibrated to actual energy consumption  Not approved for LEED verification 11

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What Modeling Tools Exist? eQuest EnergyPlus and DOE2 Software Sponsored by Commercial Firms 12

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Who Performs Such Work Energy Consultants Energy Modeling Firms Design Engineering Firms Evaluation, Measurement and Verification Specialists 13

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Calibrated Modeling Using M&V Building a Calibrated Model 14

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Calibration Modeling StepsI. Obtain and Update or Develop Initial ModelII. Equipment Level Calibration via Metering and Field ValidationIII. Utility Data Calibration of As-built ModelIV.Development of Energy Savings 15

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Calibrated Modeling - Step II. Obtain and Update or Develop Initial ModelII. Equipment Level Calibration via Metering and Field ValidationIII. Utility Data Calibration of As Built ModelIV. Development of Energy Savings 16

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Model Development with Architectural ElementsBuild model with the available information. 17

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Example Input Screen 18

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To The Best of Our Knowledge…Input available componentinformation: Equipment types and capacities Thermal zones Temperature control schemes Lighting control schemes Occupancy schedules 19

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Calibrated Modeling – Step III. Obtain and Update or Develop Initial ModelII. Equipment Level Calibration via Metering and Field ValidationIII. Utility Data Calibration of As Built ModelIV. Development of Energy Savings 20

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Development of M&V Plan  Describe efficiency measures  Identify baseline for each measure  Describe the analysis approach • Identify features to field verify • Describe measure metering • Determine measure level sampling 21

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Meters and Loggers 22

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Proxy VariablesRemotetemperaturesensor Light Intensity Logger 23

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Stratified Random SamplingDetermining the required quantity ofmeters 24

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Meter Deployment Sheet Logger Logging CT CT Begin End Equipment Tag Logger Location Interval size Qty Date Date Chiller 1 EML-5 basement MEP 5 min 500 3 2-Aug 2-Oct main power Chiller 2 EML-6 basement MEP 5 min 600 3 2-Aug 2-Oct main power P-1 chilled EML-7 penthouse MEP 5 min 150 3 2-Aug 2-Oct water pump P-2 chilled EML-8 penthouse MEP 5 min 150 3 2-Aug 2-Oct water pump outdoors in a safe place away from Outdoor air TRHE- mechanical air, 5 min na na 2-Aug 2-Octtemp and %RH 21 shaded from direct sun 25

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Implementation of the M&V Plan Interview building operator Install meters on key equipment Obtain trend data 26

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Building Management System Data 27

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Implementation of M & V Plan  Field Verify: Lighting Zones HVAC Equipment Ballasts and Lamp Types and Capacities Types Thermal Zones Window Type HVAC System Roof Type Setpoints Square Foot Spot HVAC Control Checks Configuration 28

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Model Adjustments – Round 1 Modify your model using M&V:  Is the expected equipment installed?  Is the equipment still in operation?  Scheduled hours and occupancy  Setpoints and control schemes  Match modeled kW to metered kW 29

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Case Study Model Inputs 30

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Metered and Modeled Equipment Calibration HVAC VFD fan kW 31

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Case Study Meter Findings Corridor Lighting 32

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Case Study Meter Findings Packaged HVAC Schedule 33

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Calibrated Modeling – Step IIII. Obtain and Update or Develop Initial ModelII. Equipment Level Calibration via Metering and Field ValidationIII.Utility Data Calibration of As Built ModelIV.Development of Energy Savings 34

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Obtain All Energy Use Information 35

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Model Adjustments – Round 2 Input local weather data for utility period Compare model outputs to energy use Adjust system/building level parameters: Infiltration Thermal mass Occupancy schedules Control schedules and setpoints 36

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Be Careful That… The metered component demand and energy values remain true to the meter data The building’s unmet load hours are appropriate The adjustments on each immeasurable component remain realistic 37

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Project Evaluation Tolerances ASHRAE Guideline 14 Section 5.3.2.4 Whole Building Calibrated Simulation Performance Path Allowed amount of variation across all of the months (CVRMSE) = 15% Overall allowed amount of variation in the total annual energy use (NMBE) = 5%CVRMSE = Coefficient of Variation Root Mean Square ErrorNMBE = Net Mean Bias Error 38

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Case Study Model Correlation to Energy Consumption 39

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Case Study Model Outputs 40

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Weather NormalizationRe-run using local TMY3 data 41

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Uses of this Analysis LevelThis analysis is sufficient for:  Retrocommissioning/Troubleshooting  Further energy saving opportunities  Energy Audit/Assessment/Benchmarking  Owner information on Building Performance  Performance Contracting 42

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Calibration Step IVI. Obtain and Update or Develop Initial ModelII. Equipment Level Calibration via Metering and Field ValidationIII. Utility Data Calibration of As Built ModelIV. Development of Energy Savings 43

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Baseline Model Can be a combination of code and standard practice Accurately verifies impact of efficiency measures - including interactive effects 44

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Develop Baseline Model Create Baseline Model by changing: Equipment efficiencies Building shell properties Controls Do NOT change:  Occupancy level  Occupancy schedule  Usage Type 45

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Energy Savings Calculations Example of the Impact of Energy Saving Measures over Baseline: Modeling Iterations Savings runs MWh MMBtuAs-Built Efficient Building 2,548.5 3,752.2Iterations toward Baseline Building: 1 As-Built with Code HVAC 2,667.2 3,593.8 2 Iteration 1 with Code Lighting 2,877.3 3,447.5 3 Iteration 2 with Code Windows 2,918.0 3,770.7 4 Iteration 3 with Code Insulation 2,927.5 4,030.1Baseline Building 2,927.5 4,030.1Savings 379.0 277.9 46

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Uses of this Analysis Level Evaluation energy saving realization rates LEED model comparison metrics (actual vs projected use) Retrocommissioning implementation Energy audit Performance contract: normalized annual savings 47

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Calibrated Modeling Using M&V Common Challenges 48

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Common ChallengesTypical calibration issues and solutions:Multiple iterations needed – time consumingSolutions: Consider overall impact on kWh/MMBtu Consolidate inputs when possible Use global inputs vs. zonal inputs 49

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Common ChallengesSoftware model assumptions conflictSolutions: Avoid over-specifying inputs – allow program to use defaults Avoid conflicts between global and zonal inputs 50

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Analysis ExamplesAnalysis Outcomes Can Be Counterintuitive More Usage = More Savings Building consumption Equipment savings 51

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Analysis Examples Lower Baseline = Less Savings Baseline use Control measure savingsControls Measures - savings depend stronglyon Baseline 52

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Calibrated Modeling Using M&V Results and Conclusions 53

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Reasons for Using Calibrated Modeling Determine if the efficient building design is realizing the predicted claimed savings Analyze opportunities for more savings 54

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Building Life Cycle Costing (BLCC) Calibrated modeling provides confidence in the value of investing in efficient design, and a measure of the potential risk Modeling can reveal the reasons for the level of savings impacts over the life of the building 55

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Use of Energy Saving AnalysisThis level of analysis is used for: LEED EAc5.1 M&V Credit and Verification Energy Efficiency Programs and Impact Evaluations Identification of energy savings opportunities Performance Contracting / Energy Service Companies Building feedback to designers – are the energy measures performing as expected? Building feedback to owners – how is my building performing compared to my expectations? 56

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Learning Objectives Understand the energy models on the market today Understand the value of calibrated modeling for architects, engineers and owners for existing building savings potential and adjustments to future building designs Understand the impact of interactive effects and other variables difficult to quantify at the design stage Understand the process of calibrating an energy model 57

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References and ResourcesResource Purpose LinkModeling software Select modeling software apps1.eere.energy.gov/buildings/tools_directory/alpha_list.cfmIPMVP Develop Metering Plan http://www.nrel.gov/docs/fy02osti/31505.pdfStratified Random Develop Metering Plan http://www.socialresearchmethods.net/kb/sampprob.phpSampling implementation and meter selectionWeather data Put weather data into http://bepan.info/yahoo_site_admin/assets/docs/7_- _Customizing_eQUEST_Weather_Data_by_Jeff_Hirsch.138125735.pdfinstructions eQuestASHRAE Guideline 14 Reference for calibration http://webstore.ansi.org/RecordDetail.aspx?sku=ASHRAE+Guideline+14-2002 metricsBLCC spreadsheets Impact of savings http://www.doe2.com/download/lcc/ DOE2 BLCC spreadsheet differentials on lifetime http://fire.nist.gov/bfrlpubs/build96/art068.html NIST BLCC return on investmentLEED modeling Comply with LEED http://www.usgbc.org/ShowFile.aspx?DocumentID=7795reference 58

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Questions ? Eveline Killian eveline@cx-associates.com110 Main Street Studio 1BBurlington, VT 05401 802.861.2715 59