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Calibrated Modeling - How Well Does My Building Perform? by Eveline Killian


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Energy modeling during design can be valuable, but calibrated modeling post-construction tells the truth. Learn the tools available for calibrated modeling,
and how they use energy bills, digital control systems data, and metering data to assess the actual functionality of a building. Calibrated modeling completes a valuable feedback loop that can help direct future building decisions and, in
some cases, uncover additional savings opportunities in existing structures.

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Calibrated Modeling - How Well Does My Building Perform? by Eveline Killian

  1. 1. Calibrated Modeling: How Well DoesMy Building Perform? Presented by Eveline Killian, CEM
  2. 2. 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
  3. 3. Presentation Overview What Is A Calibrated Model? Building A Model Common Challenges Results and ConclusionsAttribution for lightbulb photo: Randy Joy and Co. 3
  4. 4. Calibrated Modeling Using M&V What Is A Calibrated Model?Attribution for lightbulb photo: Randy Joy and Co. 4
  5. 5. Definition of Energy ModelingAn evaluation of the energy use ofa building through simulation,accounting for the many energyrelated components 5
  6. 6. 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
  7. 7. 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
  8. 8. 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
  9. 9. 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
  10. 10. 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
  11. 11. 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
  12. 12. What Modeling Tools Exist? eQuest EnergyPlus and DOE2 Software Sponsored by Commercial Firms 12
  13. 13. Who Performs Such Work Energy Consultants Energy Modeling Firms Design Engineering Firms Evaluation, Measurement and Verification Specialists 13
  14. 14. Calibrated Modeling Using M&V Building a Calibrated Model 14
  15. 15. 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
  16. 16. 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
  17. 17. Model Development with Architectural ElementsBuild model with the available information. 17
  18. 18. Example Input Screen 18
  19. 19. To The Best of Our Knowledge…Input available componentinformation: Equipment types and capacities Thermal zones Temperature control schemes Lighting control schemes Occupancy schedules 19
  20. 20. 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
  21. 21. 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
  22. 22. Meters and Loggers 22
  23. 23. Proxy VariablesRemotetemperaturesensor Light Intensity Logger 23
  24. 24. Stratified Random SamplingDetermining the required quantity ofmeters 24
  25. 25. 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
  26. 26. Implementation of the M&V Plan Interview building operator Install meters on key equipment Obtain trend data 26
  27. 27. Building Management System Data 27
  28. 28. 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
  29. 29. 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
  30. 30. Case Study Model Inputs 30
  31. 31. Metered and Modeled Equipment Calibration HVAC VFD fan kW 31
  32. 32. Case Study Meter Findings Corridor Lighting 32
  33. 33. Case Study Meter Findings Packaged HVAC Schedule 33
  34. 34. 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
  35. 35. Obtain All Energy Use Information 35
  36. 36. 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
  37. 37. 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
  38. 38. Project Evaluation Tolerances ASHRAE Guideline 14 Section 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
  39. 39. Case Study Model Correlation to Energy Consumption 39
  40. 40. Case Study Model Outputs 40
  41. 41. Weather NormalizationRe-run using local TMY3 data 41
  42. 42. 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
  43. 43. 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
  44. 44. Baseline Model Can be a combination of code and standard practice Accurately verifies impact of efficiency measures - including interactive effects 44
  45. 45. Develop Baseline Model Create Baseline Model by changing: Equipment efficiencies Building shell properties Controls Do NOT change:  Occupancy level  Occupancy schedule  Usage Type 45
  46. 46. 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
  47. 47. 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
  48. 48. Calibrated Modeling Using M&V Common Challenges 48
  49. 49. 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
  50. 50. Common ChallengesSoftware model assumptions conflictSolutions: Avoid over-specifying inputs – allow program to use defaults Avoid conflicts between global and zonal inputs 50
  51. 51. Analysis ExamplesAnalysis Outcomes Can Be Counterintuitive More Usage = More Savings Building consumption Equipment savings 51
  52. 52. Analysis Examples Lower Baseline = Less Savings Baseline use Control measure savingsControls Measures - savings depend stronglyon Baseline 52
  53. 53. Calibrated Modeling Using M&V Results and Conclusions 53
  54. 54. Reasons for Using Calibrated Modeling Determine if the efficient building design is realizing the predicted claimed savings Analyze opportunities for more savings 54
  55. 55. 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
  56. 56. 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
  57. 57. 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
  58. 58. References and ResourcesResource Purpose LinkModeling software Select modeling software Develop Metering Plan Random Develop Metering Plan implementation and meter selectionWeather data Put weather data into _Customizing_eQUEST_Weather_Data_by_Jeff_Hirsch.138125735.pdfinstructions eQuestASHRAE Guideline 14 Reference for calibration metricsBLCC spreadsheets Impact of savings DOE2 BLCC spreadsheet differentials on lifetime NIST BLCC return on investmentLEED modeling Comply with LEED 58
  59. 59. Questions ? Eveline Killian eveline@cx-associates.com110 Main Street Studio 1BBurlington, VT 05401 802.861.2715 59