Afternoon Workshop Sections Best Practices, Inform Design, M&V

1. Afternoon Workshop SectionsBest Practices, Inform Design, M&V • Modeling Processes • Best Practices • Integrated Design Process • Modeling Procedures • Pre-Design • Schematic Design • Design Development • Construction Documents • Post Occupancy 1

2. BEST PRACTICES IBPSA - USA Building Simulation Modeling 2

3. Overview • Consistency in methods • Reduction in input errors • Generation of reasonable performance values Modeling best practices are methods incorporated into everyday practice that support: 3

4. Destination The art in energy modeling is to create a model that is as simple as possible while still providing reasonably accurate results. This requires good judgment and experience. 4

5. Setting ExpectationsBlack Belt Energy Modeling Concept created and developed by Ellen Franconi, Rocky Mountain Institute, See http://www.ibpsa.us/workshop/ for expanded table 5

6. Real World Challenges Challenges Strategies From Michael Donn. “Quality Assurance – Simulation and the Real World” , 1999 IBPSA Proceedings . See www.ibpsa.org/proceedings/BS1999/BS99_P-05.pdf 6

7. General Principles • Be knowledgeable of the inner workings of the simulation tool • Be knowledgeable of the technologies being modeled • Prioritize efforts • Follow modeling procedures that facilitate quality assurance 7

8. General PrinciplesKnowledge of Inner Workings – Load Calcs DOE2 Envel-ope Solar Lights People/ Equip RF WF WF WF WF S Space Load Benefits Proven accurate for most cases. Fast calculations. Benefits Calculates surface temperatures, allowing comfort calculations and control. Radiant heating/cooling model. 8 EnergyPlus • Envelope gain • Transfer function • Space loads • Surface/air heat balance • Iterative calc

9. General PrinciplesKnowledge of Inner Workings DOE2.2 • Sequential Calculations • Full year loads, then systems • Load calc at constant temperature Loads Loads Each timestep Systems Systems Benefits Proven accurate for most cases. Fast calculations. Benefits Output reports show breakdown of loads by source. 9 EnergyPlus Simultaneous Calculations Temperature can vary each hour per t-stat setpoint

10. General PrinciplesKnowledge of Inner Workings • Perform test runs • Check standard reports • Create and compare hourly output data • Review documentation 10

11. General PrinciplesKnowledge of Technologies • Colleagues • Manufacturers / Distributors • Technical Journals and Conference Proceedings • DOE Building Technologies Program website http://www1.eere.energy.gov/buildings/technologies.html • http://www1.eere.energy.gov/buildings/information_resources.html • Energy Design Resources website • Design Guidelines: HVAC Simulation Guidelines • Design Guidelines: Advanced Variable Air Volume (VAV) Systems • Design Guidelines: CoolTools Chilled Water Plant • List Serve:buildingone.org 11

12. General PrinciplesPrioritizing Efforts 12

13. General PrinciplesPrioritizing Efforts Climate analysis and climate-based design strategies See EERE tool directory - http://apps1.eere.energy.gov/buildings/tools_directory/ http://www.aud.ucla.edu/energy-design-tools 13

14. General PrinciplesPrioritizing Efforts 14

15. General PrinciplesPrioritizing Efforts Resources for Gaining Insights 15

16. General PrinciplesPrioritizing Efforts Resources for Gaining Insights 16

17. General PrinciplesFacilitateQuality Assurance Checking model input • Document assumptions and input values • Use pre-processing tools/spreadsheets to convert component descriptions into modeling input values • Import input file segments for complex components modeled often in projects • Make design changes incrementally in the model RMI Tool 17

18. General PrinciplesFacilitateQuality Assurance Example Input File Snippets for DOE-2.2 $ EXTERIOR WALL "R-eff wall" = MATERIAL TYPE = RESISTANCE RESISTANCE = 7.2 $ASHRAE 4A - 7.2 eff R-value R-13 batt in 4", 24"o.c. steel frame $ Specify with parameter value - {#pa("R Stud Wall")} .. "R-ci wall" = MATERIAL TYPE = RESISTANCE RESISTANCE = 7.5 $ASHRAE 4A - 7.5 continuous insulation outside stud wall $ Specify with parameter value - {#pa("R CI Wall")} .. "ASHRAE EWall Cons Layers" = LAYERS MATERIAL = ( "GypBd 1/2in (GP01)", "Bldg Paper Felt (BP01)", "R-ci wall", "R-eff wall", "GypBd 1/2in (GP01)" ) THICKNESS = ( 0.042 ) .. "E1 EWall Construction" = CONSTRUCTION TYPE = LAYERS ABSORPTANCE = 0.6 ROUGHNESS = 1 LAYERS = "ASHRAE EWall Cons Layers" $ substitute value with parameter name - e.g. ext_wall_layers[] $ {SymIndex(#pa("Exterior Wall Layers"),"CONSTRUCTION","LAYERS")} http://www.rmi.org/rmi/ModelingTools 18

19. General PrinciplesFacilitate Quality Assurance Checking model output • Develop a review check list • Extract data for evaluating reasonableness of results • Key output values • Metrics, back-of-the-envelope calculations, hourly data • Extract results from output files and report side-by-side • Evaluate against rules-of-thumb metrics • Evaluate against performance of actual buildings • Evaluate against each run – is the change as expected? RMI Tool 19

20. General PrinciplesFacilitateQuality Assurance – Partial Check list 20

21. General PrinciplesFacilitateQuality Assurance – Key Metrics* *Typical of office buildings: low–very energy efficient, medium -code, high–existing buildings 21

22. General PrinciplesFacilitate Quality Assurance Reconciliation • Look for careless errors in input • Examine simulation output for explanation • Make sure you understand simulation algorithms • Make sure the model captures actual process/systems • Increase model detail if needed • Tweak uncertain inputs within a reasonable range of values • Peer review RMI Tool 22

23. Modeling Best Practices Presenting Results Documenting Assumptions, Energy Efficiency Measures, Packages 23

24. Modeling Best Practices Presenting Results Documenting Assumptions, Energy Efficiency Measures, Packages 24

25. Modeling Best Practices Presenting Results 25

26. Modeling Best Practices Presenting Results 26

27. Modeling Best Practices Presenting Results 27