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IBPSA - USA A FTERNOON W ORKSHOP S ECTIONS B EST P RACTICES, I NFORM D ESIGN, M&V Modeling Processes Best Practices Integrated Design Process Modeling.

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Presentation on theme: "IBPSA - USA A FTERNOON W ORKSHOP S ECTIONS B EST P RACTICES, I NFORM D ESIGN, M&V Modeling Processes Best Practices Integrated Design Process Modeling."— Presentation transcript:

1 IBPSA - USA A FTERNOON W ORKSHOP S ECTIONS B EST P RACTICES, I NFORM D ESIGN, 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 B UILDING S IMULATION M ODELING IBPSA - USA 2

3 O VERVIEW 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 IBPSA - USA D ESTINATION 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 IBPSA - USA S ETTING E XPECTATIONS B LACK B ELT E NERGY M ODELING BeltCapabilities Trainee White  Collect modeling input data Yellow  Perform input data calculations Orange  Develop building geometry and zoning Tech- nician Green  Create building input file using software wizard Blue  Build minimally-code compliant building model Core Analyst Purple  Review results for reasonableness  Complete calibrations Brown  Perform complex modeling  Complete detailed QC  Complete system level calibration Master Red  Understand the algorithms  Use supplemental analysis Black  Balance modeling level of detail against accuracy of results needed to support decision making Concept created and developed by Ellen Franconi, Rocky Mountain Institute, See for expanded table 5

6 IBPSA - USA R EAL W ORLD C HALLENGES From Michael Donn. “Quality Assurance – Simulation and the Real World”, 1999 IBPSA Proceedings. See Challenges Strategies 6

7 IBPSA - USA G ENERAL P RINCIPLES 1.Be knowledgeable of the inner workings of the simulation tool 2.Be knowledgeable of the technologies being modeled 3.Prioritize efforts 4.Follow modeling procedures that facilitate quality assurance 7

8 IBPSA - USA G ENERAL P RINCIPLES K NOWLEDGE OF I NNER W ORKINGS – L OAD C ALCS DOE2EnergyPlus Envelope gain – Transfer function Space loads – Surface/air heat balance – Iterative calc Benefits Proven accurate for most cases. Fast calculations. Benefits Proven accurate for most cases. Fast calculations. Benefits Calculates surface temperatures, allowing comfort calculations and control. Radiant heating/cooling model. Benefits Calculates surface temperatures, allowing comfort calculations and control. Radiant heating/cooling model. Envel- ope RF WF SolarLights People/ Equip WF   Space Load 8

9 IBPSA - USA G ENERAL P RINCIPLES K NOWLEDGE OF I NNER W ORKINGS DOE2.2 Sequential Calculations – Full year loads, then systems Load calc at constant temperature EnergyPlus Simultaneous Calculations Temperature can vary each hour per t-stat setpoint Loads Systems Loads Systems Each timestep Benefits Output reports show breakdown of loads by source. Benefits Output reports show breakdown of loads by source. Benefits Proven accurate for most cases. Fast calculations. Benefits Proven accurate for most cases. Fast calculations. 9

10 IBPSA - USA G ENERAL P RINCIPLES K NOWLEDGE OF I NNER W ORKINGS Perform test runs Check standard reports Create and compare hourly output data Review documentation 10

11 IBPSA - USA G ENERAL P RINCIPLES K NOWLEDGE OF T ECHNOLOGIES Colleagues Manufacturers / Distributors Technical Journals and Conference Proceedings DOE Building Technologies Program website s.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 buildingone.org 11

12 IBPSA - USA G ENERAL P RINCIPLES P RIORITIZING E FFORTS 12

13 IBPSA - USA G ENERAL P RINCIPLES P RIORITIZING E FFORTS Climate analysis and climate-based design strategies See EERE tool directory - ov/buildings/tools_director y/ ov/buildings/tools_director y/ 13

14 IBPSA - USA G ENERAL P RINCIPLES P RIORITIZING E FFORTS ParameterLowHigh Envelope to Volume Ratio Lighting Process Loads Mechanical Systems Insulation Windows Passive Systems Internal Gains Insulation Windows Passive Systems Lighting Process Loads Mechanical Systems Ventilation Mechanical Systems 14

15 IBPSA - USA G ENERAL P RINCIPLES P RIORITIZING E FFORTS Resources for Gaining Insights 15

16 IBPSA - USA G ENERAL P RINCIPLES P RIORITIZING E FFORTS Resources for Gaining Insights 16

17 IBPSA - USA G ENERAL P RINCIPLES F ACILITATE Q UALITY A SSURANCE 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 IBPSA - USA G ENERAL P RINCIPLES F ACILITATE Q UALITY A SSURANCE Example Input File Snippets for DOE-2.2 $ EXTERIOR WALL "R-eff wall" = MATERIAL TYPE = RESISTANCE RESISTANCE = 7.2 $ASHRAE 4A 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 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 = ( ).. "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")} 18

19 IBPSA - USA G ENERAL P RINCIPLES F ACILITATE Q UALITY A SSURANCE 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 IBPSA - USA G ENERAL P RINCIPLES F ACILITATE Q UALITY A SSURANCE – P ARTIAL C HECK LIST InputOutput ASHRAE climate zoneZone and plant loads met Weather data fileBuilding EUI Effective underground R-valueBuilding plugs W/ft2 Overall window U-valueBuilding lighting W/ft2 Plug loadsBuilding occupant density System type, plant typeCooling - design ft2/ton, kW/ton, loading Baseline fan per PRMCooling loop – GPM/ton VAV - min box turn down, central heating coil Heating - Btu/ft2, average efficiency, loading Outside air - fixed, % supply or cfm/person, DCV; off at night Supply air - design CFM/ft2 Controls – SAT reset, humidity, loop temp resets Ventilation air - % design flow, CFM/ft2 20

21 IBPSA - USA G ENERAL P RINCIPLES F ACILITATE Q UALITY A SSURANCE – K EY M ETRICS * MetricUnitsLowMediumHigh Building EUIkBtu/ft2 yr Cooling Designft2/ton Cooling DesignkW/ton Cooling LoopGPM/ton2.5 Heating DesignBtu/ft FanskW/CFM Supply AirCFM/ft Ventilation AirCFM/ft LightingW/ft PlugsW/ft *Typical of office buildings: low–very energy efficient, medium -code, high–existing buildings 21

22 IBPSA - USA G ENERAL P RINCIPLES F ACILITATE Q UALITY A SSURANCE 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 IBPSA - USA M ODELING B EST P RACTICES P RESENTING R ESULTS Documenting Assumptions, Energy Efficiency Measures, Packages Activity Baseline & Proposed DesignBaselineProposed Design Space AreasOutside VentilationLPDEPDLPDEPD Area%(Ft 2 /PER) (OA - CFM/PER) (W/ft 2 ) Lobby 6, Retail 1, Corridor/Storage 38, Exhibit* 16, Classroom 14, Dining 5, Computer Lab 13, Office 13, Restrooms 5, TOTAL 115,

24 IBPSA - USA M ODELING B EST P RACTICES P RESENTING R ESULTS ECMDescription As-Design30% BelowDescription Envelope Strategies BASEEnvelope and WindowsX Walls: 4" batts in 4" studs 16" o.c. + R-3.8 c.i. (effective R-7 clear wall + R-3.8) Roof: R-15 c.i. above deck Glazing: Thermally broken alum. frames, clear uninsulated (GHs), U Btu/hr-ft 2 -°F and SHGC-0.39 (all other) 1Roof Insulation XXRoof: R-30 batts between steel joists 2Exterior Wall Insulation X XWalls: 6" batts in 8" studs 16" o.c. + R-3.8 c.i. 3Window Performance X X Glazing: Thermally broken alum. frames, Low-e IGU w/gray exterior lite, U-0.4 Btu/hr-ft2-°F and SHGC-0.32 (all other) Lighting BASEASHRAE 2004 LPDs X Maximum allowable LPDs per ASHRAE , corresponds with LEED Baseline lighting ADAs Designed LPDs X LPDs as designed 415% Lower than ASHRAE X LPDs are 15% lower than those allowable per ASHRAE Heating, Cooling, and Ventilation BASEBaseline HVAC Systems X Packaged VAV with hot Water Reheat ADAs-Designed HVAC Systems X VAV with Hot Water Reheat + DirectEvaporative 5Indirect/Direct Evaporative Cooling X Add blow-through Indirect/Direct Evaporative cooling section to AHU 6Condensing Boiler X Hot Water Boilers (Forced draft, sealed combustion) 93% (Std 80F HWRT). Terminal boxes set to 10% and baseboard used for perimeter heating 7High-Efficiency Fans X Premium efficiency motors on fans. Evaporative section in AHU may increase static pressure and required fan BHP. Documenting Assumptions, Energy Efficiency Measures, Packages 24

25 IBPSA - USA M ODELING B EST P RACTICES P RESENTING R ESULTS 25

26 IBPSA - USA M ODELING B EST P RACTICES P RESENTING R ESULTS 26

27 IBPSA - USA M ODELING B EST P RACTICES P RESENTING R ESULTS 27


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