The presentation will include the following topics: - Fundamentals of energy modeling - Overview of the eQUEST energy modeling program - Recommendations for integrating energy modeling into the design process - Brief description of baseline energy modeling using ASHRAE Appendix G - Recommended strategies for reducing energy use - How to review energy modeling results -Common problems and how to avoid them

1. Building Energy
Modeling
Michael Andelman, P.E.
Andelman and Lelek Engineering, Inc.

3. Learning Objectives
Fundamentals of Building Energy Modeling
Objectives
Available tools
Process
eQUEST Overview
Energy Modeling and the Design Process
LEED Energy Modeling and ASHRAE Appendix G
Strategies to Reduce Energy Use
Reviewing Modeling Results
Common Problems and How to Avoid Them

4. Fundamentals - Objectives
Whole building design
LEED EA Credit 1
Code compliance analysis
Utility Incentives
Predict operating costs
Federal Tax Credits

5. Whole building design
Right-sizing of mechanical systems/equipment
System optimization; comparing alternative
building /system designs
Building geometry/location/orientation
Walls/roofs/windows construction materials
HVAC system/equipment
Control strategies
Lighting and lighting controls
Utility selection (electricity, gas, oil, district steam, etc.)

6. Whole building design (cont’d)
Life cycle costing of alternatives
Determine interactivity of proposed
alternatives

7. LEED EA Credit 1
Baseline model per ASHRAE App G
As-designed model per final construction
documents
LEED template/ supporting documentation

8. Code compliance analysis
MA Energy Code-Building Design by
Systems Analysis
ASHRAE Energy Cost Budget Method
Pollution generation/reduction analysis

9. Predict operating costs
Entire building
Individual building components or end uses
(chillers, pumps, lighting system, etc)
Seasonal operating costs and patterns
Building load analysis
Hourly/daily/weekly/monthly load profiles
Seasonal/annual load profiles
Peak load; design load
Individual zones/systems or entire building

10. Fundamentals- Tools
DOE-2 based tools
eQUEST
VisualDOE
Energy-10
Other
Energy Plus
Design Builder
Google sketch-up interface
EcoTec
Other
BLAST
Carrier HAP
Trane Trace/System Analyzer
TRNSYS
IES

11. Fundamentals - Process
Define scope and set priorities
Gather data
Create baseline model
Existing building
New building – code/ ASHRAE App G base
Calibrate model (for existing buildings)
Model alternatives

12. Process - Required Data
Architectural Plans
Building geometry
ACAD floor plan drawings
Walls/ windows
Elevations/ wall sections
Operating Schedules
Mechanical Plans
HVAC drawings/ system descriptions
Equipment schedules and specs
Controls specs or interview building operator for existing
building
Electrical Plans
Lighting fixture layout and schedules - COMCHECK or conduct
lighting audit of existing facility
Lighting controls type/ location

13. eQUEST Overview
DOE2.2 with GUI
Hourly building energy simulation
Heating/ cooling loads calculated using
transfer function methodology
Separate calculations for loads, HVAC
systems/ central plant equipment, and
economics

14. Loads
Building envelope
Building location
Building geometry
Walls/roofs/floors construction materials
Windows (glass, frames, exterior or interior shading devices)
Large library of manufacturer’s glass selection
Infiltration
Internal loads
Occupants
Plug loads
Lights
Other (manufacturing/process equipment, etc.)
Schedules (internal loads, infiltration, shading devices,
etc)

15. Systems
HVAC system
Type/size/performance – DX/chilled water, constant
volume/VAV, terminal units, etc.
Control strategies – temperature control, fan control, schedules,
setpoints, OA control, etc.
Physical plant
Equipment selection (type, size, performance) – chillers, boilers,
cooling towers, pumps, heat exchangers, district steam/CHW,
DHW heaters, etc.
Process loads – type (steam, hot water, chilled water,
other), size, schedule, etc.

16. Economics
Utility rates/structure
Electricity (demand charges, energy charges,
summer/winter rates, time-of-use energy charges,
ratchets, etc.)
Natural gas
Fuel oil
Purchased steam
Purchased chilled water
Other
Equipment cost – first cost, maintenance cost,
major overhaul cost

17. eQUEST Wizard
Up Side
Import AUTOCAD floor plans to trace building
geometry
Screens simplify defining building shell
components, schedules, and HVAC systems
Create working model in minutes – useful for
early schematic phase

18. eQUEST Wizard (cont’d)
Down Side
Not all eQUEST options available through
Wizard screens
Schedules; lighting and equipment power
densities based on building type –
customizing easier in detailed mode
Can’t switch from detail mode back to wizard
mode

19. eQUEST Model Limitations
Daylight Analysis
No light shelves
No internal obstacles
No daylight through interior windows
Natural Ventilation
No interzonal airflow
Limited to simple systems
Curtain Walls
Must fit frame conductance/ width to overall U-value

20. eQUEST Model Limitations (cont’d)
No air stratification
Displacement ventilation modeled through work-
around
Atriums modeled as multiple zones when required
No ventilated double skin walls
No radiant cooling system (modeled through
work-around)
One HVAC system per zone

21. Energy Modeling and the Design
Process
When to Start
Conceptual / early schematic (throw-away)
Siting/ building shape analysis
Early evaluation of HVAC systems alternatives
Design Development
Evaluation of building shell/ HVAC system alternatives
First pass estimate of LEED credit points
Progress/ first final
Estimate LEED credit points/ evaluate utility incentives
Updating Model
Update model as design progresses
Check impact of possible changes with model before
implementing changes

22. LEED MODELING & ASHRAE APP-G
Create as-design model
Create baseline model
ASHRAE 90.1 Appendix G
Used for LEED analysis
Very detailed – many requirements above code
Baseline HVAC system
Pump power
Plant equipment type and number
Special requirements for central plant/ cogeneration
Schedules same for baseline & as-designed
Items to watch
Hours loads unmet
Heated only spaces
Glass overall U-value
Utility rates
Exceptional method calculations

23. Recommended Strategies
Architectural
High performance glass (limit % glass)
Passive Solar – south glass w/ shading devices – limited north
glazing
Mechanical
Energy efficient equipment
Right sizing equipment
Airside heat recovery (heat wheel) for VAV systems w/ ~40%
OA or more (application specific)
DOA system w/ chilled beams
VFDs for fans/ pumps
Demand ventilation or occupancy based controls
Cogeneration

24. Recommended Strategies- cont.
Electrical
High performance lighting
T-5 or ‘Super’ T-8
LED downlights
High bay T-5 or MH w/ electronic ballast
Daylight controls
Occupancy controls

25. Review Results
Electric Energy UseComponents
Lights Equipment
15% 4%
Fans Cooling
68% 1%
Heat Rejection
2%
Pumps & Aux.
10%

26. eQUEST Graphic Output

27. Energy Modeling vs “Common
Sense”
Lighting energy savings in electrically heated buildings
VFDs for hot water pumps
Optimizing windows for cooling and heating
Low SC reduces passive heating
White roofs – minimal impact in this climate
Best suited for mild climates where Code insulation is low (e.g.
R-10 continuous)
Heat Recovery
high parasitic losses
heating savings for VAV systems can be low if not 100% O.A. at
minimum flow
interaction with demand ventilation controls
DOA Based Systems
Sensitive to supply air temperature
No airside economizer

28. Common Problems
and how to avoid them
Excessive hours outside throttling range
Check SS-R reports for problem zones
Check reheat and or baseboard heat assigned
Check zone cfm
Pump/ auxiliary energy too high
Check PV-A report for pump sizing
Check PS-C report for pump operating hours / part load
operation
Schedule CHW loop
Change pump control to speed if pump has VFD
Excessive winter cooling/ summer heating
Check if airside economizer is called out
Check minimum flow ratio for VAV system
Check space temperature are properly applied

29. Common Problems
and how to avoid them
Excessive cooling / heating energy use
Check PS-C for average equipment performance
Resize equipment
Change CHW loop/ CW loop controls
Change default equipment performance
Condensing boilers need custom curves
Change boiler aquastat setpoint

30. Where to Get More Information
http://doe2.com
http://gundog.lbl.gov
http://lists.onebuilding.org/listinfo.cgi/bldg-
sim-onebuilding.org

31. Thank you!
QUESTIONS?

32. Michael Andelman, P.E.
Andelman and Lelek Engineering, Inc.
1408 Providence Highway
Norwood, MA 02062
(781)769-8773
mike@andelmanlelek.com
AndelmanLelek