DOE2 Overview and Basic Concepts

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DOE-2 Overview and Basic Concepts
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Background

• US public domain programs from 1970s
• Post Office program NECAP (NASA energy-cost
  analysis program) NBSLD (National Bureau of
  Standards Load Determination)
• Cal-ERDA (California U.S. Energy Research
  Development Administration) program
• Department of Energy (DOE) funding
• First generation DOE-1.4 program (1978)
• Later DOE-2.0A, 2.1A, B, C, D, E come out
• Program description
• http//gundog.lbl.gov/dirsoft/d2whatis.html

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Background

• Current versions
• DOE-2.1E (official), DOE-2.2 PowerDOE
• Maintained by the Simulation Research Group of
  Lawrence Berkeley National Laboratory (LBNL)
• Funded by U.S. Department of Energy (DOE)
• Several PC versions interfaces, e.g.
• ADM-DOE2, FTI-DOE, VisualDOE (at a cost)
• eQUEST (freeware)

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Background

• In the past, mainly used by researchers
• DOE-2 is powerful but very complicated
• Require much input time detail
• Need efforts to learn to master
• In recent years, also used by building designers
  energy analysts
• Consider as the reference program in USA
• Becoming popular internationally (e.g. for
  developing building energy codes)
• Often used for performance-based energy codes

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Background

• Based on transfer function theory weighting
  factor method in FORTRAN language
• Program structure
• Building description language (BDL) processor
• Error diagnosis calculate response factors
• Simulation subprograms
• LOADS building loads
• SYSTEMS secondary HVAC system
• PLANT primary HVAC system
• ECONOMICS economic analysis

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Main Features

• Capabilities
• Energy conservation studies
• Building envelope design (materials,
  construction, etc.)
• Internal loads (occupant, lighting, equipment)
• HVAC systems plant
• Building design studies
• Daylighting ventilation design
• Energy environmental systems
• Such as cogeneration, desiccant cooling ice
  thermal storage
• Economic life cycle analysis

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Main Features

• Limitations
• Cannot model electrical lift systems
• Certain constraints on some building systems
• Inflexible FORTRAN structure
• Sequential calculation method (L-S-P-E)
• Not able to consider heat balance

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Simulation Process

• DOE-2 input file (BDL instructions)
• Input files in ASCII text format
• Commands, subcommands keywords
• Basic file structure
• LOADS section
• SYSTEMS section
• PLANT section
• ECONOMICS section (optional)

DOE-2 Simulation Engine
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Simulation Process

• Run periods
• Normally whole year (8,760 hours)
• May run on shorter period (say, one month)
• May carry out simulation for multiple years (if
  the weather files are available)
• Control of simulation process
• Base case design
• Design alternatives (done with interface program)
• Parametric runs analysis (may be tailored made)

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Simulation Process

• DOE-2 output reports
• Standard reports
• Verification reports Summary reports
• For loads, systems, plant economics
• Hourly reports
• Very detailed for checking by advanced users
• Program-specific output
• Summary graphs and tables
• Customised reports
• Errors diagnostics

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Simulation Process

• DOE-2 output files reports
• Commonly read summary reports
• LS-A (Space Peak Loads Summary)
• SS-A SS-B (System Monthly Loads Summary)
• PS-A (Plant Energy Utilization Sumary)
• PS-B (Monthly Peak and Total Energy Use)
• PS-E (Monthly Energy End Use Summary)
• BEPS (Building Energy Performance Summary)

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Design
Typical
Weather
Weather
Design Load
Calculations
Energy
Calculations
Peak Design
Loads
Equipment Sizes
Building Energy
and Plant Capacity
Consumption
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Input Requirements

• Input data
• Site data
• Building type, location, geometry, construction
• Weather data design weather, weather files
• Building data
• Surface areas, windows, zoning, room shapes
• Building materials, mass, finishes, shades
• Operating schedules profiles
• Internal loads, design conditions

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Input Requirements

• Input data (contd)
• Building systems
• HVAC (air side) system type performance
• Lighting electrical services
• Building plant and equipment
• Performance of refrigeration, boiler other
  plants
• Data for economic analysis
• Electricity tariffs/rates, fuel prices
• Equipment costs, interest rates

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Input Requirements

• Model zoning (thermal, not geometric)
• Should consider thermal loads (e.g.
  interior-perimeter), occupancy, lighting type and
  schedule
• For existing buildings, refer to actual zoning
• Need to simplify the model
• Combine zones with similar load and usage
• Intermediate typical floors are modelled as one
  floor
• Combine HVAC systems
• Sometimes, use ONE zone to quickly calculate the
  load

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Combine several rooms into one zone
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Input Requirements

• General rules for zoning
• One exterior zone per major orientation (4-5 m
  deep)
• One internal zone per use schedule
• One plenum zone (if plenum returns) for each air
  handler
• One zone each for special uses
• Separate ground and top floor zones