building_systems_simulation_buhlppt - Overview General

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					Building Systems
Simulation
Fred Buhl
                   General Philosophy of
                   the EnergyPlus
                   Interface




                                                           Data
                                                                                  Describe
               Input Data (IDD and IDF)                                           Building




                       EnergyPlus
                       Simulation Manager
                Data




                                                             Data
Window              Heat and                                                    Third-Party
                                                                     SPARK
 4.0                 Mass               Building                                       User
Daylighting         Balance             Systems                     TRNSYS       Interfaces
                   Simulation          Simulation
                                                                         PV
COMIS                           Zone
                                                                    Systems
                              Conditions
                                                                    Pollution
Ground HT                      Update
                                                                     Models
                              Feedback
                       Data




                                             Data




                                                                                  Display
              Output Data (ODD and ODF)                                           Results
                                                    Data
             Trade-off Between
             Simulation Flexibility and
             Simplicity
HVAC Simulation Based on Configurable
 Input Template Systems
     Code Allows Connection Flexibility
     Input Defines Specific System Configurations -
      Connections are in the Input
Completely Modular Systems and Real-
 Time Controls Handled by Links to
 SPARK and TRNSYS
                     HVAC Simulation High
                     Level Structure
                     Building Systems Simulation Manager
               Zone                                               Zone
                               Simulate Building
             Conditions                                         Conditions
             Predictor             Systems                      Corrector




                                          Plant Loop
          Air Loop                                                 Conde nse r Loop
                                 Coils,
                                 Base-                  Plant
                 Main Air        board,                Equip.   Conden-       Towers,
Zones &                          Etc.
                 Handling                                       sers,           Wells,
Equip.
                    Loop                                        Coils, Etc.      Etc.
             Defining HVAC Systems
             as Components on a Fluid
             Loop
Loops Define the Movement of Mass
 and Energy Within an HVAC System
     Air Loop
     Plant Loop
     Condenser Loop
     Electric Loop
Systems Defined by the Components on
 the HVAC Loops
            Air Loop Simulation
Connects water side with zone
 equipment
Simulates central air distribution,
 mixing, and conditioning
     Equipment: supply & return fans, central
      heating and cooling coils, heat recovery,
      mixed air box
     Control: supply air temperature, outside air
      economizer
                            Zone Equipment
                            Simulation
                                     Return Air                   Supply Air                                 Supply Air System
                                                                                                               Components
Ceiling Plenum (Opt.)




                                                                                                                                       VAV Box
                                                                                                                                       Powered
                                                                                                                             Damper




                                                                                                                                                     Damper
                                                                                                                             Mixing




                                                                                                                                                      VAV
                                                                                                                                         Fan
                                                       Re he at                            Select One
                                                                   Supply
                                                          /
                                     Diffuse r                       Air
             Zone                                      Re cool
                                                                   Control




                                                                                                                                                    Damper w/
                                                                                                                           Damper w/
                                                                                                                           Induction




                                                                                                                                        Induction

                                                                                                                                                    Induction
                                                        Coil




                                                                                                                                                      Mixing
                                                                                                                             VAV


                                                                                                                                          Unit
 Component



             Component



                         Component
    System



                System



                            System




                                        Local System Components




                                                                                                              Air-Air HP
                                                                                               Water-Air
                                          Lo-Temp
                                          Radiant




                                                                                Fan Coil
                                                                  Window
                                           Panels




                                                                                                 HP
                                                                    AC


                       Multiple
                     Components
                                       L ow Tem p
                     Allowed Per                                           Con vective Sy stems
                         Zone        Radian t Sy stems
                                           Purchased




                                                                                                             Baseboard
                                                                  Gas-Fired
                                                                  Radiators




                                                                                                 Radiators
                                                                              Radiators
                                                                  Hi-Temp



                                                                              Hi-Temp




                                                                                                              Heaters
                                                                               Electric




                                                                                                   Wall
                                              Air




                                     Air Fl ow Sizin g/                Hi Temp Rad/Con v Sy stem s
                                     Make-Up Sy stem
                       Simplified Plant Node and
                       Equipment Diagram
            Typical Plant & Condenser Loop
   Plant Supply Side                                                     Cond Supply Side Loop
                Pump                              2 Mix
                                                 -Cond

                        3 Splitter                                                               Cond Pump

                                     Purchased
                                      Heating/
                                      Cooling
                                                           Towers, Wells, Etc.


Heating or Cooling      3 Mixer
   Equipment
                                                                                 Cooling Tower

                                                 2 Split
                                                 -Cond


                             Cond De mand Side Loop
                         Typical System
                                              3 Zone Dual Duct System
                                                                                                            Plant Supply Side
       Supply Fan                   Supply Air Splitter                                      CW Pump          Cooling Loop
                                     ("Look Ahead")                                                                   34
                                                     5                                                                 3 Splitter
                    2                      CC           Plant Demand Side
                                                           Cooling Loop                                     36            37           35
                                      3                 33        50        51                   By     Chiller #1 Chiller # 2
                                                                                                                                     Purchased
                                                             Bypass                              pa                                   Cooling

                                                                                                 ss
                                   HC                32           31        40                              38            39           49
      1                                   4         6        Pl                                                          3 Mixer
      24                                                  Hean
                                      7       11
                                                     26 ati t
                                                          ng De                                        41              42           43 2 Mix-44
            Zone 1                    8                 27 m
                                                          Lo                                                2 Split-
                                                                                                             Cond                      Cond
                                                      By op an
       17      16       15                            pa     d
                             Mixing 12 Ho                                                              Cond Demand Side Loop
                                                      ss     Si
                             Damper    t                 28 de         29                                 40             45
                                                                                 Purchased
                                       Air                                                                48             46
Re                                                                                Heating
                                       Sp
tur
n           Zone 2                   9 litt                  25        30
                                                                                                                                     Cond Pump
                                       er
Air
Mi                                                 Co
       20      19       18   Mixing 13             ld
xe
                             Damper                Air                  Plant Supply Side                                                   47
r
                                                   Sp                     Heating Loop
                                                   litt
                                                   er
            Zone 3                   10                                                                                 Cooling Tower

       23      22       21   Mixing 14
                             Damper
                                                                                                       Cond Supply Side Loop
                                    Demo Building
                                          3 Zone Terminal Reheat System
                                                                                                                                    CW Pump
                                                                                                                                                                         34
                                    18                                                              33 19                                                          3 Splitter
                                                                                                                                                          36          37          35




                                                                                                                                          CW Bypass
           Air Loop             2




                                              CW Bypass
                                                                                                                     Plant Supply Side                                          Purchased
                                                                                                                                                                                 Cooling
                                                                                                                       Cooling Loop                   Chiller #1 Chiller # 2
                                    21                    Plant Demand Side
                                                                                                                                                          38         39           49
                                                                 Loop
                                                                                                                                                                    3 Mixer
                                                                              3             32 20
       1                                                                                                                                                                 40
                      Zone Equipment                                              Plant Demand Side
      17                                                                      4                                   30          31
                          Group                                                          Loop
                                              24                                                                                                 41          42         43              44
                         Zone 1                                                                                                                       2 Splitter                 2 Mixer


                                                                                                                                                      Cond Demand Side Loop
            8               7            6                 5                                                                                             40            45
                                              25                                                                                                         48            46




                                                                                       3 Splitter
                                              26                                                                                                                                Cond Pump
                                                                                                                              Purchased
                         Zone 2                                                                                                Heating
                                                                 3 Splitter
3 Mixer




                                                                                                                                                                                       47
                                                                                                                  Plant Supply Side Loop
           12              11            10                9

                                                                                                        3 Mixer
                                                                                                                  HW Bypass
                                              27                                                                                                                   Cooling Tower


                                              28
                         Zone 3
                                                                                                                                                        Cond Supply Side Loop

           16              15            14               13
                                              29                                                                  23          22
            Describing a System
System Configuration
     directed graph: arcs and nodes
Component Instantiation
     create each component with unique data
Attach Components to System Graph
     associate components with nodes
Specify System Control
             Eplus Components
Simple
     input; initialize; calculate; report
Compound
     assembled from multiple components
     simulated sequentially with overall control
Complex
     component may be a system
           Eplus System Control
High Level: Set Point Managers
  algorithms establish fluid loop set points
  similar to an EMS

Control Inividual Components
  sense state at one point in system
  control flow at another point to match
   setpoint
Plant: component sequencing & load
  management
          Zone Equipment
Exhaust Fan
Fan Coil Unit
Window Air Conditioner
Unit Ventilator
Unit Heater
Hot Water Baseboard
         Terminal Units
Dual Duct Constant Volume
Dual Duct Variable Volume
Single Duct Constant Volume Reheat
Single Duct Variable Volume Reheat
          Air System
          Components
Hot Water Coil
Chilled Water Coil
Electric Heating Coil
Gas Heating Coil
DX Coil Unit
Supply & Retrun Fan
Outside Air Mixer & Economizer
          Plant Equipment
Boiler
Water Heater
Chiller (performance curve based)
Pump
Cooling Tower
Air Cooled Condenser
          Special Input Objects
Schedules
Curves
Branches and Connectors
Nodes
Plant Operation Schemes
Etc.
            Summary
Loops are backbone of HVAC simulation
     all equipment attached to fluid loops
     zone connected to fluid loops via zone equipment
Loop structure permits assembly of any
 system through input--not hardwired
 code
Manager software structure allows
 future use of general solvers
            General Philosophy of
            Input/Output/Weather
 Simple, free-format text files
 SI units only
 Comma-separated
 Object-based
 Somewhat self-documenting
 Two parts—dictionary and data or simulation results
 Not user-friendly » Interfaces needed
 Can become large
 Designed for Flexibility for Developers
                     Input Data Dictionary
                     Example
ZONE EXHAUST FAN,
 A1 , \field Exhaust Fan Name
 A2 , \field Availability Schedule
    \type object-list
    \object-list ScheduleNames
 N1 , \field Fan Total Efficiency
    \type real
    \minimum 0.0
    \maximum 1.0
 N2 , \field Delta Pressure
    \units Pa
 N3 , \field Max Flow Rate
    \units m3/sec
 A3 , \field Fan_Inlet_Node
 A4 ; \field Fan_Outlet_Node
           Input Example
ZONE EXHAUST FAN, Zone 2 Exhaust Fan,
    FanAndCoilAvailSched,
    0.6, ! efficiency
    125., ! pressure rise
    0.1, ! flow rate
    Zone 2 Exhaust Node, ! inlet node
    Zone 2 Exhaust Fan Outlet Node; ! outlet node
             Input Summary
 IDF Objects can be in Any Order


 IDF Objects are retrieved by each module to
  keep data local


 There are No Hard-wired Input Limits in
  EnergyPlus; Limits depend on Disk and
  Memory of User’s Computer
             User Output Reporting
             Flexibility
 User can Select Any Variables Available for
  Output

 User can Specify Output at Time Step, Hourly,
  Daily, Monthly, or Environment Intervals

 User can Schedule Each Output Variable

 User can Supply a Meter, i.e. Specify All Chiller
  Plants for Total Energy Consumption

				
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