SimAirLoops Subroutine

private subroutine SimAirLoops(FirstHVACIteration, SimZoneEquipment)

Arguments

Type	Intent	Optional	Attributes		Name
logical,	intent(in)			::	FirstHVACIteration
logical,	intent(inout)			::	SimZoneEquipment
Source Code

SUBROUTINE SimAirLoops(FirstHVACIteration,SimZoneEquipment)

          ! SUBROUTINE INFORMATION
          !             AUTHOR:  Russ Taylor, Dan Fisher, Fred Buhl
          !       DATE WRITTEN:  Oct 1997
          !           MODIFIED:  Dec 1997 Fred Buhl
          !           MODIFIED:  Apr 1998 Richard Liesen
          !           MODIFIED:  Dec 1999 Fred Buhl
          !           MODIFIED:  Feb 2006 Dimitri Curtil (LBNL)
          !                      - Moved air loop simulation to SimAirLoop() routine.
          !      RE-ENGINEERED:  This is new code, not reengineered

          ! PURPOSE OF THIS SUBROUTINE:
          ! This is the driver subroutine for the air loop simulation. It simulates
          ! each primary air system in the problem and passes the outlet node conditions
          ! on to the attached Zone Equipment inlet nodes.

          ! METHODOLOGY EMPLOYED:
          ! For each primary air system:
          ! (1) each component in the system is simulated in natural order, beginning at
          !     the return air inlet and progressing to the supply air outlets. Node data
          !     is passed in the same direction.
          ! (2) The controllers and their actions are simulated.
          ! (3) Steps 2 and 3 are repeated until the control criteria are satisfied.
          ! (4) A mass balance check is performed; if it fails, mass balance is imposed
          !     and steps 1, 2, and 3 are repeated. At the end we should have a correct,
          !     self consistent primary air system simulation.
          !

          ! REFERENCES: None

          ! USE STATEMENTS:
  USE HVACInterfaceManager,   ONLY : UpdateHVACInterface
  USE MixedAir,               ONLY : SimOAController
  USE DataGlobals,            ONLY : BeginTimeStepFlag
  USE General,                ONLY : GetPreviousHVACTime
  USE DataConvergParams,      ONLY : CalledFromAirSystemSupplySideDeck1, CalledFromAirSystemSupplySideDeck2
  IMPLICIT NONE

       ! SUBROUTINE ARGUMENT DEFINITIONS:
  ! TRUE if first full HVAC iteration in an HVAC timestep
  LOGICAL, INTENT(IN)    :: FirstHVACIteration
  ! TRUE if Zone Equipment needs to be resimulated.
  LOGICAL, INTENT(INOUT) :: SimZoneEquipment

       ! SUBROUTINE PARAMETER DEFINITIONS: None

       ! INTERFACE BLOCK DEFINITIONS: None

       ! DERIVED TYPE DEFINITIONS: None

       ! SUBROUTINE LOCAL VARIABLE DEFINITIONS
  ! Last saved HVAC time stamp at beginning of step in seconds.
  ! Used to control when to reset the statistic counters for each new HVAC step.
  REAL(r64), SAVE :: SavedPreviousHVACTime = 0.0d0
  REAL(r64) :: rxTime
  ! Maximum of iteration counters across all air loops
  INTEGER, SAVE          :: IterMax = 0
  ! Aggregated number of iterations across all air loops
  INTEGER, SAVE          :: IterTot = 0
  ! Aggregated number fo times SimAirLoopComponents() has been invoked across all air loops
  INTEGER, SAVE          :: NumCallsTot = 0
  ! Primary Air Sys DO loop index
  INTEGER                :: AirLoopNum
  ! Max number of iterations performed by controllers on each air loop
  INTEGER                :: AirLoopIterMax
  ! Aggregated number of iterations across all controllers on each air loop
  INTEGER                :: AirLoopIterTot
  ! Total number of times SimAirLoopComponents() has been invoked to simulate each air loop
  INTEGER                :: AirLoopNumCalls
  ! Primary air system outlet DO loop index
  INTEGER                :: AirSysOutNum
  ! DO loop index; there are 2 passes - the 2nd is done only if mass balance fails
  INTEGER                :: AirLoopPass
  ! Output variable setup flag
  LOGICAL, SAVE          :: OutputSetupFlag = .FALSE.
  ! Flag set by ResolveSysFlow; if TRUE, mass balance failed and there must be a second pass
  LOGICAL                :: SysReSim
  INTEGER                :: CalledFrom

          ! FLOW:

  ! Set up output variables
  IF (.NOT. OutputSetupFlag) THEN
    CALL SetupOutputVariable('Air System Simulation Maximum Iteration Count []',          IterMax,     'HVAC', 'Sum', 'SimAir')
    CALL SetupOutputVariable('Air System Simulation Iteration Count []',          IterTot,     'HVAC', 'Sum', 'SimAir')
    CALL SetupOutputVariable('Air System Component Model Simulation Calls []', NumCallsTot, 'HVAC', 'Sum', 'SimAir')
    OutputSetupFlag = .TRUE.
  END IF

  ! BUG: IterMax should not be aggregated as a Sum output variable
  !      We need a new aggregation scheme to track the max value across HVAC steps
  !      instead of suming it up.
  IterMax = 0

  ! Reset counters to capture statistics for the current zone time step
  !
  ! Aggregate statistics over all HVAC time steps, even the rejected ones, to properly
  ! reflect the numerical work. The condition to detect a new HVAC time step is essentially
  ! based on the time stamp at the beginning of the current HVAC step (expressed in seconds).
  IF ( FirstHVACIteration) THEN
    rxTime=GetPreviousHVACTime()
    IF (SavedPreviousHVACTime /= rxTime) THEN
      SavedPreviousHVACTime = rxTime
      IterTot     = 0
      NumCallsTot = 0
    END IF
  END IF

  ! Loop over all the primary air loop; simulate their components (equipment)
  ! and controllers
  DO AirLoopNum = 1, NumPrimaryAirSys   ! NumPrimaryAirSys is the number of primary air loops

    ! Check to see if System Availability Managers are asking for fans to cycle on or shut off
    ! and set fan on/off flags accordingly.
    TurnFansOn  = .FALSE.
    TurnFansOff = .FALSE.
    NightVentOn = .FALSE.
    IF (PriAirSysAvailMgr(AirLoopNum)%AvailStatus .EQ. CycleOn) THEN
      TurnFansOn = .TRUE.
    END IF
    IF (PriAirSysAvailMgr(AirLoopNum)%AvailStatus .EQ. ForceOff) THEN
      TurnFansOff = .TRUE.
    END IF
    IF (AirLoopControlInfo(AirLoopNum)%NightVent) THEN
      NightVentOn = .TRUE.
    END IF

!   Set current system number for sizing routines
    CurSysNum = AirLoopNum

! RR why is this called here, it's called first in SimAirLoop. Causes no diff's to comment out.
!    IF (AirLoopControlInfo(AirLoopNum)%OACtrlNum > 0) THEN
!      CALL SimOAController( &
!        AirLoopControlInfo(AirLoopNum)%OACtrlName, &
!        AirLoopControlInfo(AirLoopNum)%OACtrlNum,  &
!        FirstHVACIteration, &
!        AirLoopNum )
!    END IF

    ! 2 passes; 1 usually suffices; 2 is done if ResolveSysFlow detects a failure of mass balance
    SimPasses : DO AirLoopPass=1,2

      SysReSim = .FALSE.

      ! Simulate controllers on air loop with current air mass flow rates
      CALL SimAirLoop( &
        FirstHVACIteration, AirLoopNum, AirLoopPass, &
        AirLoopIterMax, AirLoopIterTot, AirLoopNumCalls &
      )

      ! Update tracker for maximum number of iterations needed by any controller on all air loops
      IterMax = MAX(IterMax, AirLoopIterMax)
      ! Update tracker for aggregated number of iterations needed by all controllers on all air loops
      IterTot = IterTot + AirLoopIterTot
      ! Update tracker for total number of times SimAirLoopComponents() has been invoked across all air loops
      NumCallsTot = NumCallsTot + AirLoopNumCalls

      ! At the end of the first pass, check whether a second pass is needed or not
      IF (AirLoopPass.EQ.1) THEN
        ! If simple system, skip second pass
        IF (AirLoopControlInfo(AirLoopNum)%Simple) EXIT SimPasses
        CALL ResolveSysFlow(AirLoopNum, SysReSim)
        ! If mass balance OK, skip second pass
        IF (.NOT.SysReSim) EXIT SimPasses
      END IF

    END DO SimPasses ! end pass loop

    ! Air system side has been simulated, now transfer conditions across to
    ! the zone equipment side, looping through all supply air paths for this
    ! air loop.
    DO AirSysOutNum = 1, AirToZoneNodeInfo(AirLoopNum)%NumSupplyNodes
      IF (AirSysOutNum == 1) CalledFrom = CalledFromAirSystemSupplySideDeck1
      IF (AirSysOutNum == 2) CalledFrom = CalledFromAirSystemSupplySideDeck2
      CALL UpdateHVACInterface( AirLoopNum, CalledFrom, &
        AirToZoneNodeInfo(AirLoopNum)%AirLoopSupplyNodeNum(AirSysOutNum),   &
        AirToZoneNodeInfo(AirLoopNum)%ZoneEquipSupplyNodeNum(AirSysOutNum), &
        SimZoneEquipment )
    END DO  ! ...end of DO loop over supply air paths for this air loop.

  END DO ! End of Air Loop iteration

! Reset current system number for sizing routines
  CurSysNum = 0

  RETURN
END SUBROUTINE SimAirLoops
All Procedures

SimAirLoops Subroutine

Source Code

All Procedures

private subroutine SimAirLoops(FirstHVACIteration, SimZoneEquipment)

Uses:

Arguments

Calls

Called By

Source Code

Source Code

All Procedures
