SimUnitVentOAMixer Subroutine

private subroutine SimUnitVentOAMixer(UnitVentNum)

Uses:
DataContaminantBalance
Arguments

Type	Intent	Optional	Attributes		Name
integer,	intent(in)			::	UnitVentNum
Source Code

SUBROUTINE SimUnitVentOAMixer(UnitVentNum)

          ! SUBROUTINE INFORMATION:
          !       AUTHOR         Rick Strand
          !       DATE WRITTEN   May 2000
          !       MODIFIED       na
          !       RE-ENGINEERED  na

          ! PURPOSE OF THIS SUBROUTINE:
          ! This responsibility of this subroutine is to set the air flow rates
          ! through the mixing box portion of the unit ventilator and then perform
          ! an energy balance to arrive at outlet conditions which then would
          ! serve as inlet conditions to the coils (or outlet conditions for
          ! the device).  There is some question as to whether this needs to be
          ! called every time the coils and fan are called since how the fans and
          ! coil operate won't presumable change how the mixer operates.  The
          ! method in which this routine is called is slightly cleaner though
          ! from a code readability standpoint though less efficient.

          ! METHODOLOGY EMPLOYED:
          ! The OAMassFlowRate has already been calculated in the main control
          ! algorithm.  Use this flow rate to establish all of the other flow
          ! rates and perform an energy balance on the mixing of the return and
          ! outdoor air streams.

          ! REFERENCES:
          ! na

          ! USE STATEMENTS:
  USE DataContaminantBalance, ONLY: Contaminant

  IMPLICIT NONE    ! Enforce explicit typing of all variables in this routine

          ! SUBROUTINE ARGUMENT DEFINITIONS:
  INTEGER, INTENT(IN) :: UnitVentNum    ! Unit index in unit ventilator array

          ! SUBROUTINE PARAMETER DEFINITIONS:
          ! na

          ! INTERFACE BLOCK SPECIFICATIONS
          ! na

          ! DERIVED TYPE DEFINITIONS
          ! na

          ! SUBROUTINE LOCAL VARIABLE DECLARATIONS:
  INTEGER        :: AirRelNode         ! relief air node number in unit ventilator loop
  INTEGER        :: InletNode          ! inlet node number for unit ventilator loop
  REAL(r64)      :: OAFraction         ! Outside air fraction of inlet air
  INTEGER        :: OAMixOutNode       ! outside air mixer outlet node for unit ventilator loop
  INTEGER        :: OutsideAirNode     ! outside air node number in unit ventilator loop

          ! FLOW:
  AirRelNode     = UnitVent(UnitVentNum)%AirReliefNode
  InletNode      = UnitVent(UnitVentNum)%AirInNode
  OAMixOutNode   = UnitVent(UnitVentNum)%OAMixerOutNode
  OutsideAirNode = UnitVent(UnitVentNum)%OutsideAirNode

          ! "Resolve" the air flow rates...
  Node(OutsideAirNode)%MassFlowRate         = OAMassFlowRate
  Node(OutsideAirNode)%MassFlowRateMinAvail = OAMassFlowRate
  Node(OutsideAirNode)%MassFlowRateMaxAvail = OAMassFlowRate

  Node(AirRelNode)%MassFlowRate         = OAMassFlowRate
  Node(AirRelNode)%MassFlowRateMinAvail = OAMassFlowRate
  Node(AirRelNode)%MassFlowRateMaxAvail = OAMassFlowRate

  Node(OAMixOutNode)%MassFlowRate         = Node(InletNode)%MassFlowRate
  Node(OAMixOutNode)%MassFlowRateMinAvail = Node(InletNode)%MassFlowRate
  Node(OAMixOutNode)%MassFlowRateMaxAvail = Node(InletNode)%MassFlowRate

          ! "Inlet" conditions for InletNode and OutsideAirNode have already
          ! been set elsewhere so we just need to set the "outlet" conditions
  Node(AirRelNode)%Temp     = Node(InletNode)%Temp
  Node(AirRelNode)%Press    = Node(InletNode)%Press
  Node(AirRelNode)%HumRat   = Node(InletNode)%HumRat
  Node(AirRelNode)%Enthalpy = Node(InletNode)%Enthalpy

  IF (Node(InletNode)%MassFlowRate > 0.0d0) THEN
    OAFraction = Node(OutsideAirNode)%MassFlowRate/Node(InletNode)%MassFlowRate
  ELSE
    OAFraction = 0.0d0
  END IF

          ! Perform an energy and moisture mass balance on the mixing portion of the unit ventilator
  Node(OAMixOutNode)%Enthalpy = OAFraction*Node(OutsideAirNode)%Enthalpy &
                               +(1.0d0-OAFraction)*Node(InletNode)%Enthalpy
  Node(OAMixOutNode)%HumRat   = OAFraction*Node(OutsideAirNode)%HumRat &
                               +(1.0d0-OAFraction)*Node(InletNode)%HumRat

          ! Find the other key state points based on calculated conditions
  Node(OAMixOutNode)%Temp  = PsyTdbFnHW(Node(OAMixOutNode)%Enthalpy,Node(OAMixOutNode)%HumRat)
  Node(OAMixOutNode)%Press = Node(InletNode)%Press

  IF (Contaminant%CO2Simulation) Then
    Node(AirRelNode)%CO2 = Node(InletNode)%CO2
    Node(OAMixOutNode)%CO2 = OAFraction*Node(OutsideAirNode)%CO2+(1.0d0-OAFraction)*Node(InletNode)%CO2
  END IF
  IF (Contaminant%GenericContamSimulation) Then
    Node(AirRelNode)%GenContam = Node(InletNode)%GenContam
    Node(OAMixOutNode)%GenContam = OAFraction*Node(OutsideAirNode)%GenContam+(1.0d0-OAFraction)*Node(InletNode)%GenContam
  END IF

  RETURN

END SUBROUTINE SimUnitVentOAMixer
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SimUnitVentOAMixer Subroutine

Source Code

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private subroutine SimUnitVentOAMixer(UnitVentNum)

Uses:

Arguments

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Called By

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