modelMixingBoxMinimumFlow

Outside air mixing box with parallel damper for minimum outside air flow rate

Extends from Buildings.Fluid.Actuators.Dampers.MixingBox.

Information

Model of an outside air mixing box with air dampers and a flow path for the minimum outside air flow rate.

If dp_nominalIncludesDamper=true, then the parameter dp_nominal is equal to the pressure drop of the damper plus the fixed flow resistance at the nominal flow rate. If dp_nominalIncludesDamper=false, then dp_nominal does not include the flow resistance of the air damper.

Parameters

TypeNameDefaultDescription
Nominal condition
Modelica.Units.SI.MassFlowRatemOutMin_flow_nominalMass flow rate minimum outside air damper
Modelica.Units.SI.PressureDifferencedpDamOutMin_nominalPressure drop of damper in minimum outside air leg
Modelica.Units.SI.PressureDifferencedpFixOutMin_nominal0Pressure drop of duct and other resistances in minimum outside air leg
Dynamics › Time needed to open or close valve
RealyOutMin_starty_startInitial value of signal for minimum outside air damper

Components

TypeNameDefaultDescription
Modelica.Fluid.Interfaces.FluidPort_aport_OutMinFluid connector a (positive design flow direction is from port_a to port_b)
Modelica.Blocks.Interfaces.RealInputyOutMinDamper position minimum outside air (0: closed, 1: open)
Modelica.Blocks.Interfaces.RealOutputyOutMin_actualActual valve position
Buildings.Fluid.Actuators.Dampers.ExponentialdamOAMinDamper for minimum outside air intake

Revisions

  • September 11, 2024, by Michael Wetter:
    Renamed parameters to use_strokeTime and strokeTime, and updated actuator model.
  • June 10, 2021, by Michael Wetter:
    Changed implementation of the filter.
    This is for consistency with the changes done in #1498.
  • February 26, 2020, by Antoine Gautier:
    Updated parameter bindings consistently with refactoring of Buildings.Fluid.Actuators.BaseClasses.PartialDamperExponential.
    This is for #1188.
  • March 24, 2017, by Michael Wetter:
    Renamed filteredInput to use_inputFilter.
    This is for #665.
  • March 22, 2017, by Michael Wetter:
    Removed the assignments of AOut, AExh, AOutMin and ARec as these are done in the damper instance using a final assignment of the parameter. This allows scaling the model with m_flow_nominal, which is generally known in the flow leg, and v_nominal, for which a default value can be specified.
    This is for #544.
  • January 22, 2016, by Michael Wetter:
    Corrected type declaration of pressure difference. This is for #404.
  • February 14, 2012 by Michael Wetter:
    Added filter to approximate the travel time of the actuator.
  • February 3, 2012, by Michael Wetter:
    Removed assignment of m_flow_small as it is no longer used in its base class.
  • February 24, 2010 by Michael Wetter:
    Changed implementation of flow resistance. Instead of using a fixed resistance and a damper model in series, only one model is used that internally adds these two resistances. This leads to smaller systems of nonlinear equations. This new implementation extends Buildings.Fluid.Actuators.Dampers.MixingBox.
  • July 20, 2007 by Michael Wetter:
    First implementation.