modelPartialPrescribedOutlet

Ideal heater, cooler, humidifier or dehumidifier with prescribed outlet conditions
Diagram of PartialPrescribedOutletOpen the diagram

Extends from Buildings.Fluid.Interfaces.PartialTwoPortInterface (Partial model with two ports and declaration of quantities that are used by many models), Buildings.Fluid.Interfaces.TwoPortFlowResistanceParameters (Parameters for flow resistance for models with two ports).

Information

Base class for model for an ideal heater, cooler, humidifier or dehumidifier with a prescribed outlet conditions.

Models that extend this model need to configure the instance outCon and connect its input signals, in they are enabled.

Parameters

TypeNameDefaultDescription
BooleanhomotopyInitializationtrue= true, use homotopy method
Assumptions
BooleanallowFlowReversal (from PartialTwoPort)true= false to simplify equations, assuming, but not enforcing, no flow reversal
Nominal condition
Modelica.Units.SI.MassFlowRatem_flow_nominal (from PartialTwoPortInterface)Nominal mass flow rate
Modelica.Units.SI.PressureDifferencedp_nominal (from TwoPortFlowResistanceParameters)Pressure difference
Advanced
Modelica.Units.SI.MassFlowRatem_flow_small (from PartialTwoPortInterface)1E-4*abs(m_flow_nominal)Small mass flow rate for regularization of zero flow
Advanced › Diagnostics
Booleanshow_T (from PartialTwoPortInterface)false= true, if actual temperature at port is computed
Flow resistance
BooleancomputeFlowResistance (from TwoPortFlowResistanceParameters)true=true, compute flow resistance. Set to false to assume no friction
Booleanfrom_dp (from TwoPortFlowResistanceParameters)false= true, use m_flow = f(dp) else dp = f(m_flow)
Realn (from TwoPortFlowResistanceParameters)2Flow exponent, n=1 for laminar, n=2 for turbulent
BooleanlinearizeFlowResistance (from TwoPortFlowResistanceParameters)false= true, use linear relation between m_flow and dp for any flow rate
RealdeltaM (from TwoPortFlowResistanceParameters)0.1Fraction of nominal flow rate where flow transitions to laminar
Dynamics › Conservation equations
Modelica.Fluid.Types.DynamicsenergyDynamicsModelica.Fluid.Types.Dynamics.SteadyStateType of energy balance: dynamic (3 initialization options) or steady state
Dynamics
Modelica.Units.SI.Timetau10Time constant at nominal flow rate (used if energyDynamics not equal Modelica.Fluid.Types.Dynamics.SteadyState)

Connectors

TypeNameDefaultDescription
Modelica.Fluid.Interfaces.FluidPort_aport_a (from PartialTwoPort)Fluid connector a (positive design flow direction is from port_a to port_b)
Modelica.Fluid.Interfaces.FluidPort_bport_b (from PartialTwoPort)Fluid connector b (positive design flow direction is from port_a to port_b)

Components

TypeNameDefaultDescription
Modelica.Units.SI.MassFlowRatem_flow (from PartialTwoPortInterface)port_a.m_flowMass flow rate from port_a to port_b (m_flow > 0 is design flow direction)
Modelica.Units.SI.PressureDifferencedp (from PartialTwoPortInterface)port_a.p - port_b.pPressure difference between port_a and port_b
Medium.ThermodynamicStatesta_a (from PartialTwoPortInterface)if allowFlowReversal then Medium.setState_phX(port_a.p, noEvent(actualStream(port_a.h_outflow)), noEvent(actualStream(port_a.Xi_outflow))) else Medium.setState_phX(port_a.p, noEvent(inStream(port_a.h_outflow)), noEvent(inStream(port_a.Xi_outflow)))Medium properties in port_a
Medium.ThermodynamicStatesta_b (from PartialTwoPortInterface)if allowFlowReversal then Medium.setState_phX(port_b.p, noEvent(actualStream(port_b.h_outflow)), noEvent(actualStream(port_b.Xi_outflow))) else Medium.setState_phX(port_b.p, noEvent(port_b.h_outflow), noEvent(port_b.Xi_outflow))Medium properties in port_b

Revisions

  • June 17, 2026, by Michael Wetter:
    Updated implementation to allow a flow coefficient n that is different from 2. This allows use of the model for not fully turbulent flow.
    This is for Buildings, #4620.
  • March 10, 2022, by Michael Wetter:
    Propagated energyDynamics from instance outCon.
  • April 29, 2021, by Michael Wetter:
    Removed duplicate declaration of m_flow_nominal which is already declared in the base class.
  • April 14, 2020, by Michael Wetter:
    Changed homotopyInitialization to a constant.
    This is for IBPSA, #1341.
  • May 3, 2017, by Michael Wetter:
    Updated protected model for #763.
  • December 1, 2016, by Michael Wetter:
    Updated model as use_dh is no longer a parameter in the pressure drop model.
    This is for #480.
  • November 11, 2014, by Michael Wetter:
    Revised implementation.
  • March 19, 2014, by Christoph Nytsch-Geusen:
    First implementation.