modelConvector

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

Information

In cooling mode, this model adds heat to the water stream. The heat added is equal to:

QBeam = Qrated fΔT fSA fW

In heating mode, the heat is removed from the water stream.

Parameters

TypeNameDefaultDescription
BooleanhomotopyInitializationtrue= true, use homotopy method
Data.GenericperPerformance data
IntegernBeamsNumber of beams in parallel
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)
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 › Nominal condition
Modelica.Units.SI.Timetau30Time constant at nominal flow (if energyDynamics <> SteadyState)
Dynamics › Conservation equations
Modelica.Fluid.Types.DynamicsenergyDynamicsModelica.Fluid.Types.Dynamics.DynamicFreeInitialType of energy balance: dynamic (3 initialization options) or steady state
Initialization
Medium.AbsolutePressurep_startMedium.p_defaultStart value of pressure
Medium.TemperatureT_startMedium.T_defaultStart value of temperature
Medium.MassFraction[Medium.nX]X_startMedium.X_defaultStart value of mass fractions m_i/m
Medium.ExtraProperty[Medium.nC]C_startfill(0, Medium.nC)Start value of trace substances

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)
Modelica.Blocks.Interfaces.RealInputmAir_flowAir mass flow rate of a single beam
Modelica.Blocks.Interfaces.RealInputTRooRoom air temperature
Modelica.Blocks.Interfaces.RealOutputQ_flowActual capacity of a single beam

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

  • March 3, 2022, by Michael Wetter:
    Removed massDynamics.
    This is for issue 1542.
  • April 14, 2020, by Michael Wetter:
    Changed homotopyInitialization to a constant.
    This is for IBPSA, #1341.
  • November 2, 2016, by Michael Wetter:
    Made assignment of senTem.y final.
  • June 13, 2016, by Michael Wetter:
    Revised implementation.
  • May 20, 2016, by Alessandro Maccarini:
    First implementation.