modelBoilerPolynomialClosedLoop

Boilers with efficiency specified by polynomial and with open loop control
Diagram of BoilerPolynomialClosedLoopOpen the diagram
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Extends from Modelica.Icons.Example (Icon for runnable examples).

Information

This model illustrates how to use a boiler model with closed loop control. The controller modulates the boiler temperature between 60°C and 80°C. A three-way valve mixes recirculated water with boiler water to regulate the temperature of the volume at a constant temperature of 40°C. There is also a bypass in the boiler loop to ensure circulation when the valve position is such that it only recirculates water from the load. The bypass between valve and pump mixes recirculated water, thereby allowing the valve to work over a larger operating range. The expansion vessel near the boiler is used to set a reference pressure, and it is used to accommodate for the thermal expansion of the water.

Parameters

TypeNameDefaultDescription
Modelica.Units.SI.PowerQ_flow_nominal20000Nominal power
Modelica.Units.SI.TemperaturedT_nominal20Nominal temperature difference
Modelica.Units.SI.MassFlowRatem_flow_nominalQ_flow_nominal/dT_nominal/4200Nominal mass flow rate

Components

TypeNameDefaultDescription
Buildings.Fluid.Boilers.BoilerPolynomialboiBoiler
Modelica.Blocks.Logical.OnOffControlleronOffController
Modelica.Blocks.Math.BooleanToRealbooleanToReal
Actuators.Valves.ThreeWayEqualPercentageLinearval
Movers.FlowControlled_m_flowpumLoaPump for heating load
Movers.FlowControlled_m_flowpumBoiPump for boiler loop
Modelica.Blocks.Sources.Constantm_flow_pumMass flow rate of pump
Modelica.Blocks.Sources.ConstantTSetBoiTemperature setpoint for boiler
Controls.Continuous.LimPIDconPID
Modelica.Blocks.Sources.ConstantTSetHeaTemperature setpoint for heating load
Buildings.Fluid.FixedResistances.JunctionsplSplitter/mixer
Buildings.Fluid.FixedResistances.Junctionspl1Splitter/mixer
Buildings.Fluid.FixedResistances.Junctionspl2Splitter/mixer
Buildings.Fluid.FixedResistances.Junctionspl3Splitter/mixer
Storage.ExpansionVesselexp
Buildings.Fluid.FixedResistances.Junctionspl4Splitter/mixer
MixingVolumes.MixingVolumevol
Modelica.Thermal.HeatTransfer.Components.ThermalConductorthermalConductor
Modelica.Thermal.HeatTransfer.Sources.FixedTemperatureTBouFixed temperature boundary condition
Modelica.Blocks.Math.GaingainMultiply the mass flow rate as this circuit has a smaller temperature difference
Modelica.Thermal.HeatTransfer.Sensors.TemperatureSensorTVolSensor for volume temperature

Contents

NameDescription
MediumMedium model

Revisions

  • April 9, 2024, by Hongxiang Fu:
    Specified nominalValuesDefineDefaultPressureCurve=true in the mover component to suppress a warning. This is for #3819.
  • March 1, 2016, by Michael Wetter:
    Removed parameter dynamicBalance. This is for #484.
  • December 22, 2014 by Michael Wetter:
    Removed Modelica.Fluid.System to address issue #311.
  • October 6, 2014, by Michael Wetter:
    Corrected wrong value of m_flow_nominal for spl3.
  • March 25, 2014, by Michael Wetter:
    Updated model with new expansion vessel.
  • March 1, 2013, by Michael Wetter:
    Added nominal pressure drop for valve as this parameter no longer has a default value.
  • November 1, 2011 by Michael Wetter:
    First implementation.