modelSingleBoiler

A generic steam plant with a single boiler that discharges saturated steam

Extends from Buildings.DHC.Plants.BaseClasses.PartialPlant (Partial class for modeling a plant).

Information

This is a generic steam plant model that can be used in district heating system simulations. The model contains a feedwater tank, feedwater pump, check valve, and a boiler. The boiler is designed to discharge saturated steam vapor. For controls, the feedwater pump maintains the water volume setpoint in the drum boiler, while the boiler control maintains the discharge pressure setpoint.

References

Kathryn Hinkelman, Saranya Anbarasu, Michael Wetter, Antoine Gautier, Wangda Zuo. 2022. “A Fast and Accurate Modeling Approach for Water and Steam Thermodynamics with Practical Applications in District Heating System Simulation,” Energy, 254(A), pp. 124227. 10.1016/j.energy.2022.124227

Kathryn Hinkelman, Saranya Anbarasu, Michael Wetter, Antoine Gautier, Baptiste Ravache, Wangda Zuo 2022. “Towards Open-Source Modelica Models For Steam-Based District Heating Systems.” Proc. of the 1st International Workshop On Open Source Modelling And Simulation Of Energy Systems (OSMSES 2022), Aachen, German, April 4-5, 2022. 10.1109/OSMSES54027.2022.9769121

Parameters

Type	Name	Default	Description
Boolean	have_fue (from PartialPlant)	nFue > 0	Set to true if the plant has fuel use
Buildings.Fluid.Data.Fuels.Generic[nFue]	fue (from PartialPlant)		Fuel type
Buildings.Fluid.Data.Fuels.Generic	fueBoi	Buildings.Fluid.Data.Fuels.NaturalGasLowerHeatingValue()	Boiler fuel type
Modelica.Units.SI.MassFlowRate	m_flow_nominal	1	Nominal mass flow rate
Modelica.Units.SI.Power	Q_flow_nominal	m_flow_nominal*(MediumHea_b.specificEnthalpy(MediumHea_b.setState_pTX(p = pSteSet, T = TSat, X = MediumHea_b.X_default)) - Medium.specificEnthalpy(Medium.setState_pTX(p = pSteSet, T = TSat, X = Medium.X_default)))	Nominal heating power
Modelica.Units.SI.AbsolutePressure	pSteSet	300000	Steam pressure setpoint
Modelica.Units.SI.Temperature	TSat	MediumHea_b.saturationTemperature(pSteSet)	Saturation temperature at pressure setpoint
Modelica.Units.SI.AbsolutePressure	pTanFW	101325	Pressure of feedwater tank
Modelica.Units.SI.Volume	VBoiWatSet	VBoi/2	Setpoint for liquid water volume in the boiler
Modelica.Units.SI.Volume	VBoi	3	Total drum volume of steam boiler
Real	boiSca	1.25	Boiler heat capacity scaling factor
Buildings.Fluid.Movers.Data.Generic	per		Performance data for the feedwater pump
Configuration
Buildings.DHC.Types.DistrictSystemType	typ (from PartialPlant)	Buildings.DHC.Types.DistrictSystemType.CombinedGeneration2to4	Type of district system
Boolean	have_fan (from PartialPlant)	false	Set to true if fan power is computed
Boolean	have_pum (from PartialPlant)	false	Set to true if pump power is computed
Boolean	have_eleHea (from PartialPlant)	false	Set to true if the plant has electric heating system
Integer	nFue (from PartialPlant)	0	Number of fuel types (0 means no combustion system)
Boolean	have_eleCoo (from PartialPlant)	false	Set to true if the plant has electric cooling system
Boolean	have_weaBus (from PartialPlant)	false	Set to true to use a weather bus
Assumptions
Boolean	allowFlowReversal (from PartialPlant)	false	Set to true to allow flow reversal in service lines
Dynamics
Modelica.Units.SI.Mass	mDry	1.5E-3*Q_flow_nominal	Mass of boiler that will be lumped to water heat capacity
Initialization
Modelica.Units.SI.Volume	VTanFW_start	1	Setpoint for liquid water volume in the boiler
Modelica.Media.Interfaces.Types.AbsolutePressure	pBoi_start	pTanFW	Start value of boiler pressure
Real	yPum_start	0.7	Initial value of pump speed
Dynamics › Equations
Modelica.Fluid.Types.Dynamics	energyDynamics	Modelica.Fluid.Types.Dynamics.DynamicFreeInitial	Type of energy balance: dynamic (3 initialization options) or steady state
Modelica.Fluid.Types.Dynamics	massDynamics	energyDynamics	Type of mass balance: dynamic (3 initialization options) or steady state
Control › Boiler
Modelica.Blocks.Types.SimpleController	controllerTypeBoi	Modelica.Blocks.Types.SimpleController.PI	Type of controller
Real	kBoi	10	Gain of controller
Modelica.Units.SI.Time	TiBoi	120	Time constant of Integrator block
Modelica.Units.SI.Time	TdBoi	10	Time constant of Derivative block
Real	wpBoi	1	Set-point weight for Proportional block (0..1)
Real	wdBoi	0	Set-point weight for Derivative block (0..1)
Real	NiBoi	0.9	Ni*Ti is time constant of anti-windup compensation
Real	NdBoi	10	The higher Nd, the more ideal the derivative block
Control › Pump
Modelica.Blocks.Types.SimpleController	controllerTypePum	Modelica.Blocks.Types.SimpleController.PI	Type of controller
Real	kPum	5	Gain of controller
Modelica.Units.SI.Time	TiPum	120	Time constant of Integrator block
Modelica.Units.SI.Time	TdPum	0.1	Time constant of Derivative block
Real	wpPum	1	Set-point weight for Proportional block (0..1)
Real	wdPum	0	Set-point weight for Derivative block (0..1)
Real	NiPum	0.9	Ni*Ti is time constant of anti-windup compensation
Real	NdPum	10	The higher Nd, the more ideal the derivative block

Connectors

Type	Name	Description
Modelica.Fluid.Interfaces.FluidPort_a	port_aSerAmb (from PartialPlant)	Fluid connector for ambient water service supply line
Modelica.Fluid.Interfaces.FluidPort_b	port_bSerAmb (from PartialPlant)	Fluid connector for ambient water service return line
Modelica.Fluid.Interfaces.FluidPort_a	port_aSerHea (from PartialPlant)	Fluid connector for heating service supply line
Modelica.Fluid.Interfaces.FluidPort_b	port_bSerHea (from PartialPlant)	Fluid connector for heating service return line
Modelica.Fluid.Interfaces.FluidPort_a	port_aSerCoo (from PartialPlant)	Fluid connector for cooling service supply line
Modelica.Fluid.Interfaces.FluidPort_b	port_bSerCoo (from PartialPlant)	Fluid connector for cooling service return line
Buildings.BoundaryConditions.WeatherData.Bus	weaBus (from PartialPlant)	Weather data bus
Buildings.Controls.OBC.CDL.Interfaces.RealOutput	PHea (from PartialPlant)	Power drawn by heating system
Buildings.Controls.OBC.CDL.Interfaces.RealOutput	PCoo (from PartialPlant)	Power drawn by cooling system
Buildings.Controls.OBC.CDL.Interfaces.RealOutput	PFan (from PartialPlant)	Power drawn by fan motors
Buildings.Controls.OBC.CDL.Interfaces.RealOutput	PPum (from PartialPlant)	Power drawn by pump motors
Buildings.Controls.OBC.CDL.Interfaces.RealOutput	QFue_flow (from PartialPlant)	Fuel energy input rate

Components

Type	Name	Description
Buildings.Fluid.Movers.SpeedControlled_y	pumFW	Feedwater pump
Buildings.DHC.Plants.Steam.BaseClasses.BoilerPolynomial	boi	Steam boiler
Buildings.Controls.Continuous.LimPID	conPum	Pump control
Modelica.Blocks.Math.Gain	VNor	Normalized volume setpoint
Buildings.Controls.Continuous.LimPID	conBoi	Boiler control
Modelica.Blocks.Math.Gain	PNor	Normalized pressure setpoint
Buildings.Fluid.Sensors.Pressure	senPreSte	Steam pressure sensor
Modelica.Blocks.Sources.Constant	uni	Unitary
Buildings.Fluid.Storage.ExpansionVessel	tanFW	Feedwater tank
Buildings.Fluid.FixedResistances.CheckValve	cheVal	Check valve

Revisions

September 15, 2023, by Kathryn Hinkelman:
Added publication references.
July 18, 2023, by Michael Wetter:
Corrected assignment of allowFlowReversal, and set start pressure of boiler to be equal to start pressure of feed water tank. Otherwise, backflow occurs at the start of the simulation.
March 3, 2022 by Kathryn Hinkelman:
First implementation.