Buildings.DHC.Networks.BaseClasses
Package with base classes that are used by multiple models
Information
This package contains base classes that are used to construct the classes in Buildings.DHC.Networks.
Extends from Modelica.Icons.BasesPackage (Icon for packages containing base classes).
Package Content
| Name | Description |
|---|---|
 DifferenceEnthalpyFlowRate
|
Sensor outputting the difference between two enthalpy flow rates |
 PartialConnection1Pipe
|
Partial model for connecting an agent to a one-pipe distribution network |
 PartialConnection2Pipe
|
Partial model for connecting an agent to a two-pipe distribution network |
 PartialConnection2Pipe2Medium
|
Partial model for connecting an agent to a two-pipe distribution network with two medium declarations |
 PartialDistribution
|
Partial model for distribution network |
 PartialDistribution1Pipe
|
Partial model for one-pipe distribution network |
 PartialDistribution2Medium
|
Partial model for distribution network with two medium declarations |
 PartialDistribution2Pipe
|
Partial model for two-pipe distribution network |
 PartialDistribution2Pipe2Medium
|
Partial model for a two-pipe distribution network with two medium declarations |
Buildings.DHC.Networks.BaseClasses.DifferenceEnthalpyFlowRate
Sensor outputting the difference between two enthalpy flow rates
Information
This model outputs the difference in enthalpy flow rate between two different streams: ΔḢ = ṁ1 h1 - ṁ2 h2. Optionally the time integral of this quantity can be output. The sensor is ideal, i.e., it does not influence the fluid.
By default
-
the parameter
tauis zero, so the specific enthalpy that is used to compute each enthalpy flow rate is computed in steady-state, - the medium is the same in both streams but the model allows for specifying two different media to represent for instance the gaseous and liquid state of the same substance.
Extends from Fluid.Interfaces.PartialFourPortInterface (Partial model with four ports and declaration of quantities that are used by many models).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium1 | PartialMedium | Medium 1 in the component | |
| replaceable package Medium2 | PartialMedium | Medium 2 in the component | |
| Boolean | have_integrator | false | Set to true to output the time integral |
| Time | tau | 0 | Time constant at nominal flow rate [s] |
| Nominal condition | |||
| MassFlowRate | m1_flow_nominal | m_flow_nominal | Nominal mass flow rate [kg/s] |
| MassFlowRate | m2_flow_nominal | m_flow_nominal | Nominal mass flow rate [kg/s] |
| MassFlowRate | m_flow_nominal | Nominal mass flow rate [kg/s] | |
| Initialization | |||
| Init | initType | Modelica.Blocks.Types.Init.I... | Type of initialization (InitialState and InitialOutput are identical) |
| SpecificEnthalpy | h1_out_start | Medium1.specificEnthalpy_pTX... | Initial or guess value of measured specific enthalpy [J/kg] |
| SpecificEnthalpy | h2_out_start | Medium2.specificEnthalpy_pTX... | Initial or guess value of measured specific enthalpy [J/kg] |
| Assumptions | |||
| Boolean | allowFlowReversal1 | allowFlowReversal | = false to simplify equations, assuming, but not enforcing, no flow reversal for medium 1 |
| Boolean | allowFlowReversal2 | allowFlowReversal | = false to simplify equations, assuming, but not enforcing, no flow reversal for medium 2 |
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m1_flow_small | m_flow_small | Small mass flow rate for regularization of zero flow [kg/s] |
| MassFlowRate | m2_flow_small | m_flow_small | Small mass flow rate for regularization of zero flow [kg/s] |
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package Medium2 | Medium 2 in the component | |
| FluidPort_a | port_a1 | Fluid connector a1 (positive design flow direction is from port_a1 to port_b1) |
| FluidPort_b | port_b1 | Fluid connector b1 (positive design flow direction is from port_a1 to port_b1) |
| FluidPort_a | port_a2 | Fluid connector a2 (positive design flow direction is from port_a2 to port_b2) |
| FluidPort_b | port_b2 | Fluid connector b2 (positive design flow direction is from port_a2 to port_b2) |
| output RealOutput | dH_flow | Difference in enthalpy flow rate between stream 1 and 2 [W] |
| output RealOutput | E | Time integral of enthalpy flow rate difference between stream 1 and 2 [J] |
Modelica definition
model DifferenceEnthalpyFlowRate
"Sensor outputting the difference between two enthalpy flow rates"
extends Fluid.Interfaces.PartialFourPortInterface(
redeclare replaceable package Medium2=Medium1,
final m1_flow_nominal=m_flow_nominal,
final m2_flow_nominal=m_flow_nominal,
final allowFlowReversal1=allowFlowReversal,
final allowFlowReversal2=allowFlowReversal,
final m1_flow_small=m_flow_small,
final m2_flow_small=m_flow_small,
final show_T=false);
parameter Boolean have_integrator=false
"Set to true to output the time integral";
parameter Modelica.Units.SI.MassFlowRate m_flow_nominal(min=0)
"Nominal mass flow rate";
parameter Modelica.Units.SI.Time tau(min=0) = 0
"Time constant at nominal flow rate";
parameter Modelica.Blocks.Types.Init initType=Modelica.Blocks.Types.Init.InitialState
"Type of initialization (InitialState and InitialOutput are identical)";
parameter Boolean allowFlowReversal=true
"= false to simplify equations, assuming, but not enforcing, no flow reversal";
parameter Modelica.Units.SI.SpecificEnthalpy h1_out_start=
Medium1.specificEnthalpy_pTX(
p=Medium1.p_default,
T=Medium1.T_default,
X=Medium1.X_default)
"Initial or guess value of measured specific enthalpy";
parameter Modelica.Units.SI.SpecificEnthalpy h2_out_start=
Medium2.specificEnthalpy_pTX(
p=Medium2.p_default,
T=Medium2.T_default,
X=Medium2.X_default)
"Initial or guess value of measured specific enthalpy";
parameter Medium1.MassFlowRate m_flow_small(min=0)=1E-4*abs(m_flow_nominal)
"Small mass flow rate for regularization of zero flow";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput dH_flow(
final unit="W")
"Difference in enthalpy flow rate between stream 1 and 2";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput E(
final unit="J") if have_integrator
"Time integral of enthalpy flow rate difference between stream 1 and 2";
Fluid.Sensors.EnthalpyFlowRate senEntFlo1(
redeclare final package Medium=Medium1,
final m_flow_nominal=m_flow_nominal,
final tau=tau,
final initType=initType,
final allowFlowReversal=allowFlowReversal,
final h_out_start=h1_out_start)
"Enthalpy flow rate of fluid stream 1";
Fluid.Sensors.EnthalpyFlowRate senEntFlo2(
redeclare final package Medium=Medium2,
final m_flow_nominal=m_flow_nominal,
final tau=tau,
final initType=initType,
final allowFlowReversal=allowFlowReversal,
final h_out_start=h2_out_start)
"Enthalpy flow rate of fluid stream 2";
Buildings.Controls.OBC.CDL.Reals.Subtract dif
"Compute the difference";
Modelica.Blocks.Continuous.Integrator int(
y(unit="J")) if have_integrator
"Time integral computation";
equation
connect(port_a1,senEntFlo1.port_a);
connect(senEntFlo1.port_b,port_b1);
connect(port_b2,senEntFlo2.port_b);
connect(senEntFlo2.port_a,port_a2);
connect(dif.y,dH_flow);
connect(senEntFlo1.H_flow,dif.u1);
connect(senEntFlo2.H_flow,dif.u2);
connect(int.y,E);
connect(dif.y,int.u);
end DifferenceEnthalpyFlowRate;
Buildings.DHC.Networks.BaseClasses.PartialConnection1Pipe
Partial model for connecting an agent to a one-pipe distribution network
Information
Partial model to be used for connecting an agent (e.g. energy transfer station) to a one-pipe distribution network.
Two instances of a replaceable partial model are used to represent the pipes:
- One representing the main distribution pipe immediately upstream the connection.
- The other one representing both the supply and return lines of the connection. When replacing that model with a pipe model computing the pressure drop, one must double the length so that both the supply and return lines are accounted for.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | Modelica.Media.Interfaces.Pa... | Medium model | |
| replaceable model Model_pipDis | Fluid.Interfaces.PartialTwoP... | ||
| replaceable model Model_pipCon | Fluid.Interfaces.PartialTwoP... | ||
| Boolean | show_entFlo | false | Set to true to output enthalpy flow rate difference |
| Boolean | show_TOut | false | Set to true to output temperature at connection outlet |
| MassFlowRate | mDis_flow_nominal | Nominal mass flow rate in the distribution line [kg/s] | |
| MassFlowRate | mCon_flow_nominal | Nominal mass flow rate in the connection line [kg/s] | |
| Assumptions | |||
| Boolean | allowFlowReversal | false | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Nominal condition | |||
| Time | tau | 10 | Time constant at nominal flow for dynamic energy and momentum balance [s] |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package Medium | Medium model | |
| replaceable model Model_pipDis | ||
| replaceable model Model_pipCon | ||
| FluidPort_a | port_aDis | Distribution inlet port |
| FluidPort_b | port_bDis | Distribution outlet port |
| FluidPort_a | port_aCon | Connection return port |
| FluidPort_b | port_bCon | Connection supply port |
| output RealOutput | mCon_flow | Connection supply mass flow rate (measured) [kg/s] |
| output RealOutput | dH_flow | Difference in enthalpy flow rate between connection supply and return [W] |
| output RealOutput | mByp_flow | Bypass mass flow rate [kg/s] |
| output RealOutput | TOut | Temperature in distribution line at connection outlet [K] |
Modelica definition
partial model PartialConnection1Pipe
"Partial model for connecting an agent to a one-pipe distribution network"
replaceable package Medium=Modelica.Media.Interfaces.PartialMedium
"Medium model";
replaceable model Model_pipDis=Fluid.Interfaces.PartialTwoPortInterface (
redeclare final package Medium=Medium,
final m_flow_nominal=mDis_flow_nominal,
final allowFlowReversal=allowFlowReversal);
replaceable model Model_pipCon=Fluid.Interfaces.PartialTwoPortInterface (
redeclare final package Medium=Medium,
final m_flow_nominal=mCon_flow_nominal,
final allowFlowReversal=allowFlowReversal);
parameter Boolean show_entFlo=false
"Set to true to output enthalpy flow rate difference";
parameter Boolean show_TOut=false
"Set to true to output temperature at connection outlet";
parameter Modelica.Units.SI.MassFlowRate mDis_flow_nominal
"Nominal mass flow rate in the distribution line";
parameter Modelica.Units.SI.MassFlowRate mCon_flow_nominal
"Nominal mass flow rate in the connection line";
parameter Boolean allowFlowReversal=false
"= true to allow flow reversal, false restricts to design direction (port_a -> port_b)";
parameter Modelica.Fluid.Types.Dynamics energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial
"Type of energy balance: dynamic (3 initialization options) or steady state";
final parameter Modelica.Fluid.Types.Dynamics massDynamics=energyDynamics
"Type of mass balance: dynamic (3 initialization options) or steady state, must be steady state if energyDynamics is steady state";
parameter Modelica.Units.SI.Time tau=10
"Time constant at nominal flow for dynamic energy and momentum balance";
// IO CONNECTORS
Modelica.Fluid.Interfaces.FluidPort_a port_aDis(
redeclare final package Medium=Medium,
m_flow(
min=
if allowFlowReversal then
-Modelica.Constants.inf
else
0),
h_outflow(
start=Medium.h_default,
nominal=Medium.h_default))
"Distribution inlet port";
Modelica.Fluid.Interfaces.FluidPort_b port_bDis(
redeclare final package Medium=Medium,
m_flow(
max=
if allowFlowReversal then
+Modelica.Constants.inf
else
0),
h_outflow(
start=Medium.h_default,
nominal=Medium.h_default))
"Distribution outlet port";
Modelica.Fluid.Interfaces.FluidPort_a port_aCon(
redeclare final package Medium=Medium,
m_flow(
min=
if allowFlowReversal then
-Modelica.Constants.inf
else
0),
h_outflow(
start=Medium.h_default,
nominal=Medium.h_default))
"Connection return port";
Modelica.Fluid.Interfaces.FluidPort_b port_bCon(
redeclare final package Medium=Medium,
m_flow(
max=
if allowFlowReversal then
+Modelica.Constants.inf
else
0),
h_outflow(
start=Medium.h_default,
nominal=Medium.h_default))
"Connection supply port";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput mCon_flow(
final unit="kg/s")
"Connection supply mass flow rate (measured)";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput dH_flow(
final unit="W") if show_entFlo
"Difference in enthalpy flow rate between connection supply and return";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput mByp_flow(
final unit="kg/s") "Bypass mass flow rate";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput TOut(
final unit="K",
displayUnit="degC") if show_TOut
"Temperature in distribution line at connection outlet";
// COMPONENTS
Fluid.FixedResistances.Junction junConSup(
redeclare final package Medium=Medium,
final portFlowDirection_1=
if allowFlowReversal then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else
Modelica.Fluid.Types.PortFlowDirection.Entering,
final portFlowDirection_2=
if allowFlowReversal then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else
Modelica.Fluid.Types.PortFlowDirection.Leaving,
final portFlowDirection_3=
if allowFlowReversal then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else
Modelica.Fluid.Types.PortFlowDirection.Leaving,
final dp_nominal={0,0,0},
final energyDynamics=energyDynamics,
final tau=tau,
final m_flow_nominal={mDis_flow_nominal,-mDis_flow_nominal,-mCon_flow_nominal})
"Junction with connection supply";
Fluid.FixedResistances.Junction junConRet(
redeclare final package Medium=Medium,
final portFlowDirection_1=
if allowFlowReversal then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else
Modelica.Fluid.Types.PortFlowDirection.Entering,
final portFlowDirection_2=
if allowFlowReversal then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else
Modelica.Fluid.Types.PortFlowDirection.Leaving,
final portFlowDirection_3=
if allowFlowReversal then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else
Modelica.Fluid.Types.PortFlowDirection.Entering,
final dp_nominal={0,0,0},
final energyDynamics=energyDynamics,
final tau=tau,
final m_flow_nominal={mDis_flow_nominal,-mDis_flow_nominal,mCon_flow_nominal})
"Junction with connection return";
Model_pipDis pipDis
"Distribution pipe";
Model_pipCon pipCon
"Connection pipe";
Buildings.Fluid.Sensors.MassFlowRate senMasFloCon(
redeclare final package Medium=Medium,
final allowFlowReversal=allowFlowReversal)
"Connection supply mass flow rate (measured)";
Buildings.Fluid.Sensors.MassFlowRate senMasFloByp(
redeclare final package Medium=Medium,
final allowFlowReversal=allowFlowReversal)
"Bypass mass flow rate (measured)";
DifferenceEnthalpyFlowRate senDifEntFlo(
redeclare final package Medium1=Medium,
final allowFlowReversal=allowFlowReversal,
final m_flow_nominal=mCon_flow_nominal) if show_entFlo
"Difference in enthalpy flow rate";
Fluid.Sensors.TemperatureTwoPort senTOut(
redeclare final package Medium = Medium,
final allowFlowReversal=allowFlowReversal,
final m_flow_nominal=mDis_flow_nominal) if show_TOut
"Temperature in distribution line at connection outlet";
protected
parameter Modelica.Units.SI.SpecificHeatCapacity cp_default=
Medium.specificHeatCapacityCp(Medium.setState_pTX(
p=Medium.p_default,
T=Medium.T_default,
X=Medium.X_default))
"Specific heat capacity of medium at default medium state";
equation
// Connect statements involving conditionally removed components are
// removed at translation time by Modelica specification.
// Only obsolete statements corresponding to the default model structure need
// to be programmatically removed.
if not show_entFlo then
connect(port_bCon,senMasFloCon.port_b);
connect(port_aCon,junConRet.port_3);
end if;
if not show_TOut then
connect(junConRet.port_2,port_bDis);
end if;
connect(junConSup.port_3,pipCon.port_a);
connect(senMasFloCon.m_flow,mCon_flow);
connect(port_aDis,pipDis.port_a);
connect(junConSup.port_2,senMasFloByp.port_a);
connect(senMasFloByp.port_b,junConRet.port_1);
connect(senMasFloByp.m_flow,mByp_flow);
connect(senMasFloCon.port_b, senDifEntFlo.port_a1);
connect(senDifEntFlo.port_b1, port_bCon);
connect(senDifEntFlo.port_b2, junConRet.port_3);
connect(senDifEntFlo.port_a2, port_aCon);
connect(senDifEntFlo.dH_flow, dH_flow);
connect(port_bDis, senTOut.port_b);
connect(junConRet.port_2, senTOut.port_a);
connect(senTOut.T, TOut);
connect(pipCon.port_b, senMasFloCon.port_a);
connect(pipDis.port_b, junConSup.port_1);
end PartialConnection1Pipe;
Buildings.DHC.Networks.BaseClasses.PartialConnection2Pipe
Partial model for connecting an agent to a two-pipe distribution network
Information
Partial model to be used for connecting an agent (e.g. an energy transfer station) to a two-pipe distribution network.
Three instances of a replaceable partial model are used to represent the pipes:
- One representing the main distribution supply pipe immediately upstream the connection.
- Another one representing the main distribution return pipe immediately downstream the connection.
- The last one representing both the supply and return lines of the connection. When replacing that model with a pipe model computing the pressure drop, one must double the length so that both the supply and return lines are accounted for.
Extends from Buildings.DHC.Networks.BaseClasses.PartialConnection2Pipe2Medium (Partial model for connecting an agent to a two-pipe distribution network with two medium declarations).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package MediumSup | PartialMedium | Medium model for supply fluid | |
| replaceable package MediumRet | PartialMedium | Medium model for return fluid | |
| replaceable model Model_pipDisSup | PartialTwoPortInterface | Interface for inlet pipe for the distribution supply | |
| replaceable model Model_pipDisRet | PartialTwoPortInterface | Interface for outlet pipe for the distribution return | |
| replaceable package Medium | Modelica.Media.Interfaces.Pa... | Medium model | |
| replaceable model Model_pipCon | Fluid.Interfaces.PartialTwoP... | ||
| Boolean | show_entFlo | false | Set to true to output enthalpy flow rate difference |
| Nominal condition | |||
| MassFlowRate | mDis_flow_nominal | Nominal mass flow rate in the distribution line [kg/s] | |
| MassFlowRate | mCon_flow_nominal | Nominal mass flow rate in the connection line [kg/s] | |
| Assumptions | |||
| Boolean | allowFlowReversal | false | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Dynamics | |||
| Equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Nominal condition | |||
| Time | tau | 10 | Time constant at nominal flow for dynamic energy and momentum balance [s] |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package MediumSup | Medium model for supply fluid | |
| replaceable package MediumRet | Medium model for return fluid | |
| FluidPort_a | port_aDisSup | Distribution supply inlet port |
| FluidPort_b | port_bDisSup | Distribution supply outlet port |
| FluidPort_a | port_aDisRet | Distribution return inlet port |
| FluidPort_b | port_bDisRet | Distribution return outlet port |
| FluidPort_b | port_bCon | Connection supply port |
| FluidPort_a | port_aCon | Connection return port |
| replaceable package Medium | Medium model | |
| replaceable model Model_pipCon | ||
| output RealOutput | mCon_flow | Connection supply mass flow rate [kg/s] |
| output RealOutput | dp | Pressure drop accross the connection (measured) [Pa] |
| output RealOutput | dH_flow | Difference in enthalpy flow rate between connection supply and return [W] |
Modelica definition
partial model PartialConnection2Pipe
"Partial model for connecting an agent to a two-pipe distribution network"
extends Buildings.DHC.Networks.BaseClasses.PartialConnection2Pipe2Medium(
redeclare final package MediumSup=Medium,
redeclare final package MediumRet=Medium);
replaceable package Medium=Modelica.Media.Interfaces.PartialMedium
"Medium model";
replaceable model Model_pipCon=Fluid.Interfaces.PartialTwoPortInterface (
redeclare final package Medium=Medium,
final m_flow_nominal=mCon_flow_nominal,
final allowFlowReversal=allowFlowReversal);
parameter Boolean show_entFlo=false
"Set to true to output enthalpy flow rate difference";
// OUTPUTS
Buildings.Controls.OBC.CDL.Interfaces.RealOutput mCon_flow(
final quantity="MassFlowRate",
final unit="kg/s")
"Connection supply mass flow rate";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput dp(
final quantity="PressureDifference",
final unit="Pa",
final displayUnit="Pa")
"Pressure drop accross the connection (measured)";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput dH_flow(
final unit="W") if show_entFlo
"Difference in enthalpy flow rate between connection supply and return";
// COMPONENTS
Model_pipCon pipCon
"Connection pipe";
Buildings.Fluid.Sensors.MassFlowRate senMasFloCon(
redeclare final package Medium=Medium,
final allowFlowReversal=allowFlowReversal)
"Connection supply mass flow rate (measured)";
Fluid.Sensors.RelativePressure senRelPre(
redeclare final package Medium=Medium)
"Relative pressure sensor";
DifferenceEnthalpyFlowRate senDifEntFlo(
redeclare final package Medium1 = Medium,
final allowFlowReversal=allowFlowReversal,
final m_flow_nominal=mCon_flow_nominal) if show_entFlo
"Difference in enthalpy flow rate";
equation
// Connect statements involving conditionally removed components are
// removed at translation time by Modelica specification.
// Only obsolete statements corresponding to the default model structure need
// to be programmatically removed.
if not show_entFlo then
connect(port_bCon,senMasFloCon.port_b);
connect(port_aCon, junConRet.port_3);
end if;
connect(senMasFloCon.m_flow,mCon_flow);
connect(senRelPre.port_a,junConSup.port_1);
connect(senRelPre.port_b,junConRet.port_2);
connect(senRelPre.p_rel,dp);
connect(port_bCon, senDifEntFlo.port_b1);
connect(senDifEntFlo.port_a2, port_aCon);
connect(senDifEntFlo.dH_flow, dH_flow);
connect(senMasFloCon.port_b, senDifEntFlo.port_a1);
connect(senDifEntFlo.port_b2, junConRet.port_3);
connect(pipCon.port_a, junConSup.port_3);
connect(senMasFloCon.port_a, pipCon.port_b);
connect(pipDisSup.port_b, junConSup.port_1);
connect(pipDisRet.port_a, junConRet.port_2);
end PartialConnection2Pipe;
Buildings.DHC.Networks.BaseClasses.PartialConnection2Pipe2Medium
Partial model for connecting an
agent to a two-pipe distribution network with two medium declarations
Information
Partial model to be used for connecting an agent (e.g. an energy transfer station) to a two-pipe distribution network featuring different supply and return fluids (e.g. steam and liquid water).
Six instances of a replaceable partial model are used to represent the pipes:
- Two representing the main distribution supply and return pipes immediately upstream of the connection.
- Two representing the main distribution supply and return pipes immediately downstream of the connection.
- The other two representing the branch connection supply and return pipes immediately upstream and downstream of the connection, respectively.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package MediumSup | Modelica.Media.Interfaces.Pa... | Medium model for supply fluid | |
| replaceable package MediumRet | Modelica.Media.Interfaces.Pa... | Medium model for return fluid | |
| replaceable model Model_pipDisSup | Buildings.Fluid.Interfaces.P... | Interface for inlet pipe for the distribution supply | |
| replaceable model Model_pipDisRet | Buildings.Fluid.Interfaces.P... | Interface for outlet pipe for the distribution return | |
| Nominal condition | |||
| MassFlowRate | mDis_flow_nominal | Nominal mass flow rate in the distribution line [kg/s] | |
| MassFlowRate | mCon_flow_nominal | Nominal mass flow rate in the connection line [kg/s] | |
| Assumptions | |||
| Boolean | allowFlowReversal | false | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Dynamics | |||
| Equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Nominal condition | |||
| Time | tau | 10 | Time constant at nominal flow for dynamic energy and momentum balance [s] |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package MediumSup | Medium model for supply fluid | |
| replaceable package MediumRet | Medium model for return fluid | |
| replaceable model Model_pipDisSup | Interface for inlet pipe for the distribution supply | |
| replaceable model Model_pipDisRet | Interface for outlet pipe for the distribution return | |
| FluidPort_a | port_aDisSup | Distribution supply inlet port |
| FluidPort_b | port_bDisSup | Distribution supply outlet port |
| FluidPort_a | port_aDisRet | Distribution return inlet port |
| FluidPort_b | port_bDisRet | Distribution return outlet port |
| FluidPort_b | port_bCon | Connection supply port |
| FluidPort_a | port_aCon | Connection return port |
Modelica definition
partial model PartialConnection2Pipe2Medium "Partial model for connecting an
agent to a two-pipe distribution network with two medium declarations"
replaceable package MediumSup = Modelica.Media.Interfaces.PartialMedium
"Medium model for supply fluid";
replaceable package MediumRet = Modelica.Media.Interfaces.PartialMedium
"Medium model for return fluid";
replaceable model Model_pipDisSup = Buildings.Fluid.Interfaces.PartialTwoPortInterface
constrainedby Buildings.Fluid.Interfaces.PartialTwoPortInterface(
redeclare final package Medium = MediumSup,
final m_flow_nominal=mDis_flow_nominal,
final allowFlowReversal=allowFlowReversal)
"Interface for inlet pipe for the distribution supply";
replaceable model Model_pipDisRet = Buildings.Fluid.Interfaces.PartialTwoPortInterface
constrainedby Buildings.Fluid.Interfaces.PartialTwoPortInterface(
redeclare final package Medium = MediumRet,
final m_flow_nominal=mDis_flow_nominal,
final allowFlowReversal=allowFlowReversal)
"Interface for outlet pipe for the distribution return";
parameter Modelica.Units.SI.MassFlowRate mDis_flow_nominal
"Nominal mass flow rate in the distribution line";
parameter Modelica.Units.SI.MassFlowRate mCon_flow_nominal
"Nominal mass flow rate in the connection line";
parameter Boolean allowFlowReversal = false
"= true to allow flow reversal, false restricts to design direction (port_a -> port_b)";
parameter Modelica.Fluid.Types.Dynamics energyDynamics=
Modelica.Fluid.Types.Dynamics.FixedInitial
"Type of energy balance: dynamic (3 initialization options) or steady state";
parameter Modelica.Units.SI.Time tau=10
"Time constant at nominal flow for dynamic energy and momentum balance";
// IO CONNECTORS
Modelica.Fluid.Interfaces.FluidPort_a port_aDisSup(
redeclare final package Medium = MediumSup,
m_flow(min=if allowFlowReversal then -Modelica.Constants.inf else 0),
h_outflow(start=MediumSup.h_default, nominal=MediumSup.h_default))
"Distribution supply inlet port";
Modelica.Fluid.Interfaces.FluidPort_b port_bDisSup(
redeclare final package Medium = MediumSup,
m_flow(max=if allowFlowReversal then +Modelica.Constants.inf else 0),
h_outflow(start=MediumSup.h_default, nominal=MediumSup.h_default))
"Distribution supply outlet port";
Modelica.Fluid.Interfaces.FluidPort_a port_aDisRet(
redeclare final package Medium = MediumRet,
m_flow(min=if allowFlowReversal then -Modelica.Constants.inf else 0),
h_outflow(start=MediumRet.h_default, nominal=MediumRet.h_default))
"Distribution return inlet port";
Modelica.Fluid.Interfaces.FluidPort_b port_bDisRet(
redeclare final package Medium = MediumRet,
m_flow(max=if allowFlowReversal then +Modelica.Constants.inf else 0),
h_outflow(start=MediumRet.h_default, nominal=MediumRet.h_default))
"Distribution return outlet port";
Modelica.Fluid.Interfaces.FluidPort_b port_bCon(
redeclare final package Medium = MediumSup,
m_flow(max=if allowFlowReversal then +Modelica.Constants.inf else 0),
h_outflow(start=MediumSup.h_default, nominal=MediumSup.h_default))
"Connection supply port";
Modelica.Fluid.Interfaces.FluidPort_a port_aCon(
redeclare final package Medium = MediumRet,
m_flow(min=if allowFlowReversal then -Modelica.Constants.inf else 0),
h_outflow(start=MediumRet.h_default, nominal=MediumRet.h_default))
"Connection return port";
// COMPONENTS
Model_pipDisSup pipDisSup "Distribution supply pipe";
Model_pipDisRet pipDisRet "Distribution return pipe";
Buildings.Fluid.FixedResistances.Junction junConSup(
redeclare final package Medium = MediumSup,
final portFlowDirection_1=if allowFlowReversal then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else Modelica.Fluid.Types.PortFlowDirection.Entering,
final portFlowDirection_2=if allowFlowReversal then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else Modelica.Fluid.Types.PortFlowDirection.Leaving,
final portFlowDirection_3=if allowFlowReversal then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else Modelica.Fluid.Types.PortFlowDirection.Leaving,
final dp_nominal = {0, 0, 0},
final energyDynamics=energyDynamics,
final tau=tau,
final m_flow_nominal={mDis_flow_nominal,-mDis_flow_nominal,-mCon_flow_nominal})
"Junction with connection supply";
Buildings.Fluid.FixedResistances.Junction junConRet(
redeclare final package Medium = MediumRet,
final portFlowDirection_1=if allowFlowReversal then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else Modelica.Fluid.Types.PortFlowDirection.Entering,
final portFlowDirection_2=if allowFlowReversal then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else Modelica.Fluid.Types.PortFlowDirection.Leaving,
final portFlowDirection_3=if allowFlowReversal then
Modelica.Fluid.Types.PortFlowDirection.Bidirectional
else Modelica.Fluid.Types.PortFlowDirection.Entering,
final dp_nominal = {0, 0, 0},
final energyDynamics=energyDynamics,
final tau=tau,
final m_flow_nominal={mDis_flow_nominal,-mDis_flow_nominal,mCon_flow_nominal})
"Junction with connection return";
protected
parameter Modelica.Units.SI.SpecificHeatCapacity cp_default=
MediumRet.specificHeatCapacityCp(MediumRet.setState_pTX(
p = MediumRet.p_default,
T = MediumRet.T_default,
X = MediumRet.X_default))
"Specific heat capacity of medium at default medium state";
equation
connect(port_aDisSup, pipDisSup.port_a);
connect(pipDisRet.port_b, port_bDisRet);
connect(junConSup.port_2, port_bDisSup);
connect(junConRet.port_1, port_aDisRet);
end PartialConnection2Pipe2Medium;
Buildings.DHC.Networks.BaseClasses.PartialDistribution
Partial model for distribution network
Information
Partial model to be used for modeling various distribution networks e.g. one-pipe or two-pipe hydraulic distribution.
Extends from Buildings.DHC.Networks.BaseClasses.PartialDistribution2Medium (Partial model for distribution network with two medium declarations).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package MediumSup | PartialMedium | Medium model for supply fluid | |
| replaceable package MediumRet | PartialMedium | Medium model for return fluid | |
| Integer | nCon | Number of connections | |
| replaceable package Medium | Modelica.Media.Interfaces.Pa... | Medium model | |
| Assumptions | |||
| Boolean | allowFlowReversal | false | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package MediumSup | Medium model for supply fluid | |
| replaceable package MediumRet | Medium model for return fluid | |
| FluidPorts_a | ports_aCon[nCon] | Connection return ports |
| FluidPorts_b | ports_bCon[nCon] | Connection supply ports |
| FluidPort_a | port_aDisSup | Distribution supply inlet port |
| FluidPort_b | port_bDisSup | Distribution supply outlet port |
| replaceable package Medium | Medium model | |
Modelica definition
partial model PartialDistribution
"Partial model for distribution network"
extends Buildings.DHC.Networks.BaseClasses.PartialDistribution2Medium(
redeclare final package MediumSup=Medium,
redeclare final package MediumRet=Medium);
replaceable package Medium=Modelica.Media.Interfaces.PartialMedium
"Medium model";
end PartialDistribution;
Buildings.DHC.Networks.BaseClasses.PartialDistribution1Pipe
Partial model for one-pipe distribution network
Information
Partial model of a one-pipe distribution network.
An array of replaceable partial models is used to represent the connections along the network, including the pipe segment immediately upstream of each connection.
A replaceable partial model is used to represent the pipe segment of the return line after the last connection.
Optionally the heat flow rate transferred to each connected load can be output.
Extends from PartialDistribution (Partial model for distribution network).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | nCon | Number of connections | |
| replaceable package Medium | PartialMedium | Medium model | |
| replaceable model Model_pipDis | Fluid.Interfaces.PartialTwoP... | Model for distribution pipe | |
| Boolean | show_entFlo | false | Set to true to output enthalpy flow rate difference at each connection |
| Boolean | show_TOut | false | Set to true to output temperature at connection outlet |
| PartialConnection1Pipe | con[nCon] | con(redeclare each final pac... | Connection to agent |
| Nominal condition | |||
| MassFlowRate | mDis_flow_nominal | Nominal mass flow rate in the distribution line [kg/s] | |
| MassFlowRate | mCon_flow_nominal[nCon] | Nominal mass flow rate in each connection line [kg/s] | |
| Assumptions | |||
| Boolean | allowFlowReversal | false | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Nominal condition | |||
| Time | tau | 10 | Time constant at nominal flow for dynamic energy and momentum balance [s] |
Connectors
| Type | Name | Description |
|---|---|---|
| FluidPorts_a | ports_aCon[nCon] | Connection return ports |
| FluidPorts_b | ports_bCon[nCon] | Connection supply ports |
| FluidPort_a | port_aDisSup | Distribution supply inlet port |
| FluidPort_b | port_bDisSup | Distribution supply outlet port |
| replaceable model Model_pipDis | Model for distribution pipe | |
| output RealOutput | dH_flow[nCon] | Difference in enthalpy flow rate between connection supply and return [W] |
| output RealOutput | mCon_flow[nCon] | Connection supply mass flow rate (measured) [kg/s] |
| output RealOutput | mByp_flow[nCon] | Bypass mass flow rate [kg/s] |
| output RealOutput | TOut[nCon] | Temperature in distribution line at each connection outlet [K] |
Modelica definition
partial model PartialDistribution1Pipe
"Partial model for one-pipe distribution network"
extends PartialDistribution;
replaceable model Model_pipDis=Fluid.Interfaces.PartialTwoPortInterface (
redeclare final package Medium=Medium,
final allowFlowReversal=allowFlowReversal)
"Model for distribution pipe";
parameter Boolean show_entFlo=false
"Set to true to output enthalpy flow rate difference at each connection";
parameter Boolean show_TOut=false
"Set to true to output temperature at connection outlet";
parameter Modelica.Units.SI.MassFlowRate mDis_flow_nominal
"Nominal mass flow rate in the distribution line";
parameter Modelica.Units.SI.MassFlowRate mCon_flow_nominal[nCon]
"Nominal mass flow rate in each connection line";
parameter Modelica.Fluid.Types.Dynamics energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial
"Type of energy balance: dynamic (3 initialization options) or steady state";
parameter Modelica.Units.SI.Time tau=10
"Time constant at nominal flow for dynamic energy and momentum balance";
// IO CONNECTORS
Buildings.Controls.OBC.CDL.Interfaces.RealOutput dH_flow[nCon](
each final unit="W") if show_entFlo
"Difference in enthalpy flow rate between connection supply and return";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput mCon_flow[nCon](
each final unit="kg/s")
"Connection supply mass flow rate (measured)";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput mByp_flow[nCon](
each final unit="kg/s")
"Bypass mass flow rate";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput TOut[nCon](
each final unit="K",
each displayUnit="degC") if show_TOut
"Temperature in distribution line at each connection outlet";
// COMPONENTS
replaceable PartialConnection1Pipe con[nCon](
redeclare each final package Medium=Medium,
each final show_entFlo=show_entFlo,
each final show_TOut=show_TOut,
each final mDis_flow_nominal=mDis_flow_nominal,
final mCon_flow_nominal=mCon_flow_nominal,
each final allowFlowReversal=allowFlowReversal,
each final energyDynamics=energyDynamics,
each final tau=tau)
"Connection to agent";
Model_pipDis pipEnd(
final m_flow_nominal=mDis_flow_nominal)
"Pipe representing the end of the distribution line (after last connection)";
equation
// Connecting outlets to inlets for all instances of connection component.
if nCon >= 2 then
for i in 2:nCon loop
connect(con[i-1].port_bDis,con[i].port_aDis);
end for;
end if;
connect(con.port_bCon,ports_bCon);
connect(ports_aCon,con.port_aCon);
connect(port_aDisSup,con[1].port_aDis);
connect(con[nCon].port_bDis,pipEnd.port_a);
connect(pipEnd.port_b,port_bDisSup);
connect(con.mByp_flow,mByp_flow);
connect(con.mCon_flow,mCon_flow);
connect(con.dH_flow, dH_flow);
connect(con.TOut, TOut);
end PartialDistribution1Pipe;
Buildings.DHC.Networks.BaseClasses.PartialDistribution2Medium
Partial model for distribution network with two medium declarations
Information
Partial model to be used for modeling various distribution networks e.g. one-pipe or two-pipe hydraulic distribution.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package MediumSup | Modelica.Media.Interfaces.Pa... | Medium model for supply fluid | |
| replaceable package MediumRet | Modelica.Media.Interfaces.Pa... | Medium model for return fluid | |
| Integer | nCon | Number of connections | |
| Assumptions | |||
| Boolean | allowFlowReversal | false | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package MediumSup | Medium model for supply fluid | |
| replaceable package MediumRet | Medium model for return fluid | |
| FluidPorts_a | ports_aCon[nCon] | Connection return ports |
| FluidPorts_b | ports_bCon[nCon] | Connection supply ports |
| FluidPort_a | port_aDisSup | Distribution supply inlet port |
| FluidPort_b | port_bDisSup | Distribution supply outlet port |
Modelica definition
partial model PartialDistribution2Medium
"Partial model for distribution network with two medium declarations"
replaceable package MediumSup =
Modelica.Media.Interfaces.PartialMedium
"Medium model for supply fluid";
replaceable package MediumRet =
Modelica.Media.Interfaces.PartialMedium
"Medium model for return fluid";
parameter Integer nCon(min=1)
"Number of connections";
parameter Boolean allowFlowReversal=false
"= true to allow flow reversal, false restricts to design direction (port_a -> port_b)";
// IO CONNECTORS
Modelica.Fluid.Interfaces.FluidPorts_a ports_aCon[nCon](
redeclare each final package Medium=MediumRet,
each m_flow(
min=
if allowFlowReversal then
-Modelica.Constants.inf
else
0),
each h_outflow(
start=MediumRet.h_default,
nominal=MediumRet.h_default))
"Connection return ports";
Modelica.Fluid.Interfaces.FluidPorts_b ports_bCon[nCon](
redeclare each package Medium=MediumSup,
each m_flow(
max=
if allowFlowReversal then
+Modelica.Constants.inf
else
0),
each h_outflow(
start=MediumSup.h_default,
nominal=MediumSup.h_default))
"Connection supply ports";
Modelica.Fluid.Interfaces.FluidPort_a port_aDisSup(
redeclare final package Medium=MediumSup,
m_flow(
min=
if allowFlowReversal then
-Modelica.Constants.inf
else
0),
h_outflow(
start=MediumSup.h_default,
nominal=MediumSup.h_default))
"Distribution supply inlet port";
Modelica.Fluid.Interfaces.FluidPort_b port_bDisSup(
redeclare final package Medium=MediumSup,
m_flow(
max=
if allowFlowReversal then
+Modelica.Constants.inf
else
0),
h_outflow(
start=MediumRet.h_default,
nominal=MediumRet.h_default))
"Distribution supply outlet port";
end PartialDistribution2Medium;
Buildings.DHC.Networks.BaseClasses.PartialDistribution2Pipe
Partial model for two-pipe distribution network
Information
Partial model of a two-pipe distribution network.
An array of replaceable partial models is used to represent the connections along the network, including the pipe segment immediately upstream each connection.
A replaceable partial model is used to represent the pipe segment of the supply and return line after the last connection.
The parameter iConDpSen is provided to specify the index of the
connection where the pressure drop is measured.
Use zero for a sensor connected to the supply pipe inlet and return pipe outlet.
Use a negative value if no sensor is needed.
Optionally the heat flow rate transferred to each connected load can be output.
Extends from PartialDistribution (Partial model for distribution network).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | nCon | Number of connections | |
| replaceable package Medium | PartialMedium | Medium model | |
| replaceable model Model_pipDis | Fluid.Interfaces.PartialTwoP... | Model for distribution pipe | |
| Integer | iConDpSen | nCon | Index of the connection where the pressure drop is measured |
| Boolean | show_entFlo | false | Set to true to output enthalpy flow rate difference at each connection |
| PartialConnection2Pipe | con[nCon] | con(redeclare each final pac... | Connection to agent |
| Nominal condition | |||
| MassFlowRate | mDis_flow_nominal | Nominal mass flow rate in the distribution line before the first connection [kg/s] | |
| MassFlowRate | mCon_flow_nominal[nCon] | Nominal mass flow rate in each connection line [kg/s] | |
| MassFlowRate | mEnd_flow_nominal | mDis_flow_nominal - sum(mCon... | Nominal mass flow rate in the end of the distribution line [kg/s] |
| MassFlowRate | mDisCon_flow_nominal[nCon] | cat(1, {mDis_flow_nominal}, ... | Nominal mass flow rate in the distribution line before each connection [kg/s] |
| Assumptions | |||
| Boolean | allowFlowReversal | false | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Nominal condition | |||
| Time | tau | 10 | Time constant at nominal flow for dynamic energy and momentum balance [s] |
Connectors
| Type | Name | Description |
|---|---|---|
| FluidPorts_a | ports_aCon[nCon] | Connection return ports |
| FluidPorts_b | ports_bCon[nCon] | Connection supply ports |
| FluidPort_a | port_aDisSup | Distribution supply inlet port |
| FluidPort_b | port_bDisSup | Distribution supply outlet port |
| replaceable model Model_pipDis | Model for distribution pipe | |
| FluidPort_b | port_bDisRet | Distribution return outlet port |
| FluidPort_a | port_aDisRet | Distribution return inlet port |
| output RealOutput | dp | Pressure difference at given location (measured) [Pa] |
| output RealOutput | dH_flow[nCon] | Difference in enthalpy flow rate between connection supply and return [W] |
| output RealOutput | mCon_flow[nCon] | Connection supply mass flow rate (measured) [kg/s] |
Modelica definition
partial model PartialDistribution2Pipe
"Partial model for two-pipe distribution network"
extends PartialDistribution;
replaceable model Model_pipDis=Fluid.Interfaces.PartialTwoPortInterface (
redeclare final package Medium=Medium,
final allowFlowReversal=allowFlowReversal)
"Model for distribution pipe";
parameter Integer iConDpSen(
final max=nCon)=nCon
"Index of the connection where the pressure drop is measured";
parameter Boolean show_entFlo=false
"Set to true to output enthalpy flow rate difference at each connection";
parameter Modelica.Units.SI.MassFlowRate mDis_flow_nominal
"Nominal mass flow rate in the distribution line before the first connection";
parameter Modelica.Units.SI.MassFlowRate mCon_flow_nominal[nCon]
"Nominal mass flow rate in each connection line";
parameter Modelica.Units.SI.MassFlowRate mEnd_flow_nominal=mDis_flow_nominal
- sum(mCon_flow_nominal)
"Nominal mass flow rate in the end of the distribution line";
parameter Modelica.Units.SI.MassFlowRate mDisCon_flow_nominal[nCon]=cat(
1,
{mDis_flow_nominal},
{mDis_flow_nominal - sum(mCon_flow_nominal[1:i]) for i in 1:(nCon - 1)})
"Nominal mass flow rate in the distribution line before each connection";
parameter Modelica.Fluid.Types.Dynamics energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial
"Type of energy balance: dynamic (3 initialization options) or steady state";
parameter Modelica.Units.SI.Time tau=10
"Time constant at nominal flow for dynamic energy and momentum balance";
// IO CONNECTORS
Modelica.Fluid.Interfaces.FluidPort_b port_bDisRet(
redeclare final package Medium=Medium,
m_flow(
max=
if allowFlowReversal then
+Modelica.Constants.inf
else
0),
h_outflow(
start=Medium.h_default,
nominal=Medium.h_default))
"Distribution return outlet port";
Modelica.Fluid.Interfaces.FluidPort_a port_aDisRet(
redeclare final package Medium=Medium,
m_flow(
min=
if allowFlowReversal then
-Modelica.Constants.inf
else
0),
h_outflow(
start=Medium.h_default,
nominal=Medium.h_default))
"Distribution return inlet port";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput dp(
final unit="Pa",
displayUnit="Pa") if iConDpSen >= 0
"Pressure difference at given location (measured)";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput dH_flow[nCon](each final
unit="W") if show_entFlo
"Difference in enthalpy flow rate between connection supply and return";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput mCon_flow[nCon](
each final unit="kg/s")
"Connection supply mass flow rate (measured)";
// COMPONENTS
replaceable Buildings.DHC.Networks.BaseClasses.PartialConnection2Pipe con[nCon](
redeclare each final package Medium=Medium,
each final show_entFlo=show_entFlo,
final mDis_flow_nominal=mDisCon_flow_nominal,
final mCon_flow_nominal=mCon_flow_nominal,
each final allowFlowReversal=allowFlowReversal,
each final energyDynamics=energyDynamics,
each final tau=tau)
"Connection to agent";
Model_pipDis pipEnd(
final m_flow_nominal=mEnd_flow_nominal)
"Pipe representing the end of the distribution line (after last connection)";
Fluid.Sensors.RelativePressure senRelPre(
redeclare final package Medium=Medium) if iConDpSen == 0
"Relative pressure sensor";
initial equation
assert(
iConDpSen <= nCon,
"In "+getInstanceName()+": iConDpSen = "+String(
iConDpSen)+" whereas it must be lower than "+String(
nCon)+".");
equation
// Connecting outlets to inlets for all instances of connection component.
if nCon >= 2 then
for i in 2:nCon loop
connect(con[i-1].port_bDisSup,con[i].port_aDisSup);
connect(con[i-1].port_aDisRet,con[i].port_bDisRet);
end for;
end if;
// Connecting dp sensor (needs to be explicit because con[iConDpSen] is
// undefined if iConDpSen <= 0).
if iConDpSen > 0 then
connect(con[iConDpSen].dp,dp);
end if;
connect(senRelPre.p_rel,dp);
connect(con.port_bCon,ports_bCon);
connect(ports_aCon,con.port_aCon);
connect(port_aDisSup,con[1].port_aDisSup);
connect(port_bDisRet,con[1].port_bDisRet);
connect(con[nCon].port_aDisRet,port_aDisRet);
connect(con[nCon].port_bDisSup,pipEnd.port_a);
connect(pipEnd.port_b,port_bDisSup);
connect(con.mCon_flow,mCon_flow);
connect(port_aDisSup,senRelPre.port_a);
connect(senRelPre.port_b,port_bDisRet);
connect(con.dH_flow, dH_flow);
end PartialDistribution2Pipe;
Buildings.DHC.Networks.BaseClasses.PartialDistribution2Pipe2Medium
Partial model for a two-pipe distribution network with two medium declarations
Information
Partial model of a two-pipe distribution network.
An array of replaceable partial models is used to represent the connections along the network, including the pipe segment immediately upstream each connection.
A replaceable partial model is used to represent the pipe segment of the supply and return line after the last connection.
The parameter iConDpSen is provided to specify the index of the
connection where the pressure drop is measured.
Use zero for a sensor connected to the supply pipe inlet and return pipe outlet.
Use a negative value if no sensor is needed.
Optionally the heat flow rate transferred to each connected load can be output.
Extends from Buildings.DHC.Networks.BaseClasses.PartialDistribution2Medium (Partial model for distribution network with two medium declarations).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package MediumSup | PartialMedium | Medium model for supply fluid | |
| replaceable package MediumRet | PartialMedium | Medium model for return fluid | |
| Integer | nCon | Number of connections | |
| replaceable model Model_pipDis | Buildings.Fluid.Interfaces.P... | Model for distribution pipe | |
| Boolean | show_heaFlo | false | Set to true to output the heat flow rate transferred to each connected load |
| PartialConnection2Pipe2Medium | con[nCon] | redeclare Buildings.DHC.Netw... | Connection to agent |
| Nominal condition | |||
| MassFlowRate | mDis_flow_nominal | Nominal mass flow rate in the distribution line before the first connection [kg/s] | |
| MassFlowRate | mCon_flow_nominal[nCon] | Nominal mass flow rate in each connection line [kg/s] | |
| MassFlowRate | mEnd_flow_nominal | mDis_flow_nominal - sum(mCon... | Nominal mass flow rate in the end of the distribution line [kg/s] |
| MassFlowRate | mDisCon_flow_nominal[nCon] | cat(1, {mDis_flow_nominal}, ... | Nominal mass flow rate in the distribution line before each connection [kg/s] |
| Assumptions | |||
| Boolean | allowFlowReversal | false | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Dynamics | |||
| Equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Nominal condition | |||
| Time | tau | 10 | Time constant at nominal flow for dynamic energy and momentum balance [s] |
Connectors
| Type | Name | Description |
|---|---|---|
| FluidPorts_a | ports_aCon[nCon] | Connection return ports |
| FluidPorts_b | ports_bCon[nCon] | Connection supply ports |
| FluidPort_a | port_aDisSup | Distribution supply inlet port |
| FluidPort_b | port_bDisSup | Distribution supply outlet port |
| replaceable model Model_pipDis | Model for distribution pipe | |
| FluidPort_b | port_bDisRet | Distribution return outlet port |
| FluidPort_a | port_aDisRet | Distribution return inlet port |
Modelica definition
partial model PartialDistribution2Pipe2Medium
"Partial model for a two-pipe distribution network with two medium declarations"
extends Buildings.DHC.Networks.BaseClasses.PartialDistribution2Medium;
replaceable model Model_pipDis =
Buildings.Fluid.Interfaces.PartialTwoPortInterface
constrainedby Buildings.Fluid.Interfaces.PartialTwoPortInterface(
redeclare final package Medium = MediumSup,
final allowFlowReversal=allowFlowReversal)
"Model for distribution pipe";
parameter Boolean show_heaFlo=false
"Set to true to output the heat flow rate transferred to each connected load";
parameter Modelica.Units.SI.MassFlowRate mDis_flow_nominal
"Nominal mass flow rate in the distribution line before the first connection";
parameter Modelica.Units.SI.MassFlowRate mCon_flow_nominal[nCon]
"Nominal mass flow rate in each connection line";
parameter Modelica.Units.SI.MassFlowRate mEnd_flow_nominal=mDis_flow_nominal-sum(
mCon_flow_nominal)
"Nominal mass flow rate in the end of the distribution line";
parameter Modelica.Units.SI.MassFlowRate mDisCon_flow_nominal[nCon]=cat(
1,
{mDis_flow_nominal},
{mDis_flow_nominal-sum(mCon_flow_nominal[1:i]) for i in 1:(nCon-1)})
"Nominal mass flow rate in the distribution line before each connection";
parameter Modelica.Fluid.Types.Dynamics energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial
"Type of energy balance: dynamic (3 initialization options) or steady state";
parameter Modelica.Units.SI.Time tau=10
"Time constant at nominal flow for dynamic energy and momentum balance";
// IO CONNECTORS
Modelica.Fluid.Interfaces.FluidPort_b port_bDisRet(
redeclare final package Medium=MediumRet,
m_flow(
max=
if allowFlowReversal then
+Modelica.Constants.inf
else
0),
h_outflow(
start=MediumRet.h_default,
nominal=MediumRet.h_default))
"Distribution return outlet port";
Modelica.Fluid.Interfaces.FluidPort_a port_aDisRet(
redeclare final package Medium=MediumRet,
m_flow(
min=
if allowFlowReversal then
-Modelica.Constants.inf
else
0),
h_outflow(
start=MediumRet.h_default,
nominal=MediumRet.h_default))
"Distribution return inlet port";
// COMPONENTS
replaceable Buildings.DHC.Networks.BaseClasses.PartialConnection2Pipe2Medium
con[nCon]
constrainedby Buildings.DHC.Networks.BaseClasses.PartialConnection2Pipe2Medium
(
redeclare each final package MediumSup = MediumSup,
redeclare each final package MediumRet = MediumRet,
final mDis_flow_nominal=mDisCon_flow_nominal,
final mCon_flow_nominal=mCon_flow_nominal,
each final allowFlowReversal=allowFlowReversal,
each final energyDynamics=energyDynamics,
each final tau=tau) "Connection to agent";
Model_pipDis pipEnd(
final m_flow_nominal=mEnd_flow_nominal)
"Pipe representing the end of the distribution line (after last connection)";
initial equation
assert(
mDis_flow_nominal >= sum(
mCon_flow_nominal),
"In "+getInstanceName()+": mDis_flow_nominal = "+String(
mDis_flow_nominal)+" whereas it must be higher than sum(mCon_flow_nominal) = "+String(
sum(
mCon_flow_nominal))+".");
equation
// Connecting outlets to inlets for all instances of connection component.
if nCon >= 2 then
for i in 2:nCon loop
connect(con[i-1].port_bDisSup,con[i].port_aDisSup);
connect(con[i-1].port_aDisRet,con[i].port_bDisRet);
end for;
end if;
connect(con.port_bCon,ports_bCon);
connect(ports_aCon,con.port_aCon);
connect(port_aDisSup,con[1].port_aDisSup);
connect(port_bDisRet,con[1].port_bDisRet);
connect(con[nCon].port_aDisRet,port_aDisRet);
connect(con[nCon].port_bDisSup,pipEnd.port_a);
connect(pipEnd.port_b,port_bDisSup);
end PartialDistribution2Pipe2Medium;
Buildings.DHC.Networks.BaseClasses.PartialConnection1Pipe.Model_pipDis
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | mDis_flow_nominal | Nominal mass flow rate [kg/s] |
| Assumptions | |||
| Boolean | allowFlowReversal | allowFlowReversal | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package Medium | Medium in the component | |
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
Modelica definition
replaceable model Model_pipDis=Fluid.Interfaces.PartialTwoPortInterface (
redeclare final package Medium=Medium,
final m_flow_nominal=mDis_flow_nominal,
final allowFlowReversal=allowFlowReversal);
Buildings.DHC.Networks.BaseClasses.PartialConnection1Pipe.Model_pipCon
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | mCon_flow_nominal | Nominal mass flow rate [kg/s] |
| Assumptions | |||
| Boolean | allowFlowReversal | allowFlowReversal | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package Medium | Medium in the component | |
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
Modelica definition
replaceable model Model_pipCon=Fluid.Interfaces.PartialTwoPortInterface (
redeclare final package Medium=Medium,
final m_flow_nominal=mCon_flow_nominal,
final allowFlowReversal=allowFlowReversal);
Buildings.DHC.Networks.BaseClasses.PartialConnection2Pipe.Model_pipCon
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | mCon_flow_nominal | Nominal mass flow rate [kg/s] |
| Assumptions | |||
| Boolean | allowFlowReversal | allowFlowReversal | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package Medium | Medium in the component | |
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
Modelica definition
replaceable model Model_pipCon=Fluid.Interfaces.PartialTwoPortInterface (
redeclare final package Medium=Medium,
final m_flow_nominal=mCon_flow_nominal,
final allowFlowReversal=allowFlowReversal);
Buildings.DHC.Networks.BaseClasses.PartialConnection2Pipe2Medium.Model_pipDisSup
Interface for inlet pipe for the distribution supply
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | Nominal mass flow rate [kg/s] | |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
Modelica definition
replaceable model Model_pipDisSup = Buildings.Fluid.Interfaces.PartialTwoPortInterface
constrainedby Buildings.Fluid.Interfaces.PartialTwoPortInterface(
redeclare final package Medium = MediumSup,
final m_flow_nominal=mDis_flow_nominal,
final allowFlowReversal=allowFlowReversal)
"Interface for inlet pipe for the distribution supply";
Buildings.DHC.Networks.BaseClasses.PartialConnection2Pipe2Medium.Model_pipDisRet
Interface for outlet pipe for the distribution return
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | Nominal mass flow rate [kg/s] | |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
Modelica definition
replaceable model Model_pipDisRet = Buildings.Fluid.Interfaces.PartialTwoPortInterface
constrainedby Buildings.Fluid.Interfaces.PartialTwoPortInterface(
redeclare final package Medium = MediumRet,
final m_flow_nominal=mDis_flow_nominal,
final allowFlowReversal=allowFlowReversal)
"Interface for outlet pipe for the distribution return";
Buildings.DHC.Networks.BaseClasses.PartialDistribution1Pipe.Model_pipDis
Model for distribution pipe
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | Nominal mass flow rate [kg/s] | |
| Assumptions | |||
| Boolean | allowFlowReversal | allowFlowReversal | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package Medium | Medium in the component | |
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
Modelica definition
replaceable model Model_pipDis=Fluid.Interfaces.PartialTwoPortInterface (
redeclare final package Medium=Medium,
final allowFlowReversal=allowFlowReversal)
"Model for distribution pipe";
Buildings.DHC.Networks.BaseClasses.PartialDistribution2Pipe.Model_pipDis
Model for distribution pipe
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | Nominal mass flow rate [kg/s] | |
| Assumptions | |||
| Boolean | allowFlowReversal | allowFlowReversal | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package Medium | Medium in the component | |
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
Modelica definition
replaceable model Model_pipDis=Fluid.Interfaces.PartialTwoPortInterface (
redeclare final package Medium=Medium,
final allowFlowReversal=allowFlowReversal)
"Model for distribution pipe";
Buildings.DHC.Networks.BaseClasses.PartialDistribution2Pipe2Medium.Model_pipDis
Model for distribution pipe
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | Nominal mass flow rate [kg/s] | |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
Connectors
| Type | Name | Description |
|---|---|---|
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
Modelica definition
replaceable model Model_pipDis =
Buildings.Fluid.Interfaces.PartialTwoPortInterface
constrainedby Buildings.Fluid.Interfaces.PartialTwoPortInterface(
redeclare final package Medium = MediumSup,
final allowFlowReversal=allowFlowReversal)
"Model for distribution pipe";