Buildings.Experimental.DHC.Networks
Package of models for district energy network
Information
This package contains models for elements that form the district network.
Extends from Modelica.Icons.VariantsPackage (Icon for package containing variants).
Package Content
| Name | Description |
|---|---|
 Connection2Pipe
|
Model for connecting an agent to a two-pipe distribution network, using fixed resistance pipe model |
 Connection2PipePlugFlow
|
Model for connecting an agent to a two-pipe distribution network, using plug flow pipe models in the main line |
 Distribution2Pipe
|
Model of a two-pipe distribution network, using fixed resistance pipe model |
| Distribution2PipePlugFlow
|
Model of a two-pipe distribution network, using plug flow pipe models in the main line |
 Combined
|
Package of models for DHC distribution networks |
 Controls
|
Package of control blocks for distribution systems |
 Steam
|
Collection of models for distribution networks involving steam |
 BaseClasses
|
Package with base classes that are used by multiple models |
Buildings.Experimental.DHC.Networks.Connection2Pipe
Model for connecting an agent to a two-pipe distribution network, using fixed resistance pipe model
Information
This is a model of a connection with a two-pipe distribution network using as pipe model a fixed hydraulic resistance with no heat loss. The pressure drop of this hydraulic resistance is scaled based on the mass flow rate.
Extends from Buildings.Experimental.DHC.Networks.BaseClasses.PartialConnection2Pipe (Partial model for connecting an agent to a two-pipe distribution network).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| 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 | PartialMedium | Medium model | |
| replaceable model Model_pipCon | Fluid.FixedResistances.Lossl... | ||
| Boolean | show_entFlo | false | Set to true to output enthalpy flow rate difference |
| PressureDifference | dpDis_nominal | Pressure drop in distribution line (supply only, not counting return line) [Pa] | |
| 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 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 |
| 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
model Connection2Pipe
"Model for connecting an agent to a two-pipe distribution network, using fixed resistance pipe model"
extends Buildings.Experimental.DHC.Networks.BaseClasses.PartialConnection2Pipe
(
redeclare model Model_pipDisSup=Fluid.FixedResistances.PressureDrop (
final dp_nominal=dpDis_nominal),
redeclare model Model_pipDisRet=Fluid.FixedResistances.PressureDrop (
final dp_nominal=dpDis_nominal),
redeclare model Model_pipCon=Fluid.FixedResistances.LosslessPipe);
parameter Modelica.Units.SI.PressureDifference dpDis_nominal(
displayUnit="Pa")
"Pressure drop in distribution line (supply only, not counting return line)";
end Connection2Pipe;
Buildings.Experimental.DHC.Networks.Connection2PipePlugFlow
Model for connecting an agent to a two-pipe distribution network, using plug flow pipe models in the main line
Information
This is a model of a connection with a two-pipe distribution network using a plug flow pipe model that includes pressure drop, heat transfer, and transport delays.
The plug flow pipe model is used in the main distribution line, but not in the connection to the building, as the latter is typically short.
Extends from Buildings.Experimental.DHC.Networks.BaseClasses.PartialConnection2Pipe (Partial model for connecting an agent to a two-pipe distribution network).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| 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 | PartialMedium | Medium model | |
| replaceable model Model_pipCon | Fluid.FixedResistances.Lossl... | ||
| 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] | |
| Pipe | |||
| Length | length | Pipe length [m] | |
| Length | dIns | Thickness of pipe insulation, used to compute R [m] | |
| ThermalConductivity | kIns | Heat conductivity of pipe insulation, used to compute R [W/(m.K)] | |
| 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 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 |
| 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] |
| HeatPort_a | heatPort | Heat transfer to or from surroundings (positive if pipe is colder than surrounding) |
Modelica definition
model Connection2PipePlugFlow
"Model for connecting an agent to a two-pipe distribution network, using plug flow pipe models in the main line"
extends Buildings.Experimental.DHC.Networks.BaseClasses.PartialConnection2Pipe
(
redeclare model Model_pipDisSup =
Buildings.Fluid.FixedResistances.PlugFlowPipe (
final length=length,
final dIns=dIns,
final kIns=kIns),
redeclare model Model_pipDisRet =
Buildings.Fluid.FixedResistances.PlugFlowPipe (
final length=length,
final dIns=dIns,
final kIns=kIns),
redeclare model Model_pipCon=Fluid.FixedResistances.LosslessPipe);
parameter Modelica.Units.SI.Length length
"Pipe length";
parameter Modelica.Units.SI.Length dIns
"Thickness of pipe insulation, used to compute R";
parameter Modelica.Units.SI.ThermalConductivity kIns
"Heat conductivity of pipe insulation, used to compute R";
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a heatPort
"Heat transfer to or from surroundings (positive if pipe is colder than surrounding)";
equation
connect(pipDisRet.heatPort, heatPort);
connect(pipDisSup.heatPort, heatPort);
end Connection2PipePlugFlow;
Buildings.Experimental.DHC.Networks.Distribution2Pipe
Model of a two-pipe distribution network, using fixed resistance pipe model
Information
This is a model of a two-pipe distribution network using
- a connection model with fixed hydraulic resistance with no heat loss as a pipe model in the main line, and
- a dummy pipe model with no hydraulic resistance and no heat loss for the end of the distribution line (after the last connection).
Extends from Buildings.Experimental.DHC.Networks.BaseClasses.PartialDistribution2Pipe (Partial model for two-pipe distribution network).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | nCon | Number of connections | |
| replaceable package Medium | PartialMedium | Medium model | |
| replaceable model Model_pipDis | Fluid.FixedResistances.Lossl... | 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 |
| 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] |
| PressureDifference | dpDis_nominal[nCon] | Pressure drop in distribution line (supply only, not counting return line) [Pa] | |
| 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
model Distribution2Pipe
"Model of a two-pipe distribution network, using fixed resistance pipe model"
extends Buildings.Experimental.DHC.Networks.BaseClasses.PartialDistribution2Pipe
(
redeclare Connection2Pipe con[nCon](
final dpDis_nominal=dpDis_nominal),
redeclare model Model_pipDis=Fluid.FixedResistances.LosslessPipe);
parameter Modelica.Units.SI.PressureDifference dpDis_nominal[nCon]
"Pressure drop in distribution line (supply only, not counting return line)";
end Distribution2Pipe;
Buildings.Experimental.DHC.Networks.Distribution2PipePlugFlow
Model of a two-pipe distribution network, using plug flow pipe models in the main line
Information
This is a model of a two-pipe distribution network using
- a connection model with a plug flow pipe model (pressure drop, heat transfer, transport delays)in the main line, and
- a dummy pipe model with no hydraulic resistance and no heat loss for the end of the distribution line (after the last connection).
Extends from Buildings.Experimental.DHC.Networks.BaseClasses.PartialDistribution2Pipe (Partial model for two-pipe distribution network).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Integer | nCon | Number of connections | |
| replaceable package Medium | PartialMedium | Medium model | |
| replaceable model Model_pipDis | Fluid.FixedResistances.Lossl... | 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 |
| 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] |
| Pipe | |||
| Length | length[nCon] | Pipe length [m] | |
| Length | dIns[nCon] | fill(0.05, nCon) | Thickness of pipe insulation, used to compute R [m] |
| ThermalConductivity | kIns[nCon] | fill(0.028, nCon) | Heat conductivity of pipe insulation, used to compute R [W/(m.K)] |
| 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] |
| HeatPort_a | heatPort | Heat transfer to or from surroundings (positive if pipe is colder than surrounding) |
Modelica definition
model Distribution2PipePlugFlow
"Model of a two-pipe distribution network, using plug flow pipe models in the main line"
extends Buildings.Experimental.DHC.Networks.BaseClasses.PartialDistribution2Pipe
(
redeclare Connection2PipePlugFlow con[nCon](
final length=length,
final dIns=dIns,
final kIns=kIns),
redeclare model Model_pipDis=Fluid.FixedResistances.LosslessPipe);
parameter Modelica.Units.SI.Length length[nCon]
"Pipe length";
parameter Modelica.Units.SI.Length dIns[nCon]=fill(0.05, nCon)
"Thickness of pipe insulation, used to compute R";
parameter Modelica.Units.SI.ThermalConductivity kIns[nCon]=fill(0.028, nCon)
"Heat conductivity of pipe insulation, used to compute R";
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a heatPort
"Heat transfer to or from surroundings (positive if pipe is colder than surrounding)";
protected
Modelica.Thermal.HeatTransfer.Components.ThermalCollector theCol(final m=nCon)
"Thermal collector";
equation
connect(heatPort, theCol.port_b);
connect(con.heatPort, theCol.port_a);
end Distribution2PipePlugFlow;