Buildings.DHC.Networks.Connections
Package containing various configurations for connecting network participants to a distribution network
Information
This package contains hydronic connection models that allow an agent to connect to the distribution network.
Extends from Modelica.Icons.VariantsPackage (Icon for package containing variants).
Package Content
| Name | Description |
|---|---|
 Connection1PipePlugFlow_v
|
Model for connecting an agent to the DHC system |
 Connection1Pipe_R
|
Model for connecting an agent to the DHC system |
 Connection2PipePlugFlow_v
|
Model for connecting an agent to a two-pipe distribution network, using plug flow pipe models in the main line |
 Connection2Pipe_R
|
Model for connecting an agent to the DHC system |
 Examples
|
This package contains example models |
Buildings.DHC.Networks.Connections.Connection1PipePlugFlow_v
Model for connecting an agent to the DHC system
Information
This model represents the supply and return lines to connect an agent (e.g. an energy transfer station) to a one-pipe main distribution system. A plug flow pipe model Buildings.Fluid.FixedResistances.PlugFlowPipe that includes pressure drop, heat transfer, and transport delays is used in the main distribution line, but not in the connection to the building, as the latter is typically short.
Extends from Buildings.DHC.Networks.BaseClasses.PartialConnection1Pipe (Partial model for connecting an agent to a one-pipe distribution network).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium model | |
| replaceable model Model_pipDis | Buildings.Fluid.FixedResista... | ||
| replaceable model Model_pipCon | Buildings.Fluid.FixedResista... | ||
| 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] | |
| Length | lDis | Length of the distribution pipe before the connection [m] | |
| Velocity | v_nominal | 1.5 | Velocity at m_flow_nominal (used to compute default value for hydraulic diameter dh) [m/s] |
| Height | roughness | 2.5e-5 | Average height of surface asperities (default: smooth steel pipe) [m] |
| SpecificHeatCapacity | cPip | 2300 | Specific heat of pipe wall material. 2300 for PE, 500 for steel [J/(kg.K)] |
| Density | rhoPip | 930 | Density of pipe wall material. 930 for PE, 8000 for steel [kg/m3] |
| Length | thickness | 0.0035 | Pipe wall thickness [m] |
| Pipe | |||
| 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 | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
| Nominal condition | |||
| Time | tau | 5*60 | Time constant at nominal flow for dynamic energy and momentum balance [s] |
Connectors
| Type | Name | Description |
|---|---|---|
| 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] |
| HeatPort_a | heatPortDis | Heat transfer to and from the distribution pipe |
Modelica definition
model Connection1PipePlugFlow_v
"Model for connecting an agent to the DHC system"
extends Buildings.DHC.Networks.BaseClasses.PartialConnection1Pipe(
tau=5*60,
redeclare replaceable model Model_pipDis = Buildings.Fluid.FixedResistances.PlugFlowPipe
(
final length=lDis,
final dIns=dIns,
final kIns=kIns,
v_nominal=v_nominal,
roughness=roughness,
cPip=cPip,
rhoPip=rhoPip,
thickness=thickness),
redeclare replaceable model Model_pipCon = Buildings.Fluid.FixedResistances.LosslessPipe);
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";
parameter Modelica.Units.SI.Length lDis
"Length of the distribution pipe before the connection";
parameter Modelica.Units.SI.Velocity v_nominal=1.5
"Velocity at m_flow_nominal (used to compute default value for hydraulic diameter dh)";
parameter Modelica.Units.SI.Height roughness=2.5e-5
"Average height of surface asperities (default: smooth steel pipe)";
parameter Modelica.Units.SI.SpecificHeatCapacity cPip=2300
"Specific heat of pipe wall material. 2300 for PE, 500 for steel";
parameter Modelica.Units.SI.Density rhoPip=930
"Density of pipe wall material. 930 for PE, 8000 for steel";
parameter Modelica.Units.SI.Length thickness=0.0035 "Pipe wall thickness";
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a heatPortDis
"Heat transfer to and from the distribution pipe";
equation
connect(pipDis.heatPort, heatPortDis);
end Connection1PipePlugFlow_v;
Buildings.DHC.Networks.Connections.Connection1Pipe_R
Model for connecting an agent to the DHC system
Information
This model represents the supply and return lines to connect an agent (e.g., an energy transfer station) to a one-pipe main distribution system. The instances of the pipe model are autosized based on the pressure drop per pipe length at nominal flow rate based on the model Buildings.DHC.Networks.Pipes.PipeAutosize for the distribution line. The connection to the building as the length is typically relatively short so a losssless pipe is considered.
Extends from Buildings.DHC.Networks.BaseClasses.PartialConnection1Pipe (Partial model for connecting an agent to a one-pipe distribution network).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium model | |
| replaceable model Model_pipDis | Pipes.PipeAutosize (roughnes... | ||
| replaceable model Model_pipCon | Buildings.Fluid.FixedResista... | ||
| 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] | |
| Real | dp_length_nominal | 250 | Pressure drop per pipe length at nominal flow rate [Pa/m] |
| Length | lDis | Length of the distribution pipe before the connection [m] | |
| Length | dhDis | Hydraulic diameter of the distribution pipe [m] | |
| 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 | 5*60 | Time constant at nominal flow for dynamic energy and momentum balance [s] |
Connectors
| Type | Name | Description |
|---|---|---|
| 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
model Connection1Pipe_R "Model for connecting an agent to the DHC system"
extends Buildings.DHC.Networks.BaseClasses.PartialConnection1Pipe(
tau=5*60,
redeclare replaceable model Model_pipDis = Pipes.PipeAutosize (
roughness = 7e-6,
final length = lDis,
dh(fixed=true) = dhDis,
final dp_length_nominal = dp_length_nominal),
redeclare replaceable model Model_pipCon = Buildings.Fluid.FixedResistances.LosslessPipe,
pipDis(fac=1));
parameter Real dp_length_nominal(final unit="Pa/m") = 250
"Pressure drop per pipe length at nominal flow rate";
parameter Modelica.Units.SI.Length lDis
"Length of the distribution pipe before the connection";
parameter Modelica.Units.SI.Length dhDis
"Hydraulic diameter of the distribution pipe";
end Connection1Pipe_R;
Buildings.DHC.Networks.Connections.Connection2PipePlugFlow_v
Model for connecting an agent to a two-pipe distribution network, using plug flow pipe models in the main line
Information
This model represents the supply and return lines to connect an agent (e.g. an energy transfer station) to a two-pipe main distribution system. A plug flow pipe model Buildings.Fluid.FixedResistances.PlugFlowPipe that includes pressure drop, heat transfer, and transport delays is used in the main distribution line, but not in the connection to the building, as the latter is typically short.
Extends from Buildings.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 |
| Length | lDis | Length of the distribution pipe before the connection [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)] | |
| Velocity | v_nominal | 1.5 | Velocity at m_flow_nominal (used to compute default value for hydraulic diameter dh) [m/s] |
| Height | roughness | 2.5e-5 | Average height of surface asperities (default: smooth steel pipe) [m] |
| SpecificHeatCapacity | cPip | 2300 | Specific heat of pipe wall material. 2300 for PE, 500 for steel [J/(kg.K)] |
| Density | rhoPip | 930 | Density of pipe wall material. 930 for PE, 8000 for steel [kg/m3] |
| Length | thickness | 0.0035 | Pipe wall thickness [m] |
| 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] |
| HeatPort_a | heatPortDis | Heat transfer to or from surroundings for distribution pipe(positive if pipe is colder than surrounding) |
| HeatPort_a | heatPortRet | Heat transfer to or from surroundings for return pipe (positive if pipe is colder than surrounding) |
Modelica definition
model Connection2PipePlugFlow_v
"Model for connecting an agent to a two-pipe distribution network, using plug flow pipe models in the main line"
extends Buildings.DHC.Networks.BaseClasses.PartialConnection2Pipe(
redeclare model Model_pipDisSup = Buildings.Fluid.FixedResistances.PlugFlowPipe
(
final length = lDis,
final dIns = dIns,
final kIns = kIns,
v_nominal = v_nominal,
roughness = roughness,
cPip = cPip,
rhoPip = rhoPip,
thickness = thickness),
redeclare model Model_pipDisRet = Buildings.Fluid.FixedResistances.PlugFlowPipe
(
final length = lDis,
final dIns = dIns,
final kIns = kIns,
v_nominal = v_nominal,
roughness = roughness,
cPip = cPip,
rhoPip = rhoPip,
thickness = thickness),
redeclare model Model_pipCon = Fluid.FixedResistances.LosslessPipe);
parameter Modelica.Units.SI.Length lDis
"Length of the distribution pipe before the connection";
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";
parameter Modelica.Units.SI.Velocity v_nominal = 1.5
"Velocity at m_flow_nominal (used to compute default value for hydraulic diameter dh)";
parameter Modelica.Units.SI.Height roughness = 2.5e-5
"Average height of surface asperities (default: smooth steel pipe)";
parameter Modelica.Units.SI.SpecificHeatCapacity cPip = 2300
"Specific heat of pipe wall material. 2300 for PE, 500 for steel";
parameter Modelica.Units.SI.Density rhoPip = 930
"Density of pipe wall material. 930 for PE, 8000 for steel";
parameter Modelica.Units.SI.Length thickness = 0.0035 "Pipe wall thickness";
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a heatPortDis
"Heat transfer to or from surroundings for distribution pipe(positive if pipe is colder than surrounding)";
Modelica.Thermal.HeatTransfer.Interfaces.HeatPort_a heatPortRet
"Heat transfer to or from surroundings for return pipe (positive if pipe is colder than surrounding)";
equation
connect(pipDisSup.heatPort, heatPortDis);
connect(pipDisRet.heatPort, heatPortRet);
end Connection2PipePlugFlow_v;
Buildings.DHC.Networks.Connections.Connection2Pipe_R
Model for connecting an agent to the DHC system
Information
This model represents the supply and return lines to connect an agent (e.g., an energy transfer station) to a two-pipe main distribution system. The instances of the pipe model are autosized based on the pressure drop per pipe length at nominal flow rate based on the model Buildings.DHC.Networks.Pipes.PipeAutosize for the distribution line. The connection to the building as the length is typically relatively short so a losssless pipe is considered.
Extends from Buildings.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 |
| Real | dp_length_nominal | 250 | Pressure drop per pipe length at nominal flow rate [Pa/m] |
| Length | dhDisRet | Hydraulic diameter of the return distribution pipe [m] | |
| Length | lDis | Length of the distribution pipe before the connection [m] | |
| Length | dhDis | Hydraulic diameter of the distribution pipe [m] | |
| 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 | 5*60 | 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_R
"Model for connecting an agent to the DHC system"
extends Buildings.DHC.Networks.BaseClasses.PartialConnection2Pipe(
tau=5*60,
redeclare replaceable model Model_pipDisSup = Pipes.PipeAutosize (
roughness = 7e-6,
dh(fixed=true) = dhDis,
final length = lDis,
final dp_length_nominal = dp_length_nominal),
redeclare replaceable model Model_pipDisRet = Pipes.PipeAutosize (
roughness=7e-6,
dh(fixed=true) = dhDisRet,
final length=lDis,
final dp_length_nominal=dp_length_nominal),
redeclare model Model_pipCon = Fluid.FixedResistances.LosslessPipe,
pipDisSup(fac=1),
pipDisRet(fac=1));
parameter Real dp_length_nominal(final unit="Pa/m") = 250
"Pressure drop per pipe length at nominal flow rate";
parameter Modelica.Units.SI.Length dhDisRet
"Hydraulic diameter of the return distribution pipe";
parameter Modelica.Units.SI.Length lDis
"Length of the distribution pipe before the connection";
parameter Modelica.Units.SI.Length dhDis
"Hydraulic diameter of the distribution pipe";
end Connection2Pipe_R;