modelConnection2PipePlugFlow_v
Model for connecting an agent to a two-pipe distribution network, using plug flow pipe models in the main line
Extends from Buildings.DHC.Networks.BaseClasses.PartialConnection2Pipe (Partial model for connecting an agent to a two-pipe distribution network).
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.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | show_entFlo (from PartialConnection2Pipe) | false | Set to true to output enthalpy flow rate difference |
| Modelica.Units.SI.Length | lDis | Length of the distribution pipe before the connection | |
| Modelica.Units.SI.Length | dIns | Thickness of pipe insulation, used to compute R | |
| Modelica.Units.SI.ThermalConductivity | kIns | Heat conductivity of pipe insulation, used to compute R | |
| Modelica.Units.SI.Velocity | v_nominal | 1.5 | Velocity at m_flow_nominal (used to compute default value for hydraulic diameter dh) |
| Modelica.Units.SI.Height | roughness | 2.5e-5 | Average height of surface asperities (default: smooth steel pipe) |
| Modelica.Units.SI.SpecificHeatCapacity | cPip | 2300 | Specific heat of pipe wall material. 2300 for PE, 500 for steel |
| Modelica.Units.SI.Density | rhoPip | 930 | Density of pipe wall material. 930 for PE, 8000 for steel |
| Modelica.Units.SI.Length | thickness | 0.0035 | Pipe wall thickness |
| General › Nominal condition | |||
| Modelica.Units.SI.MassFlowRate | mDis_flow_nominal (from PartialConnection2Pipe2Medium) | Nominal mass flow rate in the distribution line | |
| Modelica.Units.SI.MassFlowRate | mCon_flow_nominal (from PartialConnection2Pipe2Medium) | Nominal mass flow rate in the connection line | |
| Assumptions | |||
| Boolean | allowFlowReversal (from PartialConnection2Pipe2Medium) | false | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Dynamics › Equations | |||
| Modelica.Fluid.Types.Dynamics | energyDynamics (from PartialConnection2Pipe2Medium) | Modelica.Fluid.Types.Dynamics.FixedInitial | Type of energy balance: dynamic (3 initialization options) or steady state |
| Dynamics › Nominal condition | |||
| Modelica.Units.SI.Time | tau (from PartialConnection2Pipe2Medium) | 10 | Time constant at nominal flow for dynamic energy and momentum balance |
Connectors
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Model_pipDisSup | pipDisSup (from PartialConnection2Pipe2Medium) | Distribution supply pipe | |
| Model_pipDisRet | pipDisRet (from PartialConnection2Pipe2Medium) | Distribution return pipe | |
| Buildings.Fluid.FixedResistances.Junction | junConSup (from PartialConnection2Pipe2Medium) | Junction with connection supply | |
| Buildings.Fluid.FixedResistances.Junction | junConRet (from PartialConnection2Pipe2Medium) | Junction with connection return | |
| Model_pipCon | pipCon (from PartialConnection2Pipe) | Connection pipe | |
| Buildings.Fluid.Sensors.MassFlowRate | senMasFloCon (from PartialConnection2Pipe) | Connection supply mass flow rate (measured) | |
| Fluid.Sensors.RelativePressure | senRelPre (from PartialConnection2Pipe) | Relative pressure sensor | |
| DifferenceEnthalpyFlowRate | senDifEntFlo (from PartialConnection2Pipe) | Difference in enthalpy flow rate |
Revisions
-
March 15, 2024, by David Blum:
Renamed. This is for issue 3712. -
June 14, 2023, by David Blum:
Fix redeclare of dis pipe models in connections. -
January 2, 2023, by Kathryn Hinkelman:
First implementation.