modelConnection1PipePlugFlow_v
Model for connecting an agent to the DHC system
Extends from Buildings.DHC.Networks.BaseClasses.PartialConnection1Pipe (Partial model for connecting an agent to a one-pipe distribution network).
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.
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Boolean | show_entFlo (from PartialConnection1Pipe) | false | Set to true to output enthalpy flow rate difference |
| Boolean | show_TOut (from PartialConnection1Pipe) | false | Set to true to output temperature at connection outlet |
| Modelica.Units.SI.MassFlowRate | mDis_flow_nominal (from PartialConnection1Pipe) | Nominal mass flow rate in the distribution line | |
| Modelica.Units.SI.MassFlowRate | mCon_flow_nominal (from PartialConnection1Pipe) | Nominal mass flow rate in the connection line | |
| Modelica.Units.SI.Length | lDis | Length of the distribution pipe before the connection | |
| 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 |
| Assumptions | |||
| Boolean | allowFlowReversal (from PartialConnection1Pipe) | false | = true to allow flow reversal, false restricts to design direction (port_a -> port_b) |
| Dynamics › Conservation equations | |||
| Modelica.Fluid.Types.Dynamics | energyDynamics (from PartialConnection1Pipe) | Modelica.Fluid.Types.Dynamics.FixedInitial | Type of energy balance: dynamic (3 initialization options) or steady state |
| Advanced › Dynamics | |||
| Modelica.Fluid.Types.Dynamics | massDynamics (from PartialConnection1Pipe) | energyDynamics | Type of mass balance: dynamic (3 initialization options) or steady state, must be steady state if energyDynamics is steady state |
| Dynamics › Nominal condition | |||
| Modelica.Units.SI.Time | tau (from PartialConnection1Pipe) | 10 | Time constant at nominal flow for dynamic energy and momentum balance |
| Pipe | |||
| 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 | |
Connectors
Components
| Type | Name | Default | Description |
|---|---|---|---|
| Fluid.FixedResistances.Junction | junConSup (from PartialConnection1Pipe) | Junction with connection supply | |
| Fluid.FixedResistances.Junction | junConRet (from PartialConnection1Pipe) | Junction with connection return | |
| Model_pipDis | pipDis (from PartialConnection1Pipe) | Distribution pipe | |
| Model_pipCon | pipCon (from PartialConnection1Pipe) | Connection pipe | |
| Buildings.Fluid.Sensors.MassFlowRate | senMasFloCon (from PartialConnection1Pipe) | Connection supply mass flow rate (measured) | |
| Buildings.Fluid.Sensors.MassFlowRate | senMasFloByp (from PartialConnection1Pipe) | Bypass mass flow rate (measured) | |
| DifferenceEnthalpyFlowRate | senDifEntFlo (from PartialConnection1Pipe) | Difference in enthalpy flow rate | |
| Fluid.Sensors.TemperatureTwoPort | senTOut (from PartialConnection1Pipe) | Temperature in distribution line at connection outlet |
Revisions
-
March 15, 2024, by David Blum:
Renamed. This is for issue 3712. -
December 10, 2023, by Ettore Zanetti:
First implementation.