modelDistribution1Pipe_R

Model of a one-pipe distribution network with hydraulic diameter of main line pipes calculated from pressure drop per length
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Extends from Buildings.DHC.Networks.BaseClasses.PartialDistribution1Pipe (Partial model for one-pipe distribution network).

Information

This is a model of a one-pipe distribution network using a connection model with pipes in the main line whose hydraulic diameters are calculated at initialization based on the pressure drop per pipe length at nominal flow rate Buildings.DHC.Networks.Connections.Connection1Pipe_R. The same pipe model is also used at the end of the distribution line (after the last connection) only on the supply side.

Modeling considerations

Note that dhDis needs to be vectorized, even if the same value is computed for each array element in case of a one-pipe network. This is because the pipe diameter is computed at initialization by the model Buildings.DHC.Networks.Pipes.PipeAutosize which is instantiated for each connection. So the initialization system of equations would be overdetermined if using a parameter binding with a scalar variable.

Parameters

TypeNameDefaultDescription
Booleanshow_entFlo (from PartialDistribution1Pipe)falseSet to true to output enthalpy flow rate difference at each connection
Booleanshow_TOut (from PartialDistribution1Pipe)falseSet to true to output temperature at connection outlet
Realdp_length_nominal250Pressure drop per pipe length at nominal flow rate
Modelica.Units.SI.Length[nCon]lDisLength of the distribution pipe before each connection
Modelica.Units.SI.LengthlEndLength of the end of the distribution line (after last connection)
Modelica.Units.SI.Length[nCon]dhDisHydraulic diameter of the distribution pipe before each connection
Modelica.Units.SI.LengthdhEndHydraulic diameter of of the end of the distribution line (after last connection)
General
IntegernCon (from PartialDistribution2Medium)Number of connections
Assumptions
BooleanallowFlowReversal (from PartialDistribution2Medium)false= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
General › Nominal condition
Modelica.Units.SI.MassFlowRatemDis_flow_nominal (from PartialDistribution1Pipe)Nominal mass flow rate in the distribution line
Modelica.Units.SI.MassFlowRate[nCon]mCon_flow_nominal (from PartialDistribution1Pipe)Nominal mass flow rate in each connection line
Dynamics › Conservation equations
Modelica.Fluid.Types.DynamicsenergyDynamics (from PartialDistribution1Pipe)Modelica.Fluid.Types.Dynamics.FixedInitialType of energy balance: dynamic (3 initialization options) or steady state
Dynamics › Nominal condition
Modelica.Units.SI.Timetau (from PartialDistribution1Pipe)10Time constant at nominal flow for dynamic energy and momentum balance

Connectors

TypeNameDefaultDescription
Modelica.Fluid.Interfaces.FluidPorts_a[nCon]ports_aCon (from PartialDistribution2Medium)Connection return ports
Modelica.Fluid.Interfaces.FluidPorts_b[nCon]ports_bCon (from PartialDistribution2Medium)Connection supply ports
Modelica.Fluid.Interfaces.FluidPort_aport_aDisSup (from PartialDistribution2Medium)Distribution supply inlet port
Modelica.Fluid.Interfaces.FluidPort_bport_bDisSup (from PartialDistribution2Medium)Distribution supply outlet port
Buildings.Controls.OBC.CDL.Interfaces.RealOutput[nCon]dH_flow (from PartialDistribution1Pipe)Difference in enthalpy flow rate between connection supply and return
Buildings.Controls.OBC.CDL.Interfaces.RealOutput[nCon]mCon_flow (from PartialDistribution1Pipe)Connection supply mass flow rate (measured)
Buildings.Controls.OBC.CDL.Interfaces.RealOutput[nCon]mByp_flow (from PartialDistribution1Pipe)Bypass mass flow rate
Buildings.Controls.OBC.CDL.Interfaces.RealOutput[nCon]TOut (from PartialDistribution1Pipe)Temperature in distribution line at each connection outlet

Components

TypeNameDefaultDescription
PartialConnection1Pipe[nCon]con (from PartialDistribution1Pipe)Connection to agent
Model_pipDispipEnd (from PartialDistribution1Pipe)Pipe representing the end of the distribution line (after last connection)

Revisions

  • March 15, 2024, by David Blum:
    Renamed. This is for issue 3712.
  • December 20, 2023, by Ettore Zanetti:
    This is for issue 3431.
  • February 23, 2021, by Antoine Gautier:
    First implementation.