modelConnection2Pipe_R

Model for connecting an agent to the DHC system

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. 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.

Parameters

TypeNameDefaultDescription
Booleanshow_entFlo (from PartialConnection2Pipe)falseSet to true to output enthalpy flow rate difference
Realdp_length_nominal250Pressure drop per pipe length at nominal flow rate
Modelica.Units.SI.LengthdhDisRetHydraulic diameter of the return distribution pipe
Modelica.Units.SI.LengthlDisLength of the distribution pipe before the connection
Modelica.Units.SI.LengthdhDisHydraulic diameter of the distribution pipe
General › Nominal condition
Modelica.Units.SI.MassFlowRatemDis_flow_nominal (from PartialConnection2Pipe2Medium)Nominal mass flow rate in the distribution line
Modelica.Units.SI.MassFlowRatemCon_flow_nominal (from PartialConnection2Pipe2Medium)Nominal mass flow rate in the connection line
Assumptions
BooleanallowFlowReversal (from PartialConnection2Pipe2Medium)false= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Dynamics › Equations
Modelica.Fluid.Types.DynamicsenergyDynamics (from PartialConnection2Pipe2Medium)Modelica.Fluid.Types.Dynamics.FixedInitialType of energy balance: dynamic (3 initialization options) or steady state
Dynamics › Nominal condition
Modelica.Units.SI.Timetau (from PartialConnection2Pipe2Medium)10Time constant at nominal flow for dynamic energy and momentum balance

Connectors

TypeNameDefaultDescription
Modelica.Fluid.Interfaces.FluidPort_aport_aDisSup (from PartialConnection2Pipe2Medium)Distribution supply inlet port
Modelica.Fluid.Interfaces.FluidPort_bport_bDisSup (from PartialConnection2Pipe2Medium)Distribution supply outlet port
Modelica.Fluid.Interfaces.FluidPort_aport_aDisRet (from PartialConnection2Pipe2Medium)Distribution return inlet port
Modelica.Fluid.Interfaces.FluidPort_bport_bDisRet (from PartialConnection2Pipe2Medium)Distribution return outlet port
Modelica.Fluid.Interfaces.FluidPort_bport_bCon (from PartialConnection2Pipe2Medium)Connection supply port
Modelica.Fluid.Interfaces.FluidPort_aport_aCon (from PartialConnection2Pipe2Medium)Connection return port
Buildings.Controls.OBC.CDL.Interfaces.RealOutputmCon_flow (from PartialConnection2Pipe)Connection supply mass flow rate
Buildings.Controls.OBC.CDL.Interfaces.RealOutputdp (from PartialConnection2Pipe)Pressure drop accross the connection (measured)
Buildings.Controls.OBC.CDL.Interfaces.RealOutputdH_flow (from PartialConnection2Pipe)Difference in enthalpy flow rate between connection supply and return

Components

TypeNameDefaultDescription
Model_pipDisSuppipDisSup (from PartialConnection2Pipe2Medium)Distribution supply pipe
Model_pipDisRetpipDisRet (from PartialConnection2Pipe2Medium)Distribution return pipe
Buildings.Fluid.FixedResistances.JunctionjunConSup (from PartialConnection2Pipe2Medium)Junction with connection supply
Buildings.Fluid.FixedResistances.JunctionjunConRet (from PartialConnection2Pipe2Medium)Junction with connection return
Model_pipConpipCon (from PartialConnection2Pipe)Connection pipe
Buildings.Fluid.Sensors.MassFlowRatesenMasFloCon (from PartialConnection2Pipe)Connection supply mass flow rate (measured)
Fluid.Sensors.RelativePressuresenRelPre (from PartialConnection2Pipe)Relative pressure sensor
DifferenceEnthalpyFlowRatesenDifEntFlo (from PartialConnection2Pipe)Difference in enthalpy flow rate

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.