modelSeriesConstantFlow

Example of series connection with constant district water mass flow rate

Extends from Buildings.DHC.Examples.Combined.BaseClasses.PartialSeries (Partial model for series network).

Information

This is a model of a so-called "reservoir network" (Sommer 2020), i.e., a fifth generation district system with unidirectional mass flow rate in the district loop, and energy transfer stations connected in series. In this model, the temperature of the district loop is stabilized through the operation of the plant and the borefield. The main circulation pump has a constant mass flow rate. Each substation takes water from the main district loop and feeds its return water back into the main district loop downstream from the intake. The pipes of the main loop are designed for a pressure drop of dpDis_length_nominal=250 Pa/m at the design flow rate.

References

Sommer T., Sulzer M., Wetter M., Sotnikov A., Mennel S., Stettler C. The reservoir network: A new network topology for district heating and cooling. Energy, Volume 199, 15 May 2020, 117418.

Parameters

TypeNameDefaultDescription
RealfacMul (from PartialSeries)10Building loads multiplier factor
RealdpDis_length_nominal (from PartialSeries)250Pressure drop per pipe length at nominal flow rate - Distribution line
RealdpCon_length_nominal (from PartialSeries)250Pressure drop per pipe length at nominal flow rate - Connection line
Modelica.Units.SI.LengthdhSto (from PartialSeries)Hydraulic diameter of the distribution pipe before each connection
Modelica.Units.SI.LengthdhPla (from PartialSeries)Hydraulic diameter of the distribution pipe before each connection
IntegernBui (from PartialSeries)datDes.nBuiNumber of buildings connected to DHC system
Buildings.DHC.Examples.Combined.BaseClasses.DesignDataSeriesdatDes (from PartialSeries)Design data
String[nBui]filNam{"modelica://Buildings/Resources/Data/DHC/Loads/Examples/SwissOffice_20190916.mos", "modelica://Buildings/Resources/Data/DHC/Loads/Examples/SwissResidential_20190916.mos", "modelica://Buildings/Resources/Data/DHC/Loads/Examples/SwissHospital_20190916.mos"}Library paths of the files with thermal loads as time series
Assumptions
BooleanallowFlowReversalSer (from PartialSeries)trueSet to true to allow flow reversal in the service lines
BooleanallowFlowReversalBui (from PartialSeries)falseSet to true to allow flow reversal for in-building systems

Components

TypeNameDefaultDescription
Buildings.DHC.Examples.Combined.BaseClasses.BorefieldborFie (from PartialSeries)Bore field
Buildings.DHC.ETS.BaseClasses.Pump_m_flowpumDis (from PartialSeries)Distribution pump
Buildings.Fluid.Sources.Boundary_pTbou (from PartialSeries)Boundary pressure condition representing the expansion vessel
Buildings.DHC.ETS.BaseClasses.Pump_m_flowpumSto (from PartialSeries)Bore field pump
Buildings.DHC.Networks.Connections.Connection1Pipe_RconPla (from PartialSeries)Connection to the plant (pressure drop lumped in plant and network model)
Buildings.DHC.Networks.Connections.Connection1Pipe_RconSto (from PartialSeries)Connection to the bore field (pressure drop lumped in plant and network model)
Buildings.DHC.Plants.Heating.SewageHeatRecoverypla (from PartialSeries)Sewage heat recovery plant
Fluid.Sensors.TemperatureTwoPortTDisWatSup (from PartialSeries)District water supply temperature
Fluid.Sensors.TemperatureTwoPortTDisWatRet (from PartialSeries)District water return temperature
Fluid.Sensors.TemperatureTwoPortTDisWatBorLvg (from PartialSeries)District water borefield leaving temperature
Buildings.DHC.Loads.Combined.BaseClasses.PartialBuildingWithETS[nBui]bui (from PartialSeries)
Buildings.Controls.OBC.CDL.Reals.Sources.Constant[nBui]THeaWatSupMaxSet (from PartialSeries)Heating water supply temperature set point - Maximum value
Buildings.Controls.OBC.CDL.Reals.Sources.Constant[nBui]TChiWatSupSet (from PartialSeries)Chilled water supply temperature set point
Buildings.Controls.OBC.CDL.Reals.Sources.Constant[nBui]THeaWatSupMinSet (from PartialSeries)Heating water supply temperature set point - Minimum value
Buildings.Controls.OBC.CDL.Reals.MultiSumPPumETS (from PartialSeries)ETS pump power
Modelica.Blocks.Continuous.IntegratorEPumETS (from PartialSeries)ETS pump electric energy
Modelica.Blocks.Continuous.IntegratorEPumDis (from PartialSeries)Distribution pump electric energy
Modelica.Blocks.Continuous.IntegratorEPumSto (from PartialSeries)Storage pump electric energy
Modelica.Blocks.Continuous.IntegratorEPumPla (from PartialSeries)Plant pump electric energy
Buildings.Controls.OBC.CDL.Reals.MultiSumEPum (from PartialSeries)Total pump electric energy
Buildings.Controls.OBC.CDL.Reals.MultiSumPHeaPump (from PartialSeries)Heat pump power
Modelica.Blocks.Continuous.IntegratorEHeaPum (from PartialSeries)Heat pump electric energy
Buildings.Controls.OBC.CDL.Reals.MultiSumETot (from PartialSeries)Total electric energy
Buildings.DHC.Loads.BaseClasses.ConstraintViolationconVio (from PartialSeries)Check if loop temperatures are within given range
Modelica.Blocks.Sources.ConstantmasFloMaiPumDistribution pump mass flow rate
Modelica.Blocks.Sources.ConstantmasFloDisPlaDistrict water flow rate to plant
Buildings.Controls.OBC.CDL.Reals.Sources.Constant[nBui]THotWatSupSetHot water supply temperature set point
Buildings.Controls.OBC.CDL.Reals.Sources.Constant[nBui]TColWatCold water temperature
Networks.Distribution1Pipe_RdisDistribution network
Modelica.Blocks.Sources.ConstantTSewWatSewage water temperature

Revisions

  • December 12, 2023, by Ettore Zanetti:
    Updated partial class, this is for issue 3431.
  • February 23, 2021, by Antoine Gautier:
    Refactored with base classes from the DHC package.
    This is for issue 1769.
  • January 12, 2020, by Michael Wetter:
    Added documentation.