modelPartialParallel

Partial ETS model with district heat exchanger and parallel connection of production systems

Extends from Buildings.DHC.ETS.BaseClasses.PartialETS (Partial class for modeling an energy transfer station).

Information

This is a base model providing the hydronic configuration for an energy transfer station as described in the schematics below. It is typically used to integrate systems providing both heating water and chilled water, such as heat recovery chillers. Furthermore, it can be connected to an adjustable number (nSouAmb) of systems serving as ambient sources (including the district heat exchanger).

Models that extend this base class must

  • specify the number of systems serving as ambient sources nSouAmb, the number of heating water production systems nSysHea, and the number of chilled water production systems nSysCoo (by default nSysCoo=nSysHea which corresponds to a configuration where both productions are ensured by the same system, such as a heat recovery chiller),
  • modify the parameter binding with the nominal mass flow rate of each connection to each collector/distributor model, namely the parameter mCon_flow_nominal (array) of the components colChiWat, colHeaWat and colAmbWat. The connection index 1 for the components colChiWat and colHeaWat is reserved for the connection with the ambient source circuit. It increases with the distance from the buffer tank. The connection index 1 for the component colAmbWat is reserved for the connection with the district heat exchanger. Note that the order of the connections has no impact on the flow distribution as the connections are in parallel.

Note that the model includes a pressure boundary condition which is shared between the hot water and chilled water circuits, the two circuits being hydronically connected.

Sequence chart

Parameters

TypeNameDefaultDescription
Buildings.Fluid.Data.Fuels.Generic[nFue]fue (from PartialETS)Fuel type
Buildings.DHC.ETS.Types.ConnectionConfigurationconConBuildings.DHC.ETS.Types.ConnectionConfiguration.PumpDistrict connection configuration
IntegernSysHeaNumber of heating systems
IntegernSysCoonSysHeaNumber of cooling systems
IntegernSouAmb1Number of ambient sources
Configuration
TypDisSystyp (from PartialETS)Buildings.DHC.Types.DistrictSystemType.CombinedGeneration2to4Type of district system
IntegernPorts_aHeaWat (from PartialETS)0Number of heating water return ports
IntegernPorts_bHeaWat (from PartialETS)0Number of heating water supply ports
IntegernPorts_aChiWat (from PartialETS)0Number of chilled water return ports
IntegernPorts_bChiWat (from PartialETS)0Number of chilled water supply ports
Booleanhave_heaWat (from PartialETS)falseSet to true if the ETS supplies heating water
Booleanhave_hotWat (from PartialETS)falseSet to true if the ETS supplies hot water
Booleanhave_chiWat (from PartialETS)falseSet to true if the ETS supplies chilled water
Booleanhave_fan (from PartialETS)falseSet to true if fan power is computed
Booleanhave_pum (from PartialETS)falseSet to true if pump power is computed
Booleanhave_eleHea (from PartialETS)falseSet to true if the ETS has electric heating system
IntegernFue (from PartialETS)0Number of fuel types (0 means no combustion system)
Booleanhave_eleCoo (from PartialETS)falseSet to true if the ETS has electric cooling system
Booleanhave_weaBus (from PartialETS)falseSet to true to use a weather bus
Assumptions
BooleanallowFlowReversalSer (from PartialETS)falseSet to true to allow flow reversal on service side
BooleanallowFlowReversalBui (from PartialETS)falseSet to true to allow flow reversal on building side
Nominal condition
Modelica.Units.SI.HeatFlowRateQHeaWat_flow_nominal (from PartialETS)0Nominal capacity of heating system (>=0)
Modelica.Units.SI.HeatFlowRateQHotWat_flow_nominal (from PartialETS)0Nominal capacity of hot water production system (>=0)
Modelica.Units.SI.HeatFlowRateQChiWat_flow_nominal (from PartialETS)0Nominal capacity of cooling system (<=0)
Modelica.Units.SI.PressureDifferencedpValIso_nominal2E3Nominal pressure drop of ambient circuit isolation valves
District heat exchanger
Modelica.Units.SI.PressureDifferencedp1Hex_nominalNominal pressure drop across heat exchanger on district side
Modelica.Units.SI.PressureDifferencedp2Hex_nominalNominal pressure drop across heat exchanger on building side
Modelica.Units.SI.HeatFlowRateQHex_flow_nominalNominal heat flow rate through heat exchanger (from district to building)
Modelica.Units.SI.TemperatureT_a1Hex_nominalNominal water inlet temperature on district side
Modelica.Units.SI.TemperatureT_b1Hex_nominalNominal water outlet temperature on district side
Modelica.Units.SI.TemperatureT_a2Hex_nominalNominal water inlet temperature on building side
Modelica.Units.SI.TemperatureT_b2Hex_nominalNominal water outlet temperature on building side
RealspePum1HexMin0.1Heat exchanger primary pump minimum speed (fractional)
RealspePum2HexMin0.1Heat exchanger secondary pump minimum speed (fractional)
Buffer Tank
Modelica.Units.SI.VolumeVTanHeaWatHeating water tank volume
Modelica.Units.SI.LengthhTanHeaWat(VTanHeaWat*16/Modelica.Constants.pi)^(1/3)Heating water tank height (assuming twice the diameter)
Modelica.Units.SI.LengthdInsTanHeaWat0.1Heating water tank insulation thickness
Modelica.Units.SI.VolumeVTanChiWatChilled water tank volume
Modelica.Units.SI.LengthhTanChiWat(VTanChiWat*16/Modelica.Constants.pi)^(1/3)Chilled water tank height (without insulation)
Modelica.Units.SI.LengthdInsTanChiWat0.1Chilled water tank insulation thickness
IntegernSegTan3Number of volume segments for tanks

Connectors

TypeNameDefaultDescription
Modelica.Fluid.Interfaces.FluidPorts_a[nPorts_aHeaWat]ports_aHeaWat (from PartialETS)Fluid connectors for heating water return (from building)
Modelica.Fluid.Interfaces.FluidPorts_b[nPorts_bHeaWat]ports_bHeaWat (from PartialETS)Fluid connectors for heating water supply (to building)
Modelica.Fluid.Interfaces.FluidPorts_a[nPorts_aChiWat]ports_aChiWat (from PartialETS)Fluid connectors for chilled water return (from building)
Modelica.Fluid.Interfaces.FluidPorts_b[nPorts_bChiWat]ports_bChiWat (from PartialETS)Fluid connectors for chilled water supply (to building)
Modelica.Fluid.Interfaces.FluidPort_aport_aSerAmb (from PartialETS)Fluid connector for ambient water service supply line
Modelica.Fluid.Interfaces.FluidPort_bport_bSerAmb (from PartialETS)Fluid connector for ambient water service return line
Modelica.Fluid.Interfaces.FluidPort_aport_aSerHea (from PartialETS)Fluid connector for heating service supply line
Modelica.Fluid.Interfaces.FluidPort_bport_bSerHea (from PartialETS)Fluid connector for heating service return line
Modelica.Fluid.Interfaces.FluidPort_aport_aSerCoo (from PartialETS)Fluid connector for cooling service supply line
Modelica.Fluid.Interfaces.FluidPort_bport_bSerCoo (from PartialETS)Fluid connector for cooling service return line
Buildings.Controls.OBC.CDL.Interfaces.RealOutputPHea (from PartialETS)Power drawn by heating system
Buildings.Controls.OBC.CDL.Interfaces.RealOutputPCoo (from PartialETS)Power drawn by cooling system
Buildings.Controls.OBC.CDL.Interfaces.RealOutputPFan (from PartialETS)Power drawn by fan motors
Buildings.Controls.OBC.CDL.Interfaces.RealOutputPPum (from PartialETS)Power drawn by pump motors
Buildings.Controls.OBC.CDL.Interfaces.RealOutput[nFue]QFue_flow (from PartialETS)Fuel energy input rate
BoundaryConditions.WeatherData.BusweaBus (from PartialETS)Weather data bus
Buildings.Controls.OBC.CDL.Interfaces.BooleanInputuHeaHeating enable signal
Buildings.Controls.OBC.CDL.Interfaces.BooleanInputuCooCooling enable signal
Buildings.Controls.OBC.CDL.Interfaces.RealInputTHeaWatSupSetHeating water supply temperature set point
Buildings.Controls.OBC.CDL.Interfaces.RealInputTChiWatSupSetChilled water supply temperature set point

Components

TypeNameDefaultDescription
Buildings.Obsolete.DHC.ETS.Combined.Controls.BaseClasses.PartialSupervisoryconSup
Buildings.Fluid.Actuators.Valves.TwoWayLinearvalIsoEvaEvaporator to ambient loop isolation valve
Buildings.Fluid.Actuators.Valves.TwoWayLinearvalIsoConCondenser to ambient loop isolation valve
Buildings.Obsolete.DHC.ETS.Combined.Subsystems.HeatExchangerhexDistrict heat exchanger
Buildings.DHC.ETS.BaseClasses.StratifiedTanktanChiWatChilled water tank
Buildings.DHC.ETS.BaseClasses.StratifiedTanktanHeaWatHeating water tank
Buildings.DHC.ETS.BaseClasses.CollectorDistributorcolChiWatCollector/distributor for chilled water
Buildings.DHC.ETS.BaseClasses.CollectorDistributorcolHeaWatCollector/distributor for heating water
Buildings.DHC.ETS.BaseClasses.CollectorDistributorcolAmbWatCollector/distributor for ambient water
Buildings.Controls.OBC.CDL.Reals.MultiSumtotPPumTotal pump power
Buildings.Controls.OBC.CDL.Reals.MultiSumtotPHeaTotal power drawn by heating system
Buildings.Controls.OBC.CDL.Reals.MultiSumtotPCooTotal power drawn by cooling system
Buildings.Fluid.Sources.Boundary_pTbouPressure boundary condition representing expansion vessel (common to HHW and CHW)

Revisions

  • November 3, 2025, by Michael Wetter:
    Moved to Buildings.Obsolete.
    This is for #4354.
  • July 14, 2021, by Antoine Gautier:
    Added pressure boundary condition.
    This is for issue #2561.
  • December 21, 2020, by Antoine Gautier:
    Added outputs for distributed energy flow rate.
  • July 31, 2020, by Antoine Gautier:
    First implementation.