modelPartialDecoupling

Partial model of primary variable circuit serving a decoupling circuit
Diagram of PartialDecouplingOpen the diagram

Extends from BaseClasses.PartialActivePrimary (Partial model of active primary network).

Information

This is a partial model of a change-over system. The variable flow primary loop includes a variable speed pump serving a variable flow decoupling circuit with a variable speed pump and two-way valves. The primary pump model takes an ideally controlled head as input. The secondary pump model takes a normalized speed as input. The pump speed is modulated to track a constant pressure differential at the boundaries of the remote terminal unit.

Two identical terminal units are served by the secondary circuit. Each terminal unit has its own hourly load profile. Each terminal unit is balanced at design conditions.

The design conditions are defined without considering any load diversity.

That model is used to construct some example models within Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.

Parameters

TypeNameDefaultDescription
Buildings.Fluid.HydronicConfigurations.Types.Controltyp (from PartialActivePrimary)Buildings.Fluid.HydronicConfigurations.Types.Control.HeatingLoad type
IntegernTer (from PartialActivePrimary)2Number of terminal units
RealkSizPum (from PartialActivePrimary)1.0Pump oversizing coefficient
Modelica.Units.SI.Pressurep_min (from PartialActivePrimary)200000Circuit minimum pressure
Modelica.Units.SI.TemperatureTLiqEnt_nominal (from PartialActivePrimary)if typ == Buildings.Fluid.HydronicConfigurations.Types.Control.Heating then 60 + 273.15 else 7 + 273.15Liquid entering temperature at design conditions
Modelica.Units.SI.TemperatureTLiqLvg_nominal (from PartialActivePrimary)TLiqEnt_nominal + (if typ == Buildings.Fluid.HydronicConfigurations.Types.Control.Heating then -10 else +5)Liquid leaving temperature at design conditions
Modelica.Units.SI.TemperatureTLiqEntChg_nominal (from PartialActivePrimary)60 + 273.15Liquid entering temperature in change-over mode
Modelica.Units.SI.TemperatureTLiqSup_nominal (from PartialActivePrimary)TLiqEnt_nominalLiquid primary supply temperature at design conditions
Modelica.Units.SI.TemperatureTLiqSupChg_nominal (from PartialActivePrimary)TLiqEntChg_nominalLiquid primary supply temperature in change-over mode
Modelica.Units.SI.PressureDifferencedp1_nominaldpPum_nominal - dpPip_nominalControl valve pressure drop at design conditions
Nominal condition
Modelica.Units.SI.MassFlowRatemTer_flow_nominal (from PartialActivePrimary)1Terminal unit mass flow rate at design conditions
Modelica.Units.SI.MassFlowRatem1_flow_nominal (from PartialActivePrimary)m2_flow_nominalMass flow rate in primary branch at design conditions
Modelica.Units.SI.MassFlowRatem2_flow_nominal (from PartialActivePrimary)nTer*mTer_flow_nominalMass flow rate in consumer circuit at design conditions
Modelica.Units.SI.PressureDifferencedpTer_nominal (from PartialActivePrimary)3E4Terminal unit pressure drop at design conditions
Modelica.Units.SI.PressureDifferencedpPip_nominal (from PartialActivePrimary)0.5E4Pipe section pressure drop at design conditions
Modelica.Units.SI.PressureDifferencedpPum_nominal (from PartialActivePrimary)Pump head at design conditions
Modelica.Units.SI.MassFlowRatemPum_flow_nominal (from PartialActivePrimary)m1_flow_nominalPrimary pump mass flow rate at design conditions
Modelica.Units.SI.PressureDifferencedp2_nominaldpPip_nominal + dp2SetConsumer circuit pressure differential at design conditions
Dynamics › Conservation equations
Modelica.Fluid.Types.DynamicsenergyDynamics (from PartialActivePrimary)Modelica.Fluid.Types.Dynamics.FixedInitialType of energy balance: dynamic (3 initialization options) or steady state
Configuration
Booleanis_baltrueSet to true for balanced primary branch
Controls
Modelica.Units.SI.PressureDifferencedp2Setloa1.dpTer_nominal + loa1.dpValve_nominalConsumer circuit pressure differential set point

Components

TypeNameDefaultDescription
Sources.Boundary_pTref (from PartialActivePrimary)Pressure and temperature boundary condition
Buildings.Fluid.HydronicConfigurations.Components.Pumppum (from PartialActivePrimary)Circulation pump
FixedResistances.PressureDropres1 (from PartialActivePrimary)Pipe pressure drop
Sensors.TemperatureTwoPortT1Ret (from PartialActivePrimary)Return temperature sensor
Sensors.TemperatureTwoPortT1Sup (from PartialActivePrimary)Supply temperature sensor
Buildings.Controls.OBC.CDL.Reals.SubtractdT1 (from PartialActivePrimary)Primary Delta-T
Delays.DelayFirstOrderdel1 (from PartialActivePrimary)Fluid transport delay
Buildings.Fluid.HydronicConfigurations.ActiveNetworks.DecouplingconHydronic connection
Sensors.RelativePressuredpDifferential pressure
BaseClasses.LoadTwoWayValveControlloaLoad
BaseClasses.LoadTwoWayValveControlloa1Load
FixedResistances.PressureDropres2Pipe pressure drop
Sensors.RelativePressuredp2Differential pressure
FixedResistances.PressureDropresEnd2Pipe pressure drop
Buildings.Controls.OBC.CDL.Reals.Sources.Constantdp2SetValPressure differential set point
Buildings.Controls.OBC.CDL.Reals.PIDWithResetctlPum2Secondary pump controller
FixedResistances.PressureDropresEnd1Pipe pressure drop
Buildings.Controls.OBC.CDL.Reals.Sources.TimeTablefraLoaLoad modulating signal
Delays.DelayFirstOrderdel2Fluid transport delay
Buildings.Controls.OBC.CDL.Integers.Sources.TimeTablemodeOperating mode (time schedule)
Buildings.Controls.OBC.CDL.Integers.GreaterThresholdisEnaReturns true if enabled
Buildings.Controls.OBC.CDL.Reals.Sources.Constant[3]T1SetValPrimary circuit temperature set point values
Buildings.Controls.OBC.CDL.Routing.RealExtractorT1SetPrimary circuit temperature set point
Sensors.TemperatureTwoPortT1ConRetPrimary branch return temperature sensor
FixedResistances.JunctionjunJunction
Buildings.Controls.OBC.CDL.Integers.AddParameteraddParConvert mode index to array index

Revisions

  • June 30, 2022, by Antoine Gautier:
    First implementation.