Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.BaseClasses
Package with base classes
Information
This package contains base classes that are used to construct the models in Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.
Extends from Modelica.Icons.BasesPackage (Icon for packages containing base classes).
Package Content
| Name | Description |
|---|---|
 Load
|
Model of a load on a hydronic circuit |
 LoadThreeWayValveControl
|
Model of a load on hydronic circuit with flow rate modulation by three-way valve |
 LoadTwoWayValveControl
|
Model of a load on hydronic circuit with flow rate modulation by two-way valve |
 PartialActivePrimary
|
Partial model of active primary network |
| PartialDecoupling
|
Partial model of primary variable circuit serving a decoupling circuit |
| PartialInjectionTwoWay
|
Partial model of primary variable circuit serving an inversion circuit with two-way valve |
| PartialLoadValveControl
|
Model of a load on hydronic circuit with flow rate modulation by control valve |
Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.BaseClasses.Load
Model of a load on a hydronic circuit
Information
This model represents a thermal load on a hydronic circuit,
typically a terminal unit with recirculating air such as
a fan coil unit.
It takes the fraction of the design load u as input
and returns the control valve demand signal yVal as output.
In steady-state conditions, the model provides zero load
for u=0 and the design load for u=1.
However, for a cooling load with condensation, the relationship between
u and the load is not linear.
The main modeling assumptions are described below.
-
The heat exchanger is modeled in steady-state by default
(dynamics may be reintroduced with the parameter
energyDynamics). -
No pressure drop is considered, neither on the load side, nor
on the source side
(the design pressure drop on the source side may be
reset with the parameter
dpLiq_nominal). - The mass flow rate and the inlet conditions on the load side are constant. The load is modulated by varying the supply temperature set point.
Extends from Buildings.Fluid.Interfaces.PartialTwoPortInterface (Partial model transporting fluid between two ports without storing mass or energy).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| replaceable package MediumAir | Buildings.Media.Air | Medium model for air | |
| replaceable package MediumLiq | Buildings.Media.Water | Medium model for liquid (CHW or HHW) | |
| Control | typ | Load type | |
| MassFlowRate | mLiq_flow_nominal | 1 | Liquid mass flow rate at design conditions [kg/s] |
| PressureDifference | dpLiq_nominal | 0 | Liquid pressure drop at design conditions [Pa] |
| MassFlowRate | mAir_flow_nominal | abs(Q_flow_nominal)/10/cpAir... | Air mass flow rate at design conditions [kg/s] |
| Temperature | TAirEnt_nominal | if typ == Buildings.Fluid.Hy... | Air entering temperature at design conditions [K] |
| Temperature | TAirEntChg_nominal | 20 + 273.15 | Air entering temperature in change-over mode [K] |
| MassFraction | phiAirEnt_nominal | 0.5 | Air entering relative humidity at design conditions [1] |
| Temperature | TLiqEnt_nominal | if typ == Buildings.Fluid.Hy... | Liquid entering temperature at design conditions [K] |
| Temperature | TLiqLvg_nominal | TLiqEnt_nominal + (if typ ==... | Liquid leaving temperature at design conditions [K] |
| Temperature | TLiqEntChg_nominal | 60 + 273.15 | Liquid entering temperature in change-over mode [K] |
| SimpleController | controllerType | Buildings.Controls.OBC.CDL.T... | Type of controller |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | mLiq_flow_nominal | Nominal mass flow rate [kg/s] |
| Control gains | |||
| Real | k | 0.1 | Gain of controller |
| Real | Ti | 60 | Time constant of integrator block [s] |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package Medium | Medium in the component | |
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
| replaceable package MediumAir | Medium model for air | |
| replaceable package MediumLiq | Medium model for liquid (CHW or HHW) | |
| input RealInput | u | Load modulating signal |
| input IntegerInput | mode | Operating mode |
| output RealOutput | yVal | Valve demand signal [1] |
| output RealOutput | u_s | Controller set point [K] |
| output RealOutput | u_m | Controller measured value [K] |
| output RealOutput | dTLiq | Liquid deltaT [K] |
| output RealOutput | Q_flow | Total heat flow rate transferred to the load [W] |
| output RealOutput | yLoa_actual | Actual load fraction met [1] |
Modelica definition
model Load "Model of a load on a hydronic circuit"
extends Buildings.Fluid.Interfaces.PartialTwoPortInterface(
redeclare final package Medium=MediumLiq,
final m_flow_nominal=mLiq_flow_nominal);
replaceable package MediumAir = Buildings.Media.Air
"Medium model for air";
replaceable package MediumLiq = Buildings.Media.Water
"Medium model for liquid (CHW or HHW)";
parameter Buildings.Fluid.HydronicConfigurations.Types.Control typ
"Load type";
parameter Modelica.Units.SI.MassFlowRate mLiq_flow_nominal = 1
"Liquid mass flow rate at design conditions";
parameter Modelica.Units.SI.PressureDifference dpLiq_nominal=0
"Liquid pressure drop at design conditions";
parameter Modelica.Units.SI.MassFlowRate mAir_flow_nominal=
abs(Q_flow_nominal) / 10 / cpAir_nominal
"Air mass flow rate at design conditions";
parameter Modelica.Units.SI.Temperature TAirEnt_nominal=
if typ==Buildings.Fluid.HydronicConfigurations.Types.Control.Heating
then 20+273.15 else 26+273.15
"Air entering temperature at design conditions";
parameter Modelica.Units.SI.Temperature TAirEntChg_nominal=20+273.15
"Air entering temperature in change-over mode";
parameter Modelica.Units.SI.MassFraction phiAirEnt_nominal = 0.5
"Air entering relative humidity at design conditions";
final parameter Modelica.Units.SI.MassFraction XAirEnt_nominal=
Buildings.Utilities.Psychrometrics.Functions.X_pTphi(
MediumAir.p_default, TAirEnt_nominal, phiAirEnt_nominal)
"Air entering water mass fraction at design conditions (kg/kg air)";
final parameter Modelica.Units.SI.MassFraction xAirEnt_nominal=
XAirEnt_nominal / (1 - XAirEnt_nominal)
"Air entering humidity ratio at design conditions (kg/kg dry air)";
parameter Modelica.Units.SI.Temperature TLiqEnt_nominal=
if typ==Buildings.Fluid.HydronicConfigurations.Types.Control.Heating
then 60+273.15 else 7+273.15
"Liquid entering temperature at design conditions";
parameter Modelica.Units.SI.Temperature TLiqLvg_nominal=TLiqEnt_nominal+(
if typ==Buildings.Fluid.HydronicConfigurations.Types.Control.Heating
then -10 else +5)
"Liquid leaving temperature at design conditions";
parameter Modelica.Units.SI.Temperature TLiqEntChg_nominal=
60+273.15
"Liquid entering temperature in change-over mode";
final parameter Modelica.Units.SI.HeatFlowRate Q_flow_nominal=
(MediumLiq.specificEnthalpy_pTX(MediumLiq.p_default, TLiqEnt_nominal, X=MediumLiq.X_default)-
MediumLiq.specificEnthalpy_pTX(MediumLiq.p_default, TLiqLvg_nominal, X=MediumLiq.X_default))*
mLiq_flow_nominal
"Transmitted heat flow rate at design conditions";
final parameter Modelica.Units.SI.HeatFlowRate QChg_flow_nominal=
eps_nominal
* min({mLiq_flow_nominal * cpLiq_nominal, mAir_flow_nominal * cpAirChg_nominal})
* (TLiqEntChg_nominal - TAirEntChg_nominal)
"Transmitted heat flow rate in change-over mode";
final parameter Modelica.Units.SI.Temperature TAirLvgChg_nominal=
TAirEntChg_nominal + QChg_flow_nominal / cpAirChg_nominal / mAir_flow_nominal
"Air leaving temperature in change-over mode";
parameter Buildings.Controls.OBC.CDL.Types.SimpleController controllerType=
Buildings.Controls.OBC.CDL.Types.SimpleController.PI
"Type of controller";
parameter Real k(
min=100*Modelica.Constants.eps)=0.1
"Gain of controller";
parameter Real Ti(unit="s")=60
"Time constant of integrator block";
parameter Modelica.Fluid.Types.Dynamics energyDynamics=
Modelica.Fluid.Types.Dynamics.SteadyState
"Type of energy balance: dynamic (3 initialization options) or steady state";
Buildings.Controls.OBC.CDL.Interfaces.RealInput u
"Load modulating signal";
Buildings.Controls.OBC.CDL.Interfaces.IntegerInput mode "Operating mode";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput yVal(final unit="1")
"Valve demand signal";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput u_s(final unit="K",
displayUnit="degC") "Controller set point";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput u_m(final unit="K",
displayUnit="degC") "Controller measured value";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput dTLiq(final unit="K",
displayUnit="K") "Liquid deltaT";
Sources.Boundary_pT outAir(
redeclare final package Medium = MediumAir,
nPorts=2)
"Pressure boundary condition at coil outlet";
Sensors.TemperatureTwoPort TAirLvg(
redeclare final package Medium = MediumAir,
final m_flow_nominal=mAir_flow_nominal,
T_start=TAirEnt_nominal)
"Leaving air temperature sensor";
HeatExchangers.WetCoilEffectivenessNTU coi(
redeclare final package Medium1 = MediumLiq,
redeclare final package Medium2 = MediumAir,
final energyDynamics=energyDynamics,
final m1_flow_nominal=mLiq_flow_nominal,
final m2_flow_nominal=mAir_flow_nominal,
final dp1_nominal=dpLiq_nominal,
dp2_nominal=0,
configuration=Buildings.Fluid.Types.HeatExchangerConfiguration.CounterFlow,
final use_Q_flow_nominal=true,
final Q_flow_nominal=Q_flow_nominal,
final T_a1_nominal=TLiqEnt_nominal,
final T_a2_nominal=TAirEnt_nominal,
final w_a2_nominal=xAirEnt_nominal)
"Coil";
Sources.MassFlowSource_T souAir(
redeclare final package Medium = MediumAir,
final X={XAirEnt_nominal,1 - XAirEnt_nominal},
final m_flow=mAir_flow_nominal,
use_T_in=true,
nPorts=1) "Source for entering air";
Controls.PIDWithOperatingMode ctl(
u_s(unit="K", displayUnit="degC"),
u_m(unit="K", displayUnit="degC"),
final controllerType=controllerType,
final k=k,
final Ti=Ti,
final reverseActing=typ == Buildings.Fluid.HydronicConfigurations.Types.Control.Heating)
"Controller for supply air temperature";
Buildings.Controls.OBC.CDL.Reals.Add TAirSupSet(
y(final unit="K", displayUnit="degC"))
"Compute set point as TAirEnt_nominal + u * (TAirLvg_nominal - TAirEnt_nominal)";
HeatExchangers.WetCoilEffectivenessNTU coiNom(
redeclare final package Medium1 = MediumLiq,
redeclare final package Medium2 = MediumAir,
final m1_flow_nominal=mLiq_flow_nominal,
final m2_flow_nominal=mAir_flow_nominal,
show_T=true,
dp1_nominal=0,
dp2_nominal=0,
configuration=Buildings.Fluid.Types.HeatExchangerConfiguration.CounterFlow,
final use_Q_flow_nominal=true,
final Q_flow_nominal=Q_flow_nominal,
final T_a1_nominal=TLiqEnt_nominal,
final T_a2_nominal=TAirEnt_nominal,
final w_a2_nominal=xAirEnt_nominal,
final energyDynamics=Modelica.Fluid.Types.Dynamics.SteadyStateInitial)
"Coil operating at design conditions (used for model parameterization)";
Sources.MassFlowSource_T souAirNom(
redeclare final package Medium = MediumAir,
final X={XAirEnt_nominal,1 - XAirEnt_nominal},
final m_flow=mAir_flow_nominal,
final T=TAirEnt_nominal,
nPorts=1)
"Source for entering air";
Sources.MassFlowSource_T souLiq(
redeclare final package Medium = MediumLiq,
final m_flow=mLiq_flow_nominal,
final T=TLiqEnt_nominal,
nPorts=1)
"Source for entering liquid";
Sources.Boundary_pT outLiq(
redeclare final package Medium = MediumLiq,
nPorts=1)
"Pressure boundary condition at liquid outlet";
Sensors.TemperatureTwoPort TLiqEnt(
redeclare final package Medium = MediumLiq,
final m_flow_nominal=mLiq_flow_nominal,
T_start=TLiqEnt_nominal)
"Entering liquid temperature sensor";
Sensors.TemperatureTwoPort TLiqLvg(
redeclare final package Medium = MediumLiq,
final m_flow_nominal=mLiq_flow_nominal,
T_start=TLiqEnt_nominal)
"Leaving liquid temperature sensor";
Buildings.Controls.OBC.CDL.Reals.Subtract dT
"Compute deltaT";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput Q_flow(
final unit="W")
"Total heat flow rate transferred to the load";
Modelica.Blocks.Sources.RealExpression heaFlo(
y=coi.Q2_flow)
"Access coil heat flow rate";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput yLoa_actual(
final unit="1")
"Actual load fraction met";
Modelica.Blocks.Sources.RealExpression loaFra(
y=Q_flow/(if mode == Buildings.Fluid.HydronicConfigurations.Controls.OperatingModes.heating
then QChg_flow_nominal else coiNom.Q2_flow))
"Compute actual load fraction";
Sensors.TemperatureTwoPort TAirLvgNom(
redeclare final package Medium = MediumAir,
final m_flow_nominal=mAir_flow_nominal,
T_start=TAirEnt_nominal)
"Leaving air temperature sensor";
Buildings.Controls.OBC.CDL.Reals.Subtract sub
"Compute TAirLvg_nominal - TAirEnt_nominal";
Buildings.Controls.OBC.CDL.Reals.Multiply pro
"Compute u * (TAirLvg_nominal - TAirEnt_nominal)";
Buildings.Controls.OBC.CDL.Reals.Sources.Constant TAirEntVal[3](final k=
{TAirEnt_nominal,TAirEnt_nominal,TAirEntChg_nominal})
"Values of entering air temperature";
Buildings.Controls.OBC.CDL.Routing.RealExtractor TAirEnt_actual(
y(final unit="K", displayUnit="degC"), final nin=3)
"Actual value of entering air temperature";
Buildings.Controls.OBC.CDL.Routing.RealExtractor TAirLvg_actual(
y(final unit="K", displayUnit="degC"), final nin=3)
"Actual value of leaving air temperature";
Buildings.Controls.OBC.CDL.Reals.Sources.Constant TAirLvgVal(
final k=TAirLvgChg_nominal) "Values of leaving air temperature";
Buildings.Controls.OBC.CDL.Integers.AddParameter addPar(final p=1)
"Convert mode index to array index";
Buildings.Controls.OBC.CDL.Routing.RealScalarReplicator reaScaRep(nout=2)
"Replicate";
protected
final parameter Modelica.Units.SI.SpecificHeatCapacity cpLiq_nominal=
MediumLiq.specificHeatCapacityCp(MediumLiq.setState_pTX(
p=MediumLiq.p_default,
T=TLiqEnt_nominal))
"Liquid specific heat capacity at design conditions";
final parameter Modelica.Units.SI.SpecificHeatCapacity cpAir_nominal=
MediumAir.specificHeatCapacityCp(MediumAir.setState_pTX(
p=MediumAir.p_default,
T=TLiqEnt_nominal,
X={XAirEnt_nominal,1 - XAirEnt_nominal}))
"Air specific heat capacity at design conditions";
final parameter Modelica.Units.SI.SpecificHeatCapacity cpAirChg_nominal=
MediumAir.specificHeatCapacityCp(MediumAir.setState_pTX(
p=MediumAir.p_default,
T=TLiqEntChg_nominal,
X={XAirEnt_nominal,1 - XAirEnt_nominal}))
"Air specific heat capacity in change-over mode";
parameter Real eps_nominal=
Buildings.Fluid.HeatExchangers.BaseClasses.epsilon_C(
UA=coiNom.UA_nominal,
C1_flow=mLiq_flow_nominal * cpLiq_nominal,
C2_flow=mAir_flow_nominal * cpAir_nominal,
flowRegime=Integer(Buildings.Fluid.Types.HeatExchangerConfiguration.CounterFlow),
CMin_flow_nominal=min({mLiq_flow_nominal * cpLiq_nominal, mAir_flow_nominal * cpAir_nominal}),
CMax_flow_nominal=max({mLiq_flow_nominal * cpLiq_nominal, mAir_flow_nominal * cpAir_nominal}));
initial equation
assert(typ<>Buildings.Fluid.HydronicConfigurations.Types.Control.None,
"In " + getInstanceName() +
": The type of built-in controls cannot be None: select any other valid option.");
equation
connect(souAir.ports[1], coi.port_a2);
connect(outAir.ports[1],TAirLvg. port_b);
connect(TAirLvg.port_a, coi.port_b2);
connect(ctl.y, yVal);
connect(TAirSupSet.y, ctl.u_s);
connect(souAirNom.ports[1], coiNom.port_a2);
connect(souLiq.ports[1], coiNom.port_a1);
connect(coiNom.port_b1, outLiq.ports[1]);
connect(TAirSupSet.y, u_s);
connect(port_a, TLiqEnt.port_a);
connect(TLiqEnt.port_b, coi.port_a1);
connect(coi.port_b1, TLiqLvg.port_a);
connect(TLiqLvg.port_b, port_b);
connect(dT.y, dTLiq);
connect(TLiqLvg.T, dT.u1);
connect(TLiqEnt.T, dT.u2);
connect(TAirLvg.T, ctl.u_m);
connect(TAirLvg.T, u_m);
connect(heaFlo.y, Q_flow);
connect(yLoa_actual, loaFra.y);
connect(coiNom.port_b2, TAirLvgNom.port_a);
connect(TAirLvgNom.port_b, outAir.ports[2]);
connect(mode, ctl.mode);
connect(TAirEntVal.y, TAirEnt_actual.u);
connect(pro.y, TAirSupSet.u2);
connect(TAirEnt_actual.y, TAirSupSet.u1);
connect(sub.y, pro.u1);
connect(u, pro.u2);
connect(TAirEnt_actual.y, souAir.T_in);
connect(sub.u1, TAirLvg_actual.y);
connect(TAirEnt_actual.y, sub.u2);
connect(addPar.y, TAirEnt_actual.index);
connect(addPar.y, TAirLvg_actual.index);
connect(mode, addPar.u);
connect(TAirLvgNom.T, reaScaRep.u);
connect(reaScaRep.y, TAirLvg_actual.u[1:2]);
connect(TAirLvgVal.y, TAirLvg_actual.u[3]);
end Load;
Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.BaseClasses.LoadThreeWayValveControl
Model of a load on hydronic circuit with flow rate modulation by three-way valve
Information
This is a model of a thermal load on a hydronic circuit that is composed of Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.BaseClasses.Load and a diversion circuit with a three-way valve that is used to modulate the flow rate through the load component.
Extends from PartialLoadValveControl (Model of a load on hydronic circuit with flow rate modulation by control valve).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package MediumAir | Air | Medium model for air | |
| replaceable package MediumLiq | Water | Medium model for liquid (CHW or HHW) | |
| Control | typ | Load type | |
| MassFlowRate | mLiq_flow_nominal | 1 | Liquid mass flow rate at design conditions [kg/s] |
| PressureDifference | dpTer_nominal | 3E4 | Liquid pressure drop across terminal unit at design conditions [Pa] |
| MassFlowRate | mAir_flow_nominal | abs(Q_flow_nominal)/10/1015 | Air mass flow rate at design conditions [kg/s] |
| Temperature | TAirEnt_nominal | if typ == Buildings.Fluid.Hy... | Air entering temperature at design conditions [K] |
| Temperature | TAirEntChg_nominal | 20 + 273.15 | Air entering temperature in change-over mode [K] |
| MassFraction | phiAirEnt_nominal | 0.5 | Air entering relative humidity at design conditions [1] |
| Temperature | TLiqEnt_nominal | if typ == Buildings.Fluid.Hy... | Liquid entering temperature at design conditions [K] |
| Temperature | TLiqLvg_nominal | TLiqEnt_nominal + (if typ ==... | Liquid leaving temperature at design conditions [K] |
| Temperature | TLiqEntChg_nominal | 60 + 273.15 | Liquid entering temperature in change-over mode [K] |
| SimpleController | controllerType | Buildings.Controls.OBC.CDL.T... | Type of controller |
| Control valve | |||
| PressureDifference | dpValve_nominal | dpTer_nominal | Control valve pressure drop at design conditions [Pa] |
| Balancing valves | |||
| PressureDifference | dpBal1_nominal | 0 | Balancing valve pressure drop at design conditions [Pa] |
| Control gains | |||
| Real | k | 0.1 | Gain of controller |
| Real | Ti | 60 | Time constant of integrator block [s] |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
Connectors
| Type | Name | Description |
|---|---|---|
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
| input RealInput | u | Load modulating signal |
| input IntegerInput | mode | Operating mode |
| output RealOutput | yLoa_actual | Actual load fraction met [1] |
| output RealOutput | Q_flow | Total heat flow rate transferred to the load [W] |
| output RealOutput | yVal_actual | Valve position feedback [1] |
Modelica definition
model LoadThreeWayValveControl
"Model of a load on hydronic circuit with flow rate modulation by three-way valve"
extends PartialLoadValveControl(
redeclare HydronicConfigurations.ActiveNetworks.Diversion con);
end LoadThreeWayValveControl;
Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.BaseClasses.LoadTwoWayValveControl
Model of a load on hydronic circuit with flow rate modulation by two-way valve
Information
This is a model of a thermal load on a hydronic circuit that is composed of Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.BaseClasses.Load and a throttle circuit with a two-way valve that is used to modulate the flow rate through the load component.
Extends from PartialLoadValveControl (Model of a load on hydronic circuit with flow rate modulation by control valve).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package MediumAir | Air | Medium model for air | |
| replaceable package MediumLiq | Water | Medium model for liquid (CHW or HHW) | |
| Control | typ | Load type | |
| MassFlowRate | mLiq_flow_nominal | 1 | Liquid mass flow rate at design conditions [kg/s] |
| PressureDifference | dpTer_nominal | 3E4 | Liquid pressure drop across terminal unit at design conditions [Pa] |
| MassFlowRate | mAir_flow_nominal | abs(Q_flow_nominal)/10/1015 | Air mass flow rate at design conditions [kg/s] |
| Temperature | TAirEnt_nominal | if typ == Buildings.Fluid.Hy... | Air entering temperature at design conditions [K] |
| Temperature | TAirEntChg_nominal | 20 + 273.15 | Air entering temperature in change-over mode [K] |
| MassFraction | phiAirEnt_nominal | 0.5 | Air entering relative humidity at design conditions [1] |
| Temperature | TLiqEnt_nominal | if typ == Buildings.Fluid.Hy... | Liquid entering temperature at design conditions [K] |
| Temperature | TLiqLvg_nominal | TLiqEnt_nominal + (if typ ==... | Liquid leaving temperature at design conditions [K] |
| Temperature | TLiqEntChg_nominal | 60 + 273.15 | Liquid entering temperature in change-over mode [K] |
| SimpleController | controllerType | Buildings.Controls.OBC.CDL.T... | Type of controller |
| Control valve | |||
| PressureDifference | dpValve_nominal | dpTer_nominal | Control valve pressure drop at design conditions [Pa] |
| Balancing valves | |||
| PressureDifference | dpBal1_nominal | 0 | Balancing valve pressure drop at design conditions [Pa] |
| Control gains | |||
| Real | k | 0.1 | Gain of controller |
| Real | Ti | 60 | Time constant of integrator block [s] |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
Connectors
| Type | Name | Description |
|---|---|---|
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
| input RealInput | u | Load modulating signal |
| input IntegerInput | mode | Operating mode |
| output RealOutput | yLoa_actual | Actual load fraction met [1] |
| output RealOutput | Q_flow | Total heat flow rate transferred to the load [W] |
| output RealOutput | yVal_actual | Valve position feedback [1] |
Modelica definition
model LoadTwoWayValveControl
"Model of a load on hydronic circuit with flow rate modulation by two-way valve"
extends PartialLoadValveControl(
redeclare HydronicConfigurations.ActiveNetworks.Throttle con);
end LoadTwoWayValveControl;
Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.BaseClasses.PartialActivePrimary
Partial model of active primary network
Information
This is a partial model of an active primary network with a replaceable pump model. That model is used to construct the various example models within Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples. It can be configured to represent either a heating or a cooling system.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Control | typ | Buildings.Fluid.HydronicConf... | Load type |
| Integer | nTer | 2 | Number of terminal units |
| Real | kSizPum | 1.0 | Pump oversizing coefficient [1] |
| Pressure | p_min | 200000 | Circuit minimum pressure [Pa] |
| Temperature | TLiqEnt_nominal | if typ == Buildings.Fluid.Hy... | Liquid entering temperature at design conditions [K] |
| Temperature | TLiqLvg_nominal | TLiqEnt_nominal + (if typ ==... | Liquid leaving temperature at design conditions [K] |
| Temperature | TLiqEntChg_nominal | 60 + 273.15 | Liquid entering temperature in change-over mode [K] |
| Temperature | TLiqSup_nominal | TLiqEnt_nominal | Liquid primary supply temperature at design conditions [K] |
| Temperature | TLiqSupChg_nominal | TLiqEntChg_nominal | Liquid primary supply temperature in change-over mode [K] |
| Nominal condition | |||
| MassFlowRate | mTer_flow_nominal | 1 | Terminal unit mass flow rate at design conditions [kg/s] |
| MassFlowRate | m1_flow_nominal | m2_flow_nominal | Mass flow rate in primary branch at design conditions [kg/s] |
| MassFlowRate | m2_flow_nominal | nTer*mTer_flow_nominal | Mass flow rate in consumer circuit at design conditions [kg/s] |
| PressureDifference | dpTer_nominal | 3E4 | Terminal unit pressure drop at design conditions [Pa] |
| PressureDifference | dpPip_nominal | 0.5E4 | Pipe section pressure drop at design conditions [Pa] |
| PressureDifference | dpPum_nominal | Pump head at design conditions [Pa] | |
| MassFlowRate | mPum_flow_nominal | m1_flow_nominal | Primary pump mass flow rate at design conditions [kg/s] |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
Modelica definition
model PartialActivePrimary
"Partial model of active primary network"
extends Modelica.Icons.Example;
package MediumLiq = Buildings.Media.Water
"Medium model for hot water";
parameter Buildings.Fluid.HydronicConfigurations.Types.Control
typ=Buildings.Fluid.HydronicConfigurations.Types.Control.Heating
"Load type";
parameter Integer nTer=2
"Number of terminal units";
parameter Modelica.Units.SI.MassFlowRate mTer_flow_nominal = 1
"Terminal unit mass flow rate at design conditions";
parameter Modelica.Units.SI.MassFlowRate m1_flow_nominal(final min=0)=
m2_flow_nominal
"Mass flow rate in primary branch at design conditions";
parameter Modelica.Units.SI.MassFlowRate m2_flow_nominal(final min=0)=
nTer * mTer_flow_nominal
"Mass flow rate in consumer circuit at design conditions";
parameter Modelica.Units.SI.PressureDifference dpTer_nominal(displayUnit="Pa")=
3E4
"Terminal unit pressure drop at design conditions";
parameter Modelica.Units.SI.PressureDifference dpPip_nominal(displayUnit="Pa")=
0.5E4
"Pipe section pressure drop at design conditions";
parameter Real kSizPum(unit="1")=1.0
"Pump oversizing coefficient";
parameter Modelica.Units.SI.PressureDifference dpPum_nominal(
final min=0,
displayUnit="Pa")
"Pump head at design conditions";
parameter Modelica.Units.SI.MassFlowRate mPum_flow_nominal=m1_flow_nominal
"Primary pump mass flow rate at design conditions";
parameter Modelica.Units.SI.Pressure p_min=200000
"Circuit minimum pressure";
parameter Modelica.Units.SI.Temperature TLiqEnt_nominal=
if typ==Buildings.Fluid.HydronicConfigurations.Types.Control.Heating
then 60+273.15 else 7+273.15
"Liquid entering temperature at design conditions";
parameter Modelica.Units.SI.Temperature TLiqLvg_nominal=TLiqEnt_nominal+(
if typ==Buildings.Fluid.HydronicConfigurations.Types.Control.Heating
then -10 else +5)
"Liquid leaving temperature at design conditions";
parameter Modelica.Units.SI.Temperature TLiqEntChg_nominal=
60+273.15
"Liquid entering temperature in change-over mode";
parameter Modelica.Units.SI.Temperature TLiqSup_nominal=TLiqEnt_nominal
"Liquid primary supply temperature at design conditions";
parameter Modelica.Units.SI.Temperature TLiqSupChg_nominal=TLiqEntChg_nominal
"Liquid primary supply temperature in change-over mode";
parameter Modelica.Fluid.Types.Dynamics energyDynamics=Modelica.Fluid.Types.Dynamics.FixedInitial
"Type of energy balance: dynamic (3 initialization options) or steady state";
Sources.Boundary_pT ref(
redeclare final package Medium = MediumLiq,
final p=p_min,
final T=TLiqSup_nominal,
nPorts=2)
"Pressure and temperature boundary condition";
Buildings.Fluid.HydronicConfigurations.Components.Pump pum(
redeclare final package Medium = MediumLiq,
final energyDynamics=energyDynamics,
addPowerToMedium=false,
use_inputFilter=energyDynamics <> Modelica.Fluid.Types.Dynamics.SteadyState,
final m_flow_nominal=mPum_flow_nominal,
final dp_nominal=dpPum_nominal)
"Circulation pump";
FixedResistances.PressureDrop res1(
redeclare final package Medium = MediumLiq,
final m_flow_nominal=mPum_flow_nominal,
final dp_nominal=dpPip_nominal) "Pipe pressure drop";
Sensors.TemperatureTwoPort T1Ret(
redeclare final package Medium = MediumLiq,
final m_flow_nominal=mPum_flow_nominal,
final tau=if energyDynamics == Modelica.Fluid.Types.Dynamics.SteadyState
then 0 else 1,
T_start=TLiqSup_nominal) "Return temperature sensor";
Sensors.TemperatureTwoPort T1Sup(
redeclare final package Medium = MediumLiq,
final m_flow_nominal=mPum_flow_nominal,
final tau=if energyDynamics == Modelica.Fluid.Types.Dynamics.SteadyState
then 0 else 1,
T_start=TLiqSup_nominal) "Supply temperature sensor";
Buildings.Controls.OBC.CDL.Reals.Subtract dT1(y(final unit="K"))
"Primary Delta-T";
Delays.DelayFirstOrder del1(
redeclare final package Medium = MediumLiq,
final energyDynamics=energyDynamics,
final m_flow_nominal=mPum_flow_nominal,
nPorts=1)
"Fluid transport delay";
equation
connect(pum.port_b, T1Sup.port_a);
connect(T1Sup.port_b, res1.port_a);
connect(T1Ret.T, dT1.u1);
connect(T1Sup.T, dT1.u2);
connect(ref.ports[1], pum.port_a);
connect(ref.ports[2], T1Ret.port_b);
connect(T1Ret.port_a, del1.ports[1]);
end PartialActivePrimary;
Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.BaseClasses.PartialDecoupling
Partial model of primary variable circuit serving a decoupling circuit
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.
Extends from BaseClasses.PartialActivePrimary (Partial model of active primary network).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Control | typ | Buildings.Fluid.HydronicConf... | Load type |
| Integer | nTer | 2 | Number of terminal units |
| Real | kSizPum | 1.0 | Pump oversizing coefficient [1] |
| Pressure | p_min | 200000 | Circuit minimum pressure [Pa] |
| Temperature | TLiqEnt_nominal | if typ == Buildings.Fluid.Hy... | Liquid entering temperature at design conditions [K] |
| Temperature | TLiqLvg_nominal | TLiqEnt_nominal + (if typ ==... | Liquid leaving temperature at design conditions [K] |
| Temperature | TLiqEntChg_nominal | 60 + 273.15 | Liquid entering temperature in change-over mode [K] |
| Temperature | TLiqSup_nominal | TLiqEnt_nominal | Liquid primary supply temperature at design conditions [K] |
| Temperature | TLiqSupChg_nominal | TLiqEntChg_nominal | Liquid primary supply temperature in change-over mode [K] |
| PressureDifference | dp1_nominal | dpPum_nominal - dpPip_nominal | Control valve pressure drop at design conditions [Pa] |
| Nominal condition | |||
| MassFlowRate | mTer_flow_nominal | 1 | Terminal unit mass flow rate at design conditions [kg/s] |
| MassFlowRate | m1_flow_nominal | 1.1*m2_flow_nominal | Mass flow rate in primary branch at design conditions [kg/s] |
| MassFlowRate | m2_flow_nominal | nTer*mTer_flow_nominal/0.9 | Mass flow rate in consumer circuit at design conditions [kg/s] |
| PressureDifference | dpTer_nominal | 3E4 | Terminal unit pressure drop at design conditions [Pa] |
| PressureDifference | dpPip_nominal | 0.5E4 | Pipe section pressure drop at design conditions [Pa] |
| PressureDifference | dpPum_nominal | 10e4 | Pump head at design conditions [Pa] |
| MassFlowRate | mPum_flow_nominal | m1_flow_nominal/0.9 | Primary pump mass flow rate at design conditions [kg/s] |
| PressureDifference | dp2_nominal | dpPip_nominal + dp2Set | Consumer circuit pressure differential at design conditions [Pa] |
| Configuration | |||
| Boolean | is_bal | true | Set to true for balanced primary branch |
| Controls | |||
| PressureDifference | dp2Set | loa1.dpTer_nominal + loa1.dp... | Consumer circuit pressure differential set point [Pa] |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
Modelica definition
partial model PartialDecoupling
"Partial model of primary variable circuit serving a decoupling circuit"
extends BaseClasses.PartialActivePrimary(
typ=Buildings.Fluid.HydronicConfigurations.Types.Control.ChangeOver,
m2_flow_nominal=nTer*mTer_flow_nominal/0.9,
m1_flow_nominal=1.1*m2_flow_nominal,
mPum_flow_nominal=m1_flow_nominal/0.9,
dpPum_nominal=10e4,
del1(nPorts=3),
pum(typ=Buildings.Fluid.HydronicConfigurations.Types.Pump.NoVariableInput,
typMod=Buildings.Fluid.HydronicConfigurations.Types.PumpModel.Head),
ref(use_T_in=true));
parameter Boolean is_bal=true
"Set to true for balanced primary branch";
parameter Modelica.Units.SI.PressureDifference dp2Set(displayUnit="Pa")=
loa1.dpTer_nominal + loa1.dpValve_nominal
"Consumer circuit pressure differential set point";
parameter Modelica.Units.SI.PressureDifference dp2_nominal(displayUnit="Pa")=
dpPip_nominal + dp2Set
"Consumer circuit pressure differential at design conditions";
parameter Modelica.Units.SI.PressureDifference dp1_nominal(displayUnit="Pa")=
dpPum_nominal - dpPip_nominal
"Control valve pressure drop at design conditions";
Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Decoupling con(
typPum=Buildings.Fluid.HydronicConfigurations.Types.Pump.VariableInput,
typCtl=typ,
redeclare final package Medium=MediumLiq,
final energyDynamics=energyDynamics,
final m1_flow_nominal=m1_flow_nominal,
final m2_flow_nominal=m2_flow_nominal,
final dp1_nominal=dp1_nominal,
final dp2_nominal=dp2_nominal,
final dpBal1_nominal=if is_bal then
dpPum_nominal-dpPip_nominal-con.dpValve_nominal-con.dpBal3_nominal else 0)
"Hydronic connection";
Sensors.RelativePressure dp(
redeclare final package Medium = MediumLiq)
"Differential pressure";
BaseClasses.LoadTwoWayValveControl loa(
redeclare final package MediumLiq = MediumLiq,
final typ=typ,
final energyDynamics=energyDynamics,
final mLiq_flow_nominal=mTer_flow_nominal,
final TLiqEnt_nominal=TLiqEnt_nominal,
final TLiqEntChg_nominal=TLiqEntChg_nominal,
final TLiqLvg_nominal=TLiqLvg_nominal,
dpBal1_nominal=dp2_nominal - loa.dpTer_nominal - loa.dpValve_nominal)
"Load";
BaseClasses.LoadTwoWayValveControl loa1(
redeclare final package MediumLiq = MediumLiq,
final typ=typ,
final energyDynamics=energyDynamics,
final mLiq_flow_nominal=mTer_flow_nominal,
final TLiqEnt_nominal=TLiqEnt_nominal,
final TLiqEntChg_nominal=TLiqEntChg_nominal,
final TLiqLvg_nominal=TLiqLvg_nominal,
dpBal1_nominal=0)
"Load";
FixedResistances.PressureDrop res2(
redeclare final package Medium = MediumLiq,
m_flow_nominal=con.pum.m_flow_nominal - loa.mLiq_flow_nominal,
dp_nominal=dpPip_nominal)
"Pipe pressure drop";
Sensors.RelativePressure dp2(redeclare final package Medium = MediumLiq)
"Differential pressure";
FixedResistances.PressureDrop resEnd2(
redeclare final package Medium = MediumLiq,
final m_flow_nominal=0.1*m2_flow_nominal,
final dp_nominal=dp2Set)
"Pipe pressure drop";
Buildings.Controls.OBC.CDL.Reals.Sources.Constant dp2SetVal(final k=
dp2Set) "Pressure differential set point";
Buildings.Controls.OBC.CDL.Reals.PIDWithReset ctlPum2(
k=0.1,
Ti=60,
r=1e4,
y_reset=0) "Secondary pump controller";
FixedResistances.PressureDrop resEnd1(
redeclare final package Medium = MediumLiq,
final m_flow_nominal=0.1*mPum_flow_nominal,
final dp_nominal=dpPum_nominal)
"Pipe pressure drop";
Buildings.Controls.OBC.CDL.Reals.Sources.TimeTable fraLoa(table=[0,0,0; 6,
0,0; 6.1,1,1; 8,1,1; 9,1,0; 14,0.5,0; 14.5,0,0; 16,0,0; 17,0,1; 21,0,1;
22,0,0; 24,0,0], timeScale=3600) "Load modulating signal";
Delays.DelayFirstOrder del2(
redeclare final package Medium = MediumLiq,
final energyDynamics=energyDynamics,
final m_flow_nominal=m2_flow_nominal,
nPorts=3) "Fluid transport delay";
Buildings.Controls.OBC.CDL.Integers.Sources.TimeTable mode(
table=[0,0; 6,0; 6,2; 13,2; 13,1; 22,1; 22,0; 24,0],
timeScale=3600,
period=86400) "Operating mode (time schedule)";
Buildings.Controls.OBC.CDL.Integers.GreaterThreshold isEna(final t=Controls.OperatingModes.disabled)
"Returns true if enabled";
Buildings.Controls.OBC.CDL.Reals.Sources.Constant T1SetVal[3](final k={
MediumLiq.T_default,TLiqSup_nominal,TLiqSupChg_nominal})
"Primary circuit temperature set point values";
Buildings.Controls.OBC.CDL.Routing.RealExtractor T1Set(nin=3,
y(final unit="K", displayUnit="degC"))
"Primary circuit temperature set point";
Sensors.TemperatureTwoPort T1ConRet(
redeclare final package Medium = MediumLiq,
final m_flow_nominal=con.m2_flow_nominal,
tau=if energyDynamics == Modelica.Fluid.Types.Dynamics.SteadyState then 0
else 1) "Primary branch return temperature sensor";
FixedResistances.Junction jun(
redeclare final package Medium=MediumLiq,
final energyDynamics=energyDynamics,
final m_flow_nominal=m2_flow_nominal .* {1,-1,-1},
final dp_nominal=fill(0, 3))
"Junction";
Buildings.Controls.OBC.CDL.Integers.AddParameter addPar(final p=1)
"Convert mode index to array index";
equation
connect(con.port_a1, dp.port_a);
connect(res1.port_b, dp.port_a);
connect(dp.port_b, del1.ports[2]);
connect(fraLoa.y[1],loa. u);
connect(fraLoa.y[2],loa1. u);
connect(mode.y[1],loa. mode);
connect(mode.y[1],loa1. mode);
connect(dp2.p_rel, ctlPum2.u_m);
connect(res1.port_b, resEnd1.port_a);
connect(resEnd1.port_b, del1.ports[3]);
connect(dp2SetVal.y, ctlPum2.u_s);
connect(mode.y[1], con.mode);
connect(mode.y[1], isEna.u);
connect(T1Set.y, ref.T_in);
connect(T1SetVal.y, T1Set.u);
connect(con.port_b1, T1ConRet.port_a);
connect(T1ConRet.port_b, dp.port_b);
connect(ctlPum2.y, con.yPum);
connect(isEna.y, pum.y1);
connect(jun.port_3, loa.port_a);
connect(jun.port_2, res2.port_a);
connect(res2.port_b, loa1.port_a);
connect(loa1.port_b, del2.ports[1]);
connect(res2.port_b, resEnd2.port_a);
connect(resEnd2.port_b, del2.ports[2]);
connect(loa.port_b, del2.ports[3]);
connect(loa1.port_a, dp2.port_a);
connect(loa1.port_b, dp2.port_b);
connect(isEna.y, ctlPum2.trigger);
connect(addPar.y, T1Set.index);
connect(mode.y[1], addPar.u);
end PartialDecoupling;
Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.BaseClasses.PartialInjectionTwoWay
Partial model of primary variable circuit serving an inversion circuit with two-way valve
Information
This is a partial model of a variable flow primary loop with a variable speed pump serving an injection circuit with a two-way valve. The primary pump model takes a normalized speed as input. The speed is modulated to track a constant pressure differential at the boundaries of the injection unit. That model is used to construct some example models within Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.
Extends from PartialActivePrimary (Partial model of active primary network).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| Control | typ | Buildings.Fluid.HydronicConf... | Load type |
| Integer | nTer | 2 | Number of terminal units |
| Real | kSizPum | 1.0 | Pump oversizing coefficient [1] |
| Pressure | p_min | 200000 | Circuit minimum pressure [Pa] |
| Temperature | TLiqEnt_nominal | 55 + 273.15 | Liquid entering temperature at design conditions [K] |
| Temperature | TLiqLvg_nominal | TLiqEnt_nominal + (if typ ==... | Liquid leaving temperature at design conditions [K] |
| Temperature | TLiqEntChg_nominal | 60 + 273.15 | Liquid entering temperature in change-over mode [K] |
| Temperature | TLiqSup_nominal | 60 + 273.15 | Liquid primary supply temperature at design conditions [K] |
| Temperature | TLiqSupChg_nominal | TLiqEntChg_nominal | Liquid primary supply temperature in change-over mode [K] |
| InjectionTwoWay | con | con(use_lumFloRes=true, typC... | Hydronic connection |
| Nominal condition | |||
| MassFlowRate | mTer_flow_nominal | 1 | Terminal unit mass flow rate at design conditions [kg/s] |
| MassFlowRate | m1_flow_nominal | m2_flow_nominal*(TLiqEnt_nom... | Mass flow rate in primary branch at design conditions [kg/s] |
| MassFlowRate | m2_flow_nominal | nTer*mTer_flow_nominal | Mass flow rate in consumer circuit at design conditions [kg/s] |
| PressureDifference | dpTer_nominal | 3E4 | Terminal unit pressure drop at design conditions [Pa] |
| PressureDifference | dpPip_nominal | 0.5E4 | Pipe section pressure drop at design conditions [Pa] |
| PressureDifference | dpPum_nominal | (dpPip_nominal + dp1Set)*kSi... | Pump head at design conditions [Pa] |
| MassFlowRate | mPum_flow_nominal | m1_flow_nominal/0.9 | Primary pump mass flow rate at design conditions [kg/s] |
| PressureDifference | dp2_nominal | Consumer circuit pressure differential at design conditions [Pa] | |
| Configuration | |||
| Boolean | is_bal | false | Set to true for balanced primary branch |
| Controls | |||
| PressureDifference | dp1Set | 1e4 | Pressure differential set point [Pa] |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
Modelica definition
partial model PartialInjectionTwoWay
"Partial model of primary variable circuit serving an inversion circuit with two-way valve"
extends PartialActivePrimary(
TLiqEnt_nominal=55+273.15,
TLiqSup_nominal=60+273.15,
dpPum_nominal=(dpPip_nominal + dp1Set) * kSizPum,
m1_flow_nominal=m2_flow_nominal * (TLiqEnt_nominal - TLiqLvg_nominal) /
(TLiqSup_nominal - TLiqLvg_nominal),
mPum_flow_nominal=m1_flow_nominal / 0.9,
del1(nPorts=3));
parameter Boolean is_bal=false
"Set to true for balanced primary branch";
parameter Modelica.Units.SI.PressureDifference dp1Set(displayUnit="Pa")=1e4
"Pressure differential set point";
parameter Modelica.Units.SI.PressureDifference dp2_nominal(displayUnit="Pa")
"Consumer circuit pressure differential at design conditions";
Sensors.RelativePressure dp1(
redeclare final package Medium = MediumLiq)
"Differential pressure";
Buildings.Controls.OBC.CDL.Integers.Sources.TimeTable mode(
table=[0,0; 6,0; 6,1; 22,1; 22,0; 24,0],
timeScale=3600,
period=86400) "Operating mode (time schedule)";
replaceable InjectionTwoWay con(
use_lumFloRes=true,
typCtl=typ,
typPum=Buildings.Fluid.HydronicConfigurations.Types.Pump.NoVariableInput,
redeclare final package Medium = MediumLiq,
final energyDynamics=energyDynamics,
final m1_flow_nominal=m1_flow_nominal,
final m2_flow_nominal=m2_flow_nominal,
final dp1_nominal=dp1Set,
final dp2_nominal=dp2_nominal,
final dpBal1_nominal=if is_bal then dp1Set - con.dpValve_nominal else 0,
pum(addPowerToMedium=false))
"Hydronic connection";
FixedResistances.PressureDrop resEnd1(
redeclare final package Medium = MediumLiq,
final m_flow_nominal=0.1*mPum_flow_nominal,
final dp_nominal=dp1Set)
"Pipe pressure drop";
Buildings.Controls.OBC.CDL.Reals.PIDWithReset ctlPum1(
k=0.1,
Ti=60,
r=1e4,
y_reset=0) "Primary pump controller";
Buildings.Controls.OBC.CDL.Reals.Sources.Constant dp1SetVal(final k=
dp1Set) "Pressure differential set point";
Delays.DelayFirstOrder del2(
redeclare final package Medium = MediumLiq,
final energyDynamics=energyDynamics,
final m_flow_nominal=m2_flow_nominal,
nPorts=1) "Fluid transport delay";
Buildings.Controls.OBC.CDL.Integers.GreaterThreshold isEna(final t=Controls.OperatingModes.disabled)
"Returns true if enabled";
equation
connect(con.port_b1, dp1.port_b);
connect(con.port_a1, dp1.port_a);
connect(dp1SetVal.y, ctlPum1.u_s);
connect(dp1.p_rel, ctlPum1.u_m);
connect(mode.y[1], con.mode);
connect(del2.ports[1], con.port_a2);
connect(res1.port_b, dp1.port_a);
connect(res1.port_b, resEnd1.port_a);
connect(dp1.port_b, del1.ports[2]);
connect(resEnd1.port_b, del1.ports[3]);
connect(ctlPum1.y, pum.y);
connect(isEna.y, pum.y1);
connect(mode.y[1], isEna.u);
connect(isEna.y, ctlPum1.trigger);
end PartialInjectionTwoWay;
Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.BaseClasses.PartialLoadValveControl
Model of a load on hydronic circuit with flow rate modulation by control valve
Information
This is a partial model of a thermal load on a hydronic circuit that is composed of Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.BaseClasses.Load and a replaceable configuration component derived from Buildings.Fluid.HydronicConfigurations.Interfaces.PartialHydronicConfiguration that is used to modulate the flow rate through the load component.
Extends from Buildings.Fluid.Interfaces.PartialTwoPortInterface (Partial model transporting fluid between two ports without storing mass or energy).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| replaceable package MediumAir | Buildings.Media.Air | Medium model for air | |
| replaceable package MediumLiq | Buildings.Media.Water | Medium model for liquid (CHW or HHW) | |
| Control | typ | Load type | |
| MassFlowRate | mLiq_flow_nominal | 1 | Liquid mass flow rate at design conditions [kg/s] |
| PressureDifference | dpTer_nominal | 3E4 | Liquid pressure drop across terminal unit at design conditions [Pa] |
| MassFlowRate | mAir_flow_nominal | abs(Q_flow_nominal)/10/1015 | Air mass flow rate at design conditions [kg/s] |
| Temperature | TAirEnt_nominal | if typ == Buildings.Fluid.Hy... | Air entering temperature at design conditions [K] |
| Temperature | TAirEntChg_nominal | 20 + 273.15 | Air entering temperature in change-over mode [K] |
| MassFraction | phiAirEnt_nominal | 0.5 | Air entering relative humidity at design conditions [1] |
| Temperature | TLiqEnt_nominal | if typ == Buildings.Fluid.Hy... | Liquid entering temperature at design conditions [K] |
| Temperature | TLiqLvg_nominal | TLiqEnt_nominal + (if typ ==... | Liquid leaving temperature at design conditions [K] |
| Temperature | TLiqEntChg_nominal | 60 + 273.15 | Liquid entering temperature in change-over mode [K] |
| SimpleController | controllerType | Buildings.Controls.OBC.CDL.T... | Type of controller |
| PartialHydronicConfiguration | con | redeclare HydronicConfigurat... | Diversion connection |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | mLiq_flow_nominal | Nominal mass flow rate [kg/s] |
| Control valve | |||
| PressureDifference | dpValve_nominal | dpTer_nominal | Control valve pressure drop at design conditions [Pa] |
| Balancing valves | |||
| PressureDifference | dpBal1_nominal | 0 | Balancing valve pressure drop at design conditions [Pa] |
| Control gains | |||
| Real | k | 0.1 | Gain of controller |
| Real | Ti | 60 | Time constant of integrator block [s] |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Advanced | |||
| MassFlowRate | m_flow_small | 1E-4*abs(m_flow_nominal) | Small mass flow rate for regularization of zero flow [kg/s] |
| Diagnostics | |||
| Boolean | show_T | false | = true, if actual temperature at port is computed |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Type of energy balance: dynamic (3 initialization options) or steady state |
Connectors
| Type | Name | Description |
|---|---|---|
| replaceable package Medium | Medium in the component | |
| FluidPort_a | port_a | Fluid connector a (positive design flow direction is from port_a to port_b) |
| FluidPort_b | port_b | Fluid connector b (positive design flow direction is from port_a to port_b) |
| replaceable package MediumAir | Medium model for air | |
| replaceable package MediumLiq | Medium model for liquid (CHW or HHW) | |
| input RealInput | u | Load modulating signal |
| input IntegerInput | mode | Operating mode |
| output RealOutput | yLoa_actual | Actual load fraction met [1] |
| output RealOutput | Q_flow | Total heat flow rate transferred to the load [W] |
| output RealOutput | yVal_actual | Valve position feedback [1] |
Modelica definition
model PartialLoadValveControl
"Model of a load on hydronic circuit with flow rate modulation by control valve"
extends Buildings.Fluid.Interfaces.PartialTwoPortInterface(
redeclare final package Medium=MediumLiq,
final m_flow_nominal=mLiq_flow_nominal);
replaceable package MediumAir = Buildings.Media.Air
"Medium model for air";
replaceable package MediumLiq = Buildings.Media.Water
"Medium model for liquid (CHW or HHW)";
parameter Buildings.Fluid.HydronicConfigurations.Types.Control typ
"Load type";
parameter Modelica.Units.SI.MassFlowRate mLiq_flow_nominal = 1
"Liquid mass flow rate at design conditions";
parameter Modelica.Units.SI.PressureDifference dpTer_nominal(
displayUnit="Pa")=3E4
"Liquid pressure drop across terminal unit at design conditions";
parameter Modelica.Units.SI.PressureDifference dpValve_nominal(
displayUnit="Pa")=dpTer_nominal
"Control valve pressure drop at design conditions";
parameter Modelica.Units.SI.PressureDifference dpBal1_nominal(
displayUnit="Pa")=0
"Balancing valve pressure drop at design conditions";
parameter Modelica.Units.SI.MassFlowRate mAir_flow_nominal=
abs(Q_flow_nominal) / 10 / 1015
"Air mass flow rate at design conditions";
parameter Modelica.Units.SI.Temperature TAirEnt_nominal=
if typ==Buildings.Fluid.HydronicConfigurations.Types.Control.Heating
then 20+273.15 else 26+273.15
"Air entering temperature at design conditions";
parameter Modelica.Units.SI.Temperature TAirEntChg_nominal=20+273.15
"Air entering temperature in change-over mode";
parameter Modelica.Units.SI.MassFraction phiAirEnt_nominal = 0.5
"Air entering relative humidity at design conditions";
parameter Modelica.Units.SI.Temperature TLiqEnt_nominal=
if typ==Buildings.Fluid.HydronicConfigurations.Types.Control.Heating
then 60+273.15 else 7+273.15
"Liquid entering temperature at design conditions";
parameter Modelica.Units.SI.Temperature TLiqLvg_nominal=TLiqEnt_nominal+(
if typ==Buildings.Fluid.HydronicConfigurations.Types.Control.Heating
then -10 else +5)
"Liquid leaving temperature at design conditions";
parameter Modelica.Units.SI.Temperature TLiqEntChg_nominal=
60+273.15
"Liquid entering temperature in change-over mode";
final parameter Modelica.Units.SI.HeatFlowRate Q_flow_nominal=
(MediumLiq.specificEnthalpy_pTX(MediumLiq.p_default, TLiqEnt_nominal, X=MediumLiq.X_default)-
MediumLiq.specificEnthalpy_pTX(MediumLiq.p_default, TLiqLvg_nominal, X=MediumLiq.X_default))*
mLiq_flow_nominal
"Transmitted heat flow rate at design conditions";
parameter Buildings.Controls.OBC.CDL.Types.SimpleController controllerType=
Buildings.Controls.OBC.CDL.Types.SimpleController.PI
"Type of controller";
parameter Real k(
min=100*Modelica.Constants.eps)=0.1
"Gain of controller";
parameter Real Ti(unit="s")=60
"Time constant of integrator block";
parameter Modelica.Fluid.Types.Dynamics energyDynamics=
Modelica.Fluid.Types.Dynamics.SteadyState
"Type of energy balance: dynamic (3 initialization options) or steady state";
Buildings.Controls.OBC.CDL.Interfaces.RealInput u
"Load modulating signal";
Buildings.Controls.OBC.CDL.Interfaces.IntegerInput mode "Operating mode";
Buildings.Fluid.HydronicConfigurations.ActiveNetworks.Examples.BaseClasses.Load
loa(
redeclare final package MediumAir = MediumAir,
redeclare final package MediumLiq = MediumLiq,
final typ=typ,
final mLiq_flow_nominal=mLiq_flow_nominal,
final dpLiq_nominal=0,
final mAir_flow_nominal=mAir_flow_nominal,
final TAirEnt_nominal=TAirEnt_nominal,
final phiAirEnt_nominal=phiAirEnt_nominal,
final TLiqEnt_nominal=TLiqEnt_nominal,
final TLiqLvg_nominal=TLiqLvg_nominal,
final TAirEntChg_nominal=TAirEntChg_nominal,
final TLiqEntChg_nominal=TLiqEntChg_nominal,
final controllerType=controllerType,
final k=k,
final Ti=Ti,
final energyDynamics=energyDynamics) "Load";
replaceable HydronicConfigurations.Interfaces.PartialHydronicConfiguration con
constrainedby HydronicConfigurations.Interfaces.PartialHydronicConfiguration
(
redeclare final package Medium=MediumLiq,
final use_siz=false,
final dp2_nominal=dpTer_nominal,
final m2_flow_nominal=m_flow_nominal,
final dpValve_nominal=dpValve_nominal,
final dpBal1_nominal=dpBal1_nominal,
use_lumFloRes=true,
final energyDynamics=energyDynamics)
"Diversion connection";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput yLoa_actual(final unit="1")
"Actual load fraction met";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput Q_flow(final unit="W")
"Total heat flow rate transferred to the load";
Buildings.Controls.OBC.CDL.Interfaces.RealOutput yVal_actual(final unit="1")
"Valve position feedback";
equation
connect(port_a, con.port_a1);
connect(con.port_b1, port_b);
connect(con.port_b2, loa.port_a);
connect(con.port_a2, loa.port_b);
connect(loa.yVal, con.yVal);
connect(u, loa.u);
connect(loa.yLoa_actual, yLoa_actual);
connect(loa.Q_flow, Q_flow);
connect(con.yVal_actual, yVal_actual);
connect(mode, loa.mode);
connect(mode, con.mode);
end PartialLoadValveControl;