Buildings.Fluid.Storage.Validation
Collection of models that validate the storage models
Information
This package contains models that validate the storage models. These model outputs are stored as reference data to allow continuous validation whenever models in the library change.
Extends from Modelica.Icons.ExamplesPackage (Icon for packages containing runnable examples).
Package Content
| Name | Description |
|---|---|
 HeatExchangerDynamics
|
Test model for stratified tank with steady-state and dynamic heat exchanger balance |
| HeatExchangerLocation
|
Test model for heat exchanger with hHex_a and hHex_b interchanged |
| StratifiedLoadingUnloading
|
Test model for stratified tank |
| StratifiedNonUniformInitial
|
Test model for stratified tank with non-uniform initial temperature |
Buildings.Fluid.Storage.Validation.HeatExchangerDynamics
Test model for stratified tank with steady-state and dynamic heat exchanger balance
Information
This validation model compares two tank models. The only difference between the two tank models is that one uses a dynamic energy balance, whereas the other uses a steady-state energy balance for the heat exchanger. The mass flow rate through the heat exchanger is varied from zero to the design flow rate and back to zero to test the model under conditions in which no water flows through the heat exchanger.Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| HeatFlowRate | QHex_flow_nominal | 2000 | Design heat flow rate of heat exchanger [W] |
| MassFlowRate | m_flow_nominal | QHex_flow_nominal/4200/4 | [kg/s] |
Modelica definition
model HeatExchangerDynamics
"Test model for stratified tank with steady-state and dynamic heat exchanger balance"
extends Modelica.Icons.Example;
package Medium = Buildings.Media.Water "Medium model";
constant Integer nSeg = 7 "Number of segments in tank";
parameter Modelica.Units.SI.HeatFlowRate QHex_flow_nominal=2000
"Design heat flow rate of heat exchanger";
parameter Modelica.Units.SI.MassFlowRate m_flow_nominal=QHex_flow_nominal/
4200/4;
Buildings.Fluid.Sources.Boundary_pT watInTan(
redeclare package Medium = Medium,
use_T_in=false,
nPorts=2,
T=273.15 + 30,
p(displayUnit="Pa")) "Boundary condition for water in the tank";
Buildings.Fluid.Sources.MassFlowSource_T mHex_flow1(
redeclare package Medium = Medium,
use_m_flow_in=true,
T=273.15 + 60,
nPorts=1) "Mass flow rate through the heat exchanger";
model Tank = StratifiedEnhancedInternalHex (
redeclare package Medium = Medium,
redeclare package MediumHex = Medium,
hTan=2,
dIns=0.3,
VTan=0.3,
nSeg=nSeg,
hHex_a=1,
hHex_b=0.2,
Q_flow_nominal=QHex_flow_nominal,
TTan_nominal=313.15,
THex_nominal=333.15,
mHex_flow_nominal=m_flow_nominal,
show_T=true,
m_flow_nominal=m_flow_nominal,
energyDynamicsHex=Modelica.Fluid.Types.Dynamics.FixedInitial)
"Tank with dynamic heat exchanger balance";
Tank tanDyn "Tank with dynamic heat exchanger balance";
Tank tanSte(energyDynamicsHex=Modelica.Fluid.Types.Dynamics.SteadyState)
"Tank with steady-state heat exchanger balance";
Modelica.Blocks.Sources.Trapezoid mHex_flow_in(
period=7200,
amplitude=m_flow_nominal,
offset=0,
rising=1800,
width=1800,
falling=1800,
startTime=900) "Control signal for mass flow rate in heat exchanger";
Buildings.Fluid.Sources.Boundary_pT sin(
redeclare package Medium = Medium,
T=273.15 + 30,
p(displayUnit="Pa"),
nPorts=2) "Sink boundary condition";
Buildings.Fluid.Sources.MassFlowSource_T mHex_flow2(
redeclare package Medium = Medium,
use_m_flow_in=true,
T=273.15 + 60,
nPorts=1) "Mass flow rate through the heat exchanger";
Buildings.Fluid.Sensors.TemperatureTwoPort senTanDyn(
redeclare package Medium = Medium,
allowFlowReversal=false,
m_flow_nominal=m_flow_nominal,
tau=0) "Temperature sensor at tank outlet";
Buildings.Fluid.Sensors.TemperatureTwoPort senTanSte(
redeclare package Medium = Medium,
allowFlowReversal=false,
m_flow_nominal=m_flow_nominal,
tau=0) "Temperature sensor at tank outlet";
Buildings.Fluid.Sources.MassFlowSource_T mWatTanDyn_flow(
redeclare package Medium = Medium,
nPorts=1) "Mass flow rate through the tank";
Buildings.Fluid.Sources.MassFlowSource_T mWatTanSte_flow(
redeclare package Medium = Medium,
nPorts=1) "Mass flow rate through the tank";
equation
connect(mHex_flow_in.y, mHex_flow1.m_flow_in);
connect(mHex_flow2.m_flow_in, mHex_flow_in.y);
connect(mHex_flow2.ports[1], tanSte.portHex_a);
connect(watInTan.ports[1], tanSte.port_a);
connect(mHex_flow1.ports[1], tanDyn.portHex_a);
connect(watInTan.ports[2], tanDyn.port_a);
connect(senTanDyn.port_a, tanDyn.portHex_b);
connect(senTanSte.port_a, tanSte.portHex_b);
connect(senTanDyn.port_b, sin.ports[1]);
connect(senTanSte.port_b, sin.ports[2]);
connect(mWatTanDyn_flow.ports[1], tanDyn.port_b);
connect(mWatTanSte_flow.ports[1], tanSte.port_b);
end HeatExchangerDynamics;
Buildings.Fluid.Storage.Validation.HeatExchangerLocation
Test model for heat exchanger with hHex_a and hHex_b interchanged
Information
This validation model compares two tank models. The only difference between
the two tank models is that tan_aTop has the hot water inlet
for the heat exchanger above its outlet, whereas tan_bTop
has the hot water inlet below its outlet. In both models, the heat exchanger
extends from element 9 to element 11.
Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| HeatFlowRate | QHex_flow_nominal | 6000 | Design heat flow rate of heat exchanger [W] |
| MassFlowRate | m_flow_nominal | QHex_flow_nominal/4200/4 | [kg/s] |
Modelica definition
model HeatExchangerLocation
"Test model for heat exchanger with hHex_a and hHex_b interchanged"
extends Modelica.Icons.Example;
package Medium = Buildings.Media.Water "Medium model";
parameter Modelica.Units.SI.HeatFlowRate QHex_flow_nominal=6000
"Design heat flow rate of heat exchanger";
parameter Modelica.Units.SI.MassFlowRate m_flow_nominal=QHex_flow_nominal/
4200/4;
Buildings.Fluid.Sources.Boundary_pT watInTan(
redeclare package Medium = Medium,
use_T_in=false,
nPorts=2,
T=273.15 + 30,
p(displayUnit="Pa")) "Boundary condition for water in the tank";
Buildings.Fluid.Sources.MassFlowSource_T mHex_flow1(
redeclare package Medium = Medium,
nPorts=2,
m_flow=m_flow_nominal/100,
T=273.15 + 60) "Mass flow rate through the heat exchanger";
model Tank = StratifiedEnhancedInternalHex (
redeclare final package Medium = Medium,
redeclare final package MediumHex = Medium,
final VTan=0.3,
final kIns=0.034,
final dIns=0.04,
final hTan=1.2,
final m_flow_nominal=m_flow_nominal,
final mHex_flow_nominal=m_flow_nominal,
final nSeg=12,
final hexSegMult=2,
final Q_flow_nominal=QHex_flow_nominal,
final TTan_nominal=293.15,
final THex_nominal=273.15+60,
final computeFlowResistance=false,
final energyDynamicsHex=Modelica.Fluid.Types.Dynamics.FixedInitial)
"Tank";
Tank tan_aTop(
hHex_a=0.3,
hHex_b=0.1)
"Tank with heat exchanger inlet above its outlet";
Tank tan_bTop(
hHex_a=0.1,
hHex_b=0.3)
"Tank with heat exchanger outlet above its inlet";
Buildings.Fluid.Sources.Boundary_pT sin(
redeclare package Medium = Medium,
T=273.15 + 30,
p(displayUnit="Pa"),
nPorts=2) "Sink boundary condition";
Buildings.Fluid.Sensors.TemperatureTwoPort senTan_aTop(
redeclare package Medium = Medium,
m_flow_nominal=m_flow_nominal,
tau=0) "Temperature sensor at tank outlet";
Buildings.Fluid.Sensors.TemperatureTwoPort senTan_bTop(
redeclare package Medium = Medium,
m_flow_nominal=m_flow_nominal,
tau=0) "Temperature sensor at tank outlet";
Buildings.Fluid.Sources.MassFlowSource_T mWatTanSte_flow(
redeclare package Medium = Medium,
nPorts=1) "Mass flow rate through the tank";
Buildings.Fluid.Sources.MassFlowSource_T mWatTanDyn_flow(
redeclare package Medium = Medium,
nPorts=1) "Mass flow rate through the tank";
equation
connect(mHex_flow1.ports[1], tan_aTop.portHex_a);
connect(senTan_aTop.port_a, tan_aTop.portHex_b);
connect(senTan_aTop.port_b, sin.ports[1]);
connect(senTan_bTop.port_b, sin.ports[2]);
connect(senTan_bTop.port_a, tan_bTop.portHex_b);
connect(tan_bTop.portHex_a, mHex_flow1.ports[2]);
connect(tan_aTop.port_a, watInTan.ports[1]);
connect(tan_bTop.port_a, watInTan.ports[2]);
connect(mWatTanDyn_flow.ports[1], tan_aTop.port_b);
connect(tan_bTop.port_b, mWatTanSte_flow.ports[1]);
end HeatExchangerLocation;
Buildings.Fluid.Storage.Validation.StratifiedLoadingUnloading
Test model for stratified tank
Information
This test model compares two tank models. The only difference between the two tank models is that one uses the third order upwind discretization scheme that reduces numerical diffusion that is induced when connecting volumes in series.Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| MassFlowRate | m_flow_nominal | 1*1000/3600/4 | [kg/s] |
Modelica definition
model StratifiedLoadingUnloading "Test model for stratified tank"
extends Modelica.Icons.Example;
package Medium = Buildings.Media.Water "Medium model";
constant Integer nSeg = 7 "Number of segments in tank";
parameter Modelica.Units.SI.MassFlowRate m_flow_nominal=1*1000/3600/4;
Buildings.Fluid.Sources.Boundary_pT sou_1(
p=300000 + 5000,
T=273.15 + 40,
redeclare package Medium = Medium,
use_T_in=false,
nPorts=2);
Buildings.Fluid.Sources.MassFlowSource_T sin_1(
redeclare package Medium = Medium,
T=273.15 + 20,
m_flow=-0.028,
use_m_flow_in=true,
nPorts=1);
Buildings.Fluid.Storage.StratifiedEnhanced tanEnh(
redeclare package Medium = Medium,
hTan=3,
dIns=0.3,
VTan=0.1,
nSeg=nSeg,
show_T=true,
m_flow_nominal=m_flow_nominal) "Tank";
Buildings.Fluid.Sources.MassFlowSource_T sin_2(
redeclare package Medium = Medium,
T=273.15 + 20,
m_flow=-0.028,
use_m_flow_in=true,
nPorts=1);
Buildings.Fluid.Storage.Stratified tan(
redeclare package Medium = Medium,
hTan=3,
dIns=0.3,
VTan=0.1,
nSeg=nSeg,
show_T=true,
m_flow_nominal=m_flow_nominal) "Tank";
Modelica.Blocks.Sources.Pulse pulse(
amplitude=2*m_flow_nominal,
offset=-m_flow_nominal,
period=7200);
Buildings.Fluid.Sensors.EnthalpyFlowRate HIn_flow(redeclare package Medium =
Medium, m_flow_nominal=m_flow_nominal) "Enthalpy flow rate";
Buildings.Fluid.Sensors.EnthalpyFlowRate HOut_flow(redeclare package Medium =
Medium, m_flow_nominal=m_flow_nominal) "Enthalpy flow rate";
Buildings.Fluid.Sensors.EnthalpyFlowRate HInEnh_flow(redeclare package Medium =
Medium, m_flow_nominal=m_flow_nominal) "Enthalpy flow rate";
Buildings.Fluid.Sensors.EnthalpyFlowRate HOutEnh_flow(redeclare package
Medium = Medium, m_flow_nominal=m_flow_nominal) "Enthalpy flow rate";
Modelica.Blocks.Math.Add add(k2=-1);
Modelica.Blocks.Continuous.Integrator dHTanEnh
"Difference in enthalpy (should be zero at steady-state)";
Modelica.Blocks.Math.Add add1(
k2=-1);
Modelica.Blocks.Continuous.Integrator dHTan
"Difference in enthalpy (should be zero at steady-state)";
equation
connect(sou_1.ports[1], HIn_flow.port_a);
connect(HIn_flow.port_b, tan.port_a);
connect(tan.port_b, HOut_flow.port_a);
connect(HOut_flow.port_b, sin_2.ports[1]);
connect(sou_1.ports[2], HInEnh_flow.port_a);
connect(HInEnh_flow.port_b, tanEnh.port_a);
connect(tanEnh.port_b, HOutEnh_flow.port_a);
connect(HOutEnh_flow.port_b, sin_1.ports[1]);
connect(HInEnh_flow.H_flow, add.u1);
connect(HOutEnh_flow.H_flow, add.u2);
connect(add.y, dHTanEnh.u);
connect(HIn_flow.H_flow, add1.u1);
connect(HOut_flow.H_flow, add1.u2);
connect(add1.y, dHTan.u);
connect(pulse.y, sin_1.m_flow_in);
connect(pulse.y, sin_2.m_flow_in);
end StratifiedLoadingUnloading;
Buildings.Fluid.Storage.Validation.StratifiedNonUniformInitial
Test model for stratified tank with non-uniform initial temperature
Information
This test model validates Buildings.Fluid.Storage.Stratified by specifying a non-uniform initial temperature.Extends from Modelica.Icons.Example (Icon for runnable examples).
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| MassFlowRate | m_flow_nominal | 1*1000/3600/4 | [kg/s] |
Modelica definition
model StratifiedNonUniformInitial
"Test model for stratified tank with non-uniform initial temperature"
extends Modelica.Icons.Example;
package Medium = Buildings.Media.Water "Medium model";
constant Integer nSeg = 7 "Number of segments in tank";
parameter Modelica.Units.SI.MassFlowRate m_flow_nominal=1*1000/3600/4;
Buildings.Fluid.Sources.Boundary_pT sou_1(
p=300000 + 5000,
T=273.15 + 40,
redeclare package Medium = Medium,
use_T_in=false,
nPorts=2);
Buildings.Fluid.Sources.MassFlowSource_T sin_1(
redeclare package Medium = Medium,
T=273.15 + 20,
m_flow=-m_flow_nominal,
nPorts=1)
"Mass flow source";
Buildings.Fluid.Storage.Stratified heaTan(
redeclare package Medium = Medium,
hTan=3,
dIns=0.3,
VTan=0.1,
nSeg=nSeg,
show_T=true,
m_flow_nominal=m_flow_nominal,
TFlu_start={313.15,312.15,311.15,310.15,309.15,308.15,307.15})
"Tank that will be heated up";
Buildings.Fluid.Sources.MassFlowSource_T sin_2(
redeclare package Medium = Medium,
T=273.15 + 20,
m_flow=m_flow_nominal,
nPorts=1)
"Mass flow source";
Buildings.Fluid.Storage.Stratified cooTan(
redeclare package Medium = Medium,
hTan=3,
dIns=0.3,
VTan=0.1,
nSeg=nSeg,
show_T=true,
m_flow_nominal=m_flow_nominal,
TFlu_start={313.15,312.15,311.15,310.15,309.15,308.15,307.15})
"Tank that will be cooled down";
Buildings.Fluid.Sensors.EnthalpyFlowRate HIn_flow(
redeclare package Medium = Medium,
m_flow_nominal=m_flow_nominal) "Enthalpy flow rate";
Buildings.Fluid.Sensors.EnthalpyFlowRate HOut_flow(
redeclare package Medium = Medium,
m_flow_nominal=m_flow_nominal) "Enthalpy flow rate";
Buildings.Fluid.Sensors.EnthalpyFlowRate HInEnh_flow(
redeclare package Medium = Medium,
m_flow_nominal=m_flow_nominal) "Enthalpy flow rate";
Buildings.Fluid.Sensors.EnthalpyFlowRate HOutEnh_flow(
redeclare package Medium = Medium,
m_flow_nominal=m_flow_nominal) "Enthalpy flow rate";
Modelica.Blocks.Math.Add add(k2=-1) "Adder for enthalpy difference";
Modelica.Blocks.Continuous.Integrator dHTanEnh
"Difference in enthalpy (should be zero at steady-state)";
Modelica.Blocks.Math.Add add1(k2=-1) "Adder for enthalpy difference";
Modelica.Blocks.Continuous.Integrator dHTan
"Difference in enthalpy (should be zero at steady-state)";
equation
connect(HIn_flow.port_b, cooTan.port_a);
connect(cooTan.port_b, HOut_flow.port_a);
connect(HOut_flow.port_b, sin_2.ports[1]);
connect(HOutEnh_flow.port_b, sin_1.ports[1]);
connect(HInEnh_flow.H_flow, add.u1);
connect(HOutEnh_flow.H_flow, add.u2);
connect(add.y, dHTanEnh.u);
connect(HIn_flow.H_flow, add1.u1);
connect(HOut_flow.H_flow, add1.u2);
connect(add1.y, dHTan.u);
connect(HInEnh_flow.port_b, heaTan.port_a);
connect(heaTan.port_b, HOutEnh_flow.port_a);
connect(sou_1.ports[1], HInEnh_flow.port_a);
connect(sou_1.ports[2], HIn_flow.port_a);
end StratifiedNonUniformInitial;
Buildings.Fluid.Storage.Validation.HeatExchangerDynamics.Tank
Tank with dynamic heat exchanger balance
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Volume | VTan | 0.3 | Tank volume [m3] |
| Length | hTan | 2 | Height of tank (without insulation) [m] |
| Length | dIns | 0.3 | Thickness of insulation [m] |
| ThermalConductivity | kIns | 0.04 | Specific heat conductivity of insulation [W/(m.K)] |
| Integer | nSeg | nSeg | Number of volume segments |
| Time | tau | 1 | Time constant for mixing [s] |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | m_flow_nominal | Nominal mass flow rate [kg/s] |
| Heat exchanger | |||
| replaceable package MediumHex | PartialMedium | Medium in the heat exchanger | |
| Height | hHex_a | 1 | Height of portHex_a of the heat exchanger, measured from tank bottom [m] |
| Height | hHex_b | 0.2 | Height of portHex_b of the heat exchanger, measured from tank bottom [m] |
| Integer | hexSegMult | 2 | Number of heat exchanger segments in each tank segment |
| Diameter | dExtHex | 0.025 | Exterior diameter of the heat exchanger pipe [m] |
| HeatFlowRate | Q_flow_nominal | QHex_flow_nominal | Heat transfer at nominal conditions [W] |
| Temperature | TTan_nominal | 313.15 | Temperature of fluid inside the tank at nominal heat transfer conditions [K] |
| Temperature | THex_nominal | 333.15 | Temperature of fluid inside the heat exchanger at nominal heat transfer conditions [K] |
| Real | r_nominal | 0.5 | Ratio between coil inside and outside convective heat transfer at nominal heat transfer conditions |
| MassFlowRate | mHex_flow_nominal | m_flow_nominal | Nominal mass flow rate through the heat exchanger [kg/s] |
| PressureDifference | dpHex_nominal | 2500 | Pressure drop across the heat exchanger at nominal conditions [Pa] |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Heat exchanger | |||
| Boolean | allowFlowReversalHex | true | = true to allow flow reversal in heat exchanger, false restricts to design direction (portHex_a -> portHex_b) |
| 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 | true | = true, if actual temperature at port is computed |
| Dynamics | |||
| Conservation equations | |||
| Dynamics | energyDynamics | Modelica.Fluid.Types.Dynamic... | Formulation of energy balance |
| Initialization | |||
| AbsolutePressure | p_start | Medium.p_default | Start value of pressure [Pa] |
| Temperature | T_start | Medium.T_default | Start value of temperature [K] |
| Temperature | TFlu_start[nSeg] | T_start*ones(nSeg) | Initial temperature of the tank segments, with TFlu_start[1] being the top segment [K] |
| MassFraction | X_start[Medium.nX] | Medium.X_default | Start value of mass fractions m_i/m [kg/kg] |
| ExtraProperty | C_start[Medium.nC] | fill(0, Medium.nC) | Start value of trace substances |
| Flow resistance heat exchanger | |||
| Boolean | computeFlowResistance | true | =true, compute flow resistance. Set to false to assume no friction |
| Boolean | from_dp | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Boolean | linearizeFlowResistance | false | = true, use linear relation between m_flow and dp for any flow rate |
| Real | deltaM | 0.1 | Fraction of nominal flow rate where flow transitions to laminar |
| Dynamics heat exchanger | |||
| Conservation equations | |||
| Dynamics | energyDynamicsHex | Modelica.Fluid.Types.Dynamic... | Formulation of energy balance for heat exchanger internal fluid mass |
| Dynamics | energyDynamicsHexSolid | energyDynamicsHex | Formulation of energy balance for heat exchanger solid mass |
| Length | lHex | rTan*abs(segHex_a - segHex_b... | Approximate length of the heat exchanger [m] |
| Area | ACroHex | (dExtHex^2 - (0.8*dExtHex)^2... | Cross sectional area of the heat exchanger [m2] |
| SpecificHeatCapacity | cHex | 490 | Specific heat capacity of the heat exchanger material [J/(kg.K)] |
| Density | dHex | 8000 | Density of the heat exchanger material [kg/m3] |
| HeatCapacity | CHex | ACroHex*lHex*dHex*cHex | Capacitance of the heat exchanger without the fluid [J/K] |
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) |
| output RealOutput | Ql_flow | Heat loss of tank (positive if heat flows from tank to ambient) |
| HeatPort_a | heaPorVol[nSeg] | Heat port that connects to the control volumes of the tank |
| HeatPort_a | heaPorSid | Heat port tank side (outside insulation) |
| HeatPort_a | heaPorTop | Heat port tank top (outside insulation) |
| HeatPort_a | heaPorBot | Heat port tank bottom (outside insulation). Leave unconnected for adiabatic condition |
| FluidPort_a | portHex_a | Heat exchanger inlet |
| FluidPort_b | portHex_b | Heat exchanger outlet |
| Heat exchanger | ||
| replaceable package MediumHex | Medium in the heat exchanger | |
Modelica definition
model Tank = StratifiedEnhancedInternalHex (
redeclare package Medium = Medium,
redeclare package MediumHex = Medium,
hTan=2,
dIns=0.3,
VTan=0.3,
nSeg=nSeg,
hHex_a=1,
hHex_b=0.2,
Q_flow_nominal=QHex_flow_nominal,
TTan_nominal=313.15,
THex_nominal=333.15,
mHex_flow_nominal=m_flow_nominal,
show_T=true,
m_flow_nominal=m_flow_nominal,
energyDynamicsHex=Modelica.Fluid.Types.Dynamics.FixedInitial)
"Tank with dynamic heat exchanger balance";
Buildings.Fluid.Storage.Validation.HeatExchangerLocation.Tank
Tank
Parameters
| Type | Name | Default | Description |
|---|---|---|---|
| replaceable package Medium | PartialMedium | Medium in the component | |
| Volume | VTan | 0.3 | Tank volume [m3] |
| Length | hTan | 1.2 | Height of tank (without insulation) [m] |
| Length | dIns | 0.04 | Thickness of insulation [m] |
| ThermalConductivity | kIns | 0.034 | Specific heat conductivity of insulation [W/(m.K)] |
| Integer | nSeg | 12 | Number of volume segments |
| Time | tau | 1 | Time constant for mixing [s] |
| Nominal condition | |||
| MassFlowRate | m_flow_nominal | m_flow_nominal | Nominal mass flow rate [kg/s] |
| Heat exchanger | |||
| replaceable package MediumHex | PartialMedium | Medium in the heat exchanger | |
| Height | hHex_a | Height of portHex_a of the heat exchanger, measured from tank bottom [m] | |
| Height | hHex_b | Height of portHex_b of the heat exchanger, measured from tank bottom [m] | |
| Integer | hexSegMult | 2 | Number of heat exchanger segments in each tank segment |
| Diameter | dExtHex | 0.025 | Exterior diameter of the heat exchanger pipe [m] |
| HeatFlowRate | Q_flow_nominal | QHex_flow_nominal | Heat transfer at nominal conditions [W] |
| Temperature | TTan_nominal | 293.15 | Temperature of fluid inside the tank at nominal heat transfer conditions [K] |
| Temperature | THex_nominal | 273.15 + 60 | Temperature of fluid inside the heat exchanger at nominal heat transfer conditions [K] |
| Real | r_nominal | 0.5 | Ratio between coil inside and outside convective heat transfer at nominal heat transfer conditions |
| MassFlowRate | mHex_flow_nominal | m_flow_nominal | Nominal mass flow rate through the heat exchanger [kg/s] |
| PressureDifference | dpHex_nominal | 2500 | Pressure drop across the heat exchanger at nominal conditions [Pa] |
| Assumptions | |||
| Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
| Heat exchanger | |||
| Boolean | allowFlowReversalHex | true | = true to allow flow reversal in heat exchanger, false restricts to design direction (portHex_a -> portHex_b) |
| 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... | Formulation of energy balance |
| Initialization | |||
| AbsolutePressure | p_start | Medium.p_default | Start value of pressure [Pa] |
| Temperature | T_start | Medium.T_default | Start value of temperature [K] |
| Temperature | TFlu_start[nSeg] | T_start*ones(nSeg) | Initial temperature of the tank segments, with TFlu_start[1] being the top segment [K] |
| MassFraction | X_start[Medium.nX] | Medium.X_default | Start value of mass fractions m_i/m [kg/kg] |
| ExtraProperty | C_start[Medium.nC] | fill(0, Medium.nC) | Start value of trace substances |
| Flow resistance heat exchanger | |||
| Boolean | computeFlowResistance | false | =true, compute flow resistance. Set to false to assume no friction |
| Boolean | from_dp | false | = true, use m_flow = f(dp) else dp = f(m_flow) |
| Boolean | linearizeFlowResistance | false | = true, use linear relation between m_flow and dp for any flow rate |
| Real | deltaM | 0.1 | Fraction of nominal flow rate where flow transitions to laminar |
| Dynamics heat exchanger | |||
| Conservation equations | |||
| Dynamics | energyDynamicsHex | Modelica.Fluid.Types.Dynamic... | Formulation of energy balance for heat exchanger internal fluid mass |
| Dynamics | energyDynamicsHexSolid | energyDynamicsHex | Formulation of energy balance for heat exchanger solid mass |
| Length | lHex | rTan*abs(segHex_a - segHex_b... | Approximate length of the heat exchanger [m] |
| Area | ACroHex | (dExtHex^2 - (0.8*dExtHex)^2... | Cross sectional area of the heat exchanger [m2] |
| SpecificHeatCapacity | cHex | 490 | Specific heat capacity of the heat exchanger material [J/(kg.K)] |
| Density | dHex | 8000 | Density of the heat exchanger material [kg/m3] |
| HeatCapacity | CHex | ACroHex*lHex*dHex*cHex | Capacitance of the heat exchanger without the fluid [J/K] |
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) |
| output RealOutput | Ql_flow | Heat loss of tank (positive if heat flows from tank to ambient) |
| HeatPort_a | heaPorVol[nSeg] | Heat port that connects to the control volumes of the tank |
| HeatPort_a | heaPorSid | Heat port tank side (outside insulation) |
| HeatPort_a | heaPorTop | Heat port tank top (outside insulation) |
| HeatPort_a | heaPorBot | Heat port tank bottom (outside insulation). Leave unconnected for adiabatic condition |
| FluidPort_a | portHex_a | Heat exchanger inlet |
| FluidPort_b | portHex_b | Heat exchanger outlet |
| Heat exchanger | ||
| replaceable package MediumHex | Medium in the heat exchanger | |
Modelica definition
model Tank = StratifiedEnhancedInternalHex (
redeclare final package Medium = Medium,
redeclare final package MediumHex = Medium,
final VTan=0.3,
final kIns=0.034,
final dIns=0.04,
final hTan=1.2,
final m_flow_nominal=m_flow_nominal,
final mHex_flow_nominal=m_flow_nominal,
final nSeg=12,
final hexSegMult=2,
final Q_flow_nominal=QHex_flow_nominal,
final TTan_nominal=293.15,
final THex_nominal=273.15+60,
final computeFlowResistance=false,
final energyDynamicsHex=Modelica.Fluid.Types.Dynamics.FixedInitial)
"Tank";