Buildings.Fluid.Sources
Package with boundary condition models
Information
Package Sources contains generic sources for fluid connectors to define fixed or prescribed ambient conditions.
Extends from Modelica.Icons.SourcesPackage (Icon for packages containing sources).
Package Content
Name | Description |
---|---|
Boundary_pT | Boundary with prescribed pressure, temperature, composition and trace substances |
Boundary_ph | Boundary with prescribed pressure, specific enthalpy, composition and trace substances |
MassFlowSource_T | Ideal flow source that produces a prescribed mass flow with prescribed temperature, composition and trace substances |
MassFlowSource_WeatherData | Ideal flow source that produces a prescribed mass flow with prescribed trace substances, outside specific enthalpy and mass fraction |
MassFlowSource_h | Ideal flow source that produces a prescribed mass flow with prescribed specific enthalpy, composition and trace substances |
Outside | Boundary that takes weather data, and optionally trace substances, as an input |
Outside_Cp | Boundary that takes weather data, and optionally the wind pressure coefficient and trace substances, as an input |
Outside_CpLowRise | Boundary that takes weather data as an input and computes wind pressure for low-rise buildings |
PropertySource_T | Model for overriding fluid properties that flow through the component, using temperature input |
PropertySource_h | Model for overriding fluid properties that flow through the component, using specific enthalpy input |
TraceSubstancesFlowSource | Source with mass flow that does not take part in medium mass balance (such as CO2) |
Examples | Collection of models that illustrate model use and test models |
Validation | Collection of validation models |
BaseClasses | Package with base classes for Buildings.Fluid.Sources |
Buildings.Fluid.Sources.Boundary_pT
Boundary with prescribed pressure, temperature, composition and trace substances
Information
Defines prescribed values for boundary conditions:
- Prescribed boundary pressure.
- Prescribed boundary temperature.
- Boundary composition (only for multi-substance or trace-substance flow).
Typical use and important parameters
If use_p_in
is false (default option),
the p
parameter is used as boundary pressure,
and the p_in
input connector is disabled;
if use_p_in
is true, then the p
parameter is ignored, and the value provided by the
input connector is used instead.
The same applies to the temperature T, composition Xi or X and trace substances C.
Options
Instead of using Xi_in
(the independent composition fractions),
the advanced tab provides an option for setting all
composition fractions using X_in
.
use_X_in
and use_Xi_in
cannot be used
at the same time.
Parameter verifyInputs
can be set to true
to enable a check that verifies the validity of the used temperatures
and pressures.
This removes the corresponding overhead from the model, which is
a substantial part of the overhead of this model.
See #882
for more information.
Note, that boundary temperature, mass fractions and trace substances have only an effect if the mass flow is from the boundary into the port. If mass is flowing from the port into the boundary, the boundary definitions, with exception of boundary pressure, do not have an effect.
Extends from Buildings.Fluid.Sources.BaseClasses.PartialSource_Xi_C (Partial component source with parameter definitions for Xi and C).
Parameters
Type | Name | Default | Description |
---|---|---|---|
replaceable package Medium | PartialMedium | Medium in the component | |
Conditional inputs | |||
Boolean | use_Xi_in | false | Get the composition (independent fractions) from the input connector |
Boolean | use_C_in | false | Get the trace substances from the input connector |
Boolean | use_p_in | false | Get the pressure from the input connector |
Boolean | use_T_in | false | Get the temperature from the input connector |
Fixed inputs | |||
MassFraction | X[Medium.nX] | Medium.X_default | Fixed value of composition [kg/kg] |
ExtraProperty | C[Medium.nC] | fill(0, Medium.nC) | Fixed values of trace substances |
AbsolutePressure | p | Medium.p_default | Fixed value of pressure [Pa] |
Temperature | T | Medium.T_default | Fixed value of temperature [K] |
Advanced | |||
Boolean | verifyInputs | false | Set to true to stop the simulation with an error if the medium temperature is outside its allowable range |
Boolean | use_X_in | false | Get the composition (all fractions) from the input connector |
Connectors
Type | Name | Description |
---|---|---|
FluidPorts_b | ports[nPorts] | Fluid ports |
input RealInput | X_in[Medium.nX] | Prescribed boundary composition [kg/kg] |
input RealInput | Xi_in[Medium.nXi] | Prescribed boundary composition [kg/kg] |
input RealInput | C_in[Medium.nC] | Prescribed boundary trace substances |
input RealInput | p_in | Prescribed boundary pressure [Pa] |
input RealInput | T_in | Prescribed boundary temperature [K] |
Modelica definition
Buildings.Fluid.Sources.Boundary_ph
Boundary with prescribed pressure, specific enthalpy, composition and trace substances
Information
Defines prescribed values for boundary conditions:
- Prescribed boundary pressure.
- Prescribed boundary specific enthalpy.
- Boundary composition (only for multi-substance or trace-substance flow).
Typical use and important parameters
If use_p_in
is false (default option),
the p
parameter is used as boundary pressure,
and the p_in
input connector is disabled;
if use_p_in
is true, then the p
parameter is ignored, and the value provided by the
input connector is used instead.
The same applies to the specific enthalpy h, composition Xi or X and trace substances C.
Options
Instead of using Xi_in
(the independent composition fractions),
the advanced tab provides an option for setting all
composition fractions using X_in
.
use_X_in
and use_Xi_in
cannot be used
at the same time.
Parameter verifyInputs
can be set to true
to enable a check that verifies the validity of the used specific enthalpy
and pressures.
This removes the corresponding overhead from the model, which is
a substantial part of the overhead of this model.
See #882
for more information.
Note, that boundary specific enthalpy, mass fractions and trace substances have only an effect if the mass flow is from the boundary into the port. If mass is flowing from the port into the boundary, the boundary definitions, with exception of boundary pressure, do not have an effect.
Extends from Buildings.Fluid.Sources.BaseClasses.PartialSource_Xi_C (Partial component source with parameter definitions for Xi and C).
Parameters
Type | Name | Default | Description |
---|---|---|---|
replaceable package Medium | PartialMedium | Medium in the component | |
Conditional inputs | |||
Boolean | use_Xi_in | false | Get the composition (independent fractions) from the input connector |
Boolean | use_C_in | false | Get the trace substances from the input connector |
Boolean | use_p_in | false | Get the pressure from the input connector |
Boolean | use_h_in | false | Get the specific enthalpy from the input connector |
Fixed inputs | |||
MassFraction | X[Medium.nX] | Medium.X_default | Fixed value of composition [kg/kg] |
ExtraProperty | C[Medium.nC] | fill(0, Medium.nC) | Fixed values of trace substances |
AbsolutePressure | p | Medium.p_default | Fixed value of pressure [Pa] |
SpecificEnthalpy | h | Medium.h_default | Fixed value of specific enthalpy [J/kg] |
Advanced | |||
Boolean | verifyInputs | false | Set to true to stop the simulation with an error if the medium temperature is outside its allowable range |
Boolean | use_X_in | false | Get the composition (all fractions) from the input connector |
Connectors
Type | Name | Description |
---|---|---|
FluidPorts_b | ports[nPorts] | Fluid ports |
input RealInput | X_in[Medium.nX] | Prescribed boundary composition [kg/kg] |
input RealInput | Xi_in[Medium.nXi] | Prescribed boundary composition [kg/kg] |
input RealInput | C_in[Medium.nC] | Prescribed boundary trace substances |
input RealInput | p_in | Prescribed boundary pressure [Pa] |
input RealInput | h_in | Prescribed boundary specific enthalpy [J/kg] |
Modelica definition
Buildings.Fluid.Sources.MassFlowSource_T
Ideal flow source that produces a prescribed mass flow with prescribed temperature, composition and trace substances
Information
Models an ideal flow source, with prescribed values of flow rate, temperature, composition and trace substances:
- Prescribed mass flow rate.
- Prescribed temperature.
- Boundary composition (only for multi-substance or trace-substance flow).
If use_m_flow_in
is false (default option),
the m_flow
parameter
is used as boundary pressure, and the m_flow_in
input connector is disabled; if use_m_flow_in
is true, then the m_flow
parameter is ignored,
and the value provided by the input connector is used instead.
The same applies to the temperature T, composition Xi or X and trace substances C.
Options
Instead of using Xi_in
(the independent composition fractions),
the advanced tab provides an option for setting all
composition fractions using X_in
.
use_X_in
and use_Xi_in
cannot be used
at the same time.
Parameter verifyInputs
can be set to true
to enable a check that verifies the validity of the used temperature
and pressures.
This removes the corresponding overhead from the model, which is
a substantial part of the overhead of this model.
See #882
for more information.
Note, that boundary temperature, mass fractions and trace substances have only an effect if the mass flow is from the boundary into the port. If mass is flowing from the port into the boundary, the boundary definitions, with exception of boundary flow rate, do not have an effect.
Extends from Buildings.Fluid.Sources.BaseClasses.PartialSource_Xi_C (Partial component source with parameter definitions for Xi and C).
Parameters
Type | Name | Default | Description |
---|---|---|---|
replaceable package Medium | PartialMedium | Medium in the component | |
Conditional inputs | |||
Boolean | use_Xi_in | false | Get the composition (independent fractions) from the input connector |
Boolean | use_C_in | false | Get the trace substances from the input connector |
Boolean | use_m_flow_in | false | Get the mass flow rate from the input connector |
Boolean | use_T_in | false | Get the temperature from the input connector |
Fixed inputs | |||
MassFraction | X[Medium.nX] | Medium.X_default | Fixed value of composition [kg/kg] |
ExtraProperty | C[Medium.nC] | fill(0, Medium.nC) | Fixed values of trace substances |
MassFlowRate | m_flow | 0 | Fixed mass flow rate going out of the fluid port [kg/s] |
Temperature | T | Medium.T_default | Fixed value of temperature [K] |
Advanced | |||
Boolean | verifyInputs | false | Set to true to stop the simulation with an error if the medium temperature is outside its allowable range |
Boolean | use_X_in | false | Get the composition (all fractions) from the input connector |
Connectors
Type | Name | Description |
---|---|---|
FluidPorts_b | ports[nPorts] | Fluid ports |
input RealInput | X_in[Medium.nX] | Prescribed boundary composition [kg/kg] |
input RealInput | Xi_in[Medium.nXi] | Prescribed boundary composition [kg/kg] |
input RealInput | C_in[Medium.nC] | Prescribed boundary trace substances |
input RealInput | m_flow_in | Prescribed mass flow rate [kg/s] |
input RealInput | T_in | Prescribed boundary temperature [K] |
Modelica definition
Buildings.Fluid.Sources.MassFlowSource_WeatherData
Ideal flow source that produces a prescribed mass flow with prescribed
trace substances, outside specific enthalpy and mass fraction
Information
Models an ideal flow source, with prescribed values of flow rate and trace substances, with temperature and specific enthalpy from outside:
- Prescribed mass flow rate.
- Boundary composition (trace-substance flow).
- Outside specific enthalpy.
- Multi-substance composition (e.g. water vapor) from outside.
If use_m_flow_in
is false (default option), the m_flow
parameter is used as boundary flow rate, and the m_flow_in
input connector is disabled;
if use_m_flow_in
is true, then the m_flow
parameter
is ignored, and the value provided by the input connector is used instead.
The same applies to the trace substances.
The
Buildings.Utilities.Psychrometrics.X_pTphi block is used with the input data
including pAtm
, TDryBul
, relHum
from
weather bus weaBus
, to calculate X
.
The same applies to the specific enthalpy.
Note, that boundary temperature, mass fractions and trace substances have only an effect if the mass flow is from the boundary into the port. If mass is flowing from the port into the boundary, the boundary definitions, with exception of boundary flow rate, do not have an effect.
Extends from Buildings.Fluid.Sources.BaseClasses.PartialSource (Partial component source with one fluid connector).
Parameters
Type | Name | Default | Description |
---|---|---|---|
replaceable package Medium | PartialMedium | Medium in the component | |
Boolean | use_m_flow_in | false | Get the mass flow rate from the input connector |
Boolean | use_C_in | false | Get the trace substances from the input connector |
MassFlowRate | m_flow | 0 | Fixed mass flow rate going out of the fluid port [kg/s] |
ExtraProperty | C[Medium.nC] | fill(0, Medium.nC) | Fixed values of trace substances |
Advanced | |||
Boolean | verifyInputs | true | Set to true to stop the simulation with an error if the medium temperature is outside its allowable range |
Connectors
Type | Name | Description |
---|---|---|
FluidPorts_b | ports[nPorts] | Fluid ports |
input RealInput | m_flow_in | Prescribed mass flow rate [kg/s] |
input RealInput | C_in[Medium.nC] | Prescribed boundary trace substances |
Bus | weaBus | Bus with weather data |
Modelica definition
Buildings.Fluid.Sources.MassFlowSource_h
Ideal flow source that produces a prescribed mass flow with prescribed specific enthalpy, composition and trace substances
Information
Models an ideal flow source, with prescribed values of flow rate, specific enthalpy, composition and trace substances:
- Prescribed mass flow rate.
- Prescribed specific enthalpy.
- Boundary composition (only for multi-substance or trace-substance flow).
If use_m_flow_in
is false (default option),
the m_flow
parameter
is used as boundary pressure, and the m_flow_in
input connector is disabled; if use_m_flow_in
is true, then the m_flow
parameter is ignored,
and the value provided by the input connector is used instead.
The same applies to the specific enthalpy h, composition Xi or X and trace substances C.
Options
Instead of using Xi_in
(the independent composition fractions),
the advanced tab provides an option for setting all
composition fractions using X_in
.
use_X_in
and use_Xi_in
cannot be used
at the same time.
Parameter verifyInputs
can be set to true
to enable a check that verifies the validity of the used specific enthalpy
and pressures.
This removes the corresponding overhead from the model, which is
a substantial part of the overhead of this model.
See #882
for more information.
Note, that boundary specific enthalpy, mass fractions and trace substances have only an effect if the mass flow is from the boundary into the port. If mass is flowing from the port into the boundary, the boundary definitions, with exception of boundary flow rate, do not have an effect.
Extends from Buildings.Fluid.Sources.BaseClasses.PartialSource_Xi_C (Partial component source with parameter definitions for Xi and C).
Parameters
Type | Name | Default | Description |
---|---|---|---|
replaceable package Medium | PartialMedium | Medium in the component | |
Conditional inputs | |||
Boolean | use_Xi_in | false | Get the composition (independent fractions) from the input connector |
Boolean | use_C_in | false | Get the trace substances from the input connector |
Boolean | use_m_flow_in | false | Get the mass flow rate from the input connector |
Boolean | use_h_in | false | Get the specific enthalpy from the input connector |
Fixed inputs | |||
MassFraction | X[Medium.nX] | Medium.X_default | Fixed value of composition [kg/kg] |
ExtraProperty | C[Medium.nC] | fill(0, Medium.nC) | Fixed values of trace substances |
MassFlowRate | m_flow | 0 | Fixed mass flow rate going out of the fluid port [kg/s] |
SpecificEnthalpy | h | Medium.h_default | Fixed value of specific enthalpy [J/kg] |
Advanced | |||
Boolean | verifyInputs | false | Set to true to stop the simulation with an error if the medium temperature is outside its allowable range |
Boolean | use_X_in | false | Get the composition (all fractions) from the input connector |
Connectors
Type | Name | Description |
---|---|---|
FluidPorts_b | ports[nPorts] | Fluid ports |
input RealInput | X_in[Medium.nX] | Prescribed boundary composition [kg/kg] |
input RealInput | Xi_in[Medium.nXi] | Prescribed boundary composition [kg/kg] |
input RealInput | C_in[Medium.nC] | Prescribed boundary trace substances |
input RealInput | m_flow_in | Prescribed mass flow rate [kg/s] |
input RealInput | h_in | Prescribed boundary specific enthalpy [J/kg] |
Modelica definition
Buildings.Fluid.Sources.Outside
Boundary that takes weather data, and optionally trace substances, as an input
Information
This model describes boundary conditions for pressure, enthalpy, and species concentration that can be obtained from weather data.
To use this model, connect weather data from
Buildings.BoundaryConditions.WeatherData.ReaderTMY3 to the port
weaBus
of this model.
This will cause the medium of this model to be
at the pressure that is obtained from the weather file, and any flow that
leaves this model to be at the temperature and humidity that are obtained
from the weather data.
If the parameter use_C_in
is false
(default option),
the C
parameter
is used as the trace substance for flow that leaves the component, and the
C_in
input connector is disabled; if use_C_in
is true
,
then the C
parameter is ignored, and the value provided by the input connector is used instead.
Note that boundary temperature, mass fractions and trace substances have only an effect if the mass flow is from the boundary into the port. If mass is flowing from the port into the boundary, the boundary definitions, with exception of boundary pressure, do not have an effect.
Extends from Buildings.Fluid.Sources.BaseClasses.Outside (Boundary that takes weather data, and optionally trace substances, as an input).
Parameters
Type | Name | Default | Description |
---|---|---|---|
replaceable package Medium | PartialMedium | Medium in the component | |
Boolean | use_C_in | false | Get the trace substances from the input connector |
ExtraProperty | C[Medium.nC] | fill(0, Medium.nC) | Fixed values of trace substances |
Connectors
Type | Name | Description |
---|---|---|
FluidPorts_b | ports[nPorts] | Fluid ports |
input RealInput | C_in[Medium.nC] | Prescribed boundary trace substances |
Bus | weaBus | Bus with weather data |
Modelica definition
Buildings.Fluid.Sources.Outside_Cp
Boundary that takes weather data, and optionally the wind pressure coefficient and trace substances, as an input
Information
This model describes boundary conditions for
pressure, enthalpy, and species concentration that can be obtained
from weather data. The model is identical to
Buildings.Fluid.Sources.Outside,
except that it allows adding the wind pressure to the
pressure at the fluid port ports
.
The pressure p at the port ports
is computed as
p = pw + Cp 1 ⁄ 2 v2 ρ
where
pw is the atmospheric pressure from the weather bus,
Cp is the wind pressure coefficient,
v is the wind speed from the weather bus, and
ρ is the fluid density.
If use_Cp_in=true
, then the
wind pressure coefficient is obtained from the input connector
Cp_in
. Otherwise, it is set to the parameter
Cp
.
Extends from Buildings.Fluid.Sources.BaseClasses.Outside (Boundary that takes weather data, and optionally trace substances, as an input).
Parameters
Type | Name | Default | Description |
---|---|---|---|
replaceable package Medium | PartialMedium | Medium in the component | |
Boolean | use_C_in | false | Get the trace substances from the input connector |
ExtraProperty | C[Medium.nC] | fill(0, Medium.nC) | Fixed values of trace substances |
Boolean | use_Cp_in | false | Get the wind pressure coefficient from the input connector |
Real | Cp | 0.6 | Fixed value of wind pressure coefficient |
Connectors
Type | Name | Description |
---|---|---|
FluidPorts_b | ports[nPorts] | Fluid ports |
input RealInput | C_in[Medium.nC] | Prescribed boundary trace substances |
Bus | weaBus | Bus with weather data |
input RealInput | Cp_in | Prescribed wind pressure coefficient [1] |
Modelica definition
Buildings.Fluid.Sources.Outside_CpLowRise
Boundary that takes weather data as an input and computes wind pressure for low-rise buildings
Information
This model describes boundary conditions for
pressure, enthalpy, and species concentration that can be obtained
from weather data. The model is identical to
Buildings.Fluid.Sources.Outside,
except that it adds the wind pressure to the
pressure at the fluid port ports
.
The correlation that is used to compute the wind pressure is based
on Swami and Chandra (1987) and valid for low-rise buildings
with rectangular shape.
The same correlation is also implemented in CONTAM (Persily and Ivy, 2001).
For other buildings, the model
Buildings.Fluid.Sources.Outside_Cp should be used that takes
the wind pressure coefficient as an input or parameter.
The wind pressure coefficient is computed based on the side ratio of the walls, which is defined as
s = x ⁄ y
where x is the length of the wall that will be connected to
this model, and y is the length of the adjacent wall.
The wind direction is computed relative to the azimuth of this surface,
which is equal to the parameter azi
.
The surface azimuth is defined in
Buildings.Types.Azimuth.
For example, if an exterior wall is South oriented, i.e., its outside-facing
surface is towards South, use
Buildings.Types.Azimuth.S
.
Based on the surface azimuth, the wind direction and the side ratio
of the walls, the model computes how much the wind pressure
is attenuated compared to the reference wind pressure Cp0
.
The reference wind pressure Cp0
is a user-defined parameter,
and must be equal to the wind pressure at zero wind incidence angle.
Swami and Chandra (1987) recommend Cp0 = 0.6 for
all low-rise buildings as this represents the average of
various values reported in the literature.
The computation of the actual wind pressure coefficient Cp
is explained in the function
Buildings.Airflow.Multizone.BaseClasses.windPressureLowRise
that is called by this model.
The pressure p at the port ports
is computed as
p = pw + Cp 1 ⁄ 2 v2 ρ,
where pw is the atmospheric pressure from the weather bus, v is the wind speed from the weather bus, and ρ is the fluid density.
References
- Muthusamy V. Swami and Subrato Chandra. Procedures for Calculating Natural Ventilation Airflow Rates in Buildings. Florida Solar Energy Center, FSEC-CR-163-86. March, 1987. Cape Canaveral, Florida.
- Andrew K. Persily and Elizabeth M. Ivy. Input Data for Multizone Airflow and IAQ Analysis. NIST, NISTIR 6585. January, 2001. Gaithersburg, MD.
Extends from Buildings.Fluid.Sources.BaseClasses.Outside (Boundary that takes weather data, and optionally trace substances, as an input).
Parameters
Type | Name | Default | Description |
---|---|---|---|
replaceable package Medium | PartialMedium | Medium in the component | |
Boolean | use_C_in | false | Get the trace substances from the input connector |
ExtraProperty | C[Medium.nC] | fill(0, Medium.nC) | Fixed values of trace substances |
Real | Cp0 | 0.6 | Wind pressure coefficient for wind normal to wall [1] |
Real | s | Side ratio, s=length of this wall/length of adjacent wall [1] | |
Angle | azi | Surface azimuth (South:0, West:pi/2) [rad] |
Connectors
Type | Name | Description |
---|---|---|
FluidPorts_b | ports[nPorts] | Fluid ports |
input RealInput | C_in[Medium.nC] | Prescribed boundary trace substances |
Bus | weaBus | Bus with weather data |
Modelica definition
Buildings.Fluid.Sources.PropertySource_T
Model for overriding fluid properties that flow through the component, using temperature input
Information
Model that changes the properties, but not the mass flow rate, of the fluid that passes through it.
If allowFlowReversal=true
, then the properties are changed for both flow directions,
i.e., from port_a
to port_b
and
from port_b
to port_a
.
Typical use and important parameters
The fluid properties h
, Xi
and C
are only modified when the corresponding boolean parameter
use_T_in
, use_Xi_in
or use_C_in
is set to true
.
Dynamics
This model has no dynamics.
Extends from Buildings.Fluid.Sources.BaseClasses.PartialPropertySource (Partial model for overriding fluid properties that flow through the component).
Parameters
Type | Name | Default | Description |
---|---|---|---|
replaceable package Medium | PartialMedium | Medium in the component | |
Inputs | |||
Boolean | use_T_in | false | Set to true to get the leaving fluid temperature from the input connector |
Boolean | use_Xi_in | false | Set to true to get the composition from the input connector |
Boolean | use_C_in | false | Set to true to get the trace substances from the input connector |
Assumptions | |||
Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
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 | Xi_in[Medium.nXi] | Prescribed values for composition |
input RealInput | C_in[Medium.nC] | Prescribed values for trace substances |
input RealInput | T_in | Prescribed value for leaving fluid temperature |
Modelica definition
Buildings.Fluid.Sources.PropertySource_h
Model for overriding fluid properties that flow through the component, using specific enthalpy input
Information
Model that changes the properties, but not the mass flow rate, of the fluid that passes through it.
If allowFlowReversal=true
, then the properties are changed for both flow directions,
i.e., from port_a
to port_b
and
from port_b
to port_a
.
Typical use and important parameters
The fluid properties h
, Xi
and C
are only modified when the corresponding boolean parameter
use_h_in
, use_Xi_in
or use_C_in
is set to true
.
Dynamics
This model has no dynamics.
Extends from Buildings.Fluid.Sources.BaseClasses.PartialPropertySource (Partial model for overriding fluid properties that flow through the component).
Parameters
Type | Name | Default | Description |
---|---|---|---|
replaceable package Medium | PartialMedium | Medium in the component | |
Inputs | |||
Boolean | use_h_in | false | Set to true to get the specific enthalpy from the input connector |
Boolean | use_Xi_in | false | Set to true to get the composition from the input connector |
Boolean | use_C_in | false | Set to true to get the trace substances from the input connector |
Assumptions | |||
Boolean | allowFlowReversal | true | = false to simplify equations, assuming, but not enforcing, no flow reversal |
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 | Xi_in[Medium.nXi] | Prescribed values for composition |
input RealInput | C_in[Medium.nC] | Prescribed values for trace substances |
input RealInput | h_in | Prescribed value for leaving specific enthalpy |
Modelica definition
Buildings.Fluid.Sources.TraceSubstancesFlowSource
Source with mass flow that does not take part in medium mass balance (such as CO2)
Information
This model can be used to inject trace substances into a system. The model adds a mass flow rate to its port with a trace substance concentration of 1.
Typical use and important parameters
A typical use of this model is to add carbon dioxide to room air, since the
carbon dioxide concentration is typically so small that it need not be
added to the room mass balance, and since the mass flow rate can be
made small compared to the room volume if the medium that leaves this
component has a carbon dioxide concentration of 1.
The parameter substanceName
must be set to the name of the substance
that is injected into the fluid.
Note however that mixing volumes from the package Buildings.Fluid.MixingVolumes allow to directly add a trace substance mass flow rate, which is more efficient than using this model.
Parameters
Type | Name | Default | Description |
---|---|---|---|
replaceable package Medium | Buildings.Media.Air (extraPr... | Medium in the component | |
String | substanceName | "CO2" | Name of trace substance |
Boolean | use_m_flow_in | false | Get the trace substance mass flow rate from the input connector |
MassFlowRate | m_flow | 0 | Fixed mass flow rate going out of the fluid port [kg/s] |
Connectors
Type | Name | Description |
---|---|---|
replaceable package Medium | Medium in the component | |
input RealInput | m_flow_in | Prescribed mass flow rate for extra property [kg/s] |
FluidPorts_b | ports[nPorts] | Connector for fluid ports |