Buildings.Fluid.Sources

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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_ph Boundary with prescribed pressure, specific enthalpy, composition and trace substances

Boundary_pT Boundary with prescribed pressure, temperature, composition and trace substances

FixedBoundary Boundary source component

MassFlowSource_h Ideal flow source that produces a prescribed mass flow with prescribed specific enthalpy, mass fraction and trace substances

MassFlowSource_T Ideal flow source that produces a prescribed mass flow with prescribed temperature, mass fraction 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

PrescribedExtraPropertyFlowRate 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

BaseClasses Package with base classes for Buildings.Fluid.Sources

Name	Description
Boundary_ph	Boundary with prescribed pressure, specific enthalpy, composition and trace substances
Boundary_pT	Boundary with prescribed pressure, temperature, composition and trace substances
FixedBoundary	Boundary source component
MassFlowSource_h	Ideal flow source that produces a prescribed mass flow with prescribed specific enthalpy, mass fraction and trace substances
MassFlowSource_T	Ideal flow source that produces a prescribed mass flow with prescribed temperature, mass fraction 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
PrescribedExtraPropertyFlowRate	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
BaseClasses	Package with base classes for Buildings.Fluid.Sources

Buildings.Fluid.Sources.Boundary_ph

Boundary with prescribed pressure, specific enthalpy, composition and trace substances

Buildings.Fluid.Sources.Boundary_ph

Information

Defines prescribed values for boundary conditions:

Prescribed boundary pressure.
Prescribed boundary temperature.
Boundary composition (only for multi-substance or trace-substance flow).

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, composition and trace substances.

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 Modelica.Fluid.Sources.BaseClasses.PartialSource (Partial component source with one fluid connector).

Parameters

Type Name Default Description

replaceable package Medium PartialMedium Medium model within the source

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

Boolean use_X_in false Get the composition from the input connector

Boolean use_C_in false Get the trace substances from the input connector

AbsolutePressure p Medium.p_default Fixed value of pressure [Pa]

SpecificEnthalpy h Medium.h_default Fixed value of specific enthalpy [J/kg]

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

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium model within the source
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
Boolean	use_X_in	false	Get the composition from the input connector
Boolean	use_C_in	false	Get the trace substances from the input connector
AbsolutePressure	p	Medium.p_default	Fixed value of pressure [Pa]
SpecificEnthalpy	h	Medium.h_default	Fixed value of specific enthalpy [J/kg]
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

Connectors

Type Name Description

FluidPorts_b ports[nPorts]

input RealInput p_in Prescribed boundary pressure

input RealInput h_in Prescribed boundary specific enthalpy

input RealInput X_in[Medium.nX] Prescribed boundary composition

input RealInput C_in[Medium.nC] Prescribed boundary trace substances

Type	Name	Description
FluidPorts_b	ports[nPorts]
input RealInput	p_in	Prescribed boundary pressure
input RealInput	h_in	Prescribed boundary specific enthalpy
input RealInput	X_in[Medium.nX]	Prescribed boundary composition
input RealInput	C_in[Medium.nC]	Prescribed boundary trace substances

Modelica definition

model Boundary_ph 
  "Boundary with prescribed pressure, specific enthalpy, composition and trace substances"
  extends Modelica.Fluid.Sources.BaseClasses.PartialSource;
  parameter Boolean use_p_in = false 
    "Get the pressure from the input connector";
  parameter Boolean use_h_in= false 
    "Get the specific enthalpy from the input connector";
  parameter Boolean use_X_in = false 
    "Get the composition from the input connector";
  parameter Boolean use_C_in = false 
    "Get the trace substances from the input connector";
  parameter Medium.AbsolutePressure p = Medium.p_default 
    "Fixed value of pressure";
  parameter Medium.SpecificEnthalpy h = Medium.h_default 
    "Fixed value of specific enthalpy";
  parameter Medium.MassFraction X[Medium.nX] = Medium.X_default 
    "Fixed value of composition";
  parameter Medium.ExtraProperty C[Medium.nC](
       quantity=Medium.extraPropertiesNames)=fill(0, Medium.nC) 
    "Fixed values of trace substances";
  Modelica.Blocks.Interfaces.RealInput p_in if              use_p_in 
    "Prescribed boundary pressure";
  Modelica.Blocks.Interfaces.RealInput h_in if              use_h_in 
    "Prescribed boundary specific enthalpy";
  Modelica.Blocks.Interfaces.RealInput X_in[Medium.nX] if 
                                                        use_X_in 
    "Prescribed boundary composition";
  Modelica.Blocks.Interfaces.RealInput C_in[Medium.nC] if 
                                                        use_C_in 
    "Prescribed boundary trace substances";
protected 
  Modelica.Blocks.Interfaces.RealInput p_in_internal 
    "Needed to connect to conditional connector";
  Modelica.Blocks.Interfaces.RealInput h_in_internal 
    "Needed to connect to conditional connector";
  Modelica.Blocks.Interfaces.RealInput X_in_internal[Medium.nX] 
    "Needed to connect to conditional connector";
  Modelica.Blocks.Interfaces.RealInput C_in_internal[Medium.nC] 
    "Needed to connect to conditional connector";
equation 
  Modelica.Fluid.Utilities.checkBoundary(Medium.mediumName, Medium.substanceNames,
    Medium.singleState, true, X_in_internal, "Boundary_ph");
  connect(p_in, p_in_internal);
  connect(h_in, h_in_internal);
  connect(X_in, X_in_internal);
  connect(C_in, C_in_internal);
  if not use_p_in then
    p_in_internal = p;
  end if;
  if not use_h_in then
    h_in_internal = h;
  end if;
  if not use_X_in then
    X_in_internal = X;
  end if;
  if not use_C_in then
    C_in_internal = C;
  end if;
  medium.p = p_in_internal;
  medium.h = h_in_internal;
  medium.Xi = X_in_internal[1:Medium.nXi];
  ports.C_outflow = fill(C_in_internal, nPorts);
end Boundary_ph;

Buildings.Fluid.Sources.Boundary_pT

Boundary with prescribed pressure, temperature, composition and trace substances

Buildings.Fluid.Sources.Boundary_pT

Information

Defines prescribed values for boundary conditions:

Prescribed boundary pressure.
Prescribed boundary temperature.
Boundary composition (only for multi-substance or trace-substance flow).

The same applies to the temperature, composition and trace substances.

Extends from Modelica.Fluid.Sources.BaseClasses.PartialSource (Partial component source with one fluid connector).

Parameters

Type Name Default Description

replaceable package Medium PartialMedium Medium model within the source

Boolean use_p_in false Get the pressure from the input connector

Boolean use_T_in false Get the temperature from the input connector

Boolean use_X_in false Get the composition from the input connector

Boolean use_C_in false Get the trace substances from the input connector

AbsolutePressure p Medium.p_default Fixed value of pressure [Pa]

Temperature T Medium.T_default Fixed value of temperature [K]

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

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium model within the source
Boolean	use_p_in	false	Get the pressure from the input connector
Boolean	use_T_in	false	Get the temperature from the input connector
Boolean	use_X_in	false	Get the composition from the input connector
Boolean	use_C_in	false	Get the trace substances from the input connector
AbsolutePressure	p	Medium.p_default	Fixed value of pressure [Pa]
Temperature	T	Medium.T_default	Fixed value of temperature [K]
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

Connectors

Type Name Description

FluidPorts_b ports[nPorts]

input RealInput p_in Prescribed boundary pressure

input RealInput T_in Prescribed boundary temperature

input RealInput X_in[Medium.nX] Prescribed boundary composition

input RealInput C_in[Medium.nC] Prescribed boundary trace substances

Type	Name	Description
FluidPorts_b	ports[nPorts]
input RealInput	p_in	Prescribed boundary pressure
input RealInput	T_in	Prescribed boundary temperature
input RealInput	X_in[Medium.nX]	Prescribed boundary composition
input RealInput	C_in[Medium.nC]	Prescribed boundary trace substances

Modelica definition

model Boundary_pT 
  "Boundary with prescribed pressure, temperature, composition and trace substances"
  extends Modelica.Fluid.Sources.BaseClasses.PartialSource;
  parameter Boolean use_p_in = false 
    "Get the pressure from the input connector";
  parameter Boolean use_T_in= false 
    "Get the temperature from the input connector";
  parameter Boolean use_X_in = false 
    "Get the composition from the input connector";
  parameter Boolean use_C_in = false 
    "Get the trace substances from the input connector";
  parameter Medium.AbsolutePressure p = Medium.p_default 
    "Fixed value of pressure";
  parameter Medium.Temperature T = Medium.T_default 
    "Fixed value of temperature";
  parameter Medium.MassFraction X[Medium.nX] = Medium.X_default 
    "Fixed value of composition";
  parameter Medium.ExtraProperty C[Medium.nC](
       quantity=Medium.extraPropertiesNames)=fill(0, Medium.nC) 
    "Fixed values of trace substances";
  Modelica.Blocks.Interfaces.RealInput p_in if              use_p_in 
    "Prescribed boundary pressure";
  Modelica.Blocks.Interfaces.RealInput T_in if         use_T_in 
    "Prescribed boundary temperature";
  Modelica.Blocks.Interfaces.RealInput X_in[Medium.nX] if 
                                                        use_X_in 
    "Prescribed boundary composition";
  Modelica.Blocks.Interfaces.RealInput C_in[Medium.nC] if 
                                                        use_C_in 
    "Prescribed boundary trace substances";
protected 
  Modelica.Blocks.Interfaces.RealInput p_in_internal 
    "Needed to connect to conditional connector";
  Modelica.Blocks.Interfaces.RealInput T_in_internal 
    "Needed to connect to conditional connector";
  Modelica.Blocks.Interfaces.RealInput X_in_internal[Medium.nX] 
    "Needed to connect to conditional connector";
  Modelica.Blocks.Interfaces.RealInput C_in_internal[Medium.nC] 
    "Needed to connect to conditional connector";
equation 
  Modelica.Fluid.Utilities.checkBoundary(Medium.mediumName, Medium.substanceNames,
    Medium.singleState, true, X_in_internal, "Boundary_pT");
  connect(p_in, p_in_internal);
  connect(T_in, T_in_internal);
  connect(X_in, X_in_internal);
  connect(C_in, C_in_internal);
  if not use_p_in then
    p_in_internal = p;
  end if;
  if not use_T_in then
    T_in_internal = T;
  end if;
  if not use_X_in then
    X_in_internal = X;
  end if;
  if not use_C_in then
    C_in_internal = C;
  end if;
  medium.p = p_in_internal;
  medium.T = T_in_internal;
  medium.Xi = X_in_internal[1:Medium.nXi];
  ports.C_outflow = fill(C_in_internal, nPorts);
end Boundary_pT;

Buildings.Fluid.Sources.FixedBoundary

Boundary source component

Buildings.Fluid.Sources.FixedBoundary

Information

This model defines constant values for boundary conditions:

Boundary pressure or boundary density.
Boundary temperature or boundary specific enthalpy.
Boundary composition (only for multi-substance or trace-substance flow).

Note, that boundary temperature, density, 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 Modelica.Fluid.Sources.BaseClasses.PartialSource (Partial component source with one fluid connector).

Parameters

Type Name Default Description

replaceable package Medium PartialMedium Medium model within the source

Boundary pressure or Boundary density

Boolean use_p true select p or d

AbsolutePressure p Medium.p_default Boundary pressure [Pa]

Density d Medium.density_pTX(Medium.p_... Boundary density [kg/m3]

Boundary temperature or Boundary specific enthalpy

Boolean use_T true select T or h

Temperature T Medium.T_default Boundary temperature [K]

SpecificEnthalpy h Medium.h_default Boundary specific enthalpy [J/kg]

Only for multi-substance flow

MassFraction X[Medium.nX] Medium.X_default Boundary mass fractions m_i/m [kg/kg]

Only for trace-substance flow

ExtraProperty C[Medium.nC] fill(0, Medium.nC) Boundary trace substances

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium model within the source
Boundary pressure or Boundary density
Boolean	use_p	true	select p or d
AbsolutePressure	p	Medium.p_default	Boundary pressure [Pa]
Density	d	Medium.density_pTX(Medium.p_...	Boundary density [kg/m3]
Boundary temperature or Boundary specific enthalpy
Boolean	use_T	true	select T or h
Temperature	T	Medium.T_default	Boundary temperature [K]
SpecificEnthalpy	h	Medium.h_default	Boundary specific enthalpy [J/kg]
Only for multi-substance flow
MassFraction	X[Medium.nX]	Medium.X_default	Boundary mass fractions m_i/m [kg/kg]
Only for trace-substance flow
ExtraProperty	C[Medium.nC]	fill(0, Medium.nC)	Boundary trace substances

Connectors

Type Name Description

FluidPorts_b ports[nPorts]

Type	Name	Description
FluidPorts_b	ports[nPorts]

Modelica definition

model FixedBoundary "Boundary source component"
  extends Modelica.Fluid.Sources.BaseClasses.PartialSource;
  parameter Boolean use_p=true "select p or d";
  parameter Medium.AbsolutePressure p=Medium.p_default "Boundary pressure";
  parameter Medium.Density d=Medium.density_pTX(Medium.p_default, Medium.T_default, Medium.X_default) 
    "Boundary density";
  parameter Boolean use_T=true "select T or h";
  parameter Medium.Temperature T=Medium.T_default "Boundary temperature";
  parameter Medium.SpecificEnthalpy h=Medium.h_default 
    "Boundary specific enthalpy";
  parameter Medium.MassFraction X[Medium.nX](
       quantity=Medium.substanceNames)=Medium.X_default 
    "Boundary mass fractions m_i/m";

  parameter Medium.ExtraProperty C[Medium.nC](
       quantity=Medium.extraPropertiesNames)=fill(0, Medium.nC) 
    "Boundary trace substances";

equation 
  Modelica.Fluid.Utilities.checkBoundary(Medium.mediumName, Medium.substanceNames,
                                        Medium.singleState, use_p, X,
                                        "FixedBoundary");
  if use_p or Medium.singleState then
    medium.p = p;
  else
    medium.d = d;
  end if;
  if use_T then
    medium.T = T;
  else
    medium.h = h;
  end if;

  medium.Xi = X[1:Medium.nXi];

  ports.C_outflow = fill(C, nPorts);
end FixedBoundary;

Buildings.Fluid.Sources.MassFlowSource_h

Ideal flow source that produces a prescribed mass flow with prescribed specific enthalpy, mass fraction and trace substances

Buildings.Fluid.Sources.MassFlowSource_h

Information

Models an ideal flow source, with prescribed values of flow rate, temperature and composition:

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 temperature, composition and trace substances.

Extends from Modelica.Fluid.Sources.BaseClasses.PartialSource (Partial component source with one fluid connector).

Parameters

Type Name Default Description

replaceable package Medium PartialMedium Medium model within the source

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

Boolean use_X_in false Get the composition 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]

SpecificEnthalpy h Medium.h_default Fixed value of specific enthalpy [J/kg]

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

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium model within the source
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
Boolean	use_X_in	false	Get the composition 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]
SpecificEnthalpy	h	Medium.h_default	Fixed value of specific enthalpy [J/kg]
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

Connectors

Type Name Description

FluidPorts_b ports[nPorts]

input RealInput m_flow_in Prescribed mass flow rate

input RealInput h_in Prescribed fluid specific enthalpy

input RealInput X_in[Medium.nX] Prescribed fluid composition

input RealInput C_in[Medium.nC] Prescribed boundary trace substances

Type	Name	Description
FluidPorts_b	ports[nPorts]
input RealInput	m_flow_in	Prescribed mass flow rate
input RealInput	h_in	Prescribed fluid specific enthalpy
input RealInput	X_in[Medium.nX]	Prescribed fluid composition
input RealInput	C_in[Medium.nC]	Prescribed boundary trace substances

Modelica definition

model MassFlowSource_h 
  "Ideal flow source that produces a prescribed mass flow with prescribed specific enthalpy, mass fraction and trace substances"
  extends Modelica.Fluid.Sources.BaseClasses.PartialSource;
  parameter Boolean use_m_flow_in = false 
    "Get the mass flow rate from the input connector";
  parameter Boolean use_h_in= false 
    "Get the specific enthalpy from the input connector";
  parameter Boolean use_X_in = false 
    "Get the composition from the input connector";
  parameter Boolean use_C_in = false 
    "Get the trace substances from the input connector";
  parameter Medium.MassFlowRate m_flow = 0 
    "Fixed mass flow rate going out of the fluid port";
  parameter Medium.SpecificEnthalpy h = Medium.h_default 
    "Fixed value of specific enthalpy";
  parameter Medium.MassFraction X[Medium.nX] = Medium.X_default 
    "Fixed value of composition";
  parameter Medium.ExtraProperty C[Medium.nC](
       quantity=Medium.extraPropertiesNames)=fill(0, Medium.nC) 
    "Fixed values of trace substances";
  Modelica.Blocks.Interfaces.RealInput m_flow_in if     use_m_flow_in 
    "Prescribed mass flow rate";
  Modelica.Blocks.Interfaces.RealInput h_in if              use_h_in 
    "Prescribed fluid specific enthalpy";
  Modelica.Blocks.Interfaces.RealInput X_in[Medium.nX] if 
                                                        use_X_in 
    "Prescribed fluid composition";
  Modelica.Blocks.Interfaces.RealInput C_in[Medium.nC] if 
                                                        use_C_in 
    "Prescribed boundary trace substances";
protected 
  Modelica.Blocks.Interfaces.RealInput m_flow_in_internal 
    "Needed to connect to conditional connector";
  Modelica.Blocks.Interfaces.RealInput h_in_internal 
    "Needed to connect to conditional connector";
  Modelica.Blocks.Interfaces.RealInput X_in_internal[Medium.nX] 
    "Needed to connect to conditional connector";
  Modelica.Blocks.Interfaces.RealInput C_in_internal[Medium.nC] 
    "Needed to connect to conditional connector";
equation 
  Modelica.Fluid.Utilities.checkBoundary(
    Medium.mediumName,
    Medium.substanceNames,
    Medium.singleState,
    true,
    X_in_internal,
    "MassFlowSource_h");
  connect(m_flow_in, m_flow_in_internal);
  connect(h_in, h_in_internal);
  connect(X_in, X_in_internal);
  connect(C_in, C_in_internal);
  if not use_m_flow_in then
    m_flow_in_internal = m_flow;
  end if;
  if not use_h_in then
    h_in_internal = h;
  end if;
  if not use_X_in then
    X_in_internal = X;
  end if;
  if not use_C_in then
    C_in_internal = C;
  end if;
  sum(ports.m_flow) = -m_flow_in_internal;
  medium.h = h_in_internal;
  medium.Xi = X_in_internal[1:Medium.nXi];
  ports.C_outflow = fill(C_in_internal, nPorts);
end MassFlowSource_h;

Buildings.Fluid.Sources.MassFlowSource_T

Ideal flow source that produces a prescribed mass flow with prescribed temperature, mass fraction and trace substances

Buildings.Fluid.Sources.MassFlowSource_T

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).

The same applies to the temperature, composition and trace substances.

Extends from Modelica.Fluid.Sources.BaseClasses.PartialSource (Partial component source with one fluid connector).

Parameters

Type Name Default Description

replaceable package Medium PartialMedium Medium model within the source

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

Boolean use_X_in false Get the composition 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]

Temperature T Medium.T_default Fixed value of temperature [K]

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

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium model within the source
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
Boolean	use_X_in	false	Get the composition 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]
Temperature	T	Medium.T_default	Fixed value of temperature [K]
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

Connectors

Type Name Description

FluidPorts_b ports[nPorts]

input RealInput m_flow_in Prescribed mass flow rate

input RealInput T_in Prescribed fluid temperature

input RealInput X_in[Medium.nX] Prescribed fluid composition

input RealInput C_in[Medium.nC] Prescribed boundary trace substances

Type	Name	Description
FluidPorts_b	ports[nPorts]
input RealInput	m_flow_in	Prescribed mass flow rate
input RealInput	T_in	Prescribed fluid temperature
input RealInput	X_in[Medium.nX]	Prescribed fluid composition
input RealInput	C_in[Medium.nC]	Prescribed boundary trace substances

Modelica definition

model MassFlowSource_T 
  "Ideal flow source that produces a prescribed mass flow with prescribed temperature, mass fraction and trace substances"
  extends Modelica.Fluid.Sources.BaseClasses.PartialSource;
  parameter Boolean use_m_flow_in = false 
    "Get the mass flow rate from the input connector";
  parameter Boolean use_T_in= false 
    "Get the temperature from the input connector";
  parameter Boolean use_X_in = false 
    "Get the composition from the input connector";
  parameter Boolean use_C_in = false 
    "Get the trace substances from the input connector";
  parameter Medium.MassFlowRate m_flow = 0 
    "Fixed mass flow rate going out of the fluid port";
  parameter Medium.Temperature T = Medium.T_default 
    "Fixed value of temperature";
  parameter Medium.MassFraction X[Medium.nX] = Medium.X_default 
    "Fixed value of composition";
  parameter Medium.ExtraProperty C[Medium.nC](
       quantity=Medium.extraPropertiesNames)=fill(0, Medium.nC) 
    "Fixed values of trace substances";
  Modelica.Blocks.Interfaces.RealInput m_flow_in if     use_m_flow_in 
    "Prescribed mass flow rate";
  Modelica.Blocks.Interfaces.RealInput T_in if         use_T_in 
    "Prescribed fluid temperature";
  Modelica.Blocks.Interfaces.RealInput X_in[Medium.nX] if 
                                                        use_X_in 
    "Prescribed fluid composition";
  Modelica.Blocks.Interfaces.RealInput C_in[Medium.nC] if 
                                                        use_C_in 
    "Prescribed boundary trace substances";
protected 
  Modelica.Blocks.Interfaces.RealInput m_flow_in_internal 
    "Needed to connect to conditional connector";
  Modelica.Blocks.Interfaces.RealInput T_in_internal 
    "Needed to connect to conditional connector";
  Modelica.Blocks.Interfaces.RealInput X_in_internal[Medium.nX] 
    "Needed to connect to conditional connector";
  Modelica.Blocks.Interfaces.RealInput C_in_internal[Medium.nC] 
    "Needed to connect to conditional connector";
equation 
  Modelica.Fluid.Utilities.checkBoundary(
    Medium.mediumName,
    Medium.substanceNames,
    Medium.singleState,
    true,
    X_in_internal,
    "MassFlowSource_T");
  connect(m_flow_in, m_flow_in_internal);
  connect(T_in, T_in_internal);
  connect(X_in, X_in_internal);
  connect(C_in, C_in_internal);
  if not use_m_flow_in then
    m_flow_in_internal = m_flow;
  end if;
  if not use_T_in then
    T_in_internal = T;
  end if;
  if not use_X_in then
    X_in_internal = X;
  end if;
  if not use_C_in then
    C_in_internal = C;
  end if;
  sum(ports.m_flow) = -m_flow_in_internal;
  medium.T = T_in_internal;
  medium.Xi = X_in_internal[1:Medium.nXi];
  ports.C_outflow = fill(C_in_internal, nPorts);
end MassFlowSource_T;

Buildings.Fluid.Sources.Outside

Boundary that takes weather data, and optionally trace substances, as an input

Buildings.Fluid.Sources.Outside

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 model within the source
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]

input RealInput C_in[Medium.nC] Prescribed boundary trace substances

Bus weaBus Bus with weather data

Type	Name	Description
FluidPorts_b	ports[nPorts]
input RealInput	C_in[Medium.nC]	Prescribed boundary trace substances
Bus	weaBus	Bus with weather data

Modelica definition

model Outside 
  "Boundary that takes weather data, and optionally trace substances, as an input"
  extends Buildings.Fluid.Sources.BaseClasses.Outside;

equation 
  connect(weaBus.pAtm, p_in_internal);
  connect(weaBus.TDryBul, T_in_internal);
end Outside;

Buildings.Fluid.Sources.Outside_Cp

Boundary that takes weather data, and optionally the wind pressure coefficient and trace substances, as an input

Buildings.Fluid.Sources.Outside_Cp

Information

The pressure p at the port ports is computed as

p = p_w + C_p 1 ⁄ 2 v² ρ

where p_w is the atmospheric pressure from the weather bus, C_p 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 model within the source

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

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium model within the source
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]

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]

Type	Name	Description
FluidPorts_b	ports[nPorts]
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

model Outside_Cp 
  "Boundary that takes weather data, and optionally the wind pressure coefficient and trace substances, as an input"
  extends Buildings.Fluid.Sources.BaseClasses.Outside;

  parameter Boolean use_Cp_in= false 
    "Get the wind pressure coefficient from the input connector";
  parameter Real Cp = 0.6 "Fixed value of wind pressure coefficient";

  Modelica.Blocks.Interfaces.RealInput Cp_in(unit="1") if 
     use_Cp_in "Prescribed wind pressure coefficient";
  Modelica.SIunits.Pressure pWin(displayUnit="Pa") 
    "Change in pressure due to wind force";

protected 
  Modelica.Blocks.Interfaces.RealInput Cp_in_internal(unit="1") 
    "Needed to connect to conditional connector";
  Modelica.Blocks.Interfaces.RealInput pWea(min=0, nominal=1E5, unit="Pa") 
    "Pressure from weather bus";
  Modelica.Blocks.Interfaces.RealInput vWin(unit="m/s") 
    "Wind speed from weather bus";
  Modelica.Blocks.Interfaces.RealOutput pTot(min=0, nominal=1E5, unit="Pa") 
    "Sum of atmospheric pressure and wind pressure";
equation 
  connect(Cp_in, Cp_in_internal);
  if not use_Cp_in then
    Cp_in_internal = Cp;
  end if;
  pWin = 0.5*Cp_in_internal*medium.d*vWin*vWin;
  pTot = pWea + pWin;

  connect(weaBus.winSpe, vWin);
  connect(weaBus.pAtm, pWea);
  connect(p_in_internal, pTot);
  connect(weaBus.TDryBul, T_in_internal);
end Outside_Cp;

Buildings.Fluid.Sources.Outside_CpLowRise

Boundary that takes weather data as an input and computes wind pressure for low-rise buildings

Buildings.Fluid.Sources.Outside_CpLowRise

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.HeatTransfer.Types.Azimuth. For example, if an exterior wall is South oriented, i.e., its outside-facing surface is towards South, use Buildings.HeatTransfer.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 C_p0 = 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 C_p 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 = p_w + C_p 1 ⁄ 2 v² ρ,

where p_w 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 model within the source

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

Real s Side ratio, s=length of this wall/length of adjacent wall

Angle azi Surface azimuth (South:0, West:pi/2) [rad]

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium model within the source
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
Real	s		Side ratio, s=length of this wall/length of adjacent wall
Angle	azi		Surface azimuth (South:0, West:pi/2) [rad]

Connectors

Type Name Description

FluidPorts_b ports[nPorts]

input RealInput C_in[Medium.nC] Prescribed boundary trace substances

Bus weaBus Bus with weather data

Type	Name	Description
FluidPorts_b	ports[nPorts]
input RealInput	C_in[Medium.nC]	Prescribed boundary trace substances
Bus	weaBus	Bus with weather data

Modelica definition

model Outside_CpLowRise 
  "Boundary that takes weather data as an input and computes wind pressure for low-rise buildings"
  extends Buildings.Fluid.Sources.BaseClasses.Outside;

  parameter Real Cp0(min=0, max=1) = 0.6 
    "Wind pressure coefficient for wind normal to wall";
  parameter Real s(min=0) 
    "Side ratio, s=length of this wall/length of adjacent wall";
  parameter Modelica.SIunits.Angle azi "Surface azimuth (South:0, West:pi/2)";

  Modelica.SIunits.Angle alpha "Wind incidence angle (0: normal to wall)";
  Real CpAct "Actual wind pressure coefficient";
  Modelica.SIunits.Pressure pWin(displayUnit="Pa") 
    "Change in pressure due to wind force";
protected 
  Modelica.Blocks.Interfaces.RealInput pWea(min=0, nominal=1E5, unit="Pa") 
    "Pressure from weather bus";
  Modelica.Blocks.Interfaces.RealInput vWin(unit="m/s") 
    "Wind speed from weather bus";
  Modelica.Blocks.Interfaces.RealOutput pTot(min=0, nominal=1E5, unit="Pa") 
    "Sum of atmospheric pressure and wind pressure";
  final parameter Real G = Modelica.Math.log(s) 
    "Natural logarithm of side ratio";

  Modelica.Blocks.Interfaces.RealInput winDir(unit="rad") 
    "Wind direction from weather bus";
  Modelica.SIunits.Angle surOut = azi-Modelica.Constants.pi 
    "Angle of surface that is used to compute angle of attack of wind";
equation 
  alpha = winDir-surOut;
  CpAct = Buildings.Airflow.Multizone.BaseClasses.windPressureLowRise(
            Cp0=Cp0, incAng=alpha, G=G);
  pWin = 0.5*CpAct*medium.d*vWin*vWin;
  pTot = pWea + pWin;

  connect(weaBus.winDir, winDir);
  connect(weaBus.winSpe, vWin);
  connect(weaBus.pAtm, pWea);
  connect(p_in_internal, pTot);
  connect(weaBus.TDryBul, T_in_internal);
end Outside_CpLowRise;

Buildings.Fluid.Sources.PrescribedExtraPropertyFlowRate

Source with mass flow that does not take part in medium mass balance (such as CO2)

Buildings.Fluid.Sources.PrescribedExtraPropertyFlowRate

Information

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.

Extends from Modelica.Fluid.Sources.BaseClasses.PartialSource (Partial component source with one fluid connector).

Parameters

Type Name Default Description

replaceable package Medium PartialMedium Medium model within the source

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]

Type	Name	Default	Description
replaceable package Medium	PartialMedium	Medium model within the source
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

FluidPorts_b ports[nPorts]

input RealInput m_flow_in Prescribed mass flow rate for extra property

Type	Name	Description
FluidPorts_b	ports[nPorts]
input RealInput	m_flow_in	Prescribed mass flow rate for extra property

Modelica definition

model PrescribedExtraPropertyFlowRate 
  "Source with mass flow that does not take part in medium mass balance (such as CO2)"
  extends Modelica.Fluid.Sources.BaseClasses.PartialSource(nPorts=1);

  parameter String substanceName = "CO2" "Name of trace substance";
  parameter Boolean use_m_flow_in = false 
    "Get the trace substance mass flow rate from the input connector";

  parameter Medium.MassFlowRate m_flow = 0 
    "Fixed mass flow rate going out of the fluid port";
  Modelica.Blocks.Interfaces.RealInput m_flow_in if 
       use_m_flow_in "Prescribed mass flow rate for extra property";

protected 
  Modelica.Blocks.Interfaces.RealInput m_flow_in_internal 
    "Needed to connect to conditional connector";
  parameter Medium.ExtraProperty C_in_internal[Medium.nC](
       fixed=false,
       quantity=Medium.extraPropertiesNames)=fill(0, Medium.nC) 
    "Boundary trace substances";
initial algorithm 
  for i in 1:Medium.nC loop
    if ( Modelica.Utilities.Strings.isEqual(string1=Medium.extraPropertiesNames[i],
                                            string2=substanceName,
                                            caseSensitive=false)) then
      C_in_internal[i] := 1;
    else
      C_in_internal[i] := 0;
    end if;
  end for;
  assert(sum(C_in_internal) > 1E-4, "Trace substance '" + substanceName + "' is not present in medium '"
         + Medium.mediumName + "'.\n"
         + "Check source parameter and medium model.");
equation 
  connect(m_flow_in, m_flow_in_internal);
  if not use_m_flow_in then
    m_flow_in_internal = m_flow;
  end if;

  assert(sum(m_flow_in_internal) >= 0, "Reverse flow for species source is not yet implemented.");
  sum(ports.m_flow) = -m_flow_in_internal;
  medium.T = Medium.T_default;
  medium.Xi = Medium.X_default[1:Medium.nXi];
  ports.C_outflow = fill(C_in_internal, nPorts);
end PrescribedExtraPropertyFlowRate;

Automatically generated Thu Jul 26 10:21:36 2012.