Buildings.Fluid.Sensors

Information

Package Sensors consists of idealized sensor components that provide variables of a medium model and/or fluid ports as output signals. These signals can be, e.g., further processed with components of the Modelica.Blocks library. Also more realistic sensor models can be built, by further processing (e.g., by attaching block Modelica.Blocks.FirstOrder to model the time constant of the sensor).

For the thermodynamic state variables temperature, specific entalpy, specific entropy and density the fluid library provides two different types of sensors: regular one port and two port sensors.

• The regular one port sensors have the advantage of easy introduction and removal from a model, as no connections have to be broken. A potential drawback is that the obtained value jumps as flow reverts. Modelica.Fluid.Test.TestComponents.Sensors.TestTemperatureSensor provides a test case, which demonstrates this.
• The two port sensors offer the advantages of an adjustable regularized step function around zero flow. Moreover the obtained result is restricted to the value flowing into port_a if allowFlowReversal is false.

Package Content

Name	Description
Conversions	Package with conversions for sensor models
Density	Ideal one port density sensor
DensityTwoPort	Ideal two port density sensor
EnthalpyFlowRate	Ideal enthalphy flow rate sensor
LatentEnthalpyFlowRate	Ideal enthalphy flow rate sensor that outputs the latent enthalpy flow rate only
MassFlowRate	Ideal sensor for mass flow rate
MassFraction	Ideal one port mass fraction sensor
Pressure	Ideal pressure sensor
RelativeHumidity	Ideal one port relative humidity sensor
RelativePressure	Ideal relative pressure sensor
RelativeTemperature	Ideal relative temperature sensor
SensibleEnthalpyFlowRate	Ideal enthalphy flow rate sensor that outputs the sensible enthalpy flow rate only
SpecificEnthalpy	Ideal one port specific enthalpy sensor
SpecificEnthalpyTwoPort	Ideal two port sensor for the specific enthalpy
SpecificEntropy	Ideal one port specific entropy sensor
SpecificEntropyTwoPort	Ideal two port sensor for the specific entropy
Temperature	Ideal one port temperature sensor
TemperatureDryBulbDynamic	Ideal temperature sensor
TemperatureTwoPort	Ideal two port temperature sensor
TemperatureWetBulb	Ideal wet bulb temperature sensor
TraceSubstances	Ideal one port trace substances sensor
TraceSubstancesTwoPort	Ideal two port sensor for trace substance
VolumeFlowRate	Ideal sensor for volume flow rate
Examples	Collection of models that illustrate model use and test models

Buildings.Fluid.Sensors.Density

Information

This component monitors the density of the fluid passing its port. The sensor is ideal, i.e. it does not influence the fluid.

If using the one port sensor please read the Information first.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor (Partial component to model a sensor that measures a potential variable), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the sensor

Connectors

Type	Name	Description
FluidPort_a	port
output RealOutput	d	Density in port medium [kg/m3]

Modelica definition

model Density "Ideal one port density sensor"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor;
  extends Modelica.Icons.RotationalSensor;
  Modelica.Blocks.Interfaces.RealOutput d(final quantity="Density",
                                          final unit="kg/m3",
                                          min=0) "Density in port medium";

equation 
  d = Medium.density(Medium.setState_phX(port.p, inStream(port.h_outflow), inStream(port.Xi_outflow)));
end Density;

Buildings.Fluid.Sensors.DensityTwoPort

Information

This component monitors the density of the fluid flowing from port_a to port_b. The sensor is ideal, i.e. it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor (Partial component to model sensors that measure flow properties), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
MassFlowRate	m_flow_small	system.m_flow_small	For bi-directional flow, density is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required) [kg/s]

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)
output RealOutput	d	Density of the passing fluid [kg/m3]

Modelica definition

model DensityTwoPort "Ideal two port density sensor"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor;
  extends Modelica.Icons.RotationalSensor;
  Modelica.Blocks.Interfaces.RealOutput d(final quantity="Density",
                                          final unit="kg/m3",
                                          min=0) "Density of the passing fluid";
  parameter Medium.MassFlowRate m_flow_small(min=0) = system.m_flow_small 
    "For bi-directional flow, density is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required)";
protected 
  Medium.Density rho_a_inflow "Density of inflowing fluid at port_a";
  Medium.Density rho_b_inflow 
    "Density of inflowing fluid at port_b or rho_a_inflow, if uni-directional flow";
equation 
  if allowFlowReversal then
     rho_a_inflow = Medium.density(Medium.setState_phX(port_b.p, port_b.h_outflow, port_b.Xi_outflow));
     rho_b_inflow = Medium.density(Medium.setState_phX(port_a.p, port_a.h_outflow, port_a.Xi_outflow));
     d = Modelica.Fluid.Utilities.regStep(port_a.m_flow, rho_a_inflow, rho_b_inflow, m_flow_small);
  else
     d = Medium.density(Medium.setState_phX(port_b.p, port_b.h_outflow, port_b.Xi_outflow));
     rho_a_inflow = d;
     rho_b_inflow = d;
  end if;
end DensityTwoPort;

Buildings.Fluid.Sensors.EnthalpyFlowRate

Information

This component monitors the enthalphy flow rate of the medium in the flow between fluid ports. The sensor is ideal, i.e., it does not influence the fluid.

For a sensor that measures the latent enthalpy flow rate, use Buildings.Fluid.Sensors.LatentEnthalpyFlowRate.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor (Partial component to model sensors that measure flow properties), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)

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)
output RealOutput	H_flow	Enthalpy flow rate, positive if from port_a to port_b [W]

Modelica definition

model EnthalpyFlowRate "Ideal enthalphy flow rate sensor"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor;
  extends Modelica.Icons.RotationalSensor;
  Modelica.Blocks.Interfaces.RealOutput H_flow(unit="W") 
    "Enthalpy flow rate, positive if from port_a to port_b";

equation 
  if allowFlowReversal then
     H_flow = port_a.m_flow * actualStream(port_a.h_outflow);
  else
     H_flow = port_a.m_flow * port_b.h_outflow;
  end if;
end EnthalpyFlowRate;

Buildings.Fluid.Sensors.LatentEnthalpyFlowRate

Information

This component monitors the latent enthalphy flow rate of the medium in the flow between fluid ports. In particular, if the enthalpy flow rate is

  HTotal_flow = HSensible_flow + HLatent_flow,

For a sensor that measures HTotal_flow, use Buildings.Fluid.Sensors.EnthalpyFlowRate.
For a sensor that measures HSensible_flow, use Buildings.Fluid.Sensors.SensibleEnthalpyFlowRate.

The sensor is ideal, i.e., it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor (Partial component to model sensors that measure flow properties), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)

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)
output RealOutput	H_flow	Latent enthalpy flow rate, positive if from port_a to port_b [W]

Modelica definition

model LatentEnthalpyFlowRate 
  "Ideal enthalphy flow rate sensor that outputs the latent enthalpy flow rate only"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor;
  extends Modelica.Icons.RotationalSensor;
  // redeclare Medium with a more restricting base class. This improves the error
  // message if a user selects a medium that does not contain the function
  // enthalpyOfLiquid(.)
  replaceable package Medium =
      Modelica.Media.Interfaces.PartialCondensingGases;

  Modelica.Blocks.Interfaces.RealOutput H_flow(unit="W") 
    "Latent enthalpy flow rate, positive if from port_a to port_b";
  Medium.MassFraction XiActual[Medium.nXi] "Medium mass fraction in port_a";
  Medium.SpecificEnthalpy hActual "Medium enthalpy in port_a";
  Medium.ThermodynamicState sta "Medium properties in port_a";

protected 
  parameter Integer i_w(min=1, fixed=false) "Index for water substance";
initial algorithm 
  i_w :=1;
    for i in 1:Medium.nXi loop
      if Modelica.Utilities.Strings.isEqual(Medium.substanceNames[i], "Water") then
        i_w :=i;
      end if;
    end for;
equation 
  if allowFlowReversal then
     XiActual = actualStream(port_a.Xi_outflow);
     hActual = actualStream(port_a.h_outflow);
     sta = Medium.setState_phX(port_a.p, hActual, XiActual);
  else
     XiActual = port_b.Xi_outflow;
     hActual = port_b.h_outflow;
     sta = Medium.setState_phX(port_b.p, port_b.h_outflow, XiActual);
  end if;
     // Compute H_flow as difference between total enthalpy and enthalpy on non-condensing gas.
     // This is needed to compute the liquid vs. gas fraction of water, using the equations
     // provided by the medium model
     H_flow = port_a.m_flow * (hActual -
       (1-XiActual[i_w]) * Medium.enthalpyOfNonCondensingGas(Medium.temperature(sta)));
end LatentEnthalpyFlowRate;

Buildings.Fluid.Sensors.MassFlowRate

Information

This component monitors the mass flow rate flowing from port_a to port_b. The sensor is ideal, i.e., it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor (Partial component to model sensors that measure flow properties), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)

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)
output RealOutput	m_flow	Mass flow rate from port_a to port_b [kg/s]

Modelica definition

model MassFlowRate "Ideal sensor for mass flow rate"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor;
  extends Modelica.Icons.RotationalSensor;
  Modelica.Blocks.Interfaces.RealOutput m_flow(quantity="MassFlowRate",
                                               final unit="kg/s") 
    "Mass flow rate from port_a to port_b";

equation 
  m_flow = port_a.m_flow;
end MassFlowRate;

Buildings.Fluid.Sensors.MassFraction

Information

This component monitors the mass fraction contained in the fluid passing its port. The sensor is ideal, i.e. it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor (Partial component to model a sensor that measures a potential variable), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the sensor
String	substanceName	"water"	Name of species substance

Connectors

Type	Name	Description
FluidPort_a	port
output RealOutput	X	Mass fraction in port medium

Modelica definition

model MassFraction "Ideal one port mass fraction sensor"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor;
  extends Modelica.Icons.RotationalSensor;
  parameter String substanceName = "water" "Name of species substance";

  Modelica.Blocks.Interfaces.RealOutput X "Mass fraction in port medium";

protected 
  parameter Integer ind(fixed=false) 
    "Index of species in vector of auxiliary substances";
  Medium.MassFraction XiVec[Medium.nXi](
      quantity=Medium.extraPropertiesNames) 
    "Trace substances vector, needed because indexed argument for the operator inStream is not supported";
initial algorithm 
  ind:= -1;
  for i in 1:Medium.nX loop
    if ( Modelica.Utilities.Strings.isEqual(Medium.substanceNames[i], substanceName)) then
      ind := i;
    end if;
  end for;
  assert(ind > 0, "Species with name '" + substanceName + "' is not present in medium '"
         + Medium.mediumName + "'.\n"
         + "Check sensor parameter and medium model.");
equation 
  XiVec = inStream(port.Xi_outflow);
  X = if ind > Medium.nXi then (1-sum(XiVec)) else XiVec[ind];
end MassFraction;

Buildings.Fluid.Sensors.Pressure

Information

This component monitors the absolute pressure at its fluid port. The sensor is ideal, i.e., it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor (Partial component to model a sensor that measures a potential variable), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the sensor

Connectors

Type	Name	Description
FluidPort_a	port
output RealOutput	p	Pressure at port [Pa]

Modelica definition

model Pressure "Ideal pressure sensor"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor;
  extends Modelica.Icons.RotationalSensor;
  Modelica.Blocks.Interfaces.RealOutput p(final quantity="Pressure",
                                          final unit="Pa",
                                          min=0) "Pressure at port";
equation 
  p = port.p;
end Pressure;

Buildings.Fluid.Sensors.RelativeHumidity

Information

This component monitors the relative humidity contained in the fluid passing its port. The sensor is ideal, i.e. it does not influence the fluid.

Note that this sensor can only be used with media that contain the variable phi, which is typically the case for moist air models.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor (Partial component to model a sensor that measures a potential variable), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the sensor

Connectors

Type	Name	Description
FluidPort_a	port
output RealOutput	phi	Relative humidity in port medium

Modelica definition

model RelativeHumidity "Ideal one port relative humidity sensor"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor;
  extends Modelica.Icons.RotationalSensor;

  Modelica.Blocks.Interfaces.RealOutput phi "Relative humidity in port medium";

  Medium.BaseProperties med "Medium state at dry bulb temperature";

equation 
  med.p = port.p;
  med.h = inStream(port.h_outflow);
  med.Xi = inStream(port.Xi_outflow);
  phi = med.phi;

end RelativeHumidity;

Buildings.Fluid.Sensors.RelativePressure

Information

The relative pressure "port_a.p - port_b.p" is determined between the two ports of this component and is provided as output signal. The sensor should be connected in parallel with other equipment, no flow through the sensor is allowed.

Extends from Modelica.Icons.TranslationalSensor (Icon representing translational measurement device).

Connectors

Type	Name	Description
FluidPort_a	port_a
FluidPort_b	port_b
output RealOutput	p_rel	Relative pressure signal [Pa]

Modelica definition

model RelativePressure "Ideal relative pressure sensor"
  extends Modelica.Icons.TranslationalSensor;
  replaceable package Medium =
    Modelica.Media.Interfaces.PartialMedium "Medium in the sensor";

  Modelica.Fluid.Interfaces.FluidPort_a port_a(m_flow(min=0),
                                p(start=Medium.p_default),
                                redeclare package Medium = Medium);
  Modelica.Fluid.Interfaces.FluidPort_b port_b(m_flow(min=0),
                                p(start=Medium.p_default),
                                redeclare package Medium = Medium);

  Modelica.Blocks.Interfaces.RealOutput p_rel(final quantity="Pressure",
                                              final unit="Pa",
                                              displayUnit="bar") 
    "Relative pressure signal";
equation 
  // Zero flow equations for connectors
  port_a.m_flow = 0;
  port_b.m_flow = 0;

  // No contribution of specific quantities
  port_a.h_outflow = 0;
  port_b.h_outflow = 0;
  port_a.Xi_outflow = zeros(Medium.nXi);
  port_b.Xi_outflow = zeros(Medium.nXi);
  port_a.C_outflow  = zeros(Medium.nC);
  port_b.C_outflow  = zeros(Medium.nC);

  // Relative pressure
  p_rel = port_a.p - port_b.p;
end RelativePressure;

Buildings.Fluid.Sensors.RelativeTemperature

Information

The relative temperature "T(port_a) - T(port_b)" is determined between the two ports of this component and is provided as output signal. The sensor should be connected in parallel with other equipment, no flow through the sensor is allowed.

Extends from Modelica.Icons.TranslationalSensor (Icon representing translational measurement device).

Connectors

Type	Name	Description
FluidPort_a	port_a
FluidPort_b	port_b
output RealOutput	T_rel	Relative temperature signal [K]

Modelica definition

model RelativeTemperature "Ideal relative temperature sensor"
  extends Modelica.Icons.TranslationalSensor;
  replaceable package Medium =
    Modelica.Media.Interfaces.PartialMedium "Medium in the sensor";
  Modelica.Fluid.Interfaces.FluidPort_a port_a(m_flow(min=0),
                                p(start=Medium.p_default),
                                redeclare package Medium = Medium);
  Modelica.Fluid.Interfaces.FluidPort_b port_b(m_flow(min=0),
                                p(start=Medium.p_default),
                                redeclare package Medium = Medium);

  Modelica.Blocks.Interfaces.RealOutput T_rel(final quantity="ThermodynamicTemperature",
                                              final unit = "K", displayUnit = "degC", min=0) 
    "Relative temperature signal";
equation 
  // Zero flow equations for connectors
  port_a.m_flow = 0;
  port_b.m_flow = 0;

  // No contribution of specific quantities
  port_a.h_outflow = 0;
  port_b.h_outflow = 0;
  port_a.Xi_outflow = zeros(Medium.nXi);
  port_b.Xi_outflow = zeros(Medium.nXi);
  port_a.C_outflow  = zeros(Medium.nC);
  port_b.C_outflow  = zeros(Medium.nC);

  // Relative temperature
  T_rel = Medium.temperature(Medium.setState_phX(port_a.p, inStream(port_a.h_outflow), inStream(port_a.Xi_outflow))) -
          Medium.temperature(Medium.setState_phX(port_b.p, inStream(port_b.h_outflow), inStream(port_b.Xi_outflow)));
end RelativeTemperature;

Buildings.Fluid.Sensors.SensibleEnthalpyFlowRate

Information

This component monitors the sensible enthalphy flow rate of the medium in the flow between fluid ports. In particular, if the enthalpy flow rate is

  HTotal_flow = HSensible_flow + HLatent_flow,

For a sensor that measures HTotal_flow, use Buildings.Fluid.Sensors.EnthalpyFlowRate.
For a sensor that measures HLatent_flow, use Buildings.Fluid.Sensors.LatentEnthalpyFlowRate.

The sensor is ideal, i.e., it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor (Partial component to model sensors that measure flow properties), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)

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)
output RealOutput	H_flow	Sensible enthalpy flow rate, positive if from port_a to port_b [W]

Modelica definition

model SensibleEnthalpyFlowRate 
  "Ideal enthalphy flow rate sensor that outputs the sensible enthalpy flow rate only"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor;
  extends Modelica.Icons.RotationalSensor;
  // redeclare Medium with a more restricting base class. This improves the error
  // message if a user selects a medium that does not contain the function
  // enthalpyOfLiquid(.)
  replaceable package Medium =
      Modelica.Media.Interfaces.PartialCondensingGases;

  Modelica.Blocks.Interfaces.RealOutput H_flow(unit="W") 
    "Sensible enthalpy flow rate, positive if from port_a to port_b";
  Medium.MassFraction XiActual[Medium.nXi] "Medium mass fraction in port_a";
  Medium.ThermodynamicState sta "Medium properties in port_a";

protected 
  parameter Integer i_w(min=1, fixed=false) "Index for water substance";
initial algorithm 
  i_w :=1;
    for i in 1:Medium.nXi loop
      if Modelica.Utilities.Strings.isEqual(Medium.substanceNames[i], "Water") then
        i_w :=i;
      end if;
    end for;
equation 
  if allowFlowReversal then
     XiActual = actualStream(port_a.Xi_outflow);
     sta = Medium.setState_phX(port_a.p, actualStream(port_a.h_outflow), XiActual);
  else
     XiActual = port_b.Xi_outflow;
     sta = Medium.setState_phX(port_b.p, port_b.h_outflow, XiActual);
  end if;
     H_flow = port_a.m_flow * (1-XiActual[i_w]) * Medium.enthalpyOfNonCondensingGas(Medium.temperature(sta));
end SensibleEnthalpyFlowRate;

Buildings.Fluid.Sensors.SpecificEnthalpy

Information

This component monitors the specific enthalpy of the fluid passing its port. The sensor is ideal, i.e. it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor (Partial component to model a sensor that measures a potential variable), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the sensor

Connectors

Type	Name	Description
FluidPort_a	port
output RealOutput	h_out	Specific enthalpy in port medium [J/kg]

Modelica definition

model SpecificEnthalpy "Ideal one port specific enthalpy sensor"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor;
  extends Modelica.Icons.RotationalSensor;
  Modelica.Blocks.Interfaces.RealOutput h_out(final quantity="SpecificEnergy",
                                              final unit="J/kg") 
    "Specific enthalpy in port medium";

equation 
  h_out = inStream(port.h_outflow);
end SpecificEnthalpy;

Buildings.Fluid.Sensors.SpecificEnthalpyTwoPort

Information

This component monitors the specific enthalpy of a passing fluid. The sensor is ideal, i.e. it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor (Partial component to model sensors that measure flow properties), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
MassFlowRate	m_flow_small	system.m_flow_small	For bi-directional flow, specific enthalpy is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required) [kg/s]

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)
output RealOutput	h_out	Specific enthalpy of the passing fluid [J/kg]

Modelica definition

model SpecificEnthalpyTwoPort 
  "Ideal two port sensor for the specific enthalpy"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor;
  extends Modelica.Icons.RotationalSensor;
  Modelica.Blocks.Interfaces.RealOutput h_out(final quantity="SpecificEnergy",
                                              final unit="J/kg") 
    "Specific enthalpy of the passing fluid";

  parameter Medium.MassFlowRate m_flow_small(min=0) = system.m_flow_small 
    "For bi-directional flow, specific enthalpy is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required)";

equation 
  if allowFlowReversal then
     h_out = Modelica.Fluid.Utilities.regStep(port_a.m_flow, port_b.h_outflow, port_a.h_outflow, m_flow_small);
  else
     h_out = port_b.h_outflow;
  end if;
end SpecificEnthalpyTwoPort;

Buildings.Fluid.Sensors.SpecificEntropy

Information

This component monitors the specific entropy of the fluid passing its port. The sensor is ideal, i.e. it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor (Partial component to model a sensor that measures a potential variable), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the sensor

Connectors

Type	Name	Description
FluidPort_a	port
output RealOutput	s	Specific entropy in port medium [J/(kg.K)]

Modelica definition

model SpecificEntropy "Ideal one port specific entropy sensor"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor;
  extends Modelica.Icons.RotationalSensor;
  Modelica.Blocks.Interfaces.RealOutput s(final quantity="SpecificEntropy",
                                          final unit="J/(kg.K)") 
    "Specific entropy in port medium";

equation 
  s = Medium.specificEntropy(Medium.setState_phX(port.p, inStream(port.h_outflow), inStream(port.Xi_outflow)));
end SpecificEntropy;

Buildings.Fluid.Sensors.SpecificEntropyTwoPort

Information

This component monitors the specific entropy of the passing fluid. The sensor is ideal, i.e. it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor (Partial component to model sensors that measure flow properties), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
MassFlowRate	m_flow_small	system.m_flow_small	For bi-directional flow, specific entropy is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required) [kg/s]

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)
output RealOutput	s	Specific entropy of the passing fluid [J/(kg.K)]

Modelica definition

model SpecificEntropyTwoPort 
  "Ideal two port sensor for the specific entropy"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor;
  extends Modelica.Icons.RotationalSensor;
  Modelica.Blocks.Interfaces.RealOutput s(final quantity="SpecificEntropy",
                                          final unit="J/(kg.K)") 
    "Specific entropy of the passing fluid";
  parameter Medium.MassFlowRate m_flow_small(min=0) = system.m_flow_small 
    "For bi-directional flow, specific entropy is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required)";

protected 
  Medium.SpecificEntropy s_a_inflow 
    "Specific entropy of inflowing fluid at port_a";
  Medium.SpecificEntropy s_b_inflow 
    "Specific entropy of inflowing fluid at port_b or s_a_inflow, if uni-directional flow";
equation 
  if allowFlowReversal then
     s_a_inflow = Medium.specificEntropy(Medium.setState_phX(port_b.p, port_b.h_outflow, port_b.Xi_outflow));
     s_b_inflow = Medium.specificEntropy(Medium.setState_phX(port_a.p, port_a.h_outflow, port_a.Xi_outflow));
     s = Modelica.Fluid.Utilities.regStep(port_a.m_flow, s_a_inflow, s_b_inflow, m_flow_small);
  else
     s = Medium.specificEntropy(Medium.setState_phX(port_b.p, port_b.h_outflow, port_b.Xi_outflow));
     s_a_inflow = s;
     s_b_inflow = s;
  end if;
end SpecificEntropyTwoPort;

Buildings.Fluid.Sensors.Temperature

Information

This component monitors the temperature of the fluid passing its port. The sensor is ideal, i.e. it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor (Partial component to model a sensor that measures a potential variable).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the sensor

Connectors

Type	Name	Description
FluidPort_a	port
output RealOutput	T	Temperature in port medium [K]

Modelica definition

model Temperature "Ideal one port temperature sensor"
    extends Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor;

  Modelica.Blocks.Interfaces.RealOutput T(final quantity="ThermodynamicTemperature",
                                          final unit = "K", min=0,
                                          displayUnit = "degC") 
    "Temperature in port medium";

equation 
  T = Medium.temperature(Medium.setState_phX(port.p, inStream(port.h_outflow), inStream(port.Xi_outflow)));
end Temperature;

Buildings.Fluid.Sensors.TemperatureDryBulbDynamic

Information

This component monitors the temperature of the medium in the flow between fluid ports. The sensor does not influence the fluid. Its output is computed using a first order differential equation.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor (Partial component to model sensors that measure flow properties).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Time	tau	10	Time constant [s]
Nominal condition
MassFlowRate	m_flow_nominal		Nominal mass flow rate [kg/s]
Initialization
Init	initType	Modelica.Blocks.Types.Init.N...	Type of initialization (InitialState and InitialOutput are identical)
Temperature	T_start	Medium.T_default	Initial or guess value of output (= state) [K]
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
MassFlowRate	m_flow_small	1E-4*m_flow_nominal	For bi-directional flow, temperature is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required) [kg/s]

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)
output RealOutput	T	Temperature of the passing fluid [K]

Modelica definition

model TemperatureDryBulbDynamic "Ideal temperature sensor"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor;

  parameter Modelica.SIunits.Time tau(min=0) = 10 "Time constant";
  Modelica.Blocks.Interfaces.RealOutput T( final quantity="ThermodynamicTemperature",
                                           final unit="K",
                                           displayUnit = "degC",
                                           min = 0,
                                           start=T_start) 
    "Temperature of the passing fluid";

  parameter Medium.MassFlowRate m_flow_nominal(min=0) "Nominal mass flow rate";
  parameter Medium.MassFlowRate m_flow_small(min=0) = 1E-4*m_flow_nominal 
    "For bi-directional flow, temperature is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required)";

  parameter Modelica.Blocks.Types.Init initType = Modelica.Blocks.Types.Init.NoInit 
    "Type of initialization (InitialState and InitialOutput are identical)";
  parameter Modelica.SIunits.Temperature T_start=Medium.T_default 
    "Initial or guess value of output (= state)";
// temporarily made public for testing of large model protected
  Medium.Temperature T_a_inflow "Temperature of inflowing fluid at port_a";
  Medium.Temperature T_b_inflow 
    "Temperature of inflowing fluid at port_b or T_a_inflow, if uni-directional flow";
  Medium.Temperature TMed "Medium to which sensor is exposed";
initial equation 
  if initType == Modelica.Blocks.Types.Init.SteadyState then
    der(T) = 0;
  elseif initType == Modelica.Blocks.Types.Init.InitialState or 
         initType == Modelica.Blocks.Types.Init.InitialOutput then
    T = T_start;
  end if;
equation 
  if allowFlowReversal then
     T_a_inflow = Medium.temperature(Medium.setState_phX(port_b.p, port_b.h_outflow, port_b.Xi_outflow));
     T_b_inflow = Medium.temperature(Medium.setState_phX(port_a.p, port_a.h_outflow, port_a.Xi_outflow));
     TMed = Modelica.Fluid.Utilities.regStep(port_a.m_flow, T_a_inflow, T_b_inflow, m_flow_small);
  else
     TMed = Medium.temperature(Medium.setState_phX(port_b.p, port_b.h_outflow, port_b.Xi_outflow));
     T_a_inflow = TMed;
     T_b_inflow = TMed;
  end if;
  der(T)  = (TMed-T)/tau;
end TemperatureDryBulbDynamic;

Buildings.Fluid.Sensors.TemperatureTwoPort

Information

This component monitors the temperature of the passing fluid. The sensor is ideal, i.e. it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor (Partial component to model sensors that measure flow properties).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
MassFlowRate	m_flow_small	system.m_flow_small	For bi-directional flow, temperature is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required) [kg/s]

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)
output RealOutput	T	Temperature of the passing fluid [K]

Modelica definition

model TemperatureTwoPort "Ideal two port temperature sensor"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor;

  Modelica.Blocks.Interfaces.RealOutput T( final quantity="ThermodynamicTemperature",
                                           final unit="K",
                                           displayUnit = "degC",
                                           min = 0) 
    "Temperature of the passing fluid";
  parameter Medium.MassFlowRate m_flow_small(min=0) = system.m_flow_small 
    "For bi-directional flow, temperature is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required)";

protected 
  Medium.Temperature T_a_inflow "Temperature of inflowing fluid at port_a";
  Medium.Temperature T_b_inflow 
    "Temperature of inflowing fluid at port_b or T_a_inflow, if uni-directional flow";
equation 
  if allowFlowReversal then
     T_a_inflow = Medium.temperature(Medium.setState_phX(port_b.p, port_b.h_outflow, port_b.Xi_outflow));
     T_b_inflow = Medium.temperature(Medium.setState_phX(port_a.p, port_a.h_outflow, port_a.Xi_outflow));
     T = Modelica.Fluid.Utilities.regStep(port_a.m_flow, T_a_inflow, T_b_inflow, m_flow_small);
  else
     T = Medium.temperature(Medium.setState_phX(port_b.p, port_b.h_outflow, port_b.Xi_outflow));
     T_a_inflow = T;
     T_b_inflow = T;
  end if;
end TemperatureTwoPort;

Buildings.Fluid.Sensors.TemperatureWetBulb

Information

This component monitors the wet bulb temperature of the medium in the flow between fluid ports. The sensor is ideal, i.e., it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor (Partial component to model sensors that measure flow properties).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
MassFlowRate	m_flow_small	1e-4	For bi-directional flow, specific enthalpy is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required) [kg/s]

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)
output RealOutput	T	Wet bulb temperature in port medium [K]

Modelica definition

model TemperatureWetBulb "Ideal wet bulb temperature sensor"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor;

  Modelica.Blocks.Interfaces.RealOutput T(
    start=Medium.T_default,
    final quantity="Temperature",
    final unit="K",
    displayUnit = "degC") "Wet bulb temperature in port medium";
  parameter Medium.MassFlowRate m_flow_small(min=0) = 1e-4 
    "For bi-directional flow, specific enthalpy is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required)";
protected 
  Buildings.Utilities.Psychrometrics.Twb_TdbXi wetBulMod(redeclare package
      Medium = Medium) "Block for wet bulb temperature";
  Modelica.SIunits.SpecificEnthalpy h "Specific enthalpy";
  Medium.MassFraction Xi[Medium.nXi] 
    "Species vector, needed because indexed argument for the operator inStream is not supported";
  //Medium.MassFraction X[Medium.nX] "Species vector";
equation 

  if allowFlowReversal then
    h  = Modelica.Fluid.Utilities.regStep(port_a.m_flow, port_b.h_outflow, port_a.h_outflow, m_flow_small);
    Xi = Modelica.Fluid.Utilities.regStep(port_a.m_flow, port_b.Xi_outflow, port_a.Xi_outflow, m_flow_small);
  else
    h = port_b.h_outflow;
    Xi = port_b.Xi_outflow;
  end if;
  // Compute wet bulb temperature
  wetBulMod.Tdb = Medium.T_phX(port_a.p, h, cat(1,Xi,{1-sum(Xi)}));
  wetBulMod.Xi = Xi;
  wetBulMod.p  = port_a.p;
  T = wetBulMod.Twb;
end TemperatureWetBulb;

Buildings.Fluid.Sensors.TraceSubstances

Information

This component monitors the trace substances contained in the fluid passing its port. The sensor is ideal, i.e. it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor (Partial component to model a sensor that measures a potential variable), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the sensor
String	substanceName	"CO2"	Name of trace substance

Connectors

Type	Name	Description
FluidPort_a	port
output RealOutput	C	Trace substance in port medium

Modelica definition

model TraceSubstances "Ideal one port trace substances sensor"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialAbsoluteSensor;
  extends Modelica.Icons.RotationalSensor;
  parameter String substanceName = "CO2" "Name of trace substance";

  Modelica.Blocks.Interfaces.RealOutput C "Trace substance in port medium";

protected 
  parameter Integer ind(fixed=false) 
    "Index of species in vector of auxiliary substances";
  parameter Real s[Medium.nC](fixed=false) 
    "Vector with zero everywhere except where species is";
  Medium.ExtraProperty CVec[Medium.nC](
      quantity=Medium.extraPropertiesNames) 
    "Trace substances vector, needed because indexed argument for the operator inStream is not supported";
initial algorithm 
  ind:= -1;
  for i in 1:Medium.nC loop
    if ( Modelica.Utilities.Strings.isEqual(Medium.extraPropertiesNames[i], substanceName)) then
      ind := i;
      s[i] :=1;
    else
      s[i] :=0;
    end if;
  end for;
  assert(ind > 0, "Trace substance '" + substanceName + "' is not present in medium '"
         + Medium.mediumName + "'.\n"
         + "Check sensor parameter and medium model.");
equation 
  CVec = inStream(port.C_outflow);
  // We obtain the species concentration with a vector multiplication
  // because Dymola 7.3 cannot find the derivative in the model
  // Buildings.Examples.VAVSystemCTControl.mo
  // if we set C = CVec[ind];
  C = s*CVec;
end TraceSubstances;

Buildings.Fluid.Sensors.TraceSubstancesTwoPort

Information

This component monitors the trace substance of the passing fluid. The sensor is ideal, i.e. it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor (Partial component to model sensors that measure flow properties), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
String	substanceName	"CO2"	Name of trace substance
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
MassFlowRate	m_flow_small	system.m_flow_small	For bi-directional flow, trace substance is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required) [kg/s]

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)
output RealOutput	C	Trace substance of the passing fluid

Modelica definition

model TraceSubstancesTwoPort 
  "Ideal two port sensor for trace substance"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor;
  extends Modelica.Icons.RotationalSensor;
  Modelica.Blocks.Interfaces.RealOutput C 
    "Trace substance of the passing fluid";
  parameter String substanceName = "CO2" "Name of trace substance";
  parameter Medium.MassFlowRate m_flow_small(min=0) = system.m_flow_small 
    "For bi-directional flow, trace substance is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required)";

protected 
  parameter Integer ind(fixed=false) 
    "Index of species in vector of auxiliary substances";
initial algorithm 
  ind:= -1;
  for i in 1:Medium.nC loop
    if ( Modelica.Utilities.Strings.isEqual(Medium.extraPropertiesNames[i], substanceName)) then
      ind := i;
    end if;
  end for;
  assert(ind > 0, "Trace substance '" + substanceName + "' is not present in medium '"
         + Medium.mediumName + "'.\n"
         + "Check sensor parameter and medium model.");
equation 
  if allowFlowReversal then
     C = Modelica.Fluid.Utilities.regStep(port_a.m_flow, port_b.C_outflow[ind], port_a.C_outflow[ind], m_flow_small);
  else
     C = port_b.C_outflow[ind];
  end if;
end TraceSubstancesTwoPort;

Buildings.Fluid.Sensors.VolumeFlowRate

Information

This component monitors the volume flow rate flowing from port_a to port_b. The sensor is ideal, i.e. it does not influence the fluid.

Extends from Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor (Partial component to model sensors that measure flow properties), Modelica.Icons.RotationalSensor (Icon representing rotational measurement device).

Parameters

Type	Name	Default	Description
replaceable package Medium		PartialMedium	Medium in the component
Assumptions
Boolean	allowFlowReversal	system.allowFlowReversal	= true to allow flow reversal, false restricts to design direction (port_a -> port_b)
Advanced
MassFlowRate	m_flow_small	system.m_flow_small	For bi-directional flow, density is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required) [kg/s]

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)
output RealOutput	V_flow	Volume flow rate from port_a to port_b [m3/s]

Modelica definition

model VolumeFlowRate "Ideal sensor for volume flow rate"
  extends Modelica.Fluid.Sensors.BaseClasses.PartialFlowSensor;
  extends Modelica.Icons.RotationalSensor;
  Modelica.Blocks.Interfaces.RealOutput V_flow(final quantity="VolumeFlowRate",
                                               final unit="m3/s") 
    "Volume flow rate from port_a to port_b";
  parameter Medium.MassFlowRate m_flow_small(min=0) = system.m_flow_small 
    "For bi-directional flow, density is regularized in the region |m_flow| < m_flow_small (m_flow_small > 0 required)";

protected 
  Medium.Density rho_a_inflow "Density of inflowing fluid at port_a";
  Medium.Density rho_b_inflow 
    "Density of inflowing fluid at port_b or rho_a_inflow, if uni-directional flow";
  Medium.Density d "Density of the passing fluid";
equation 
  if allowFlowReversal then
     rho_a_inflow = Medium.density(Medium.setState_phX(port_b.p, port_b.h_outflow, port_b.Xi_outflow));
     rho_b_inflow = Medium.density(Medium.setState_phX(port_a.p, port_a.h_outflow, port_a.Xi_outflow));
     d = Modelica.Fluid.Utilities.regStep(port_a.m_flow, rho_a_inflow, rho_b_inflow, m_flow_small);
  else
     d = Medium.density(Medium.setState_phX(port_b.p, port_b.h_outflow, port_b.Xi_outflow));
     rho_a_inflow = d;
     rho_b_inflow = d;
  end if;
  V_flow = port_a.m_flow/d;
end VolumeFlowRate;