modelSensibleEnthalpyFlowRate

Ideal enthalphy flow rate sensor that outputs the sensible enthalpy flow rate only

Extends from BuildingSystems.Fluid.Sensors.BaseClasses.PartialDynamicFlowSensor, BuildingSystems.Fluid.BaseClasses.IndexMassFraction, Modelica.Icons.RoundSensor.

Information

This model outputs the sensible enthalphy flow rate of the medium in the flow between its fluid ports. In particular, if the total enthalpy flow rate is

Ḣtot = Ḣsen + Ḣlat,

where Ḣsen = ṁ (1-Xw) cp,air, then this sensor outputs Ḣ = Ḣsen.

If the parameter tau is non-zero, then the measured specific sensible enthalpy hout that is used to compute the sensible enthalpy flow rate Ḣsen = ṁ hout is computed using a first order differential equation. See BuildingSystems.Fluid.Sensors.UsersGuide for an explanation.

For a sensor that measures Ḣtot, use BuildingSystems.Fluid.Sensors.EnthalpyFlowRate.
For a sensor that measures Ḣlat, use BuildingSystems.Fluid.Sensors.LatentEnthalpyFlowRate.

The sensor is ideal, i.e., it does not influence the fluid. The sensor can only be used with medium models that implement the function enthalpyOfNonCondensingGas(T).

Parameters

TypeNameDefaultDescription
Initialization
Modelica.Units.SI.SpecificEnthalpyh_out_startMedium.enthalpyOfNonCondensingGas(T = Medium.T_default)Initial or guess value of measured specific sensible enthalpy

Components

TypeNameDefaultDescription
Modelica.Blocks.Interfaces.RealOutputH_flowSensible enthalpy flow rate, positive if from port_a to port_b

Revisions

  • October 19, 2020, by Antoine Gautier:
    Changed default value for tau from 1 to 0.
    This is for #1406.
  • February 25, 2020, by Michael Wetter:
    Changed icon to display its operating state.
    This is for #1294.
  • January 18, 2016 by Filip Jorissen:
    Using parameter tauInv since this now exists in BuildingSystems.Fluid.Sensors.BaseClasses.PartialDynamicFlowSensor. This is for #372.
  • September 10, 2013, by Michael Wetter:
    Changed medium declaration in the extends statement to replaceable to avoid a translation error in OpenModelica.
  • August 31, 2013, by Michael Wetter:
    Removed default value tau=0 as the base class already sets tau=1. This change was made so that all sensors use the same default value.
  • December 18, 2012, by Michael Wetter:
    Moved computation of i_w to new base class BuildingSystems.Fluid.BaseClasses.IndexWater. The value of this parameter is now assigned dynamically and does not require to be specified by the user.
  • November 3, 2011, by Michael Wetter:
    Moved der(h_out) := 0; from the initial algorithm section to the initial equation section as this assignment does not conform to the Modelica specification.
  • August 10, 2011 by Michael Wetter:
    Added parameter i_w and an assert statement to make sure it is set correctly. Without this change, Dymola cannot differentiate the model when reducing the index of the DAE.
  • June 3, 2011 by Michael Wetter:
    Revised implementation to add dynamics in such a way that the time constant increases as the mass flow rate tends to zero. This can improve the numerics.
  • February 22, by Michael Wetter:
    Improved code that searches for index of 'water' in the medium model.
  • September 9, 2009 by Michael Wetter:
    First implementation. Implementation is based on enthalpy sensor of Modelica.Fluid.