modelLatentEnthalpyFlowRate

Ideal enthalphy flow rate sensor that outputs the latent enthalpy flow rate only
▶ Check in your browser

Extends from IBPSA.Fluid.Sensors.BaseClasses.PartialDynamicFlowSensor, IBPSA.Fluid.BaseClasses.IndexMassFraction, Modelica.Icons.RotationalSensor.

Information

This model outputs the latent 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 = Ḣlat.

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

For a sensor that measures Ḣtot, use IBPSA.Fluid.Sensors.EnthalpyFlowRate.
For a sensor that measures Ḣsen, use IBPSA.Fluid.Sensors.SensibleEnthalpyFlowRate.

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.SIunits.SpecificEnthalpyh_out_startMedium.specificEnthalpy_pTX(p = Medium.p_default, T = Medium.T_default, X = Medium.X_default) - Medium.enthalpyOfNonCondensingGas(T = Medium.T_default)Initial or guess value of measured specific latent enthalpy

Components

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

Revisions

  • January 18, 2016 by Filip Jorissen:
    Using parameter tauInv since this now exists in IBPSA.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 IBPSA.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 medium model.
  • September 9, 2009 by Michael Wetter:
    First implementation. Implementation is based on enthalpy sensor of Modelica.Fluid.