.BuildingSystems.Fluid.Sources.Boundary_ph

Information

Defines prescribed values for boundary conditions:

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

Typical use and important parameters

If use_p_in is false (default option), the p parameter is used as boundary pressure, and the p_in input connector is disabled; if use_p_in is true, then the p parameter is ignored, and the value provided by the input connector is used instead.

The same applies to the specific enthalpy h, composition X_i or X and trace substances C.

Options

Instead of using Xi_in (the independent composition fractions), the advanced tab provides an option for setting all composition fractions using X_in. use_X_in and use_Xi_in cannot be used at the same time.

Parameter verifyInputs can be set to true to enable a check that verifies the validity of the used specific enthalpy and pressures. This removes the corresponding overhead from the model, which is a substantial part of the overhead of this model. See #882 for more information.

Note, that boundary specific enthalpy, mass fractions and trace substances have only an effect if the mass flow is from the boundary into the port. If mass is flowing from the port into the boundary, the boundary definitions, with exception of boundary pressure, do not have an effect.

Revisions

• March 11, 2024, by Michael Wetter:
  Corrected use of HideResult.
  This is for #1850.
• Juni 7, 2019, by Michael Wetter:
  Added constant boolean expressions to avoid a potential string comparison in an equation section.
  See #1148.
• Juni 4, 2019, by Filip Jorissen:
  Added check for the value of p and p_in.
  See #1148.
• January 25, 2019, by Michael Wetter:
  Refactored use of base classes.
  See #1072.
• February 2nd, 2018 by Filip Jorissen
  Made medium conditional and refactored inputs. See #882.
• April 18, 2017, by Filip Jorissen:
  Changed checkBoundary implementation such that it is run as an initial equation when it depends on parameters only. See #728.
• January 26, 2016, by Michael Wetter:
  Added unit and quantity attributes.
• May 29, 2014, by Michael Wetter:
  Removed undesirable annotation Evaluate=true.
• September 29, 2009, by Michael Wetter:
  First implementation. Implementation is based on Modelica.Fluid.