.Buildings.Fluid.FixedResistances.Validation.PlugFlowPipes.PlugFlowULg

Information

The example contains experimental data from a real district heating network.

This model compares the results with the original Modelica Standard Library pipes.

The pipes' temperatures are not initialized. Therefore, results of outflow temperature before approximately the first 10000 seconds should not be considered.

Test bench schematic

Calibration

There are some uncertainties about the heat loss coefficient between pipe and surrounding air as well as regarding the heat conductivity of the insulation material. With the given data, the length specific thermal resistance is R = 2.164 ((m K)/W), calculated as follows:

R=((1/(2*pipe.kIns)*log((0.0603+2*pipe.dIns)/(0.0603)))+1/(5*(0.0603+2*pipe.dIns)))/Modelica.Constants.pi

U = 1/R = 0.462 W/(m K)

Contents

Name	Description
Medium

Revisions

• April 29, 2026, by Michael Wetter:
  Changed configuration of table to cause the parameters to be evaluated, as this leads to more efficient code.
  This is for IBPSA, #2111.
• March 7, 2020, by Michael Wetter:
  Replaced measured data from specification in Modelica file to external table, as this reduces the computing time.
  This is for #1289.
• November 24, 2016 by Bram van der Heijde:
  Add pipe thickness for wall capacity calculation and expand documentation section.
• April 2, 2016 by Bram van der Heijde:
  Change thermal conductivity and put boundary condition in K.
• Januar 26, 2016 by Carles Ribas:
  First implementation.