modelExample3

Information

This example demonstrates the importance of merging pressure drop components that are connected in series, into one pressure drop component. Parameter mergeDp.k can be used to merge two components that are connected in series. Parameter from_dp also has an influence of the computational speed.

Following script can be used in Dymola to compare the CPU times. For this script to work, make sure that Dymola stores at least 4 results.

cpuOld=OutputCPUtime;
evaluateOld=Evaluate;
OutputCPUtime:=true;
simulateModel("Buildings.Fluid.Examples.Performance.Example3(from_dp.k=false, mergeDp.k=false, nRes.k=10)", stopTime=1000, numberOfIntervals=10, method="dassl", resultFile="Example3");
simulateModel("Buildings.Fluid.Examples.Performance.Example3(from_dp.k=false, mergeDp.k=true, nRes.k=10)", stopTime=1000, numberOfIntervals=10, method="dassl", resultFile="Example3");
simulateModel("Buildings.Fluid.Examples.Performance.Example3(from_dp.k=true, mergeDp.k=false, nRes.k=10)", stopTime=1000, numberOfIntervals=10, method="dassl", resultFile="Example3");
simulateModel("Buildings.Fluid.Examples.Performance.Example3(from_dp.k=true, mergeDp.k=true, nRes.k=10)", stopTime=1000, numberOfIntervals=10, method="dassl", resultFile="Example3");
createPlot(id=1, position={15, 10, 592, 421}, range={0.0, 1000.0, -0.01, 8}, autoscale=false, grid=true);
plotExpression(apply(Example3[end-3].CPUtime), false, "from_dp=false, mergeDp=false", 1);
plotExpression(apply(Example3[end-2].CPUtime), false, "from_dp=false, mergeDp=true", 1);
plotExpression(apply(Example3[end-1].CPUtime), false, "from_dp=true, mergeDp=false", 1);
plotExpression(apply(Example3[end].CPUtime), false, "from_dp=true, mergeDp=true", 1);
OutputCPUtime=cpuOld;
Evaluate=evaluateOld;

See Jorissen et al. (2015) for a discussion.

References

• Filip Jorissen, Michael Wetter and Lieve Helsen.
  Simulation speed analysis and improvements of Modelica models for building energy simulation.
  Submitted: 11th Modelica Conference. Paris, France. Sep. 2015.

Parameters

Components

Contents

Name	Description
Medium

Revisions

• January 22, 2016, by Michael Wetter:
  Corrected type declaration of pressure difference. This is for #404.
• July 14, 2015, by Michael Wetter:
  Revised documentation.
• April 17, 2015, by Filip Jorissen:
  First implementation.