01114nas a2200121   4500008003900000245009700039210006900136520064700205100002000852700002000872700001800892856008200910       2015                          d00aSimulation Speed Analysis and Improvements of Modelica Models for Building Energy Simulation0 aSimulation Speed Analysis and Improvements of Modelica Models fo3 a<p>This paper presents an approach for speeding up Modelica models. Insight is provided into how Modelica models are solved and what determines the tool’s computational speed. Aspects such as algebraic loops, code efficiency and integrator choice are discussed. This is illustrated using simple building simulation examples and Dymola. The generality of the work is in some cases verified using OpenModelica. Using this approach, a medium sized office building including building envelope, heating ventilation and air conditioning (HVAC) systems and control strategy can be simulated at a speed five hundred times faster than real time.</p>1 aJorissen, Filip1 aWetter, Michael1 aHelsen, Lieve  uhttps://simulationresearch.lbl.gov/publications/simulation-speed-analysis-and