The OpenModelica Integrated Environment for Modeling, Simulation, and Model-Based Development

Fritzson, Peter; Pop, Adrian; Abdelhak, Karim; Ashgar, Adeel; Bachmann, Bernhard; Braun, Willi; Bouskela, Daniel; Braun, Robert; Buffoni, Lena; Casella, Francesco; Castro, Rodrigo; Franke, Rüdiger; Fritzson, Dag; Gebremedhin, Mahder; Heuermann, Andreas; Lie, Bernt; Mengist, Alachew; Mikelsons, Lars; Moudgalya, Kannan M.; Ochel, Lennart; Palanisamy, Arunkumar; Ruge, Vitalij; Schamai, Wladimir; Sjölund, Martin; Thiele, Bernhard; Tinnerholm, John; Östlund, Per

doi:10.4173/mic.2020.4.1

Cited by 106 publications

(59 citation statements)

References 82 publications

(75 reference statements)

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“…Also, the trajectory of the input guard γ (here called g) has been fully specified: it takes the value T between t 1 and t 2 and F otherwise. This model is deemed structurally nonsingular by the two Modelica tools we had the opportunity to test: OpenModelica 1.17.0 (Fritzson et al 2020) and Dymola 2021 (Dassault Systèmes AB 2020). However, none of these tools generates correct simulation code from this model.…”

Section: An Ideal Clutchmentioning

confidence: 99%

Handling Multimode Models and Mode Changes in Modelica

Benveniste¹,

Caillaud²,

Malandain³

2021

Linköping Electronic Conference Proceedings

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Since its version 3.3, the Modelica language offers the possibility to model multimode systems having different DAE-based dynamics in each mode, thanks to the introduction of state machines. When the differentiation index and structure varies with mode changes, compilers generate erroneous simulation code, often resulting in runtime exceptions. We propose in this paper a multimode structural analysis for both multiple modes and mode change events and we show how correct code for restarts can be generated. Our approach is illustrated on two simple but representative mechanical systems.

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Section: An Ideal Clutchmentioning

confidence: 99%

Handling Multimode Models and Mode Changes in Modelica

Benveniste¹,

Caillaud²,

Malandain³

2021

Linköping Electronic Conference Proceedings

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“…The OPTIMICA Compiler Toolkit [34], with its a graphical user interface IMPACT, is also available commercially. OpenModelica [35] and JModelica [36] provide open-source environments for Modelica-based modeling and simulation. While there are many suitable numerical solvers for solving DC system models, we frequently adopt CVODE [37] for its suitability for solving stiff problems.…”

Section: Step 5: Run Numerical Simulationsmentioning

confidence: 99%

Modelica-Based Modeling and Simulation of District Cooling Systems: A Case Study

Hinkelman¹,

Wang²,

Gautier³

et al. 2021

Preprint

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While equation-based object-oriented modeling language Modelica can evaluate practical energy improvements for district cooling systems, few have adapted Modelica for this type of large-scale thermo-fluid system. Further, to our best knowledge, district cooling modeling studies have yet to include hydraulics in piping network nor waterside economizers. These are critical details to include when looking to make energy and control improvements in many physical system installations. To fi?ll these gaps, this study applies newly developed open-source models from the Modelica Buildings library. For a real-world case study, we modeled and simulated a district cooling system at a college campus in Colorado, United States, with six buildings connected to a central chiller plant featuring a waterside economizer. Several energy saving strategies are pursued based on the validated model, including control setpoint optimization, equipment modification, and pump setpoint adjustments. Results indicate that optimizing the condenser water supply temperature setpoint can save 2.5% to 4.4% energy; the nonintegrated waterside economizer saves 6.4% energy while cutting down the chillers' run times by 201 days/year, reducing maintenance costs, and extending chiller life; and adjusting the condenser water pump flow settings can save 10.2% energy. Through a combinationof the studied measures, the campus can annually save 84.6 MWh of energy, 8.9% of electricity costs, and 58.0 metric tons of carbon dioxide emissions. Further, the numerical results of simulating districts from tens to hundreds of buildings are presented.

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“…As an objectoriented language, it is designed to model the behavior of general systems and to extend those models to particular systems derived from the previous ones (inheritance mechanism). Tools such as OpenModelica [19] or Dymola ® process symbolically these models to obtain the differential equations for simulating the system behavior.…”

Section: A Motivationmentioning

confidence: 99%

Port-Hamiltonian Modeling of Thermofluid Systems and Object-Oriented Implementation With Modelica I: Thermodynamic Part

2021

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In this paper, we present the physical foundations and the development of the thermodynamic part of a Modelica library with the fundamental components for modeling thermofluid systems. We have chosen Modelica because it is an object-oriented modeling language that allows an elegant design of the library, with a top-down conception that starts from very general components where we model the thermodynamic properties common to all simple substances and descend by inheritance to model the properties of each particular substance. To model the behavior of each component, we have used: classical thermodynamics to define the equilibrium states, the local equilibrium hypothesis of Classical Irreversible Thermodynamics to model the changes of state, and the port-Hamiltonian approach to obtain the equations of the system dynamics. With this formulation, we implement the thermodynamic behavior of ideal gases (including monatomic gases as a particular case), the 2073 substances defined for the CEA (Chemical Equilibrium with Applications) NASA Glenn computer program, the IAPWS Formulation 1995 for the Thermodynamic Properties of Water Substance for General and Scientific Use, and the Syltherm 800 HTF (Heat Transfer Fluid). We also define graphical symbols for each library component that facilitate modeling complex systems with simple drag-and-drop manipulations, component connection, and parameter selection. These symbols are a slightly modified version of those used in bond graphs to facilitate their reading and the representation of the structure of complex systems. We also show the modeling, simulation, and comparison for accuracy, performance, and scalability of some thermodynamic systems implemented with the Modelica Standard Library (MSL) and the proposed library.INDEX TERMS Bond graphs, Modelica language, object oriented modeling, port-Hamiltonian systems, thermodynamic systems, thermofluid systems.

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The OpenModelica Integrated Environment for Modeling, Simulation, and Model-Based Development

Cited by 106 publications

References 82 publications

Handling Multimode Models and Mode Changes in Modelica

Handling Multimode Models and Mode Changes in Modelica

Modelica-Based Modeling and Simulation of District Cooling Systems: A Case Study

Port-Hamiltonian Modeling of Thermofluid Systems and Object-Oriented Implementation With Modelica I: Thermodynamic Part

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