Piecewise-Steady-State Modelica Simulations for the Conceptual Design Phase of Industrial Processes


  • Raphael Agner
  • Jonas Grand
  • Andrin Duss
  • Beat Wellig




Piecewise-Steady-State, Conceptual Design, Process Simulation, Energy Systems


The conceptual design of industrial processes is challenging as relatively little information about the eventually selected equipment and their operation is known in this early design stage. Furthermore, the systems are increasingly integrated with themselves, and their design must be addressed systematically. Simulation can assist in better understanding the effects of design decisions on the resulting system performance. To facilitate the simulation of industrial processes in this early design phase, this paper proposes an approach to modeling system components specifically aimed at employing known key design parameters and assuming steady-state behavior of the process for a certain period of time (e.g. one hour). A solution over a longer period of time (e.g. for a year) can then be obtained by simulating a multitude of such shorter periods, leading to the piecewise-steady-state solution. The proposed approach is developed with an exemplary case study, based on a real industrial site. The resulting model computes the annual load profile within the range of seconds for the given case study.