The Spawn of EnergyPlus, called SOEP, is a next-generation simulation engine, for building and control energy systems. SOEP will combine

  • The OpenStudio front-end for model authoring, simulation and as a workflow automation tool,

  • the Modelica Buildings Library as a repository of models,

  • OPTIMICA as a translator that translate models from the Modelica standard to the Functional Mockup Interface standard for simulation and for execution on control systems,

  • QSS solvers, a class of new solvers that we develop for Spawn,

  • PyFMI as a suite of state-of-the-art numerical solvers that conduct a time domain simulation.

The intent is for SOEP and EnergyPlus to live side-by-side, with the OpenStudio software development kit providing access to both and insulating users and client vendors from implementation differences. Equation-based models allow SOEP to unify building energy modeling with control workflows, and allow users and manufacturers to insert their own models into SOEP.


Fig. 1 : Spawn-of-EnergyPlus (SOEP) is a next-generation BEM engine that leverages open standards for equation-based modeling (Modelica) and co-simulation (FMI).

This documentation is a working document for the design, development and implementation of the Spawn of EnergyPlus (SOEP).

To cite Spawn of EnergyPlus, use

Michael Wetter, Kyle Benne, Hubertus Tummescheit and Christian Winther.
Journal of Building Performance Simulation. Pages 1-19. 2023.

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