Application of Richardson Extrapolation to the Co-Simulation of FMUs from Building Simulation

Abstract

The application of the FMI technology gains ground in building simulation. As far as specialized tools support the FMI simulator coupling becomes an important option to simulate complex building models. Cosimulation needs a master algorithm which controls the communication time steps as well as the signal exchange between FMUs. Often a constant communication step size is applied chosen by the user. The Richardson extrapolation approach allows variable master step sizes. An extension of this approach is presented, and the method is applied to both academic test examples as well as examples of building simulation which co-simulate FMUs from NANDRAD and SimulationX. Although variable step size control could improve the performance this cannot be observed at the building simulation examples presented. But Richardson extrapolation turns out to guarantee finding an appropriate step size at the prize of downgraded performance.

Robust and accurate co-simulation master algorithms applied to FMI slaves with discontinuous signals using FMI 2.0 features

“…Typical choices for such co-simulation master algorithms have already been investiged (Clauß et al, 2017;Schierz et al, 2012). The authors also show that other new features of the FMI standard, like input/output extrapolation, positively influence simulation performance and stability.…”

Co-Simulation between detailed building energy performance simulation and Modelica HVAC component models

“…We implemented the step-doubling technique in MASTERSIM as adaptive communication step method (Clauß et al, 2017). Clauß discusses such an approach within in context of FMI Co-Simulation.…”

“…However, as soon as the Co-Simulation master is using an iterative or error controling algorithm, the slaves must be repeatedly set back in time (see, for example (Clauß et al, 2017)). The master needs to retrieve and restore each FMU's state.…”