Multiscale co-simulation of EnergyPlus and CitySim models derived from a building information model

Abstract

We present an approach for rapidly assessing the per- formance of early design stage building information models (BIM) from both the building and urban sys- tems scale. This effort builds upon two previously de- veloped tools, the Design Performance Viewer (DPV) and the CitySim urban simulation engine. It couples them to produce a more informed model. The DPV is a plugin for Autodesk Revit Architecture that creates a model for the EnergyPlus building performance en- gine based on information contained in the BIM. We combine the two simulation engines using the Func- tional Mock-up Interface (FMI) co-simulation frame- work to improve the accuracy of both simulations. This work extends the DPV to extract a CitySim model in addition to the EnergyPlus model. The CitySim model contains not only the building being investi- gated, but also a simplified representation of the sur- rounding buildings. We extend the CitySim solver to use the FMI standard for co-simulation to exchange simulation variables with the EnergyPlus model at each time step. This process includes an automated workflow that enables simulation driven design em- ploying these techniques. We compare the results of the coupled and uncoupled simulations and explain discrepancies. We then discuss further refinements to the models such as more accurate representation of the long wave radiation exchange.