Paper Conference

Proceedings of Building Simulation 2023: 18th Conference of IBPSA


A validated high-fidelity simulator for an ultra-efficient office building based on coupled EnergyPlus-Modelica models

Xu Han 1,2, Shide Salimi 1,2, Ali Malkawi 1,2, Xiaoshi Wang 1,2, Na Li 3
1 Graduate School of Design, Harvard University, United States of America
2 Center for Green Buildings and Cities, Harvard University, United States of America
3 School of Engineering and Applied Sciences, Harvard University, United States of America

Abstract: This paper presents the development and validation of a high-fidelity simulator for an ultra-efficient office building, which functions as a living laboratory that integrates natural ventilation with automated windows, and geothermal heat pump assissted thermally active building systems. Specifically, The simulator is developed with coupled EnergyPlus-Modelica models, in which the building envelop, equipment and occupant profile are modeled in EnergyPlus, and the radiant floor, HVAC system and controls are modeled in Modelica. The natural ventilation under different wind conditions is simulated with Computational Fluid Dynamics, which is integrated into the Modelica model for ventilation rate prediction through interpolation from a lookup table. The developed models are calibrated and validated with the measured building operational data from the extensive senor network in the building. The normalized Mean Bias Error (MBE%) and the Coefficient of Variation of the root mean square error (CV (RMSE)) for heating/cooling loads simulated by the EnergyPlus model are 2%/1% and 11%/16%, respectively. The RMSEs of the simulated hourly water loop temperature and slab temperature range from 0.48 K to 1.06 K. The RMSE of the simulated daily heat pump power is 236.4 W. The use of the simulator is then demonstrated to improve the control of the room and slab temperature. To conclude, the developed simulator shows effectiveness to serve as a digital twin to support optimal operation of the studied building as well as a virtual testbed for advanced controls development, evaluation and benchmarking for ultra-efficient buildings.
Keywords: Coupled EnergyPlus-Modelica Models, Calibration and Validation, Zero Energy Buildings, Natural Ventilation, Thermally Active Building System
Pages: 1255 - 1262