Performance optimization of an office building with a dynamic façade system

Buildings account for a substantial portion of global energy consumption, and heating, ventilation and air conditioning (HVAC) systems are responsible for approximately 40% of the buildings’ energy consumption. A building façade, with HVAC, has a great influence on the internal environment. An optimization of the façade design and operation can help improve building energy efficiency. This research utilized building energy simulation to assess and optimize the operational strategy for a dynamic façade system (including natural ventilation and shading functions) in an office building. The work focused on building energy demand based on a validated simulation model. Several parameters in the model were recalibrated, based on an existed simulation model, by historical weather and building operation data, resulting in a yearly mean absolute error of 2.1% in heating and cooling energy demand. The model then was used to study different dynamic façade control strategies. Based on the base model, different control strategies of shading and natural ventilation were designed, and the control parameter (solar irradiation) for the shading system was optimized, with energy efficiency as a performance indicator. Based on monthly energy demand data, a combined strategy model was selected. It was found that utilizing an optimized strategy for natural ventilation through the dynamic façade resulted in 14.9% energy-saving when compared to the case without natural ventilation. Next, a parameter study was carried out on the combined strategy model. Notably, natural ventilation airflow rate and occupancy density parameters showed less impact on the total energy demand, while the occupancy density had a significant impact on the ratio between the heating and cooling energy demand. Additionally, the parameter study confirmed the energy saving potential of applying a wider range of cooling and heating setpoints. The results of this research confirmed the significant energy-saving potential for the dynamic façade system, consisting of a natural ventilation and shading. Performance optimization of the investigated dynamic façade can be found by combining the control strategy for both control elements of the façade system, to deal best with the (Dutch) seasonal changes in weather conditions. Furthermore, with various building operation goals, such as cooperating with long-term energy storage systems or providing thermal comfort, the research suggests flexibly in arranging the occupancy and HVAC setpoints.