Integrated Daylight and Energy Evaluation of Passive Solar Shadings in a Nordic Climate

Modern well-insulated and highly glazed buildings experience increased overheating, even in cold climates. The study focused on external and internal passive solar shadings on a south-oriented façade, having predetermined that external and internal shadings’ main function is solar heat gain and glare protection, respectively. A daytime-occupied office space with several external shading geometry variations was simulated using an integrated daylight and energy approach aided by Radiance, Daysim, and EnergyPlus within Grasshopper. The method involved preparation of daylight-driven lighting schedules, and glare-driven internal blinds operation schedules for each design scenario, which were further applied to annual energy simulations. The interdependence of light in visible and thermal form, its impact on the building performance, and the resulting occupant response to the changing indoor conditions are core to this study. The comparative nature of the study allowed to evaluate thermal and visual performance of fixed external shadings in Nordic climates. The chief study findings highlight the gross impact of internal shading operation on overall building performance and indoor comfort, and the holistic benefit of external solar protection that includes reduction of total energy use and improvement of occupants’ thermal and visual comfort