Energy performance of internal shading attachments: Comparative analysis of control strategies in Canadian cold climates

Commercial buildings in Canada consume 1057 PJ of energy annually, with space heating and cooling responsible for 61% of this energy use. Windows play a crucial role in building energy efficiency, but often contribute to significant thermal losses. Automated shading attachments offer a promising retrofit strategy for enhancing building energy efficiency in commercial buildings. The current study uses EnergyPlus and WINDOW to assess the annual energy performance of four internal shading attachments in a US Department of Energy-defined small office building in Canadian cold-climate zones. Six distinct control strategies are analyzed to optimize heating and cooling reductions across five Canadian cities spanning the five climate zones of Canada. The window-shade systems are modelled as Complex Fenestration Systems on WINDOW and integrated into EnergyPlus. The Energy Management System Feature is used to implement custom control strategies. Intermediate shading positions are studied, demonstrating a more refined approach towards automated shading. Findings indicate that a maximum of 22% reduction in the annual heating loads is observed with Shade 2 (Cellular Shade) for the case of Vancouver (ASHRAE 4C) with Control Strategy 3 (CS3), and a maximum of 47% reduction in cooling loads is observed for the case of Yellowknife (ASHRAE 8) with Shade 1 (BO Roller Shade) and CS4 (T ave ). CS4 emerges as an effective control strategy for optimizing heating and cooling load reductions, with heating energy demand reductions in the range of 7.04%–19.69%, compared to 4.14%–17.20% using CS4 (T ave ). However, no improvement in energy performance was observed with the use of intermediate shading positions. These findings support the use of season-specific control strategies for automated shading as an effective means of reducing heating and cooling loads in cold-climate zones.