Study on the occlusion control of external venetian blinds considering building energy demand and visual comfort

In South Korea, external shading is recommended to reduce energy consumption in the building discipline. This study proposes occlusion control strategy based on building energy demand and visual comfort for External Venetian Blinds (EVB), which are variable external shades. To apply the EVB occlusion control, the window of the EnergyPlus model was divided into 10 windows, and the schedule of each window was controlled. The control criteria selected included the minimum zone energy demand, and the satisfaction of the visual discomfort criterion or the minimum visual discomfort. The visual discomfort was determined by the Discomfort Glare Index (DGI), with the standard value set to 22. As a result of one-year simulation with standard weather data in Seoul, the EVB occlusion control tendency had significant changes on March 21 and June 1. A case study including Internal Venetian Blinds(IVB) was performed to identify the advantages of EVB occlusion control. As a result, it was confirmed that if blinds were always lowered, lighting and heating energy were required more than IVB case, and that EVB occlusion control was needed to solve this problem and minimize energy demand.