The role of structures in daylighting retrofits for existing buildings

As a greater emphasis is put on reducing the environmental impact of buildings, the implementation of successful daylighting strategies becomes an integral part of this process as electric lighting accounts for thirty percent of all electricity used in buildings in the United States. Daylighting contributes to two critical factors in the design of sustainable buildings. First, proper daylighting levels within a space reduce the need for electric lighting as well as decrease internal heating loads, thus lowering the overall energy consumption of the building. Secondly, successful daylighting schemes have been proven to improve occupant health and well being, also increasing worker productivity. While new buildings can be designed with favorable orientations, shallow floor plates, light shelves and other strategies for optimizing the use of daylight, existing buildings, particularly those with deep floor plates, must be retrofitted to reduce electricity consumption. The structural systems of existing buildings can both inhibit and support daylighting retrofits, specifically the use of skylights. This paper explores the interactions of structural systems and daylighting through the use of simulation software, specifically the ability of structure to reduce glare by blocking direct sunlight and distributing light more evenly. The development of a parametric methodology for optimizing daylighting based on the existing structure and programmatic goals for the space is explored through the design of a retrofit of an existing 1960s laboratory building that is being converted into office space.