| Designing spaces that use daylight to advantage is a main component of architectural design. In recent decades, daylighting has been pursued as a strategy for reducing lighting energy consumption in buildings. Research has been conducted into designing buildings that provide benefits of daylight such as illumination, view, or heat (during the cold season) without inconveniences like glare or overheating (during the warm season). This includes developing fenestration systems that reduce the need for daytime electric lighting use by redirecting daylight deeper into rooms. Generally, the systems developed so far do not deliver those benefits evenly throughout the day and year. They also often cause visual discomfort.; This dissertation presents a method to determine the optical properties that fenestration systems should have in order to provide the benefits of daylighting without its drawbacks. With this method, given the geometry and surface properties of a space and knowledge about available daylight, one can determine the optimal bidirectional transmittance of the fenestration, based on a specified set of lighting goals defined for that space and geographical location.; This optimization problem is solved by judiciously using the constraints imposed by the physical problem---lighting goals defined over space and time---to constrain the solution set of the mathematical problem, making it tractable. The optimum not only provides a theoretical limit to the performance of fenestration systems, but also allows inferring the performance of any fenestration system, relative to the optimum, by comparing the system's properties to the optimum's, i.e. without actually determining performance by simulation or measurement. This can be useful to designers, in selecting the systems most likely to perform as desired in a space, and also to manufacturers in developing new systems, or improving existing ones.; The method is demonstrated by determining the optimal properties for a realistic design case, with the following goals: providing as close as possible to a specified workplane illuminance without exceeding luminance values that cause glare within an occupant's field of view. It is predicted that the optimum thus determined performs acceptably close to the specified goals and significantly better than several currently available daylighting systems. |
