| The early decisions made during the design phase of a building regarding the choice of windows have a large impact on future energy consumption. Although the final selection depends on many issues not directly related to energy concerns including aesthetics, cost, material, views, and client preferences, energy consumption is a major factor for several reasons. These include environmental concerns, financial aspects, code compliance, operations and maintenance over the lifetime of the building, and occupant comfort. One technique for saving energy is to harvest daylight; this lessens the amount of electricity needed for indoor artificial lighting while maintaining adequate lighting levels. There are trade-offs, however, as larger windows that allow more daylight can be detrimental in other areas, such as increased heating and cooling loads depending on the location of the building, the climate, and even the season as benefits and drawbacks change over the year.;This thesis explores balancing daylight harvesting and energy demands of fenestration in the early design stage for office buildings in two climate zones in California. Window orientation, height, aspect ratio, window-to-wall ratio, lighting design level, glazing, and exterior shading are parameters that were analyzed by DIVA for Grasshopper, EQUEST, and COMFEN. The simulation results provide guidelines for designers reducing cooling loads and electric lighting use throughout the year. These guidelines are, for example, window-to-wall ratio of 10%--30% is recommended for south and window-to-wall ratios of 30%--60% promise better energy performance on north, a window-aspect-ratio of 2/1 saves most energy load for all orientations. |
