Study of the Effect of Light Emitting Diode (LED) on the Optimum Window-to-Wall Ratio and Whole-Building Energy Consumption in Open Offices

Daylight harvesting is an essential strategy that is often used to enhance both the design and performance of an architectural project. Windows, as crucial architectural elements, not only admit natural light into spaces but also provide the occupants with visual connections. However, the excessive usage of windows brings an uncontrolled amount of solar energy to the spaces and negatively affect the building's energy performance.

When utilizing passive design strategies such as daylight harvesting, several parameters, including the electrical lighting system, can impact the outcome. The current study investigates the role of lighting systems on daylight harvesting's effectiveness and their impact on window dimension and total energy consumption. In this study, the optimum window-to-wall ratio of an open office in the presence of two different light sources (LED and fluorescent) is explored through a computer simulation method. A combination of tools including AGi32, ElumTools, OpenStudio, EnergyPlus, Radiance, and MATLAB helps to conduct the simulation and deliver optimal results.

In the results and conclusion chapter, the study provides guidelines to specify optimal window percentages considering two lighting systems in each cardinal direction. Importantly, the guideline focuses only on energy performance and not on the spatial quality of the design.