Journal of Korean Institute of Architectural Sustainable Environment and Building Systems ISSN:1976-6483(Print) 2586-0666(Online) 한국건축친환경설비학회논문집

Increasing use of lighting energy has become a social issue that needs to be urgently resolved and, as a solution to this problem, light duct is being actively researched as a natural lighting system. However, light diffuser has not been studied as thoroughly as light collector and light transmitter, despite being an important part of daylight ducts as it directly concerns light environemnt and comfort of occupants. This study proposed a double reflective light diffuser (Case 2) and demonstrated its performance by comparing its lighting performance with that of conventional light diffuser (Case 1) by using light environment analysis system Radiance. The results were as follows: 1) the average indoor illumination of Case 2 was higher than that of Case 1 and this was caused by light diffuser by double reflection in Case 2; 2) uniformity ratio of illuminance of Case 2, in comparison to Case 1, was improved by 77.4%, 74.1%, and 70.0% in summer, middle season, and winter, respectively; 3) daylight factor of Case 2, in comparison to Case 1, was improved by 74.4%, 76.9%, and 81.0% in summer, middle season, and winter, respectively, proving effectiveness of Case 2 proposed by this study.