Study on Indoor Temperature Variation Depending on External Type Light Shelf Angle

Abstract

Among natural light systems, the light shelf, which reflects external natural light and introduces the light deep into the indoor space, has been studied and applied in various areas, as its efficiency is well recognized. However, previous studies related to the light shelf have been limited to simple variables such as light shelf angle, width, height, and reflection rate in a specific environment or lighting energy, and the change of the thermal environment due to the reflection by a light shelf and the heating and energy consumption caused by the change have not been investigated. Therefore, the present study was conducted as a fundamental study focusing on temperature change in an indoor space depending on the installation of a light shelf and the variables of a light shelf. The following results were obtained from the present study. 1) The average temperature when the angle of a light shelf was 0° and 10° was lower than when no light shelf was installed. This indicates that the introduction of light by light shelf reflection was decreased as a shade was formed by the light shelf. 2) The indoor temperature with a light shelf having a light shelf angle of 30° was higher than that without an installed light shelf, which may be because more light was introduced by the reflection on the light shelf. The optimum light shelf angle of 30° found in previous studies may be inappropriate since the energy consumption for cooling is increased, which should be taken into account in the design of a light shelf. Future studies may need to be conducted on the evaluation of light shelf performance with respect to the light and cooling and heating energy consumption depending on the variation of indoor space temperature.