A Basic Study on the Performance Evaluation of a Movable Light Shelf with a Rolling Reflector That Can Change Reflectivity to Improve the Visual Environment.

Heangwoo Lee

doi:10.3390/ijerph17228338

Abstract

In recent years, the need for comfortable visual environments in indoor spaces has increased energy use in buildings. There have been diverse studies on using a light shelf to solve this problem. It is an effective system that allows external natural light deep into indoor spaces through reflection. However, prior studies have used light shelves with a fixed reflectivity, and there are few studies on improving the visual environment through light shelf control. Therefore, this study proposes a movable light shelf with a rolling reflector that can change the reflectivity. To achieve these objectives, we conducted a performance evaluation of the system’s ability to save energy and improve the visual environment. This study built a real scale testbed and conducted a performance evaluation by deriving values for lighting energy consumption, uniformity, and luminance contrast depending on the light shelf variables. We conclude that (1) the light shelf system achieved an energy savings of 13.6% and 5.7%, respectively, compared to a fixed type light shelf, whose reflectivity cannot be changed, and a traditional movable light shelf; (2) in terms of improving the visual environment, results suggest that the visual environment could be improved using a light shelf by deriving light shelf variables that disturb indoor uniformity; and (3) the results verified glare generation conditions by deriving luminance contrast caused by the variables of light shelf angle and its reflectivity.

Highlights

Creating a comfortable environment in an indoor space requires controlling various equipment such as lighting, ventilation, air conditioning, and heating equipment, rapidly increasing building energy consumption [1,2,3,4,5,6,7]
Based on the collected information, words, a light shelf with a rolling reflector that can change reflectivity must be wider to achieve the the light shelf automatically returns to an angle that can increase the visual environment’s comfort
Environment enters the room, the light shelf is configured at an angle of −10° and a reflectivity of 70%

Summary

Introduction

Creating a comfortable environment in an indoor space requires controlling various equipment such as lighting, ventilation, air conditioning, and heating equipment, rapidly increasing building energy consumption [1,2,3,4,5,6,7]. As much as 17% of the sector’s total energy consumption is for lighting, according to “Electricity use in U.S commercial buildings by major end uses”, which was released by U.S Energy Information Administration in 2012 [9]. While it is advantageous to increase the light shelf reflector’s reflectivity [25,26], it can give the indoor space occupants an uncomfortable visual environment [27]

Methods

Results

Discussion

Conclusion