Development of a Solar Tracking-Based Movable Louver System to Save Lighting Energy and Create a Comfortable Light Environment

Abstract

A louver is a technical component of building envelopes that determines the energy performance of buildings. Despite its simple structure of several slats, applications are increasing due to its effectiveness. However, because most previous studies on louvers have focused on performance evaluation based on the width and angle of the slat, there are limitations in improving their efficiency. Therefore, this study proposes a solar tracking-based movable louver (STML) system and validates its effectiveness using a full-scale test bed. The main findings are as follows: 1) The proposed STML is a hybrid louver with four movable shafts due to its structural characteristics. The shading area is increased sequentially by controlling the length of the movable shaft adjacent to the sun through solar tracking. 2) Compared with conventional vertical and horizontal louvers, the STML can improve indoor uniformity by 5.0% and 13.9%, respectively. Unlike conventional louvers, the STML awnings are installed at the end of the daylighting window, reducing window view obstruction and creating a more pleasant indoor visual environment. 3) Compared with conventional louvers, the STML can reduce lighting and heating/cooling energy by 35.7%–49.7%. These findings prove the effectiveness of the proposed system.

Keywords: Louver, Sun tracking, Energy saving, Daylighting environment, Performance evaluation