Heliostats Based Daylighting System using Light Pipe

Objective

Conventional daylighting systems have their difficulties in making a large-scale system to illuminate the entire building. To this end, a daylighting system is proposed, which delivers sunlight to each floor of the building. Sunlight is captured, guided, and distributed through the heliostats, mirror light pipe, and light guide, respectively. The light guide is made of prismatic optical lighting film and multi-layer optical film for achieving uniform illumination in the interior. The proposed system is advantageous because it can be made according to the building structure and the size. Finally, extensive acceptance of the system can reduce electric lighting power consumption in buildings, which would help to reduce carbon dioxide emissions.

The main purpose of this study is to deliver uniform daylight in the interior (e.g., a multi-floor building’s interior) through MLP. For this purpose, heliostats are preferred to capture high intensity sunlight and make the system cost-effective. Uniform light is distributed in the interior through a light guide. This research will improve the efficiency of the light pipe-based daylighting system.

Design

A cost-effective approach for the daylighting system is proposed to achieve high-intensity sunlight. Sunlight is captured through heliostats of circular plane mirrors that are arranged in circular arcs around the MLP, as shown in the following Figure. Each heliostat directs sunlight toward the focusing mirror, which is installed upstream of the MLP. The Focusing mirror inserts light into the MLP and then light is transported through the MLP. To deliver the light at each floor, a directing mirror is used to insert the light into the light guide. Sunlight is distributed in the interior through the light guide. In future, we shall add solar cells at the end of the MLP to generate electricity.

Hybrid Daylighting System using Heliostats

Daylighting for multi-floor buildings

The MLP is installed on the left side of the building. It can also be installed in the center of the building to illuminate the interior of the building. The building has five floors, including basement. The number of floors to illuminate can be increased by increasing heliostats or by changing the size of the MLP and the heliostats. Therefore, the required design can be easily created to satisfy the required illumination for a specific area.

To spread the light from the MLP, which has a high beam of light, prismatic light guide was used. The light guide is made of prismatic optical lighting film and multilayer optical film, as shown in the following Figure. The light guide gives uniform illumination with better illumination quality, and it transmits light at a long distance. Thus, the system is capable to capture high intensity sunlight and to illuminate core region of the building through the light guide.

Daylighting System for multi-floor buildings using Heliostats Ray-tracing of daylighting System

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