1. Uniform Light Distribution Using Simulation Systems Alejandra Estrada, Marisa S. Downey, Adviser: Dr. Bahram Asiabanpour   Texas State University- Ingram School of Engineering 601 University Drive, San Marcos, Texas, 78666, USA
Abstract
Utilizing natural light in indoor plant growth is becoming a trending practice. The objective of this study is to investigate the effect of distance in light intensity and light uniformity using fiber optics as a method of light transfer.
A commercialized light simulation software has been adopted, which is commonly used for indoor architectural lighting designs. In order to optimize the results, it is important to consider factors such as placement, spacing, room dimensions, light type, and light shape. Results show that end glows and shorter light to surface distances provide more light intensity while side glows and larger light to surface distances provide better light distribution uniformity.
1. Introduction
Daylighting systems deliver natural light indoors with the use of optical fibers, solar tubes, parabolic mirrors, windows, and many others. There are different methods of collecting and delivering light using daylighting systems. As part of this research, the utilization of natural light is applied for plant growth in an indoor application where light is delivered through fiber optic cables using passive light system. The goal of this research is to produce efficient light uniformity and light intensity necessary for plant cultivation. To distribute sufficient natural light indoors, it is important to conduct a simulation of light distribution before physical implementation. The lighting simulation software was utilized in order to determine the efficiency of two different fiber optic: end glow and side glow (See Fig1.), which were tested to determine the light intensity and light uniformity point of view and in different light pattern, spacing, and height setting.
2. Method and Modeling
The distribution of the natural light is performed by positioning the end effectors in a certain height and position. In this research, a light simulation software (AGI32) was
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adopted to find the optimum position of end effectors in a way that it produces uniform light distribution. AGI32 can compute a numerical point-by-point calculation, where luminaries are placed on any surface to then evaluate its distribution in any simulated environment [1]. In order to model the design 5 different heights, 6 different light patterns for side glow, and 3 different light patterns for end glow were used (See Fig2.)
3. Results and Conclusion
The objective of the simulation was not to pick the pattern with the highest light illumination but the one displaying uniformity within these 9 patterns. The coefficients of variation for the lighting scenarios were graphed (Fig 3). This chart shows that Side glow 5 bar and 6 bars are relatively close to each other, meaning that both patterns are uniform. Light intensity is also an important factor as it provide the amount light needed for the plant growth. Fig. 4 summarizes the light intensity for side glow 6 bars and end glow 2 rows. Based on the results of the simulation it is seen that the end glows have better light intensity than side glow but side glows have better light uniformity
Fig. 3 Light distribution designs and coefficient of variation
Fig. 1 Fiber optics: end and side glow
Fig. 2 Light Design Details
Fig. 4 Results from side and end glow patterns
Proceedings of the 2018 ASEE Gulf-Southwest Section Annual Conference The University of Texas at Austin
April 4-6, 2018