New mechanism of a daylighting system using optical-fiber-less design for illumination in multi-storey building

Vu, Duc Tu; Vu, Hoang; Shin, Seoyong; Tien, Tran Quoc; Vu, Ngoc Hai

doi:10.1016/j.solener.2021.07.053

Cited by 10 publications

(5 citation statements)

References 30 publications

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“…Optical efficiency (OE) is defined as the ratio of light energy incident on the receiver to light energy exiting from the light source, according to equation (3) 23,24 OE ¼ Flux on Receiver Flux of LED source × 100%…”

Section: Simulation Resultsmentioning

confidence: 99%

“…Optical efficiency (OE) is defined as the ratio of light energy incident on the receiver to light energy exiting from the light source, according to equation (3) 23,24 where the luminous flux on the receiver and luminous flux of the LED source was determined by LightTools™ software. It was anticipated that the illumination performance of LED light would be strongly influenced by varying the key structural parameter, for example, the number of freeform lenslet in a row ( N ).…”

Section: Simulation Resultsmentioning

confidence: 99%

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A simple design of uniform LED illumination using catadioptric collimator and freeform lenslet array

Shin

et al. 2021

Lighting Research & Technology

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We introduce a compact lenslet array principle that takes advantage of freeform optics to deploy a light distributor, beneficial for highly efficient, inexpensive, low energy consumption light-emitting diode (LED) lighting system. We outline here a simple strategy for designing the freeform lens that makes use of an array of the identical plano-convex lenslet. The light is redistributed from such lenslet, hinging on the principle of optical path length conservation, and then delivered to the receiver plane. The superimposing of such illumination area from every lenslet occurs on the receiver plane, in which the non-uniform illumination area located in the boundary should have the same dimension as the size of the freeform lenslet array. Such an area, insofar, is negligible due to their small size, which is the crux of our design, representing a large departure from the former implementations. Based on simulations that assess light performance, the proposed design exhibited the compatibility for multiple radiation geometries and off-axis lighting without concern for the initial radiation pattern of the source. As simulated, the LED light source integrated with such proposed freeform lenslet array revealed high luminous efficiency and uniformity within the illumination area of interest were above 70% and 85%, respectively. Such novel design was then experimentally demonstrated to possess a uniformity of 75% at hand, which was close to the simulation results. Also, proposed indoor lighting was implemented in comparison with the commercial LED downlight and LED panel, whereby the energy consumption, number of luminaires and illumination performance were assessed to show the advantage of our simplified model.

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Section: Simulation Resultsmentioning

confidence: 99%

Section: Simulation Resultsmentioning

confidence: 99%

A simple design of uniform LED illumination using catadioptric collimator and freeform lenslet array

Shin

et al. 2021

Lighting Research & Technology

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“…Silica fibers and polymethylmethacrylate (PMMA) plastic fibers are both used to transmit focused sunlight. The high cost of using silica fibers as a transmission medium makes it difficult to scale up [25]. The diameter of the focused spot generated by the lens is generally 0.5-2 mm.…”

Section: Introductionmentioning

confidence: 99%

Measurement and Analysis of Light Leakage in Plastic Optical Fiber Daylighting System

Liu

Zou

et al. 2023

Sustainability

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The daylighting systems via polymethylmethacrylate (PMMA) plastic optical fibers have obvious cost advantages and have been widely studied. However, there is light leakage when PMMA optical fibers transmit concentrated sunlight, resulting in a transmission efficiency lower than the theoretical value. This research aims to quantitatively study the light leakage effect of PMMA optical fibers. Concentrated sunlight was used as the sunlight source instead of a monochromatic laser. An adjustable diaphragm was used to adjust the angle of the incident light, and the infrared filter and heat-absorbing glass were used to solve the overheating problem of PMMA fibers. The results show that when the incident angle is greater than 13°, the relative transmission efficiency of the fibers drops rapidly, which means that the light leakage deteriorates. The data also show that the angle of the output beam of PMMA optical fibers is ±30°, which is independent of the angle of the incident beam. Based on this conclusion, a PMMA optical fiber daylighting system with an incident angle of 13° was developed, which has higher transmission efficiency than previously developed systems. This study indicates that the angle effect of light leakage should be considered in the design of a plastic optical fiber daylighting system.

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“…The modified system is able to accurately track the sun, even in cloudy weather. Vu et al studied a fiberless design for illumination in multistory buildings [9]. The authors compared the effectiveness of a fiber optic solar tracker with a wave guide concentrator, where the latter showed a 15% higher optical efficiency.…”

Section: Introductionmentioning

confidence: 99%

Identifying the Photometric Characteristics and Applicability of Hybrid Solar Lighting

Han

Mehmood²,

Park³

et al. 2022

Energies

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The present research aims at promoting the stability and applicability of a hybrid daylighting system combining daylight and artificial light, which eventually enables a constant and pleasant luminous flux of the mixed light delivered by a terminal device installed indoors. That is, the present system allows a constant amount of luminous flux through its terminal device similar to an electric lamp, demonstrating its energy efficiency as well as comfortableness. The system effectively combines two different types of light, as solar rays are collected by a solar tracking sun light collector. The mixed light is transmitted indoors by optical fiber cables all the way to terminal devices installed indoors and discharged as needed. This feature enables the utilization of daylight to its full capacity, promoting solar availability. In this study, the photometry of hybrid lighting was experimentally measured and analyzed by using a spectrometer for different portions of sunlight when maintaining a constant luminous flux of mixed light. The effectiveness of hybrid lighting was explored for a number of cases in actual conditions, and the system was capable of delivering a constant illuminance of 1200 lux on a plane located 1.1 m away from the terminal device (light emitter). Finally, the system was installed in a test cell to verify its effectiveness for indoor illumination.

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New mechanism of a daylighting system using optical-fiber-less design for illumination in multi-storey building

Cited by 10 publications

References 30 publications

A simple design of uniform LED illumination using catadioptric collimator and freeform lenslet array

A simple design of uniform LED illumination using catadioptric collimator and freeform lenslet array

Measurement and Analysis of Light Leakage in Plastic Optical Fiber Daylighting System

Identifying the Photometric Characteristics and Applicability of Hybrid Solar Lighting

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