• Journal of Environmental Science International
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• v.28 no.5
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• pp.521-526
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• 2019

In this study, a solar light collector that collects and transmits solar light required for crop production in a closed plant production system was developed. The solar light collector consisted of a Fresnel lens for collecting solar light, and a tracking actuator for tracking solar light from sunrise to sunset to increase the light collection efficiency. The optical fiber that transmitted solar light was made of Glass Optical Fiber (GOF), and it had an excellent optical transmission rate. After collecting the solar light, the amount of light was measured at 5, 10, 15, 20, 25, and 30 cm distances from the GOF through the darkroom by using a light sensor logger connected to a quantum and pyranometer sensor. Compared with solar light, the light intensity of pyranometer sensor measured at 5 cm was 114% higher than solar light, and 61% at 10 cm. In addition, it was observed that it is possible to transmit the necessary amount of light for growing crops up to about 15 cm (as over 22%) through GOF. Therefore, adding diffusers to the solar light collector should be expected to replace artificial light in plant factories or plug seedlings nurseries for leafy vegetables. More studies on the solar light collection devices and the light transmission devices that have high light collection efficiency should be conducted.

• Journal of the Korean Solar Energy Society
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• v.39 no.1
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• pp.1-9
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• 2019

Light induced degradation is one of the major research challenges of hydrogenated amorphous silicon related thin film silicon solar cells. Amorphous silicon shows creation of metastable defect states, originating from elevated concentration of dangling bonds during light exposure. The metastable defect states work as recombination centers, and mostly affects quality of intrinsic layer in solar cells. In this paper we present results of light induced degradation in thin film silicon solar cells and discussion on physical origin, mechanism and practical solutions of light induced degradation in thin film silicon solar cells. In-situ light-soaking IV measurement techniques are presented. We also present thin film silicon material with silicon nano-quantum dots embedded within amorphous matrix, which shows superior stability during light-soaking. Our results suggest that solar cell using silicon nano-quantum dots in abosrber layer shows superior stability under light soaking, compared to the conventional amorphous silicon solar cell.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.350-355
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• 2009

The crysralline silicon solar cell where the solar cell market grows rapidly is occupying of about 85% or more high efficiency and low cost endeavors many crystalline solar cells. The fabricaion process of high efficiency crystalline silicon solar cells necessitate complicated fabrication processes and Ti/Pd/AG contact, This metal contacts have only been used in limited areas in spite of their good srability and low contact resistance because of expensive materials and process. Commercial solar cells with screen-printed solar cells formed by using Ag paste suffer from loe fill factor and high contact resistance and low aspect ratio. Ni and Cu metal contacts have been formed by using electroless plating and light-induced electro plating techniques to replace the Ti/Pd/Ag and screen-printed Ag contacts. Copper and Silver can be plated by electro & light-induced plating method. Light-induced plating makes use the photovoltaic effect of solar cell to deposit the metal on the front contact. The cell is immersed into the electrolytic plating bath and irradiated at the front side by light source, which leads to a current density in the front side grid. Electroless plated Ni/ Electro&light-induced plated Cu/ Light-induced plated Ag contact solar cells result in an energy conversion efficiency of 16.446 % on 0.2~0.6${\Omega}$ cm, $20{\times}20mm^2$, CZ(Czochralski) wafer.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.4
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• pp.106-117
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• 2016

Recently, solar power plants have spread widely as part of the transition to greater environmental protection and renewable energy. Therefore, regular solar plant inspection is necessary to efficiently manage solar-light modules. This study implemented a test that can detect solar-light module faults using an UAV based thermal infrared camera and GIS spatial analysis. First, images were taken using fixed UAV and an RGB camera, then orthomosaic images were created using Pix4D SW. We constructed solar-light module layers from the orthomosaic images and inputted the module layer code. Rubber covers were installed in the solar-light module to detect solar-light module faults. The mean temperature of each solar-light module can be calculated using the Zonalmean function based on temperature information from the UAV thermal camera and solar-light module layer. Finally, locations of solar-light modules of more than $37^{\circ}C$ and those with rubber covers can be extracted automatically using GIS spatial analysis and analyzed specifically using the solar-light module's identifying code.

• Journal of Photoscience
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• v.10 no.2
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• pp.217-218
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• 2003

A noncoherent, broadband, intense pulsed light source has been used for the symptoms of photoaging skin as a nonablative method. The purpose of this study is to investigate the efficacy and tolerability of intense pulsed light in solar lentigines and ephelides on the face. An open study was performed in patients with solar lentigines and ephelides who received three to five treatments of intense pulsed light. Forty-eight percent of patients had more than 50% improvement and 20% had more than 75% improvement. In the group of solar lentigines, 40% of patients showed more than 50% improvement and 16% did more than 75% improvement. Patients with solar 1entigines＋ephelides and ephelides responded remarkably with 75% and 71 % of patients having more than 50% improvement, respectively. Intense pulsed light was well tolerated and may be a new modality for the therapy of solar lentigines and ephelides.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.6
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• pp.440-444
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• 2011

We have analyzed electrical characteristics of spot light solar cell modules and have completed fabrication of spot light solar cell modules. Before we test modules, we have carried about UV test of hologram. As a result of test, we have obtained 165% efficiency of hologram film. the other hand, we obtained 75% efficiency of general films. After we have fabricated solar modules and carried about field test, spot light solar cell modules with hologram have been investigated 17.3 A of Isc and 155.4 W of power.

• Journal of the Korean Solar Energy Society
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• v.22 no.1
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• pp.81-86
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• 2002

Solar daylighting system provides free and comfort lighting, but its design and control has been key issue due to heavy light collecting system. One of the solutions for the heavy weight issues would be using a light framed film such as fresnel and prism lens. This prototype system consists of light collector, light transformer and light guide luminaire. The light collector which is installed at window or the rooftop concentrates solar light, the collected beam is converted to suitable light by the light transformer. and the prism light guide luminaire has been used to distribute light emitted from light transformer for illumination. In this paper, the design concept and performance of light collector in this prototype system are presented.

• Journal of Sensor Science and Technology
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• v.23 no.4
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• pp.238-244
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• 2014

In this paper, we introduce a new passive transponder that operates without external power in a visible light identification system. The transponder consists of a solar cell, a photodiode, a microprocessor, and a visible LED. When a reader sends light to the transponder, the solar cell generates current from the reader light and supplies power to the other elements in the transponder. At the same time, the photodiode detects the pulse in the reader light and initiates a microprocessor to generate and send a responding light to the reader. In experiments, we realized a passive transponder using a solar cell that operated at a distance of 1m without external power.

• Journal of Environmental Science International
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• v.15 no.7
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• pp.677-688
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• 2006

Currently, the application of $TiO_2$ photocatalyst has been focused on purification and treatment of wastewater. However, the use of conventional $TiO_2$ slurry photocatalyst results in disadvantage of stirring during the reaction and of separation after the reaction. And the usage of artificial UV lamp has made the cost of photocatalyst treatment system high. Consequently, we studied that solar light/$TiO_2$ film system was designed and developed in order to examine disinfection characteristics of sewage wastewater treatment. The optimum conditions for disinfection such as solar light intensity, characteristic of sewage wastewater, amounts of $TiO_2$ and comparison of solar ligth/$TiO_2$ systems with UV light/$TiO_2$ system was examined. The results are as follows: (1) photocatalytic disinfection process with solar light in the presence of $TiO_2$ film more effectively killed total coliform (TC) than solar light or $TiO_2$ film absorption only. (2) The survival ratio of TC and residual ratio of organic material (BOD, CODcr) decreased with remain resistant material. (3) The survival ratio of TC and residual ratio of organic material (BOD, CODcr) decreased with the increase of amounts of $TiO_2$. (4) TC survival ratio decreased linearly with increasing UV light intensity. (5) The disinfection effect of solar light/$TiO_2$ slurry system decreased more than UV light/$TiO_2$ film systems. (6) The disinfection reaction followed first-order kinetics. We suggest that solar light instead of using artificial UV light was conducted to investigate the applicability of alternative energy source in the disinfection of TC and the degradation of organic material.

• Design & Manufacturing
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• v.16 no.2
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• pp.20-25
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• 2022

In line with the rapid economic growth of many countries, fossil fuel energy sources are also rapidly depleting. Therefore, the price is also rising rapidly, so it is necessary to develop new and renewable energy sources such as hydropower, geothermal power, nuclear power, wind power and solar energy to replace fossil fuel energy in the future. In this study, development of rotating concentrator module system, development of rotating module control control system, development of lamp and charge control controller, configuration and prototype production of rotating concentrating solar LED street light system, efficiency of rotating concentrating solar LED street light, and power production. The research was conducted in the order of evaluation of comprehensive performance tests such as consumption and consumption. As a result, the developed high-efficiency rotation-concentrating hybrid solar LED street light module system has a 50% higher light-gathering efficiency than existing products by tracing sunlight by self-developing a rotation-collecting module on existing solar LED street lamps according to the characteristics of Korea's topography. and the power generation was improved by more than 40%.