• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.563-566
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• 2006

An investigation has been carried for the thermal characteristics of the seasonal storage installation in Cheju. It features the solar collector area of $340m^2$ and the storage capacity of $600m^3$. Four different types of solar collector systems are compared for their performance of collecting solar energy throughout the year. Of these, two are made of tubular shaped vacuum collectors and the others are flat plate collectors. Results indicate that each system could play an important role in exploiting solar energy depending on the temperature range in its operation. Especially, the vacuum collectors outperformed the others when the inlet temperatures of the collector loop were raised beyond $40m^2$. This became more conspicuous as the return temperatures from the storage tank rose reflecting the seasonal variation. Due to the large heat capacity of the storage tank, temperature changes were rather small compared to those in the collecting loop regardless of seasonal fluctuations.

• Journal of the Korean Solar Energy Society
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• v.31 no.2
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• pp.99-106
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• 2011

Since the solar energy resource is the main input for sizing any solar photovoltaic system, it is essential to utilize the solar radiation data as an application and development of solar energy system increase. It will be necessary to understand and evaluate the insolation data. The Korea Institute of Energy Research(KIER) has begun collecting horizontal global insolation data since May, 1982 at 16 different locations in Korea and for the more detailed analysis, images taken by geostationary satellite may be used to estimate solar irradiance fluxes at earth"s surface. It is based on the empirical correlation between a satellite derived cloud index and the irradiance at the ground. From the results, the measured data has been collected at 16 different stations and estimated using satellite at 23 different stations over the South Korea from 1982 to 2009. The Result of analysis shows that the annual-average daily global radiation on the horizontal surface is 3.56 kWh/ $m^2$/day and estimated solar radiation fluxes show reliable results for estimating the global radiation with average deviation of -7.27 to +3.65% from the measured values.

• 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.29 no.3
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• pp.12-18
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• 2009

The Knowledge of the solar radiation components are essential for modeling many solar energy systems. This is particularly the case for applications that concentrate the incident energy to attain high thermodynamic efficiency achievable only at the higher temperatures. In order to estimate the performance of concentrating thermal systems, it is necessary to know the intensity of the beam radiation, as only this component can be concentrated. The Korea Institute of Energy Research(KIER) has began collecting solar radiation component data since January, 2002. KIER's component data will be extensively used by concentrating system users or designers as well as by research institutes. The theoretical analysis of solar radiation as a component has compared with the experimental data obtained by the KIER station. The Result of simulation analysis shows that the annual-average daily diffuse radiation on the horizontal surface is $1,457cal/m^2$ and daily direct radiation on the horizontal surface is $1,632cal/m^2$ for all over the 16 areas in Korea.

• Journal of the Korean Solar Energy Society
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• v.37 no.5
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• pp.39-47
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• 2017

In a hot water system using solar energy, solar heat is not simply collected by the heat collecting plate, but by heat exchange between the solar collector (flat or vacuum type) and the hot water storage tank. Therefore, the amount of collected solar energy depends on the hot water usage patterns that determine the temperature of the thermal storage tank. Also, if the temperature of the hot water stored in the storage tank exceeds the dangerous temperature during the summer, the heat must be released for safety. If the temperature of the hot water in the storage tank is low, it is necessary to heat by the auxiliary heat source. In this study, three buildings are defined as hotel, swimming pool, and school facilities. And we calculated the released heat energy, auxiliary heat source, and pure storage heat energy based on different hot water usage patterns and installation angle of the solar collectors.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.31-36
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• 2009

There have been many solar tracking systems developed for the high accuracy in solar tracking. One of the key components of any motion control system is software. LabVIEW offers an ideal combination of flexibility, ease-of-use and well-integration with other I/O pieces for developing solar tracking system. Real-time solar positions which vary with GPS's data are used simultaneously to control the solar tracker by a chain of operating modes between the open and closed loops. This paper introduces a step by step procedure for the fabrication and performance assessment of a precision solar tracking system. The system developed in this study consists of motion controllers, motor drives, step-motors, feedback devices and application. CRD sensors are applied for the solar tracking system which play a primary role in poor conditions for tracking due to a gear backlash and a strong wind. Mini-dish was used as a concentrator for collecting sun light. The solar position data, in terms of azimuth and elevation, sunrise and sunset times was compared with those of KASI(Korea Astronomy & Space Science Institute). The results presented in this paper demonstrate the accuracy of the present system in solar tracking and utilization.

• Journal of the Korean Solar Energy Society
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• v.29 no.3
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• pp.59-65
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• 2009

In this paper, to find effective way of the production of the distilled water with solar radiation, 4 different boxes of condensation systems were compared. The bottom size of boxes are identical but the angles of top collecting plates are different. During the solar radiation, condensation did not occur and the condensation start when solar radiation was decreased. The maximum condensation reached when the temperatures of the top and bottom parts are equal. The condensation was continued until sunrise with gradually reduced amount. When top plate angle was $45^{\circ}$, condensation was highest compared with the other angles.

• KIEAE Journal
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• v.13 no.2
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• pp.61-66
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• 2013

This study is to eliminate the need for conventional high density plant factory's artificial light source such as LED to reduce the initial investment of the light source installation as well as the operation cost. Use of solar light could enhance the quality of the vegetables similar to those grown in the natural environment. Provision of solar light into the multilayer vegetable cultivation facilities and collecting maximum and sustainable sunlight without too much loss by tracing solar path and properly distributing it through careful control during daytime are crucial for realizing the investigated rooftop light shelf system for multi-layered vegetable cultivation. In this study, we developed an innovative way of effectively allocating sunlight inside even to otherwise shaded zone of a multi-layer vegetable cultivation facility. To prove the effectiveness of the system's sunlight collection and distribution capability, both simulation and experiment in Daejeon are performed and the outcome is analyzed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.9 no.5
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• pp.579-589
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• 1985

The storage tank of the natural-circulation-solar-hot-water system equipped with flat-plate solar collectors is located at higher elevation than the solar collectors. Therefore, the heat loss from the system due to a reversed flow during the night-time is an important factor as well as the day-time thermal performance of the system. The thermal performance of the natural-circulation-solar-hot-water system with flat-plate solar collectors during the day-time depends mainly on the heat collecting efficiency of the solar collectors, whereas its thermal performance during the night-time depends on the system configuration , such as the elevation of the water storage tank with respect to the solar collectors and the piping connections between the storage tank and the solar collectors, as well as thermo-physical properties of the circulating fluid. In the present work, a computer program has been developed to simulate a typical natural-circulation-solar-hot-water-system, and a series of simulation tests have been carried out with the computer program to examine the thermal performance of the system during the day-time as well as the hight-time. In addition , a series of experiment have been conducted under a real sun condition using a natural-circulation-solar-hot-water-system constructed and installed at the KAIST building to compare with the results obtained from computer simulations.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.63.1-63.1
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• 2010

Since the solar energy resource is the main input for sizing any solar photovoltaic system and solar thermal power system, it is essential to utilize the solar radiation data as a application and development of solar energy system increase. It will be necessary to understand and evaluate the insolation data. The Korea Institute of Energy Research(KIER) has begun collecting horizontal global insolation data since May, 1982 at 16 different locations in Korea and for the more detailed analysis, Images taken by geostationary satellite may be used to estimate solar irradiance fluxes at earth's surface. It is based on the empirical correlation between a satellite derived cloud index and the irradiance at the ground. From the results, the measured data has been collected at 16 different stations and estimated using satellite at 23 different stations over the South Korea from 1982 to 2009. The Result of analysis shows that the annual-average daily global radiation on the horizontal surface is $3.56kWh/m^2/day$.