• Journal of the Korean Society of Marine Environment & Safety
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• v.17 no.2
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• pp.179-185
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• 2011

A marine collision accident occurred at the Jin-do water way. A barge loaded with heavy equipment of Power Generation Plant was being towed at its side by two tugs "A" and "B" from Byeg-pa harbour to the designated position to be used for power generation plant near Jin-do bridge. The Power Generation Plant was 40-meters high loaded atop the barge. When the "tugs and tow" were approaching the Jin-do the bridge, the two towing tugs lost maneuvering control of the barge and it went off-course, hit first the waterway embankment and finally struck the lower part of bridge's span and post musing the barge to capsize and sunk its cargo into the sea. The bridge also suffered damages where the top of the Plant struck At the time of the accident, there was a strong tidal current at the waterway. This paper calculates the safe towing force of barges with heavy loads when traversing in a strong tidal current situation in narrow waterway.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.166.1-166.1
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• 2011

The rotor design is fundamental to the performance and dynamic response of the Counter-rotating marine tidal current turbine. The wind industry has seen significant advancement single rotor blade technology, offering considerable knowledge and making it easy to transfer to tidal stream energy converters. In this paper, 3D flow and performance an alysis on a 100 kW counter-rotating marine current turbine blade was carried out by using the 3-D Navier-Stokes commercial solver(ANSYS CFX-11.0) to provide more efficient design techniques to design engineers. The front and rear rotor diameter is 8m and the rotating speed is 24.72rpm. Hexahedral meshing was generated by ICEM-CFD to achieve better quality of results. The rated power and its approaching stream velocity for design are 100 kW and 2 m/s respectively. The pressure distribution on the blade's suction side tells us that the pressure becomes low at the leading edge of the airfoil as it moves from the hub to the tip.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.8
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• pp.653-660
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• 2015

In this study, we conduct power performance and load analyses of two different types of vertical-axis tidal-current turbines using the computational fluid dynamics (CFD) method. To analyze the power output and loads, we perform transient CFD simulations considering the cavitation model using ANSYS CFX. The averaged power output of an H-type rotor was 7.47 kW and 67.6 kW in normal and extreme operating conditions, respectively, which did not satisfy the initial design conditions. However, in the case of the helical-type rotor, the power output under normal and extreme conditions were close to the expected values. The cavitation, which may cause instantaneous power fluctuation, occurred repeatedly at the suction side of the rotors. In order to guarantee a more stable power supply and to prevent fatigue failure, we require a design that minimizes cavitation.

• Journal of the Korean Association of Geographic Information Studies
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• v.14 no.3
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• pp.22-35
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• 2011

Incheon Bay has a suitable condition for tidal power generation due to the high tidal range by topographical effect. Therefore a study on the technology development for tidal energy utilization has been promoted since 2006. It is needed to deduce optimal alternatives to determine the suitable location of facilities for tidal power generation and to reduce the environmental damage from development. In order to carry out efficiently this mission, spatial information system is essential to manage and use various spacial elements related to the development and conservation. In this study, for the development of tidal energy, spatial data could be defined as three kinds of dataset. Fundamental dataset is defined as spatial data such as tide, tidal current, wave, erosion and sedimentation. Framework dataset is composed of topographical map, facility map and bathymetry. The reference dataset is composed of marine ecology and environment having the characteristics of thematic map. This study is mainly aimed at establishing methodology of conceptual spatial data modeling classifying as essential data model and optional data model through the definition of the components of spatial data.

• New & Renewable Energy
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• v.16 no.1
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• pp.31-40
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• 2020

Most countries in the world are trying to reduce the use of fossil fuels in the production of electricity and replace them with renewable energy technologies. In Korea, there are abundant ocean renewable energy sources that will play an important role in power generation in the future. This paper introduces a new tidal energy converter utilizing flow induced vibration (FIV), which can work efficiently, even in the currents slower than 1.0m/s. All tests were conducted at the Marine Renewable Energy Laboratory at the University of Michigan to examine the effects of the damping ratio of the electric generators on the power outputs and power efficiencies. In these tests, two identical circular cylinders were used, and passive turbulence controllers were applied to the surface of the cylinders to enhance the FIV. The experimental results showed that by using the two cylinders in the FIV, the power output and efficiency reached up to 31 W and 36%, respectively. In particular, the results showed that the power efficiency was higher at the relatively low flow speed (4

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.121-124
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• 2006

국내외에 아직 적용 실적이 없는 발전소의 해수방류수를 이용한 조류식발전시스템의 개발을 위하여 하동화력발전소 방수로에 시험용 조류식 발전시스템을 설계 및 제작하여 현장시험이 진행 중이며, 이를 확장하여 상업용 발전을 위한 총 개발 규모를 산정하고 경제성을 분석하였다. 조류식발전구조물의 형상 설계, 가이드 베인을 이용한 출력 조정을 통하여 방수로의 수류상태를 적절히 조절하여 설계하는 것이 가능할 것으로 판단되며, 조류식발전구조물 설치시 방수로의 수류특성 수치계산 결과로 판단할 때 발전출력에 의한 에너지 회수뿐만 아니라 조류식발전구조물의 단면축소 효과 및 수두손실이 방수로의 수위 변화에 상당한 규모로 영향을 주고 있음을 확인하였다. 조류식발전구조물 설치 이전의 유속 관측 결과를 이용하여 발전량을 산정한 경우 소수력발전 단가 적응시 경제성이 떨어지지만, 조류식발전시스템의 설치시 유속 증가 효과가 나타날 뿐만 아니라 가이드 베인 등을 이용하여 발전량 증대를 꾀하면 충분한 경제성을 확보할 수 있는 조류식발전시스템의 설치가 가능할 것으로 판단된다.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.509-512
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• 2006

국내 대형 기력발전단지에서 냉각수로 사용되고 방류되는 해수는 약 150cms로 (100Mwe 당 약 5cms) 약 3,000kW 이상의 수력에너지를 보유하고 있으나, 현재 활용되지 못하고 그대로 해양으로 방류되고 있다. 발전소 방수로는 흐름조건이 비교적 균일하고, 파랑 내습이 없으며 부유사 해조류, 부유물 충돌 등의 문제가 발생하지 않아 자연 해양조건보다 조류력 발전에 매우 유리하나 수심이 낮고, 순환수 계통에의 영향으로 다수의 수차를 설치하기는 어려운 조건을 지니고 있다. 따라서, 인공수로의 균일하고 양호한 흐름조건에 적합한 보다 경제적인 수차를 개발하고, 발전량을 증대하기 위한 수차 배치 기술, 수차 및 발전기 지지구조물의 설계 기술, 계통 연결기술 등을 개발할 필요가 있으며, 이를 위하여 시험용 조류식 발전시스템을 제작하여 수차의 성능 및 전체 발전시스템의 성능을 평가하여 발생되는 문제점을 해결하고자 한다. 본 연구에서는 시험용 조류식 발전시스템을 하동화력발전소 방수로에 적용하기 위하여 현장 특성 분석, 형식 선정, 발전량 산정 등의 시스템 설계를 수행하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.32 no.1
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• pp.48-54
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• 2020

Numerical analysis was carried out to analyze the flow fields and mechanical output of a rotor for various positions and inlet flow rates in a shroud, and it was compared with experimental data. Rotor and seawater current largely affects the flow field characteristics in the shroud system. Especially the mechanical output of the rotor increased with axial position near the center of the cylinder, and it gradually decreased close to the entrance and exit. Also, the rotor output increased with the inlet velocity. Axial and angular momentum of flow along the cylinder region rapidly increased and reached a peak, and then decreased as it passed through the rotor, while there was no significant change in the cylinder region. It is expected that these results can be used as applicable design data for the development of the tidal power generation system.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.1355-1355
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• 2005

• Korean Journal of Materials Research
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• v.24 no.8
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• pp.434-442
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• 2014

Serious environmental problems have been caused by the greenhouse effect due to carbon dioxide($CO_2$) or nitrogen oxides($NO_x$) generated by the use of fossil fuels, including oil and liquefied natural gas. Many countries, including our own, the United States, those of the European Union and other developed countries around the world; have shown growing interest in clean energy, and have been concentrating on the development of new energy-saving materials and devices. Typical non-fossil-fuel sources include solar cells, wind power, tidal power, nuclear power, and fuel cells. In particular, organic solar cells(OSCs) have relatively low power-conversion efficiency(PCE) in comparison with inorganic(silicon) based solar cells, compound semiconductor solar cells and the CIGS [$Cu(In_{1-x}Ga_x)Se_2$] thin film solar cells. Recently, organic cell efficiencies greater than 10 % have been obtained by means of the development of new organic semiconducting materials, which feature improvements in crystalline properties, as well as in the quantum-dot nano-structure of the active layers. In this paper, a brief overview of solar cells in general is presented. In particular, the current development status of the next-generation OSCs including their operation principle, device-manufacturing processes, and improvements in the PCE are described.