• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2007.12a
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• pp.357-359
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• 2007

해양에너지원 중에서 파랑은 모든 해역에 폭넓게 분포하므로 가용에너지원이 풍부하고 에너지를 회수하기 위한 장치를 설치할 수 있는 해역 또한 광범위하며 반도의 지형을 지닌 우리나라의 연안 해역에 대규모로 활용이 가능한 에너지 자원중 하나이다. 본 연구는 새로운 방식인 파력발전용 횡류형터빈인 케이슨 내장형 횡류터빈을 개발하기에 앞서 파랑수조의 왕복운동을 CFD해석을 통하여 구현하는 것이다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.28 no.4
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• pp.250-255
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• 2016

Ocean environmental data such as tide, wind, significant wave height etc. along the expected route were collected and analyzed to secure the safe towing and installation of floating pendulum wave energy converter(FPWEC) at planned sea area. Data from Korea Meteorological Administration(KMA) and Korea Hydrographic and Oceanographic Agency(KHOA) were reviewed and those were used to estimate the external forces exerting on the FPWEC during the towing operation. ANSYS system was used for the structural analysis of the FPWEC which is subject to complex environmental load to confirm the safety.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.26 no.4
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• pp.225-243
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• 2014

As the economic matters are involved, applying the WEC, which is used for controlling waves as well as utilizing the wave energy on existing breakwater, is preferred rather than installing exclusive WEC. This study examines the OWC mounted on a pressurized air chamber floating breakwater regarding the functionality of both breakwater and wave-power generation. In order to verify the performance as a WEC, the velocity of air flow from pressurized air chamber to WEC has to be evaluated properly. Therefore, numerical simulation was implemented based on BEM from linear velocity potential theory as well as Boyle's law with the state equation to analyze pressurized air flow. The validity of the obtained values can be determined by comparing the previous results from numerical analysis and empirically obtained values of different shapes. In the actual numerical analysis, properties of wave deformation around OWC system mounted on fixed type and floating type breakwaters, motions of the structure with air flow velocities are investigated. Since, the wind power generating system can be hybridized on the structure, it is expected to be applied on complex power generation system which generates both wind and wave power energy.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2019.11a
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• pp.150-152
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• 2019

In this study, the effects of the wave field changes due to the coastal structure on the hydrodynamic performance of the OWC wave energy, converter are analyzed using a three-dimensional numerical wave tank technique (NWT). The OWC device is simulated numerically by introducing a linear pressure drop model, considering the coupling effect between the turbine and the OWC chamber in the time domain. The flow distribution around the chamber is different due to the change of reflection characteristics depending on the consideration of the breakwater model. The wave energy captured from the breakwater is spatially distributed on the plane of the front of the breakwater, and the converted pneumatic power increased when concentrated in front of the chamber. The change of the standing wave distribution is repeated according to the relationship between the incident wavelength and the length of the breakwater, and the difference in energy conversion performance of the OWC was confirmed.

• Proceedings of the KIEE Conference
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• 2011.07a
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• pp.1836-1837
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• 2011

본 논문에서는 AWS형 파력발전 시스템의 최대전력 추종(Maximum Power Point Tracking: MPPT)을 위한 알고리즘 개발 기법에 대한 제안을 하고자 한다. AWS형 파력발전 시스템은 2004년 포르투갈에서 제안된 파도에너지 변환장치로, 해저에 위치하여 전력을 생산하는 특징을 지니고 있다. 파도의 상하 운동에 맞추어 AWS의 주요 부위인 본체가 움직이기 때문에 전력 생산량이 일정치 못하며, 특히 계절 및 환경에 따른 영향을 많이 받게 된다. 이러한 문제점을 해결하기 위한 방법으로, 신재생 발전에서 많이 활용되는 MPPT 제어 기법을 제안하게 된다. 제안된 기법의 활용을 통해 AWS형 파력발전 시스템의 전력 생산성 향상 및 전력 안정도에 대한 연구를 수행하게 된다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.17 no.2
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• pp.81-89
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• 2014

The present study aims to design an optimized hull shape of a floating pendulum-type wave energy converter(WEC). The purpose of these structure is to improve the performance and stability of the WEC by reducing its motion under operating and survival wave conditions. In this study, motion reduction structures, like restoring and dampling plates were installed on a floating pendulum WEC that has been the subject of previous studies. Restoring plates were installed to increase the restoring force and shift the natural period to a shorter period. Damping plates were installed to shift the natural period to a longer period by increasing the added mass. The effects of the structures were then analyzed under different incident wave conditions. The design parameters for the motion reduction structures were size, shape, and installed position. The wave-induced motion characteristics and performance of the floating pendulum WEC were also investigated numerically. Based on the simulation results, we are able to optimize the motion reduction structure of the WEC, thus improving its efficiency and durability.

• Water for future
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• v.54 no.1
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• pp.20-28
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• 2021

• Proceedings of the Korean Institute of Navigation and Port Research Conference
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• 2018.11a
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• pp.85-87
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• 2018

전 세계적으로 온실가스 배출 규제가 강화되고 있고 에너지 절감 및 환경오염 문제가 없는 재생에너지에 대한 관심이 높아지고 있다. 육상 전력을 공급받기 어려움 해양 구조물의 경우에는 배터리와 같은 에너지 저장장치 또는 재생에너지를 활용하여 독립 전원 시스템을 구성하게 된다. 해양에서 활용이 가능한 재생에너지로는 태양광, 풍력, 파력, 조력등이 있으며 이러한 자연 에너지를 활용하는 재생에너지 발전 시스템의 경우 환경의 영향을 많이 받게 되므로 안정적인 전력 생산에 어려움이 있다. 예를 들어 태양광 발전 시스템의 경우 일조량에 따라 발전량이 결정되고, 풍력 발전 시스템의 경우 풍속 및 풍향이 발전량에 영향을 미친다. 따라서 독립전원시스템에서 태양광-풍력-파력의 멀티소스를 갖는 하이브리드 발전 시스템을 구성하여 기상상태에 따른 발전량을 보완가능하게 구성하면 보다 안정적으로 전력을 얻을 수 있다. 본 연구에서는 항만 및 협수로를 항해하는 선박 안전을 위해 설치된 등부표에 적용하는 해상하이브리드발전시스템을 설계하고 실증을 통해 하이브리드 발전시스템의 발전 특성을 확인한다.

• Journal of the Korean Society for Marine Environment & Energy
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• v.13 no.1
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• pp.12-17
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• 2010

Oscillating Water Column (OWC) device has been widely employed in the wave energy conversion. Wave Focusing Device (WFD) is proposed to be helpful for improving the operating performance of OWC chamber. In the present paper, a Numerical Wave Tank (NWT) using two-phase VOF model is utilized to simulate the generation and propagation of incident regular waves, water column oscillation inside the chamber. The NWT consists of the continuity equation, Reynolds-averaged Navier-Stokes equations and two-phase VOF functions. The standard k- turbulence model, the finite volume method, NITA-PISO algorithm and dynamic mesh technique are employed. Effects of WFD on the operating performance of OWC chamber are investigated numerically.

• Journal of the Korean Society for Marine Environment & Energy
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• v.10 no.3
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• pp.173-180
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• 2007

Oscillating wave amplitude in a bottom-mounted OWC chamber designed for wave energy converter is investigated by applying characteristic wave conditions in Korean coastal water. The effects of shape parameters of OWC chamber in a view of wave energy absorbing capability are analyzed. Both experimental and numerical approaches are adopted and their results are compared to optimize the shape parameters which can result in a maximum power production under given wave distribution. The experiment was carried out in a wave flume under 2-D assumption of OWC chamber. The numerical scheme employed a hybrid Green integral equation which adopts the Rankine Green function inside chamber to take account of fluctuating air pressure, while it uses the Kelvin Green function in outer domain. Air duct diameter, chamber width, and submerged depths of front skirt and back wall of chamber changes the magnitude and peak frequency of wave absorption significantly.