• Title/Summary/Keyword: Ocean energy

Search Result 2,454, Processing Time 0.03 seconds

Study on the Buoy and Vibration System in Broadband Ocean Wave Power Generator (광대역 파력발전기의 진동시스템과 부양 체에 대한 연구)

  • Lee, Hong-Chan;Yea, Kyung-Soo;Hwang, Sung-Il;Han, Ki-Bong
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.36 no.6
    • /
    • pp.780-787
    • /
    • 2012
  • In general, the ocean wave vibration power generator consists of buoy, vibration system and linear generation system. It maximized energy efficiency by using resonance phenomenon that turned to the natural frequency of vibration system and frequency of ocean wave energy. But it is difficult to obtain efficiently energy from ocean wave because the frequency of ocean wave changes from moment to moment. In this paper, we study the buoy and vibration system of ocean wave power generator to solve these problem. Firstly, we designed the buoy that gives rise to resonance between ocean wave and buoy. Secondly, we designed vibration system that is occurred to resonance between buoy and vibration system. And then the relative velocity between the buoy and magnetic of ocean wave vibration generator increases and the relative displacement between buoy and ocean wave decreases at the same time. As a result, the method which is proposed in this paper has merits not only securing its stability from harsh ocean wave environment but also obtaining more kinetic energy from ever-changing ocean wave.

Internal Oscillating Flow Field Analysis in Air Chamber of Wave Energy Conversion (파력발전장치 공기실 내 왕복유동장 해석)

  • Moon, Jae-Seung;Hyun, Beom-Soo;Hong, Key-Yong;Shin, Seung-Ho;Kim, Gil-Won
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
    • /
    • 2006.11a
    • /
    • pp.427-430
    • /
    • 2006
  • This paper deals with the internal oscillating flaw in air chamber and duct of an OWC-type wave energy converter by numerical analysis using commercial CFD code, FLUENT. Whole oscillating flaw from OWC-type chamber to outlet through duct was solved by unsteady analysis in order that performance of wave energy conversion was made better. Results show that whole oscillating flaw field of this system in unsteady condition. Duct shape at setting place of turbine is curved with elbow, because profile of inlet condition to turbine is important in its efficiency. This paper is found internal flaw in air chamber and duct. Also, this research was found effect of duct shape.

  • PDF

A Study on Motion and Wave Drift Force of a BBDB Type OWC Wave Energy Device (BBDB형 진동수주 파력발전장치의 운동 및 파랑표류력 연구)

  • Kim Jin-Ha;Lew Jae-Moon;Hong Do-Chun;Hong Seok-Won
    • Journal of Ocean Engineering and Technology
    • /
    • v.20 no.2 s.69
    • /
    • pp.22-28
    • /
    • 2006
  • The motion and wave drift forces of floating BBDB (backward-bent duct buoy) wave energy absorbers in regular waves are calculated, taking account of the oscillating surface-pressure due to the pressure drop in the air chamber above the oscillating water column, within the scope of the linear wave theory. A series of model tests has been conducted in order to order to verify the motion and time mean wave drift force reponses in regular waves at the ocean engineering basin, MOERI/KORDI. The pneumatic damping through an orifice-type duct for the BBDB wave energy device are deducted from experimental research. Numerical simulation for motion and drift force responses of the BBDB wave energy device, considering pneumatic damping coefficients, has been carried out, and the results are compared with those of model tests.

Simplified planar model for damage estimation of interlocked caisson system

  • Huynh, Thanh-Canh;Lee, So-Young;Kim, Jeong-Tae;Park, Woo-Sun;Han, Sang-Hun
    • Smart Structures and Systems
    • /
    • v.12 no.3_4
    • /
    • pp.441-463
    • /
    • 2013
  • In this paper, a simplified planar model is developed for damage estimation of interlocked caisson systems. Firstly, a conceptual dynamic model of the interlocked caisson system is designed on the basis of the characteristics of existing harbor caisson structures. A mass-spring-dashpot model allowing only the sway motion is formulated. To represent the condition of interlocking mechanisms, each caisson unit is connected to adjacent ones via springs and dashpots. Secondly, the accuracy of the planar model's vibration analysis is numerically evaluated on a 3-D FE model of the interlocked caisson system. Finally, the simplified planar model is employed for damage estimation in the interlocked caisson system. For localizing damaged caissons, a damage detection method based on modal strain energy is formulated for the caisson system.

Fatigue Design of Mooring Lines of Floating Type Combined Renewable Energy Platforms

  • Choung, Joon-Mo;Jeon, Sang-Ik;Lee, Min-Seong
    • International Journal of Ocean System Engineering
    • /
    • v.1 no.3
    • /
    • pp.171-179
    • /
    • 2011
  • This paper presents the concept design procedure of a floating-type combined renewable energy platform based on hydrodynamic analyses and is focused on the fatigue design of taut-type mooring lines of the platform. Two types of combined renewable energy platforms are considered: a combination of wind turbine, wave turbine and photovoltaic energy plant and a combination of wind turbine, current turbine and photovoltaic energy plant. The basic configurations are conceptually determined from the understanding of floating offshore plants, while the main dimensions have been determined based on a hydrostatic calculation. Fully coupled hydrodynamic analyses have been carried out to identify the motion characteristics of the floating body and the tension histories of the mooring lines. The tension history is used for the fatigue life prediction based on the rain-flow cycle counting method. For the fatigue life prediction, tension life curves from API and the Palmgren-Miner rule are employed.

Aerodynamic Characteristics of Impulse Turbine with an End Plate for Wave Energy Conversion

  • HYUN BEOM SOO;MOON JAE SEUNG;HONG SEOK WON;KIM KI SUP
    • Journal of Ocean Engineering and Technology
    • /
    • v.19 no.6 s.67
    • /
    • pp.1-7
    • /
    • 2005
  • This paper deals with the design and aerodynamic analysis of a special-type impulse turbine, with an end plate for wave energy conversion. Numerical analysis was performed using a CFD code, FLUENT. The main idea of the proposed end plate was to minimize the adverse effect of tip clearance of turbine blade, and was borrowed from ducted propeller, with so-called penetrating end plate for special purpose marine vehicles. Results show that efficiency increases up to $5\%$, depending on the flow coefficient; a higher flow coefficient yields increased efficiency. Decrease of input coefficient CAwith an end plate is the main reason for higher efficiency. Performance of end plate at various design parameters, as well as flow conditions, was investigated; the advantages and disadvantages of the presentimpulse turbine were also discussed.

Trend in suction bucket foundation for offshore wind turbine (해상풍력발전설비를 위한 버켓기초의 기술동향 및 기술개발 방향)

  • Youn, Hee-Jung;Jang, In-Sung;Oh, Myoung-Hak;Kwon, O-Soon;Jung, Sung-Jun
    • Proceedings of the Korean Geotechical Society Conference
    • /
    • 2010.09a
    • /
    • pp.494-503
    • /
    • 2010
  • This paper reviews research trend in suction bucket foundation. Wind energy farm has been considered as an efficient alternative to fuel energy as world markets attempt to discover renewable resources. Recently, Korean government initiated the research projects investigating installation method of offshore wind energy foundation and design guideline as well as verifying feasibility of offshore wind farm. In fact, the installation of monopile and gravity type foundation has been sucessfully carried out in European and other advanced countries, and design guideline of those foundations are well established; however, various types of foundation would be necessary in the near future as offshore wind farm demands abundant wind resources in deep sea. In this paper, bucket foundation is spot lighted as a powerful and economic alternative applicable to deep sea condition.

  • PDF

Resource Assessment of Tidal Current Energy Using API in Korea (API를 적용한 국내 조류에너지 잠재량 추정)

  • Jo, Chul-Hee;Lee, Kang-Hee;Cho, Bong-Kun;Hwang, Su-Jin
    • Journal of the Korean Solar Energy Society
    • /
    • v.36 no.1
    • /
    • pp.75-81
    • /
    • 2016
  • The west and south coastal regions of Korea are known to be of strong tidal current speed. With the increasing demand for renewable energies, the resource assessment has been a crucial issue which should be conducted before any detail planning and development of the potential sites for tidal current farm. Although there are several results of resource assessment of tidal current energy in Korea, the resource assessment method is not officially announced. This undefined methodology makes the results unreliable and useless. Recently new renewable energy potential definition has been announced by KIER (Korea Institute of Energy Research). This categorizes energy potential as four steps; theoretical, geographical, technical and market potentials. This paper describes the resource assessment of tidal current power in Korea based on API (Averaged Power Intercepted). The results show that the Incheon-Gyeonggi and Jeollanam-do are very promising areas for tidal current power in Korea.

Numerical Investigation of Multi-body Wave Energy Converters' Configuration

  • Heo, Kyeonguk;Choi, Yoon-Rak
    • Journal of Ocean Engineering and Technology
    • /
    • v.36 no.2
    • /
    • pp.132-142
    • /
    • 2022
  • We investigate the performance of multi-body wave energy converters (WECs). This investigation considers multiple scattering of water waves by the buoys of a WEC under the generalized mode approach. Predominantly, the effect of a WEC's configuration on its energy extraction is studied in this research. First, single-row terminator and single-column attenuator arrays of vertical cylinders have been studied. The performance of these attenuator arrays shows that the wall effect induced by the periodic buoys influences the wave propagation and energy extraction in these WECs. Further studies show that a single-row terminator array of vertical cylinders performs better than the corresponding single-column attenuator array. Subsequently, multi-row terminator arrays of vertical cylinders are investigated by conducting a parametric study. This parametric study shows that the hydrodynamic property of three resonance phenomena makes energy extraction efficiency drop down, and the magnitude of energy extracted oscillates between the resonance points in these WECs. Finally, a 4×8 terminator array of vertical cylinders is studied to determine the effect of various dx (x-directional distance between adjacent rows) within this WEC on its performance. In particular, this study enforces at least two equal dx values within the 4×8 terminator array of vertical cylinders. It shows that a small value of this dx leads to better energy extraction efficiency in some of these various dx arrays than that of a corresponding regular array with the same dx.

Molecular Dynamics Investigation of the Effects of Concentration on Hydrogen Bonding in Aqueous Solutions of Methanol, Ethylene Glycol and Glycerol

  • Zhang, Ning;Li, Weizhong;Chen, Cong;Zuo, Jianguo;Weng, Lindong
    • Bulletin of the Korean Chemical Society
    • /
    • v.34 no.9
    • /
    • pp.2711-2719
    • /
    • 2013
  • Hydrogen bonding interaction between alcohols and water molecules is an important characteristic in the aqueous solutions of alcohols. In this paper, a series of molecular dynamics simulations have been performed to investigate the aqueous solutions of low molecular weight alcohols (methanol, ethylene glycol and glycerol) at the concentrations covering a broad range from 1 to 90 mol %. The work focuses on studying the effect of the alcohols molecules on the hydrogen bonding of water molecules in binary mixtures. By analyzing the hydrogen bonding ability of the hydroxyl (-OH) groups for the three alcohols, it is found that the hydroxyl group of methanol prefers to form more hydrogen bonds than that of ethylene glycol and glycerol due to the intra-and intermolecular effects. It is also shown that concentration has significant effect on the ability of alcohol molecule to hydrogen bond water molecules. Understanding the hydrogen bonding characteristics of the aqueous solutions is helpful to reveal the cryoprotective mechanisms of methanol, ethylene glycol and glycerol in aqueous solutions.