• Title/Summary/Keyword: annual production

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Annual Variations in Fisheries Productivity Index in Jinhae Bay (진해만의 수산생산성지표의 경년변화)

  • Kang, Min-Hea;Lee, In-Cheol
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.43 no.5
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    • pp.547-550
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    • 2010
  • Jinhae Bay is a typical aquaculture farm with active fisheries. However, it has been contaminated by the development of a major city and industrial area, and has therefore diminished in value as a fishing ground. To preserve the continuing productivity of the ocean, we have to estimate fisheries resources. To analyze the fisheries resources in Jinhae Bay, we evaluated the Fisheries Productivity Index (FPI). The FPI is composed of the Total production ($T_p$), Total amount ($T_a$), and Production of edible protein ($E_p$), nitrogen ($N_p$) and phosphorous ($P_p$). To calculate the FPI, we used Annual statistics on cooperative sales of fishery products data from 1979 to 2004 and the Food composition table. The results of the FPI were as follows. $T_p$ ranged from 70,235 tons to 113,556 tons and $T_a$ ranged from 107,004 million won to 373,776 million won. $E_p$ ranged from 8,124 tons to 13,357 tons, $N_p$ ranged from 1,965 tons to 3,273 tons, and $P_p$ ranged from 168 tons to 276 tons. According to the FPI, maximum fisheries productivity occurred in 1994, when $T_a$, $E_p$, $N_p$ and $P_p$ were at their highest values.

Evaluation of the Performance on WindPRO Prediction in the Northeast Region of Jeju Island (제주 북동부지역을 대상으로 한 WindPRO의 예측성능 평가)

  • Oh, Hyun-Seok;Ko, Kyung-Nam;Huh, Jong-Chul
    • Journal of the Korean Solar Energy Society
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    • v.29 no.2
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    • pp.22-30
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    • 2009
  • In order to clarify predictive accuracy for the wind resource predicted by running WindPRO(Ver. 2.5) which is software for wind farm design developed by EMD from Denmark, an investigation was carried out at the northeast region of Jeju island. The Hangwon, Susan and Hoichun sites of Jeju island were selected for this study. The measurement period of wind at the sites was for one year. As a result, when the sites had different energy roses, though the two Wind Statistics made by STATGEN module were used for the prediction, it was difficult to exactly predict the energy rose at a given site. On the other hand, when the two Wind Statistics were used to predict the average wind speed, the wind power density and the annual energy production, the relative error was under ${\pm}20%$ which improved more than that when using only one Wind Statistics.

Characteristics of Wind Energy for Long-term Period (10 years) at Seoguang Site on Jeju Island (제주 서광지역에 대한 풍력에너지의 장기간 (10년) 특성)

  • Ko, Kyung-Nam;Kim, Kyoung-Bo;Huh, Jong-Chul
    • Journal of the Korean Solar Energy Society
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    • v.28 no.3
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    • pp.45-52
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    • 2008
  • In order to clarify characteristics of variation in wind energy over a long-term period, an investigation was carried out at Seoguang site on Jeju island. The wind data for 10 years from Automatic Weather System (AWS) were analyzed for each year. The variation in the annual energy production (AEP) for the 2 MW wind turbine was estimated through statistical work. The result shows that the range of the yearly average wind speed at 15 m above ground level for 10 years was from -22.6% to +13.7%, which is wider range than that in Japan. The coefficient of variation for the AEP was 22.7%, which is about twice of that for the yearly average wind speed. Therefore, for estimating the wind energy potential accurately at a given site, the wind data should be analyzed over a long-term period based on the data from the meteorological station.

Wind Farm Design Considering Turbulence Intensity on Complex Terrain (복잡지형에서 난류강도를 고려한 풍력발전단지설계)

  • Park, Mi-Ho;Ko, Kyung-Nam;Huh, Jong-Chul
    • Journal of the Korean Solar Energy Society
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    • v.33 no.6
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    • pp.1-11
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    • 2013
  • The investigation on wind farm design using CFD technique was carried out to reduce turbulence intensity in a wind farm. A potential wind farm in Gasiri of Jeju Island was selected for the design and the commercial S/W of Meteodyn WT was used for applying CFD technique. The initial layout of wind turbines was derived using WindPRO which is mainly used for wind farm design in Korea. Then, the distribution of turbulence intensity on complex terrain was calculated and visible by Meteodyn WT. Based on the distribution, wind turbines were positioned properly. As a result, wind turbines could be deployed at positions with minimum turbulence intensity as well as maximum Annual Energy Production, AEP, using Meteodyn WT. It is necessary to take into account turbulence intensity in wind farm design to avoid wind turbine failure.

The Energy Flow and Mineral Cycles in a Zoysia japonica and a Miscanthus sinensis Ecosystem on Mt. Kwanak 8. The Cycles of Sulphur (관악산의 잔디와 억새 생태계에 있어서 에너지 흐름과 무기물의 순환 8.황의 순환)

  • 강경미;장남기
    • Asian Journal of Turfgrass Science
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    • v.11 no.4
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    • pp.281-288
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    • 1997
  • This study was performed to find out the mineral cycles of sulphur in dynamic grassland ecosystems in a steady state condition at the northwest side on Mt. Kwanak. The experimental results may be summarized on the communities of a Zoysia japonica and a Miscanthus sinensis as follows. As compared with some properties of the surface soils among two semi-natural grasslands, sulphur war greater quantity in a Miscanthus sinensis than in a Zoysia japonica on Mt. Kwanak . For the case of steady production and release, the raion of annual mineral production to the amount accumulated on the top of mineral soil in a steady state provides the estimates of release constant k. The release constants on sulphur of the litter were 0.54 in a Zoysia japonica and 0.36 in a Miscanthus sinensis grassland. The half times of S required for the release or accumulation of the litter on the grassland were 1.28 years in a Zoysia japonica and 1.93 years in a Miscauthus sinensis The amounts of annual cycles for sulphur in the grassland ecosystem under the steady-state conditions were 20.65g /$m^2$ in a Zoysia japonica and 26.28g /$m^2$ in a Miacanthus sinensis grassland. Key words: Zoysia japonica Miscanthus sinensis Mt. Kwanak, Sulphur, Mineral cycles.

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Wake Losses and Repositioning of Wind Turbines at Wind Farm (풍력발전단지의 후류손실 및 터빈 재배치에 관한 연구)

  • Park, Kun-Sung;Ryu, Ki-Wahn;Kim, Hyun-Goo
    • Journal of the Korean Solar Energy Society
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    • v.35 no.3
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    • pp.17-25
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    • 2015
  • The main objective of this study is to predict the wind power generation at the wind farm using various wake models. Modeling of wind farm is a prerequisite for prediction of annual energy production at the wind farm. In this study, we modeled 20 MW class Seongsan wind farm which has 10 wind turbines located at the eastern part of Jeju Island. WindSim based on the computational fluid dynamics was adopted for the estimation of power generation. The power curve and thrust coefficient with meteorology file were prepared for wind farm modelling. The meteorology file was produced based on the measured data of the Korea Wind Atlas provided by Korea Institute of Energy Research. Three types of wake models such as Jensen, Larsen, and Ishihara et al. wake models were applied to investigate the wake effects. From the result, Jensen and Ishihara wake models show nearly the same value of power generation whereas the Larsen wake model shows the largest value. New positions of wind turbines are proposed to reduce the wake loss, and to increase the annual energy production of the wind farm.

The Power Performance Testing for 3MW Wind turbine System (3MW 풍력발전시스템 출력성능평가에 관한 연구)

  • Ko, Suk-Whan;Jang, Moon-Seok;Park, Jong-Po;Lee, Yoon-Su
    • Journal of the Korean Solar Energy Society
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    • v.31 no.4
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    • pp.19-26
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    • 2011
  • We are carried out power performance testing for 3MW wind turbine system at Je-ju wind turbine testing Site and analyzed measured data which was stored through monitoring system. In this paper, we described the power performance testing results and analyzed an uncertainty of measured data sets. The power curve with measured power data is closely coincide with designed power curve except for the low wind speed sections(4m/s~7m/s) and the annual energy production which is given Ray leigh distribution was included with 1.5~5.9% of uncertainty in the wind speed region as 4~11m/s. Although the deviation of curve between measured power and designed power is high, the difference of annual energy production is low in the low wind speed region.

Development of a Micro-Bubble System for Ozone Off-Gas Recycling in the Ozone Treatment Process (오존처리공정의 배오존 재활용 마이크로버블시스템 개발)

  • Young-Man, Cho;Jae-Ouk, Jung;Kwang-Heon, Lee;Yong-Jun, Jung
    • Journal of Environmental Science International
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    • v.31 no.12
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    • pp.1061-1068
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    • 2022
  • The purpose of this study was to develop a recycling system for ozone off-gas. Although the ozone transmission rate of the injector method differs slightly depending on the ozone injection rate, it reaches approximately 99%, which is very high. During the increase in water inflow to the ozone recycling system from 2 L/min to 10 L/min, the average ozone recycling rate was 99.4% at a 1 ppm ozone injection rate, 98.6% at a 2 ppm ozone injection rate, 98.1% at a 3 ppm ozone injection rate. Ozone treatment facility operating costs can be divided into the costs of pure oxygen production, ozone production, and maintenance. The annual operating costs of ozone treatment facilities in Korea are estimated to be approximately 38.9 billion won. The annual savings are estimated to be approximately 5.8 billion won when the ozone transfer rate of the diffuser method, which is mostly employed in domestic water treatment plants, is 85% and 15% of the ozone is recycled.

Strengthening Food Security through Food Quality Improvement - Focus on Grain Quality and Self-Sufficiency Rate

  • Meera Kweon
    • Proceedings of the Korean Society of Crop Science Conference
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    • 2022.10a
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    • pp.10-10
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    • 2022
  • The concern about food security is rising as the unstable situation of food supply and demand due to the Covid-19 pandemic, climate change, and turbulent political situation. Korea's global food security index (GFSI), analyzed by the Economist Group, is considered good, but the level continuously decreases in comparing food security levels by country. In particular, Korea is highly dependent on food imports, and food and grain self-sufficiency rates continuously decrease. Therefore, increasing those rates to strengthen food security is urgent. Among the major grains, the self-sufficiency of wheat, com, and soybeans, except rice, is relatively low. Unlike the decrease in the annual rice consumption, the annual wheat consumption has been continuously maintained or increased, which is required public-private efforts to increase the self-sufficiency rate of wheat. Applying the government's policies implemented to increase the self-sufficiency rate of rice in the past will help increase the self-sufficiency rate of wheat. In other words, expanding wheat production and infrastructure, stabilizing supply and demand, and establishing a distribution system can be applied. However, the processing capability of wheat and rice is different, which is necessary to improve wheat quality and processing technology to produce consumer-preferred wheat-based products. The wheat and flour quality can be improved through breeding, cultivation, post-harvest management, and milling. In addition, research on formulation, processes, packaging, and storage to improve the quality of wheat-based products should be done continuously. Overall, food security could be strengthened by expanding wheat production and consumption, improving wheat quality, and increasing wheat self-sufficiency.

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Analysis of Wind Energy Potential on the West Coast of South Korea Using Public Data from the Korea Meteorological Administration (기상청 공공데이터를 활용한 대한민국 서해안 일대의 바람자원 분석)

  • Sangkyun Kang;Sung-Ho Yu;Sina Hadadi;Dae-Won Seo;Jungkeun Oh;Jang-Ho Lee
    • Journal of Wind Energy
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    • v.14 no.3
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    • pp.14-24
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    • 2023
  • The significance of renewable energy has been on the rise, as evidenced by the 3020 renewable energy plan and the 2050 carbon neutrality strategy, which seek to advance a low-carbon economy by implementing a power supply strategy centered around renewable energy sources. This study examines the wind resources on the west coast of South Korea and confirms the potential for wind power generation in the area. Wind speed data was collected from 22 automatic weather system stations and four light house automatic weather system stations provided by the Korea Meteorological Administration to evaluate potential sites for wind farms. Weibull distribution was used to analyze the wind data and calculate wind power density. Annual energy production and capacity factors were estimated for 15-20 MW-class large wind turbines through the height correction of observed wind speeds. These findings offer valuable information for selecting wind power generation sites, predicting economic feasibility, and determining optimal equipment capacity for future wind power generation sites in the region.