• Journal of Korea Water Resources Association
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• v.52 no.12
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• pp.975-984
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• 2019

As an essential prerequisite for systematic and integrated management of river water, it is necessary to secure the basic data such as discharge supplied to the river and released from the river. Under the current permit system for river water use, 59.1% of licensed facilities were found to have no discharge meters in 2017, especially for agricultural water, which makes it difficult to secure reliable data as a large portion of the reports are voluntarily reported by users. In this study, the indirect discharge measurement method of calculating the discharge through the power usage of the pumping station was applied to secure reliable discharge data. In particular, focusing on the fact that the discharge calculated by the power usage method differed with the actual discharge according to the level of the river, the study was conducted on improving the power usage method reflecting the river water level and improving the accuracy of discharge data. Analysis of the discharge calculated using the power usage method considering river water level using the correlation analysis method such as regression analysis, percent difference, root mean square error etc. confirmed that the results are not high compared to the conventional power usage method, but are slightly more approximated to the actual discharge. Therefore, although reliable discharge data can be obtained from the existing power usage method, it is expected that more accurate data on intaking water of river water can be obtained if the improved power usage method is used at points where the variation in the water level of the river is large.

• The KSFM Journal of Fluid Machinery
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• v.13 no.1
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• pp.23-28
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• 2010

A draft tube which has impeller to elevate bottom water and spread it over surface of lake water, induces convective circulation of lake water, a Long-Distance Circulation (LDC). Circulation of lake water make stratified water mixed and enhance DO (Dissolved Oxygen) of bottom water. Circulation rate of water is determined by draft rate of the tube, which is dependent on design parameters of the draft tube system, i. e. dimension of impeller and diffuser, inclined angle of impeller, impeller shape, and rotational speed. In this study, change in draft rate and power consumption of circulation equipment was investigated numerically with changing impeller dimension, angle and rotational speed. It was found that flowrate of draft water was increased as the dimensions of draft tube and impeller, and rotational speed and inclined angle of impeller increased. The power consumption was also elevated with increasing parameter values, and final selection of parameter values was made to satisfy target flowrates and power consumption.

• Journal of Korean Society of Water and Wastewater
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• v.33 no.4
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• pp.281-289
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• 2019

Desalination plants are generally studied with higher operating costs compared to water supply facilities. This study was conducted to reduce the cost of water production and to preserve existing water resources. Therefore, the purpose of this study was to utilize the control valves to increase maximum efficiency, thereby reducing the power of the pumps and operating costs. Specific energy consumption was shown to reduce the process operating power by up to 1.7 times from 6.17 to $3.55kWh/m^3$ based on seawater reverse osmosis 60 bar. In addition, the water intake process was divided into pre, inter, and post-according to the use method of blasting, and the water treatment process was divided into pre, inter, and post blending. In order to reduce power consumption, the blending process was combined to operate the facility, which resulted in the reduction of power consumption in the order post > pre-inter> inter blending.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.09b
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• pp.1264-1265
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• 2005

• Journal of Korean Society of Water and Wastewater
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• v.26 no.4
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• pp.555-563
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• 2012

Due to the importance of energy-saving and CO2 reduction is being emphasized in the world, efforts to find a solution for the problems is increasing rapidly. In particular, the renewable energy is on understanding as a breakthrough for the protection of the environment and the economic development, so it is intensively fostered as future industries. Developed countries are already pursuing policy and technology development related with renewable energy. In this paper, we will develop MHD(Magneto Hydro Dynamics) technology to supply the commercial power that can is targeted at water pipe related with hydro power among renewable energy technologies. Kinetic energy of fluid flowing in the water pipe is converted into electric power. It allows stable power supply to the various sensors and devices on water pipe. We have performed several experiments to verify the application possibility of the developed technologies and present the result and a method of performance improvement of the technologies.

• Journal of Power Electronics
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• v.5 no.4
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• pp.305-311
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• 2005

Throughout the world, studies on the water energization are currently under way. Of those, Brown gas, which is generated through the electrolyzation of water and is a mixed gas of the constant volume of 2 parts hydrogen to 1 part oxygen, has better characteristics in terms of economy, energy efficiency, and environmental affinity than those of acetylene gas and LPG (Liquefied Petroleum Gas) used for existing welding machines. This paper analyzes the characteristics of Brown gas and presents methods for increasing the generating efficiency of Brown gas by designing a power supply to deliver power to a water-electrolytic cell and designing a cylindrical electrode to improve the efficiency of the electrolyzer needed for water electrolyzation. Based on the above the methods, a welding machine using Brown gas is developed. And the generation efficiency of Brown gas is measured tinder different conditions (duty ratio, frequency and amplitude) of supplied power.

• International journal of advanced smart convergence
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• v.12 no.2
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• pp.182-186
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• 2023

In this study, we measured the power and temperature of the floating horizontal solar cell in a coastal lagoon and compared with those of ground solar cell and water platform solar cell. Because the bottom surface of the floating horizontal solar cell was contacting the water, cooling effect was expected stronger than other cells. As a result of the measurement, the power of floating horizontal cell was 11.7% higher than that of the ground cell and 15% higher than that of the water platform cell. During the measurement, it was observed that water waves were continuously flowed on the top surface of floating horizontal cell by the wind, and it could be assumed that the cooling effect occurred not only on the bottom surface of the cell but also on the top surface. In order to analyze the cooling effect and power increasing of the horizontal cell in the wave situation, we measured power and temperature of the cell while generating artificial waves in a laboratory equipped with Zenon lamp as a solar simulator. At the height of thewater surface, the power of the cell with waves was 3.7% higherthan without waves and temperature was 4.6℃ lower. At 1 cm and 2 cm below the watersurface, power of the cell with waves was decreased by 14% and 11% than without waves while temperature was same . At 3 cm below the water surface, there was no effect of waves.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.28 no.6
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• pp.106-112
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• 2014

Recently, tidal power generation has gained much attention. South Korea's tidal power generation systems were imported from abroad by turnkey type and have being operated. Therefore, for efficient operation and technological independence of a tidal power system, development of core technology is required. This paper deals with the start stop control system of water turbine generator in the tidal power plant, as one of our development project results. Using the SCADA system, the status and operations of water turbine generator in the tidal power plant, as well as simulation for calculation of maximum power were carried out. A small model type of start stop control device was also developed. In addition, the control system in Sihwa tidal power plant was modeled, and the results obtained by the dynamic simulation were given in graphics by 2D simulator.

• Nuclear Engineering and Technology
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• v.54 no.3
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• pp.877-887
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• 2022

A new reactor concept is described that directly couples a supercritical CO₂ (sCO₂) power cycle with a CO₂-cooled, heavy water moderated pressure tube core. This configuration attains the simplification and economic potential of past direct-cycle sCO₂ concepts, while also providing safety and power density benefits by using the moderator as a heat sink for decay heat removal. A 200 MWe design is described that heavily leverages existing commercial nuclear technologies, including reactor and moderator systems from Canadian CANDU reactors and fuels and materials from UK Advanced Gas-cooled Reactors (AGRs). Descriptions are provided of the power cycle, nuclear island systems, reactor core, and safety systems, and the results of safety analyses are shown illustrating the ability of the design to withstand large-break loss of coolant accidents. The resulting design attains high efficiency while employing considerably fewer systems than current light water reactors and advanced reactor technologies, illustrating its economic promise. Prospects for the design are discussed, including the ability to demonstrate its technologies in a small (~20 MWe) initial system, and avenues for further improvement of the design using advanced technologies.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.5
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• pp.391-404
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• 2009

A small hydropower plant(SHP) using cooling water discharged from the power plant was constructed in Samcheonpo. This study presents predicted and measured hydrological data in the construction process of small hydropower plant in order to evaluate characteristics of water level variation of cooling water discharge channel which is a key factor in the design of SHP since the water level rise of channel is related to impact on circulating water system of the existing power plant. Various methods were applied for prediction of water level variation in the design stage from simple empirical formula to sophisticated 3-dimensional CFD method. Measured results reveal that mean value was similar between measured and predicted, but measured results were larger than predicted in deviation. Moreover, simple formula, i.e. standard weir equation and Honma equation, were more useful before installation of SHP, but sophisticated methods during operation of SHP.