• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.49-52
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• 2006

should be in English, A make out an economical, reliable and easy to adoptable instrument in turbine discharge measurement was restricted from lots of it's foundational condition. Not with standing the brilliant progress in new technology of these day, useful instrument for flow measurement in turbine is still ongoing. Nowaday, the increasing importance of renewable energy makes it more important that the measuring turbine efficiency as a decision making index of old turbines' replacement. In Turbine performance diagnosis, Kwater(Korea Water Corporation) got an enough ability and decent reputation for who has invested lots of time and effort for buildup and development. In Korea as a public corporation who should take a crucial roll in Turbine business, Kwater has introduced some developed new technology for other domestic concerned one. With this writing, I'd like to introduce ASFM system as a newly developed instrument that can cope with lots restriction in discharge measurement in turbine. Kwater adopted the system in 2005, and performed 2 times of trial test. The test result was good enough to use the system as a reference test method.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.109.2-109.2
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• 2011

A photovoltaic system is getting the spotlight for a environment-friendly energy source. But its location is limited because a lot of land is necessary for photovoltaic arrays. Nevertheless, its dissemination is rapidly increasing more than 40 % every year and exceeded about 400 MW in 2009. The radical growth of a photovoltaic system aggravated a lack of sites, so that forests and farmland were destroyed. It is demanded to make use of a vacant lot or little piece of land for the way to solve the lack of sites and improve the location requirements for a photovoltaic system. General photovoltaic arrays are consist of a single layer structure and needs enough separation distances to maximize the amount of solar radiation and to eliminate influences by the shadow of other arrays. So that a large amount of land is required for the site. The solar cell arrays with long separation distances can not be placed in a small vacant lot and its site application efficiency is low. This study optimized photovoltaic arrays as multilayered structure with movable sleeves for the efficient photovoltaic in a small site. The existing photovoltaic arrays with a single layer structure were fixed or tracking systems. In this experimental equipment, photovoltaic arrays attached to the multilayers have rectilinear movement and rotary motion using sleeves. Therefore, shadow influences were removed and the generation capacity was improved. On the simulation result, generation increased by about 30% in the same site considering shadow influences and so on.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.511-514
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• 2007

Gas hydrate has a unique property that can store a large volume of gas in water as a solid form. Even though investigations for natural gas storage technology have been carried out for several decades, there are still a lot of unsolved problems due to complex formation process, low formation speed, high energy consumption and so on. So, lots of experiments were conducted to overcome these weaknesses and to develop artificial NGH formation technology applicable to industrial-scale storage and commercial transport. In this study, some series of experiments were performed to analyze both stirred and unstirred system especially about the influences of several gas hydrate formation factors such as agitation speed, system temperature, SDS concentration, etc. As a result, optimum range of SDS concentration and temperature that could enhance the storage capacity and shorten the formation time were found. And it is obviously presented that SDS such a kind of surfactant promotes gas hydrate formation dramatically and the quantity of stored gas are proportional to agitation speed in stirred system.

• Proceedings of the KIEE Conference
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• 2002.04a
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• pp.201-203
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• 2002

In recent years there has been a growing interest in renewable energy systems due to the environmental problem and the economic benefits of fuel savings. Such systems are usually connected to the existing power grid for "fuel displacement" purpose as well as of earning some "capacity credit". Wind power generation system(WPGS) is one of the most useful energy resource using natural environment. So far, it was very difficult to simulate the dispersed generation system including WPGS using EMTP or EMTDC because the source of the dispersed generation system has a particular wind power characteristic equation. In this paper, a novel simulation method of WPGS has proposed and a new wind turbine component for EMTDC is also developed. The wind power characteristic equation of wind turbine is used in order to realize the WPGS in EMTDC simulation. And the real field data of weather conditions is interfaced to EMTDC using Fortran program interface method. Consequently the simulation of WPGS using field data is realized in this paper and shows acceptable results.

• Tunnel and Underground Space
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• v.23 no.6
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• pp.547-560
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• 2013

The importance of renewable energy has increased continuously due to the energy insecurity and the necessity of reducing carbon dioxide which is causing global climate change. In such a situation, the Pohang Enhanced Geothermal System (EGS) power plant project which is launched in December 2010 shall be a new opportunity for the development of EGS related technologies in Korea. In this paper, the case studies of Fenton Hill project in the USA and Hijiori project in Japan are introduced in order to help a part of the domestic EGS demonstration project. As a result, it could be helpful to minimize the trial and error of the domestic EGS project by acquiring the achievements and limitations of existing EGS projects.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.133-133
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• 2009

연료전지는 연료의 화학적 에너지를 전기화학 반응을 통하여 직접 전기로 변환하기 때문에 에너지 전환효율이 높고 공해물질을 배출하지 않는 환경친화적인 고효율 발전방식으로, 특히 용융탄산염 연료전지(MCFC) 및 고체산화물 연료전지(SOFC)같은 고온형 연료전지의 경우 분산전원이나 중앙집중발전 같은 발전용에 적합한 연료전지로 평가받고 있다. 현재 MCFC 및 SOFC등의 발전용 연료전지 시스템의 효율은 약 50% 정도이며, 시스템의 발전효율을 높이기 위한 여러 연구가 진행되고 있다. 그 중에서 고온의 배열을 이용하여 연료전지 발전시스템의 효율을 향상시키기 위해 FuelCell Energy, Ansaldo Fuel Cells 및 Simens Westinghouse 등에서 수백 kW급의 fuel cell - gas turbine hybrid system에 대한 상용화 수준의 실증연구가 진행되었다. 본 연구에서는 발전용 연료전지 시스템의 발전효율을 높이기 위한 방안 중 하나로 배열을 이용하여 steam을 발생시켜 air amplifier에 사용함으로써 연료전지 시스템의 MBOP(Mechanical Balance of Plant)중 전력을 소비하는 air blower를 대체하여, 시스템 효율을 향상시키고 시스템의 가용성을 높일 수 있는 설계안에 대하여 논하고자 한다.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.6
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• pp.618-626
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• 2011

Solar cell is one of the most important new renewable energy for future energy generation. This paper presents a novel two stage DC/DC converter topology for PV PCSs. The proposed converter consists of an interleaved boost converter and a two-tank LLC resonant converter which is connected in parallel in primary and series in secondary. The main idea of this topology is that the system can achieve either unilateral or bilateral operations due to the input voltage level of the PV module, which leads to a better performance. The operating schemes on the proposed converter are analyzed and described. A 2.2kW prototype product is built, tested and verified.

• Journal of Hydrogen and New Energy
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• v.33 no.6
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• pp.845-855
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• 2022

In response to climate change, the world is continuing efforts to reduce fossil fuels, expand renewable energy, and improve energy efficiency with the goal of achieving carbon neutrality. In particular, R&D is being made on the value chain covering the entire cycle of hydrogen production, storage, transportation, and utilization in order to shift the energy supply system to focus on hydrogen energy. Hydrogen-based energy sources can produce heat and electricity at the same time, so it is possible to utilize heat energy, which can increase overall efficiency. In this study, calculation of the optimal scale for hydrogen-based cogeneration and the composition of heat sources were reviewed. It refers to a method of the optimal heat source size according to the external heat supply and heat storage to be considered. The results of this study can be used as basic data for establishing a hydrogen-based energy supply model in the future.

• 한국신재생에너지학회:학술대회논문집
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• 2011.05a
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• pp.167.1-167.1
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• 2011

Sustainable energy generation is becoming extremely imperative due to the expected limitations in current energy resources and to reduce pollution. Especially, because of its considerable energy potential, ocean wave energy has been investigated with regard to power generation. To develop large high power wave generator system, it is important to make a small scale proto type and to test that. Thus the objective of this research is to examine the characteristics of a mechanically excited generator system having small power capacity experimentally. The water reservoir (4 m length, 1.5 m width and 1.8 m depth) having a wave maker to make arbitrary height and period of the water wave was made. The proto type consists of three main parts; a buoy, rack-pinion base one-way mechanism, and a wave generator(Fig.1). The water wave is going up and down and the hexahedron buoy is following the wave. The rack gear attached to the buoy is also going up and down to roll the pinion connected to an electric generator then it produces electricity. The experiments were performed with several conditions of water waves, and the power outputs over 30 W could be measured for some conditions. In future works, to achieve higher performance for the proto type, the effects of primary parameters (buoy shape and mass, etc.) on the system efficiency will be identified.

• International Journal of Highway Engineering
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• v.13 no.1
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• pp.87-96
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• 2011

According to adverse effects of ecosystems due to a bulk of fossil fuel consumption, utilization of sustainable and renewable energy is required. In this paper, converting the energy crisis into an opportunity of new growth is expected by converting heat energy in asphalt pavement into electric power using thermoelectric effect. For this, experiments of inserting heat collector pipe and thermoelectric element into asphalt were performed, and the electric power of heat energy harvesting was measured for development of efficient harvesting system of heat energy. As the results of experiments, electric conversion of average 19.86W per day is possible at $1m^2$ conversion area at a depth of 5cm, and possibility of this system was confirmed. Consequently, a systematic "Green Road" using sustainable heat energy source in asphalt pavement simultaneously with environmental maintenance and econovic growth was suggested.