• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.319-322
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• 2006

Under the national project for the development of 2MW wind energy convert system, we are under development of the prototype of 2MW wind turbine with low speed gearbox. This system adopts low speed gear box with planetary and spur gear and is pitch regulated variable speed type with the synchronous permanent magnet generator. The compromised size of generator in diameter and width are adopted to meet the structural design requirements. In this paper, the concept study for the type, the aerodynamic design for the blade and the details of load calculation will be presented. The detailed characteristics of the system will also be introduced.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.152.2-152.2
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• 2010

LFG는 매립된 폐기물 중 유기성분이 혐기성조건에서 미생물에 의해 분해가 되면서 발생하며, 이러한 매립지가스는 주변 지역의 자연 및 생활환경에 악영향을 미치기 때문에 소각 등의 방법으로 LFG를 처리하고 있다. 일반적으로 매립지로부터 발생하는 가스의 량은 폐기물 1톤 당 $150{\sim}250m^3$로서 매립 후 2~3년 후에 최대량이 발생하며 매립 후 20~30년 후까지 지속적으로 발생함으로 안정적인 LFG의 공급이 가능하며, 메탄함량이 50%인 경우 약 $5,000kcal/m^3$의 높은 발열량을 가지므로 대체에너지원으로 이용할 경우 환경적인 문제 해결 및 신재생에너지원으로 활용할 수 있다. LFG 자원화 할 경우 가장 안정적인 방안으로 발전 및 중질가스로 활용하는 것이나, 발전의 경우 최소 200만톤 이상의 매립용량을 갖추어야 경제적인 사업성을 확보할 수 있으며, 중질가스로 활용하는 경우 인근에 가스 수요처를 확보해야 하는 어려움이 있다. 만약 중 소규모의 매립장에서 발생하는 LFG를 안전하고 경제적인 조건으로 저장 및 수송할 수 있다면 중 소규모의 매립지에서 발생하는 LFG도 활용할 수 있을 것으로 기대되며, 안전하고 경제적인 저장과 수송기술을 통하여 발전이 아닌 중질가스로의 활용도 가능하게 될 것이다. 또한 여러 곳의 매립장에서 발생한 LFG를 한 곳으로 집중시켜 고질가스로 전환하는 설비비용을 절감할 수 있으며, 정제된 고질가스를 이용하여 발전보다 경제적인 자동차 연료나 도시가스로 활용할 수 있을 것이다. 본 연구에서는 LFG의 저장과 수송기술 중 GTS 기술을 통하여 저장과 수송에 제약이 크고 많은 비용이 소비되는 기체 상태의 에너지원을 하이드레이트화 시킴으로서 중 소규모 매립지에서 상대적으로 적은 비용으로 가스저장과 지상수송이 가능하게 할 수 있다. 본 연구의 결과로 LFG 에너지화 실증화 플랜트를 설계/제작 하였으며, 메탄+이산화탄소+물 하이드레이트 형성 실험 결과 4.56 Mpa, 277.2 K 조건에서 3시간을 한 사이클로 하는 공정운전을 가지는 것을 확인하였다. 이때 생성된 슬러리상의 하이드레이트를 고압으로 배출하여 펠릿으로 형성시켰으며, 형성된 하이드레이트 펠릿의 경우 92.27%의 메탄을 포함하는 것을 확인하였다.

• Journal of Plant Biotechnology
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• v.40 no.4
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• pp.185-191
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• 2013

Over the past decades, carbon dioxide concentration of the atmosphere of the world has increased significantly, and thereby the greenhouse effect has become a social issue. To solve this problem, new renewable energy sources including solar, hydrogen, geothermal, wind and bio-energy are suggested as alternatives. Among these new energy sources, bio-energy crops are widely introduced and under rapid progress. For example, corn and oilseed rape plants are used for the production of bio-ethanol and bio-diesel, respectively. However, grain prices has increased severely because of the use of corn for bio-ethanol production. Therefore, non-edible switchgrass draws attention as an alternative source for bio-ethanol production in USA. This review describes the shortage of fossil energy and an importance of switchgrass as a bio-energy crop. Also, some characteristics of its major cultivars are introduced including growth habit, total output of biomass yields. Furthermore, biotechnological approaches have been conducted to improve the productivity of switchgrass using tissue culture and genetic transformation.

• KEPCO Journal on Electric Power and Energy
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• v.7 no.1
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• pp.93-99
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• 2021

The government has proposed a mission to enhance intelligent power networks, decrease coal-fired generation, expand distributed energy resources, and promote energy prosumer into the distribution network in Korea. Installation cost of facility expansion to guaranteed interconnection with small distributed energy resources increases dramatically on KEPCO's distribution sector. And it is hard to withdraw in time. In addition, there are explicit research is required to meet the reliability on grid corresponding to the increase of distributed power. Infrastructure support for accommodating energy prosumer is also needed. Therefore, KEPCO is pushing transition to DSO by expanding distribution management scope and changing its roles. In addition, KEPCO is proactively preparing for integrated operation between distribution network and existing distributed power which is accommodated passively. KEPCO is also trying to accept multiple network users, e.g. building platforms, to manage a data and promote new markets. In the long term, transition to DSO will achieve saving investment costs for accommodating distributed sources and maintaining stable electrical quality. And it will be possible to create new business model using the platform to secure revenue.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.131.1-131.1
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• 2010

This study was conducted for engineering optimization for the gasification process which is the key factor for success of Taean IGCC gasification plant which has been driven forward under the government support in order to expand to supply new and renewable energy and diminish the burden of the responsibility for the reduction of the green house gas emission. The gasification process consists of coal milling and drying, pressurization and feeding, gasification, quenching and HP syngas cooling, slag removal system, dry flyash removal system, wet scrubbing system, and primary water treatment system. The configuration optimization is essential for the high efficiency and the cost saving. For this purpose, it was designed to have syngas cooler to recover the sensible heat as much as possible from the hot syngas produced from the gasifier which is the dry-feeding and entrained bed slagging type and also applied with the oxygen combustion and the first stage cylindrical upward gas flow. The pressure condition inside of the gasifier is around 40~45Mpg and the temperature condition is up to $1500{\sim}1700^{\circ}C$. It was designed for about 70% out of fly ash to be drained out throughout the quenching water in the bottom part of the gasifier as a type of molten slag flowing down on the membrane wall and finally become a byproduct over the slag removal system. The flyash removal system to capture solid particulates is applied with HPHT ceramic candle filter to stand up against the high pressure and temperature. When it comes to the residual tiny particles after the flyash removal system, wet scurbbing system is applied to finally clean up the solids. The washed-up syngas through the wet scrubber will keep around $130{\sim}135^{\circ}C$, 40~42Mpg and 250 ppmv of hydrochloric acid(HCl) and hydrofluoric acid(HF) at maximum and it is turned over to the gas treatment system for removing toxic gases out of the syngas to comply with the conditions requested from the gas turbine. The result of this study will be utilized to the detailed engineering, procurement and manufacturing of equipments, and construction for the Taean IGCC plant and furthermore it is the baseline technology applicable for the poly-generation such as coal gasification(SNG) and liquefaction(CTL) to reinforce national energy security and create new business models.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.262-265
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• 2009

This study was carried out to evaluate the clear day operating performances for the decentralized desalination system with the solar thermal system and the photovoltaic power system. In a clear day, we used a solar thermal system as heat source of the single-stage fresh water generator with plate-type heat exchangers and a photovoltaic power system as electric source for hydraulic pumps. The demonstration system generation was designed and installed at Jeju-island in 2006. The system was comprised of the desalination unit with daily fresh water capacity designed as $2m^3$, a $120m^3$ evacuated tubular solar collector to supply the heat, a $6m^3$ heat storage tank, and a 5.2kW photovoltaic power generation to supply the electricity of hydraulic pumps for the heat medium fluids. In a clear day, solar irradiance daily averaged was measured $518W/m^3$, the daily fresh water yield showed that about 565 liter.

• Earthquakes and Structures
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• v.15 no.1
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• pp.1-8
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• 2018

A new site classification system and site coefficients based on local site conditions in Korea were developed and implemented as a part of minimum design load requirements for general seismic design. The new site classification system adopted bedrock depth and average shear wave velocity of soil above the bedrock as parameters for site classification. These code provisions were passed through a public hearing process before it was enacted. The public hearing process recommended to modify the naming of site classes and adjust the amplification factors so that the level of short-period amplification is suitable for economical seismic design. In this paper, the new code provisions were assessed using dynamic centrifuge tests and by comparing the design response spectra (DRS) with records from 2016 Gyeongju earthquake, the largest earthquake in history of instrumental seismic observation in Korea. The dynamic centrifuge tests were performed to simulate the representative Korean site conditions, such as shallow depth to bedrock and short-period amplification characteristics, and the results corroborated with the new DRS. The Gyeongju earthquake records also showed good agreement with the DRS. In summary, the new code provisions are reliable for representing the site amplification characteristic of shallow bedrock condition in Korea.

• 한국태양에너지학회:학술대회논문집
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• 2012.03a
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• pp.364-369
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• 2012

The development of solar thermal energy used adsorption desalination technology have been examined as a viable option for supplying clean energy. In this study, the modelling of the main devices for solar thermal energy used and adsorption desalination system was introduced. Silica gel type adsorption desalination system is considered to be a promising low-temperature heat utilization system. The design is divided into three parts. First, the evaporator for the vaporization of the tap water is designed, and then the reactor for the adsorption and release of the steam is designed, followed by the condenser for the condensation of the fresh water is designed. In addition, new features based on the energy balance are also included to design absorption desalination system. In this basic research, One-bed(reactor) adsorption desalination plant that employ a low-temperature solar thermal energy was proposed and experimentally studied. The specific water yield is measured experimentally with respect to the time controlling parameters such as heat source temperatures, coolant temperatures, system switching and half-cycle operational times. Desalination is processes that permeate our daily lives, but It requires substantial energy input, powered either from electricity or from thermal input. From the environmental and sustainability perspecives, innovative thermodynamic cycles are needed to produce the above-mentioned useful effects at a lower specific energy input. This article describes the development of adsorption cycles for the production of desalting effects. We want that this adsorption system can be driven by low temperature heat sources at 60 to $80^{\circ}C$, such as renewable, solar thermal energy.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.4
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• pp.629-634
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• 2013

This study aims to investigate a new structure for a concentrating photovoltaic (PV) module using a III-V compound semiconductor solar cellto solve the problems of existing concentrating PV modules and to explore a concentrating optical system with a flat structure, which shows remarkable advantages in terms of manufacturing cost, installation, and maintenance. This study should greatly contribute toward the development of concentrating PV modules. This study was performed to achieve an improvement in efficiency and economy and to implement an actual product. A new source of renewable energy is the only way in which countries that cannot produce oil can even emerge as an energy power. Therefore, this work can serve as a fundamental study that will help South Korea grow into a country that is a PV power generation force.

• Journal of Hydrogen and New Energy
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• v.27 no.6
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• pp.721-726
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• 2016

Alcohols are particularly attractive as alternative fuels because they are a renewable resource. This paper describes the performance and emission characteristics of ethanol and diesel blended fuels in a compression ignition engine. This experimental results showed that ethanol diesel blended fuels decreased the torque and brake mean effective pressure. And experimental results indicated that using ethanol-diesel blended fuel, smoke, CO and HC emissions decreased as a result of the ethanol addition.