• Journal of Welding and Joining
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• 제31권4호
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• pp.1-6
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• 2013

Nowadays, the weight lightening of automotive is required as conserving the environment has become a major worldwide issue. To solve this issue, various researches for the use of light materials(Alalloy, Mgalloy)and ultra high strength steel as substitutes of the current structural material have been carried out. Application of laser stitch welding to the assembly of automotive produces improvement in strength, lightening of body, higher fuel efficiency, lower production cost as well as reduction in assemble line due to its fast welding speed, superior accessible and weld quality. This process overcomes the shortcomings of the current resistance spot welding such as high electricity consumption, electrode replacement, and economical, technical limitation in design and production method of automotives.

• Transactions on Control, Automation and Systems Engineering
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• 제3권1호
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• pp.10-14
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• 2001

We studied the use of time-related information, with and without prediction, to support human operators performing moni-toring and control tasks in the process. Based on monitoring and control techniques used for Project Management we developed a display design for the process industries. A simulated power plant was used to test the hypothesis that availability of predictions along with information on past trends can improve the performances of the human operator handling faults. Several designs of dis-plays were tested in the experiment in which human operators had to detect and handle two types of faults(local and systems wide) in the simulated electricity generation process. Analysis of the results revealed that temporal data, with and without prediction, signifi-cantly reduced response time. Our results encourage the integration of temporal information and prediction in displays used for the control processes to enhance the capabilities of the human operators. Based on the analysis we proposed some guidelines for the de-signer of the human interface of a process control system.

• Advances in Energy Research
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• 제1권2호
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• pp.127-146
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• 2013

Torrefaction technologies convert assorted biomass feedstocks into energy-concentrated, carbon neutral fuel that is economically transported and easily ground for blending with fossil coals at numerous power plants around the world without needs to retrofit. Utilization of torrefied biomass in conventional electric generating units may be an increasingly attractive alternative for electricity generation as aging power plants in the world need to be upgraded or improved. This paper examines the economic feasibility of torrefaction in different scenarios by modeling torrefaction plants producing 136,078 t/year (150,000 ton/year) biocoal from wood and corn stover. The utilization of biocoal blends in existing coal-fired power plants is modeled to determine the demand for this fuel in the context of emerging policies regulating emissions from coal in the U.S. setting. Opportunities to co-locate torrefaction facilities adjacent to corn ethanol plants and coal-fired power plants are explored as means to improve economics for collaborating businesses. Life cycle analysis was conducted in parallel to this economic study and was used to determine environmental impacts of converting biomass to biocoal for blending in coal-fired power plants as well as the use of substantial flows of off-gasses produced in the torrefaction process. Sensitivity analysis of the financial rates of return of the different businesses has been performed to measure impacts of different factors, whether input prices, output prices, or policy measures that render costs or rewards for the businesses.

• Journal of the Korean Wood Science and Technology
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• 제33권1호통권129호
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• pp.97-110
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• 2005

본 연구는 최근 미국 에너지 시장에서 바이에너지가 차지하는 위치와 공급상황에 대하여 조사 연구되었다. 특히 제 1보에서는 미국에서 실용화되고 있는 목질 바이오매스를 이용한 바이오매스 전기제조기술(직접 연소 발전, 산업체의 폐열발전, 가스터빈과 스팀터빈 연합 발전 및 모듈화된 발전시스템등), 전기생산 시설 및 공급가의 경제성등에 대하여 검토하였고, 제 2보에서는 바이오매스 전기에 대한 미국의 정책 및 마케팅전략, 그리고 바이오매스 전기 사용이 가져오는 환경적 경제적 이익 및 발전 장벽(Benefit and Barriers)등에 대하여 조사 연구되었다.

• Nuclear Engineering and Technology
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• 제53권5호
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• pp.1658-1663
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• 2021

Research on climate change and global warming on the power generation systems are rapidly increasing because of the Importance of the sustainable energy supply, thus the electricity supply since its growing share, in the end, uses energy supply. However, some researchers conducted this field, but many research gaps are not mentioned and filled in this field's literature since the lack of general statements and the quantitative models and formulation of the issue. In this research, an exergy-based model is implemented to model a set of six power generation technologies (combined cycle, gas turbine, nuclear plant, solar PV, and wind turbine) and use this model to simulate each technology's responses to climate change impacts. Finally, using these responses to define and calculate a formulation for the relationship between the system's energy performance in different environmental situations and a dimensionless index to quantize each power technology's reliability against the climate change impacts called the Pahlev reliability index (P-index) of the power technology. The results have shown that solar and nuclear technologies are the most, and wind turbines are the least reliable power generation technologies.

• 에너지공학
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• 제24권3호
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• pp.40-47
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• 2015

석탄가스화 복합발전소는 기존 석탄화력 발전소에 비해 온실가스 및 대기오염물질을 적게 배출할 뿐만 아니라 국제적으로 쉽게 확보할 수 있는 저렴한 저품위 석탄을 사용할 수 있어서 연료를 안정적으로 공급받을 수 있다. 이에 본 논문에서는 석탄가스화 복합발전 건설의 에너지안보 확보편익을 추정하고자 한다. 이를 위해 무작위로 추출된 전국 600가구를 대상으로 설문조사를 수행한 후 얻은 자료에 조건부 가치측정법을 적용하여 분석한 결과를 제시한다. 통계적 효율성의 확보를 위해 이중경계 모형을 적용하며 영(0)의 응답자료를 적절하게 다루기 위해 스파이크 모형을 적용한다. 분석결과 석탄가스화 복합발전소로부터 생산되는 전력 1kWh에 대해 응답자들은 평균적으로 6.05원의 추가적인 지불의사액을 가졌다. 즉 석탄가스화 복합발전소로부터 생산되는 전력에 대한 에너지안보 확보편익은 6.05원/kWh이다. 올해 완공되는 태안 석탄가스화 복합발전소의 예상 연간 발전량은 2.27TWh이므로 에너지안보 확보편익은 연간 13,740백만원으로 추정된다.

• 대한기계학회논문집 C: 기술과 교육
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• 제2권2호
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• pp.89-97
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• 2014

내륙의 주전력 공급계통과 단절되어 있는 도서지역은 대부분의 전력공급을 디젤발전설비가 담당하고 있다. 디젤발전설비는 특성상 예방정비 및 유지보수를 통해 사용수명을 연장시킬 수 있으나, 계속 사용에 따른 기계설비의 노후화 및 발전 효율 감소로 인해 운영비가 증가한다. 즉, 적기에 노후 발전설비를 교체할 경우 발전소 운영비용을 줄일 수 있다. 이에 본 연구에서는 디젤발전설비의 상태를 대표할 수 있는 지표를 도출하고, 몬테카를로 시뮬레이션을 이용하여 각 지표별 민감도 분석을 수행하고자 한다. 이를 통해 디젤발전설비의 현상태를 정량적으로 나타낼 수 있는 상태점수를 정의하고 이를 바탕으로 설비 교체의 기준을 마련하고자 한다.

• 에너지공학
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• 제26권4호
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• pp.45-56
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• 2017

Coal power plants produce electricity for the nation's power grid, but they also produce more hazardous air emissions than any other industrial pollution sources. The quantity is staggering, over 386,000 tons of 84 separate hazardous air pollutants spew from over 400 plants in 46 states. In South Korea also, annual coal ash generation from coal-fired power plants were about 6 million tons in 2015. Pollutants containing particulate matter 10, 2.5 (PM10, PM2.5), heavy metals and dioxins from coal-fired power plant. The emissions threaten the health of people who live near these power plants, as well as those who live hundreds of miles away. These pollutants that have long-term impacts on the environment because they accumulate in soil, water and animals. The present study is to investigate the physical and chemical characteristics of coal-fired power plant fly ash and bottom ash contains particulate matter, whose particulate sizes are lower than $PM_{10}$ and $PM_{2.5}$ and heavy metals. There are wide commercial technologies were available for monitoring the PM 2.5 and ultra-fine particles, among those carbonation technology is a good tool for stabilizing the alkaline waste materials. We collected the coal ash samples from different coal power plants and the chemical composition of coal fly ash was characterized by XRF. In the present laboratory research approach reveals that potential application of carbonation technology for particulate matter $PM_{10}$, $PM_{2.5}$ and stabilization of heavy metals. The significance of this emerging carbonation technology was improving the chemical and physical properties of fly ash and bottom ash samples can facilitate wide re use in construction applications.

• 농업과학연구
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• 제23권2호
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• pp.272-284
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• 1996

The present study has quantitatively assessed the regional production, income and employment impact resulting from the construction and operation of nuclear power plant (NPP) upon the domestic local areas by applying the regional input-output analysis model to the case of Wolsong unit-l site. The conclusions regarding the most likely regional economic impacts upon the wolsong site are summarized as follows: 1. The income multipliers are calculated to be 1.563 for the construction phase and 1.500 for the operation phase. These values are relatively high compared with those of other conventional facilities. 2. The level of total employee's wage induced employment associated with the construction phase has been estimated to be 37,000 while that with the operational phase in 1990 to be 5,610. 3. With relation to the aspect of resident welfare it is found that the industrial sector associated with electricity, gas and water supply have remarkably improved with the construction of the NPP. 4. The NPP siting has induced substantial changes in interindustry (input-output) structures of the Wolsong unit-l site which is one of the rural areas where all the domestic NPPs are sited. Such changes are attributed to the industrial recomposition of the region. 5. With the application of other regional economic analysis models and the use of more sufficient regional data, other detailed studies on the economic impact analysis of domestic NPP-related facility sitings are suggested to be carried out further since the influence of NPP sitings is significant to the national economic impact as well as the regional economic impact.

• 한국인터넷방송통신학회논문지
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• 제19권4호
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• pp.113-118
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• 2019

태양광 발전소는 전기를 생산하는 시설물로써 화재와 감전 사고의 위험이 설치장소의 다변화로 근무자와 주변인, 시설물에 대한 위험도가 증가하여 안전사고를 예방하고 안전사고 발생에 따른 빠른 대처를 할 수 있는 시스템을 개발이 대두되고 있다. 위와 같은 개발에 필요성을 비추어 볼 때 태양광발전 시스템에서 생산되는 데이터를 취합, 분석하는 기술을 개발하여 발전시스템의 문제를 실시간으로 진단하고 유지/보수할 수 있는 태양광발전 관리시스템을 개발하여야 하고 이를 통해 이용률 증가 및 유지보수 비용이 감소하는 효과를 볼 수 있다. 이를 위해서는 우선적으로 현재의 상태에서 태양광 발전량을 정확히 예측하여, 현 발전상태의 이상 유/무를 진단 및 이상 위치를 파악하여야 하고 이상 위치가 파악되면 경제성이 고려된 모델을 이용하여 수리/교체의 필요성, 시기 등의 정보가 제공되어야 한다.