• Journal of Korean Society of Environmental Engineers
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• v.33 no.6
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• pp.405-412
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• 2011

Environmental impact by proposed pump and treatment remediation of groundwater contaminated with TCE over 0.6 mg/L down to 0.005 mg/L was assessed for 30 years operation in an industrial park. Total amount of groundwater treated was $2.96{\times}10^7m^3$ and the amount of TCE removed was 17.6 kg at most. The life cycle assessment was used to estimate the environmental cost and environmental benefit and their effects on the environment could be analyzed. Most of the environmental cost was accrued from electricity generation for 30 years pump operation, which includes energy consumption, resources consumption such as coal, crude oil, emission of global warming gas and acid gas into air, waste water production, and waste generation. Environmental impact could be quantified with a Life Cycle Assessment (LCA) model for soil and groundwater remediation and normalized based upon consumption and emission quantities per capita in the world. Among the normalized values, acidification material release was the most significant.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.123.2-123.2
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• 2010

Fuel Cell cogeneration system is a promising technology for generating electricity and heat with high efficiency of low pollutant emission. We have been developed 5kW class fuel cell cogeneration system for commercial and residential application. The fuel processor is a crucial part of producing hydrogen from the fossil fuels such as LNG and LPG. The 5kW class high efficiency fuel processor consists of steam reformer, CO shift converter, CO preferential oxidation(PrOx) reactor, burner and heat exchanger. The one-stage CO shift converter process using a metal oxide catalyst was adopted. The efficiency of 5 kW class fuel processor shows 75% based on LHV. In addition, for the purpose of continuous operation with load fluctuations in the commercial system for residential use, load change of fuel processor was tested. Efficiency of 30%, 50%, 70% and 100% load shows 75%, 75%, 73% and 72%(LHV), respectively. Also, during the load change conditions, the product gas composition was stable and the outlet CO concentration was below 5 ppm. The Fuel processor operation was carried out in residential fuel cell cogeneration system with fuel cell stack under dynamic conditions. The 5kW class fuel processor have been evaluated for long-term durability and reliability test including with improvement in optimal operation logic.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.139.1-139.1
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• 2010

제 3차 국가에너지기본계획이 시행됨에 따라 전체 에너지 공급량 중 신재생에너지가 차지하는 비율은 점차 늘어날 전망이다. 이와 관련하여 2012년부터 RPS 시행이 확정되었다. RPS(신재생에너지 의무비율할당제)는 신재생에너지에 의한 발전 비율을 설정함으로써 공급을 늘리는 긍정적인 측면이 있으나 이와 동시에 전기요금 인상을 수반한다. 요금 인상으로 인하여 발생할 수 있는 소비자의 반감을 완화시키고 전기요금에 대한 현실적인 합의점을 찾으려면 소비자가 재생에너지 전력에 대하여 어느 정도의 지불의사를 가지고 있는지에 대한 연구가 선행적으로 진행되어야 한다. 한편 RPS의 도입은 신재생에너지 원간 가격경쟁을 촉진시키게 된다. 이 과정에서 성장잠재력이 높은 에너지원이라 하더라도 현재의 발전단가가 높다면 잠재력을 발휘하기 전에 도태될 가능성이 있다. 이러한 RPS 도입의 영향에 대처할 수 있는 정책수립의 기초자료를 마련하기 위해, 재생에너지 전력에 대한 소비자 측면의 효용이 원별로 분석될 필요가 있다. 본 연구에서는 조건부 가치평가법(Contingent Valuation)을 적용하여 수력, 풍력, 태양광으로 발전된 재생에너지 전력에 대한 지불의사액(Willingness to Pay)을 추정하였다. 단일 설문지 내에서 여러 에너지원에 대한 지불의사액을 순차적으로 물어보게 될 경우, 질문순서가 지불의사액 추정에 편의를 가져오는 순서효과(Sequence Effect)가 발생할 수 있다(Boyle et al.,1993). 이러한 순서효과를 제거하기 위해서 유형에 따라 질문순서를 다르게 하여 각 에너지원에 대한 지불의사액을 묻는 방향으로 설문을 설계하였다. 분석결과 수력, 풍력, 태양광으로 발전한 전력에 대한 지불의사액 간에는 유의한 차이 가 나타나지 않았으며, 순서효과로 인한 편의 또한 지불의사액에 유의한 영향을 미치지 않는 것으로 관측되었다.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.20 no.1
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• pp.199-204
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• 2020

In case of the silicon solar panel being used in Korea, the production specification is designed to give maximum output at the limit of -0.5 to 0.05℃, so the output of 0.45~0.55% decreases when the temperature rises by 1℃. As a result, the photovoltaic power generation is reduced according to the surface temperature rise of the photovoltaic module due to the characteristics of the solar cell. The decrease in output reduces the efficiency of photovoltaic power generation, and if the efficiency decreases, the result is that the profit of electricity sales according to the amount of photovoltaic power generation decreases. Therefore, this paper proposes a method of spraying cooling air to the lower (or surrounding) of the photovoltaic module when it is identified above the set temperature by the temperature detection sensor. In addition, the amount of power generated is increased by utilizing the lost solar energy, and by applying cooling function through cooling air, the power generation can be further increased.

• KEPCO Journal on Electric Power and Energy
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• v.4 no.1
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• pp.25-31
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• 2018

A boiler system transforms water to pressured supercritical steam which drives the running of the turbine to rotate in the generator to produce electricity in power plants. Materials for building the tube system face challenges from high temperature creep damage, thermal fatigue/expansion, fireside and steam corrosion, etc. A database on the creep resistance strength and steam oxidation of the materials is important to the long-term reliable operation of the boiler system. Generally, the ferritic steels, i.e., grade 1, grade 2, grade 9, and X20, are extensively used as the superheater (SH) and reheater (RH) in supercritical (SC) and ultra supercritcal (USC) power plants. Currently, advanced austenitic steel, such as TP347H (FG), Super304H and HR3C, are beginning to replace the traditional ferritic steels as they allow an increase in steam temperature to meet the demands for increased plant efficiency. The purpose of this paper is to provide the state-of-the-art knowledge on boiler tube materials, including the strengthening, metallurgy, property/microstructural degradation, oxidation, and oxidation property improvement and then describe the modern microstructural characterization methods to assess and control the properties of these alloys. The paper covers the limited experience and experiment results with the alloys and presents important information on microstructural strengthening, degradation, and oxidation mechanisms.

• Journal of Environmental Science International
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• v.22 no.4
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• pp.453-461
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• 2013

This study, changes in raw water quality is to indicate on the efficiency of ozone treatment of each pollutant as compared to derive the appropriate operating measures. The appropriate selection for injection rate of pre-ozone and did not inject pre-ozone assess changes in the water. When good water quality, you not injected of pre-ozone to evaluate the economic efficiency of electricity and put the most cost-effective ozone concentration were evaluated. Evaluation remove organic matter and chlorophyll-a concentration level in experiments with each factor of the water DOC> 2.5 mg/L, THMFP> 70 ${\mu}g/L$, Chl-a> 30 $mg/m^3$or less constant process, if you do not need to put pre-ozone showed little impact. It also does not put you in pre-ozone appropriate produce enough power rate savings was calculated as approximately 90 million won. Ability to remove organic materials and the ability to produce disinfection byproducts, and cost-effective decisions by considering the concentration of injection if pre-ozone 1 mg/L was investigated by the appropriate concentration of ozone injection.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.3
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• pp.293-299
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• 2012

The thermodynamic efficiency characteristics of R245fa and water as working fluids have been analyzed for the electricity generation system applying the Rankine cycle to recover the waste heat of the exhaust gas from a diesel engine for the propulsion of a large ship. The theoretical calculation results showed that the cycle, system, and total efficiencies were improved as the turbine inlet pressure was increased for R245fa at a fixed mass flow rate. In addition, the net work rate generated by the Rankine cycle was elevated with increasing turbine inlet pressure. In the case of water, however, the maximum system efficiencies were demonstrated at relatively small ratios of mass flow rate and turbine inlet pressure, respectively, compared to those of R245fa. The optimized values of the net power of the cycle, system efficiency, and total efficiency for water had relatively large values compared to those of R245fa.

• 한국신재생에너지학회:학술대회논문집
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• 2005.06a
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• pp.339-344
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• 2005

A PEMFC system model for FCEV was constructed and simulated numerically to examine the heat/water flow of the system and air/fuel humidification process for various operation conditions (ambient pressure /temperature/humidity, operating temperature, power load). We modeled PEMFC stack which can generate maximum electricity of about 80 kW. This stack consists of 400 unit cells and each unit cell has $250cm^2$ reacting area. Uniform current density and uniform operating voltage per each cell was assumed. The results show the flow characteristics of heat and water at each component of PEMFC system in macro-scale. The capacity shortage of the radiator occurred when the ambient was hot $(over\;40^{\circ}C)$ and power level was high (over 50 kW). In spite of some heat release by evaporation of water in stack, heat unbalance reached to 20kW approximately in such a severe operating condition. This heat unbalance could be recovered by auxiliary radiators or high speed cooling fan with additional cost. In cold environment, the capacity of radiator exceeded the net heat generation to be released, which may cause a problem to drop the operating temperature of stack. We dealt with this problem by regulating mass flow rate of coolant and radiator fan speed. Finally, water balance was not easily broken when we retrieved condensed and/or unused water.

• Journal of the Korea Convergence Society
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• v.8 no.8
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• pp.17-26
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• 2017

CPV system is composed with CPV cells, modules, PCS(power conditioning system), solar tracker, system installation and balance of systems(BOS). Mention about modelling method which is applied for CPV system simulation and evaluation system analysis. This paper focuses on CPV system modeling and optimal design of the electric energy production analysis through the development of proposed optimal CPV system simulation. Calculated simulation results of the generalized CPV system in regard to loss parameter calculation method can make out optimal configuration of CPV system with high reliability and stability. The loss parameter calculation method establish a mathematical modeling for the purposed of simulation and utilization various data for economical analysis of the CPV system design.

• KEPCO Journal on Electric Power and Energy
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• v.2 no.4
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• pp.631-638
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• 2016

Offshore wind power can be an alternative for onshore wind power which suffers from not only civil complaints regarding to landscape damage and noise but also wind power siting due to lack of onshore site candidates. Compared to onshore wind power, offshore wind power is free from these problems considering that generally the sites are far enough from the coast. And more electricity is generated in offshore wind turbines due to abundant offshore wind resources. However high installation costs of offshore turbines could deteriorate the economical efficiency. The main cause of the high installation costs comes from a long-term lease of the heavy marine equipment and the consequential high rental cost. In this paper, the conceptual design of the support structure for offshore wind turbines will be suggested for the installation of them with less heavy marine equipment.