• Journal of Energy Engineering
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• v.25 no.3
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• pp.104-113
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• 2016

This study analyzes correlation between methane gas production and injection of food waste water to motivate to expand renewable energy as a way of GHG (Green House Gas) mitigation to achieve the national GHG target proposed for the climate agreement in Paris last year. Pretreatment of food waste water was processed with pH 6 at $35^{\circ}C$ and used the fixed-bed upflow type reactor with the porous media. As a result of operation of pilot-scaled bioreactor with food waste water, the methane gas production was 6 times higher than the methane gas production of control group with rain water. The average production of methane was $56{\ell}/day/m^3$ which is possible to produce $20m^3$ of methane in $1m^3$ of landfill. As a way of energy source, when it is applied to the landfill over $250,000m^3$, it is also able to achieve financial feasibility along with GHG reduction effect. GHG reductions of $250,000m^3$ scale landfill were assessed by registered CDM project and the annual amount of reductions was 40,000~50,000 $tCO_2e$.

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.18-27
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• 2020

This study presents flow assurance analysis in subsea pipeline considering system availability of topside in LNG-FPSO. A hydrate management strategy was established, which consisted of PVCap experiments, system availability analysis of LNG-FPSO topside, hydrate risk analysis in the pipeline, and calculation of PVCap injection concentration. The experimental data required for the determination of PVCap injection concentration were obtained by measuring the hydrate induction time of PVCap at the subcooling temperatures of 6.1, 9.2, and 12.1℃. The availability of LNG-FPSO topside system for 20 years was 89.3%, and the longest downtime of 50 hours occurred 2.9 times per year. The subsea pipeline model for multiphase flow simulation was created using field geometry data. As a result of risk analysis of hydrate plugging using subsea pipeline model, hydrate was formed at the end of flowline in 23.2 hours under the condition of 50 hours shutdown. The injection concentration of PVCap was determined based on the PVCap experiment results. The hydrate plugging in subsea pipeline of LNG-FPSO can be completely prevented by injecting PVCap 0.25 wt% 2.9 times per year.

• Journal of Korean Society of Environmental Engineers
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• v.31 no.8
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• pp.679-689
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• 2009

Light olefins are very important hydrocarbons widely used as the raw materials of the most petrochemicals including plastics and medicines. In addition, the nation's olefin production capacity is regarded as one of the key indicators to predict the nation's economic scale and growth. Steam cracking of naphtha (or called "NCC (Naphtha Cracking Center) technology"), the traditional process to produce light olefins, is one of the most consuming energy processes among the chemical industries. Therefore, this process causes tremendous $CO_2$ emission. To reduce the energy consumption and $CO_2$ emission from NCC process, the present paper, firstly, investigates and analyses some alternative technologies which can be potentially substituted for traditional process. Secondly, applying the alternative technologies to NCC process, their effects such as energy savings, $CO_2$ emission reduction and CER (Certified Emission Reduction) were estimated. It is found that the advanced NCC process can reduce approximately 35% of SEC (Specific Energy Consumption) of traditional NCC process. This effect can lead to the reduction of 3.3 million tons of $CO_2$ and the acquisition of the 128 billion won of CER per year. Catalytic cracking of naphtha technology, which is other alternative processes, can save up to approximately 40% of SEC of traditional NCC process. This value equates to the 3.8 million tons of $CO_2$ mitigation and 147 billion won of CER per year.

• Proceedings of the KSRS Conference
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• 2009.03a
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• pp.213-218
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• 2009

에너지 전달 과정과 밀접한 관계가 있는 증발산(Evapotranspiration)은 기후 변화나 육상 생태계 생산성에서 매우 중요한 요소이며, 수문학적 순환과 지역적 물 관리 측면에서 매우 중요하다. 최근 인공위성을 이용하여 증발산을 추정하기 위한 노력이 많이 진행되고 있으며, 특히 MODIS (Moderate Resolution Imaging Spectroradiometer)는 증발산을 추정하기 위한 좋은 정보를 제공하고 있다 하지만, 구름 등에 의한 증발산 입력 자료 결측은 전체 자료의 획득률을 낮추고, 연속적인 증발산 모니터 링을 제한한다. 따라서 본 연구에서는 MODIS 기반의 증발산 입력 자료의 개선하여 서로 다른 식생과 지형 구조를 갖는 플럭스 연구지에 대한 증발산의 추정 및 평가하고, 남한에 대한 MODIS 기반의 증발산 지도 작성하였다. 또한 구름에 의해 결측된 날에 대해서는 MODIS-MM5 4차원 자료동화 기법을 이용한 증발산의 연속적인 모니터링 기법을 개발하였다. MODIS 기반의 증발산을 추정하기 위해 Revised RS-PM 알고리즘을 사용하였다. 증발산을 평가하기 위해 4 곳의 플럭스 연구지(광릉, 해남 이상 대한민국, 타카야마, 토마코아미 이상 일본) 자료와 비교하였고, 매우 신뢰성 있는 결과를 얻을 수 있었다. MODIS 입력 자료의 개선으로 획득률은 2배 가량 증가하였다. 남한에 대한 연간 증발산은 평균적으로 약 35%의 획득률 (365일 중 약 120일)과 함께 산출되었고, 시 공간적인 분포를 잘 나타내었다. 구름 낀 날에 대한 MODIS-MM5 자료 동화 기법의 적용은 증발산의 연속적인 모니터링을 가능하게 하였다.

• Journal of the Korea Organic Resources Recycling Association
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• v.6 no.2
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• pp.7-30
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• 1998

Generation and recycling potential of organic waste in Korea were estimated. Status of organic waste composting and compost utilization also were surveyed to promote the recycling of organic waste. From 1994 to 1997, generation of garbage decreased gradually while recycling rate increased due to positive governmental strategy. During the same period, livestock waste increased 11.2%. Municipal wastewater sludge was generated 3,500 ton/day which was 0.03% of wastewater treated in 1996. The energy Potential of industrial organic waste was estimated to 288 million TOE which was 1.75% of the nationwide first energy consumption in 1996. Recycling of industrial sludge was low to 31%, while recycling of animal waste, plant scraps, and wasted paper were relatively high over 50%. Industrial sludge should be recycled more as it was the most part of industrial organic waste. Conventional composting materials were mainly livestock waste, food processing waste, fishery waste, sawdust, and nightsoil. Garbage and sludge have been composted recently. 420,000 tons of compost in 1996 were produced by 288 makers, the most of which were utilized in agriculture. It was suggested that separated collection, compost standard, and quality management should be provided to promote the composting of organic waste.

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.169.1-169.1
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• 2010

Due to global warming, the need to secure an alternative resource has become the international issue. Not like other renewable energy sources, TCP is the high reliable and predictable and continuous energy source as the current pattern and speed can be predicted throughout the year. Having very strong tidal current speeds, there are many suitable site for the application of TCP (Tidal Current Power) on the west and south coastal region in Korea. The maximum current speed in the south is recorded up to 6.5m/s. Due to the high tidal current speed on the west coast of Korea, numerous tidal current projects are being planned. To extract a significant quantity of power, a tidal current farm with number of devices is required in the ocean. However, it is important to estimate the potential quantity of energy in the area. Also the realistic quantity that can be extracted is to be investigated. Based on the estimated energy production considering the number of devices and the interactional effects, system type, the water depth and etc., the cost of the development and the benefit from SMP can be estimated. The feasibility study for the 200MW tidal in Incheon, Korea has been performed recently. Based on the actual feasibility study, the procedure and the key points for the application of tidal current power farm are introduced in the paper.

• Journal of Energy Engineering
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• v.22 no.2
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• pp.211-225
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• 2013

To run an optimal operation of Integrated energy supply facilities, we need to analyze heat consumption patterns of District heating users and derive optimum and maximum load ratio of heat production facilities unit. This study selects three District heat production facilities. It also classifies District heating users into residential apartment buildings and eight non-residential buildings and analyzes heat consumption results for an year. Finally it carries out the analysis of how the ratio change of each type affects maximum load ratio, facility utilization ratio, heat supply range. According to this study, three different District heat facilities of residential apartment building show similar daily and annual heat consumption patterns. Annual average load ratio, maximum load ratio and annual heat demand increase as outdoor temperatures decrease. Non-residential buildings in urban District focused on apartment buildings display similar by the daily and annual heat consumption patterns. Yet their daily and annual maximum load ratio differ according to outdoor temperature, District, building types and their composition ratio. In the case of urban District focused on apartment buildings reach optimum and maximum load ratio when apartment buildings reaches 60-70% of the total. At that point heat supply range becomes maximized and the most economic efficiency is obtained.

• Progress in Medical Physics
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• v.20 no.1
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• pp.37-42
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• 2009

Proton therapy facility, which is recently installed at National Cancer Center in Korea, generally produces a large amount of radiation near cyclotron due to the secondary particles and radioisotopes caused by collision between proton and nearby materials during the acceleration. Although the level of radiation by radioisotope decreases in length of time, radiation exposure problem still exists since workers are easily exposed by a low level of radiation for a long time due to their job assignment for maintenance or repair of the proton facility. In this paper, the working environment near cyclotron, where the highest radiation exposure is expected, was studied by measuring the degree of radiation and its duration for an appropriate level of protective action guide. To do this, we measured the radiation change in the graphite based energy degrader, the efficiency of transmitted beam and relative activation degree of the transmission beam line. The results showed that while the level of radiation exposure around cyclotron and beam line during the operation is much higher than the other radiation therapy facilities, the radiation exposure rate per year is under the limit recommended by the law showing 1~3 mSv/year.

• Journal of Digital Convergence
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• v.11 no.5
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• pp.119-133
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• 2013

This study aims to provide power generating plants with eco-efficiency information. To implement the purposes, of study, both DEA(Data, Envelopment Analysis) model and interview were incorporated in terms of methodologies. To analyze the managerial efficiency, total labor cost and number of employees were considered as input factors. CO2, NOx, and water also were considered as input factors to analyze eco-efficiency. Both annual total power product and annual total revenue were used as output factors. CRS(Constant Return to Scale) and VRS(Variable Return to) model were facilitated in this analysis. According to the findings, most of the power plants were evaluated as 'Efficient'' taking into consideration of average value, both 0.928 from CCR model and 0.969 from VRS model. 7 DMUs including DMU3 and DMU12 are efficient out of 35 DMUs relatively, other DMUs are inefficient. For results of inefficient output factors distribution, it was found that inefficiency for NOx was marked relatively higher than CO2. In order to improve the eco-efficiency in the power plants in the long term, the target amount of Co2 as well as NOx reduction needs to be properly proposed in consideration of particularity of power plants. In the long run, renewable energy, alternative fuels should be adapted to reduce the eco-inefficient.

• Journal of the Korean Society for Railway
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• v.19 no.5
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• pp.592-599
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• 2016

In the 21st yearly session of the Conference of the Parties (COP 21) of the 2015 United Nations Climate Change Conference, held in Paris, France, in December 2015, the "Paris Agreement" was negotiated; this is a new global agreement on the reduction of climate change, which encourages every country to participate in countermeasures for global climate change. Along with such movements, the electric railway sector has also been actively engaged in low carbon technology. This paper studied the building of a 1.5MW photovoltaic power generation system using the rooftop of the Gwangmyeong Station Building, which is the largest roof among the high-speed railway station buildings in Korea; this station has passenger traffic that reached about 7 million in 2014. For this study, we configured an optimized photovoltaic (PV) power generation system and then estimated the expected annual energy production by using PV system software; we also calculated the expected revenue that could be obtained by linking this source to the power distribution system. The obtained data were used to analyze the contribution of low-carbon energy that could be obtained by introducing a PV power generation system on the roof of an electric railway station building.