• Title/Summary/Keyword: New and renewable energy system

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Effect of Hydrophilic- and Hydrophobic-Media on the Fermentative Hydrogen Production in Trickling Bed Biofilter (생물학적 수소생산을 위한 Trickling Bed Biofilter에서의 친수성과 소수성 담체의 영향)

  • Jeon, Byung-Seung;Lee, Sun-Mi;Kim, Yong-Hwan;Chae, Hee-Jeong;Sang, Byoung-In
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.06a
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    • pp.465-469
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    • 2006
  • Two mesophilic trickling bed bioreactors filled with two different types of media, hydrophilic- and hydrophobic-cubes, were designed and tested for hydrogen production via anaerobic fermentation of sucrose. Each reactor consisted of a column packed with polymeric cubes and inoculated with heat-treated sludge obtained from anaerobic digestion tank. A defined medium containing sucrose was fed with changing flow rate into the capped reactor, hydraulic retention time and recycle rate. Hydrogen concentrations in gas-phase were constant, averaging 40% for all conditions tested. Hydrogen production rates increased up to $10.5 L{\cdot};h^{-1}{\cdot}L^{-1}$ of reactor when influent sucrose concentrations and recycle rates were varied. Hydrophobic media provided higher value of hydrogen production rate than hydrophilic media at the same operation conditions. No methane was detected when the reactor was under a normal operation. The major fermentation by-products in the liquid effluent of the both trickling biofilters were acetate and butyrate. The reactor filled with hydrophilic media became clogged with biomass and bio gas, requiring manual cleaning of the system, while no clogging occurred in the reactor with hydrophobic media. In order to make long-term operation of the reactor filled with hydrophilic media feasible, biofilm accumulation inside the media in the reactor with hydrophilic media and biogas produced from the reactor will need to be controlled through some process such as periodical backwashing or gas-purging. These tests using trickling bed biofilter with hydrophobic media demonstrate the feasibility of the process to produce hydrogen gas in a trickle-bed type of reactor. A likely application of this reactor technology could be hydrogen gas recovery from pre-treatment of high carbohydrate-containing wastewaters.

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Synthesis characterization of a high conductivity LSCF cathode materials and electrochemical studies for IT-SOFC (중.저온 고체산화물 연료전지용 고전도성 공기극 소재 합성 및 전기화학적 특성 평가)

  • Kim, Hyoshin;Lee, Jongho;Kim, Ho-Sung;Lee, Yunsung
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.139-139
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    • 2010
  • LSM is widely used as a cathode material in SOFC, because of its high electrochemical activity, good stability and compatibility with YSZ electrolyte at high temperature. However, LSM in traditional cathode materials will not generate a satisfactory performance at intermediate temperature. In order to reduce the polarization resistance of cell with the operating temperature of SOFC system, the cathode material of LSCF is one of the most suitable electrode materials because of its high mixed ionic and electronic conductivity. In this report, cathode material, $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_3$ powder for intermediate temperature SOFC was synthesized by Pechini method using the starting materials such as nitrate of La, Sr, Co and Fe including ethylene glycol, etc. As a result, the synthesized powder that calcined above $700^{\circ}C$ exhibits successfully perovskite structure, indicating phase-pure of LSCF. Moreover, the particle size, surface area, crystal structure and morphology of the synthesized oxide powders were characterized by SEM, XRD, and BET, etc. In order to evaluate the electrochemical performance for the synthesized powder, slury mixture using the synthesized cathode material was coated by screen-printing process on the anode-supported electrolyte which was prepared by a tape casting method and co-sintering. Finally, electrochemical studies of the SOFC unit cell, including measurements such as power density and impedance, were performed.

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Gas trasport and Gas hydrate distribution characteristics of Southern Hydrate Ridge: Results from ODP Leg 204

  • Lee, Young-Joo;Ryu, Byong-Jae;Kim, Ji-Hoon;Lee, Sang-Il
    • 한국신재생에너지학회:학술대회논문집
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    • 2006.06a
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    • pp.407-409
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    • 2006
  • Geochemical analyses carried out on samples collected from cores on and near the southern smit of Hydrate Ridge have advanced understanding by providing a clear contrast of the two major modes of marine gas hydrate occurrence. High concentrations (15%-40% of pore space) of gas hydrate occurring at shallow depths (0-40 mbsf) on and near the southern summit are fed by gas migrating from depths of as much as 2km within the accretionary prism. This gas carries a characteristic minor component of C2-C5 thermogenic hydrocarbons that enable tracing of migration pathways and may stabilize the occurrence of some structure II gas hydrate. A structure II wet gas hydrate that is stable to greater depths and temperatures than structure I methane hydrate may account for the deeper, faint second bottom simulating reflection (BSR2) that occurs on the seaward side of the ridge. The wet gas is migrating In an ash/turbidite layer that intersects the base of gas hydrate stability on the seaward side of and directly beneath the southern summit of Hydrate Ridge. The high gas saturation (>65%) of the pore space within this layer could create a two-phase (gas + solid) system that would enable free gas to move vertically upward through the gas hydrate stability zone. Away from the summit of the ridge there is no apparent influx of the gas seeping from depth and sediments are characterized by the normal sequence of early diagenetic processes involving anaerobic oxidation of sedimentary organic matter, initially linked to the reduction of sulfate and later continued by means of carbonate reduction leading to the formation of microbial methane.

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Characterization analysis of $CuInS_2$ absorber layer grown by heat treatment of low temperature (저온에서 열처리한 $CuInS_2$ 광흡수층 박막 특성분석)

  • Yang, Hyeon-Hun;Back, Su-Ung;Kim, Han-Wool;Han, Chang-Jun;Lee, Suk-Ho;Jeong, Woon-Jo;Park, Gye-Choon;Lee, Jin;Chung, Hae-Deok
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.98.2-98.2
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    • 2010
  • $CuInS_2$ thin films were synthesized by sulfurization of Cu/In Stacked elemental layer deposited onto glass Substrates by vacuum furnace annealing at temperature 200[$^{\circ}C$]. And structural and electrical properties were measured in order to certify optimum conditions for growth of the ternary compound semiconductor $CuInS_2$ thin films with non-stoichiometry composition. $CuInS_2$ thin film was well made at the heat treatment 200[$^{\circ}C$] of SLG/Cu/In/S stacked elemental layer which was prepared by thermal evaporator, and chemical composition of the thin film was analyzed nearly as the proportion of 1 : 1 : 2. Physical properties of the thin film were investigated at various fabrication conditions substrate temperature, annealing and temperature, annealing time by XRD, FE-SEM and hall measurement system. At the same time, carrier concentration, hall mobility and resistivity of the thin films was $9.10568{\times}10^{17}$ [$cm^{-3}$], 312.502 [$cm^2/V{\cdot}s$] and $2.36{\times}10^{-2}$ [${\Omega}{\cdot}cm$], respectively.

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Electrical mechanism analysis of $Al_2O_3$ doped zinc oxide thin films deposited by rotating cylindrical DC magnetron sputtering (원통형 타겟 형태의 DC 마그네트론 스퍼터링을 이용한 산화 아연 박막의 전기적 기제에 대한 분석)

  • Jang, Juyeon;Park, Hyeongsik;Ahn, Sihyun;Jo, Jaehyun;Jang, Kyungsoo;Yi, Junsin
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.11a
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    • pp.55.1-55.1
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    • 2010
  • Cost efficient and large area deposition of superior quality $Al_2O_3$ doped zinc oxide (AZO) films is instrumental in many of its applications including solar cell fabrication due to its numerous advantages over ITO films. In this study, AZO films were prepared by a highly efficient rotating cylindrical dc magnetron sputtering system using AZO target, which has a target material utilization above 80%, on glass substrates in argon ambient. A detailed analysis on the electrical, optical and structural characteristics of AZO thin films was carried out for solar cell application. The properties of films were found to critically depend on deposition parameters such as sputtering power, substrate temperature, working pressure, and thickness of the films. A low resistivity of ${\sim}5.5{\times}10-4{\Omega}-cm$ was obtained for films deposited at 2kW, keeping the pressure and substrate temperature constant at 3 mtorr and $230^{\circ}C$ respectively, mainly due to an increase in carrier mobility and large grain size which would reduce the grain boundary scattering. The increase in carrier mobility with power can be attributed to the columnar growth of AZO film with (002) preferred orientation as revealed by XRD analysis. The AZO films showed a high transparency of>87% in the visible wavelength region irrespective of deposition conditions. Our results offers a cost-efficient AZO film deposition method which can fabricate films with significant low resistivity and high transmittance that can find application in thin-film solar cells.

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Development of the Organic Solar Cell Technology using Printed Electronics (인쇄전자 기술을 이용한 유기 태양전지 기술 개발)

  • Kim, Jungsu;Yu, Jongsu;Yoon, Sungman;Jo, Jeongdai;Kim, Dongsoo
    • 한국신재생에너지학회:학술대회논문집
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    • 2011.05a
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    • pp.113.1-113.1
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    • 2011
  • PEMS (printed electro-mechanical system) is fabricated by means of various printing technologies. Passive and active compo-nents in 2D or 3D such as conducting lines, resistors, capacitors, inductors and TFT(Thin Film Transistor), which are printed withfunctional materials, can be classified in this category. And the issue of PEMS is applied to a R2R process in the manu-facturing process. In many electro-devices, the vacuum process is used as the manufacturing process. However, the vacuum process has a problem, it is difficult to apply to a continuous process such as a R2R(roll to roll) printing process. In this paper, we propose an ESD (electro static deposition) printing process has been used to apply an organic solar cell of thin film forming. ESD is a method of liquid atomization by electrical forces, an electrostatic atomizer sprays micro-drops from the solution injected into the capillary with electrostatic force generated by electric potential of about several tens kV. ESD method is usable in the thin film coating process of organic materials and continuous process as a R2R manufacturing process. Therefore, we experiment the thin films forming of PEDOT:PSS layer and active layer which consist of the P3HT:PCBM. The organic solar cell based on a P3HT/PCBM active layer and a PEDOT:PSS electron blocking layer prepared from ESD method shows solar-to-electrical conversion efficiency of 1.42% at AM 1.5G 1sun light illumination, while 1.86% efficiency is observed when the ESD deposition of P3HT/PCBM is performed on a spin-coated PEDOT:PSS layer.

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Advances in the Technology of Solid State Hydrogen Storage Methods Using Novel Nanostructured Materials (나노구조물질을 이용한 고체수소저장 기술 동향)

  • Zacharia, Renju;Kim, Keun Young;Nahm, Kee Suk
    • Korean Chemical Engineering Research
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    • v.43 no.4
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    • pp.439-451
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    • 2005
  • This article provides a panoramic overview of the state-of-the-art technologies in the field of solid-state hydrogen storage methods. The emerging solid-state hydrogen storage techniques, such as nanostructured carbon materials, metal organic framework (MOFs), metal and inter-metal hydrides, clathrate hydrates, complex chemical hydride are discussed. The hydrogen storage capacity of the solid-sate hydrogen storage materials increases in proportion to the surface area of the solid materials. Also, it is believed that new functional nanostructured materials will offer far-reaching solutions to the development of on-board hydrogen storage system for the application of the transportation vehicles.

Estimation of High-resolution Sea Wind in Coastal Areas Using Sentinel-1 SAR Images with Artificial Intelligence Technique (Sentinel-1 SAR 영상과 인공지능 기법을 이용한 연안해역의 고해상도 해상풍 산출)

  • Joh, Sung-uk;Ahn, Jihye;Lee, Yangwon
    • Korean Journal of Remote Sensing
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    • v.37 no.5_1
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    • pp.1187-1198
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    • 2021
  • Sea wind isrecently drawing attraction as one of the sources of renewable energy. Thisstudy describes a new method to produce a 10 m resolution sea wind field using Sentinel-1 images and low-resolution NWP (Numerical Weather Prediction) data with artificial intelligence technique. The experiment for the South East coast in Korea, 2015-2020,showed a 40% decreased MAE (Mean Absolute Error) than the generic CMOD (C-band Model) function, and the CC (correlation coefficient) of our method was 0.901 and 0.826, respectively, for the U and V wind components. We created 10m resolution sea wind maps for the study area, which showed a typical trend of wind distribution and a spatially detailed wind pattern as well. The proposed method can be applied to surveying for wind power and information service for coastal disaster prevention and leisure activities.

The Estimation of Carrying Capacity in Deukryang Bay by EMERGY Analysis (EMERGY 분석법에 의한 득량만의 환경용량 산정)

  • EUM Ki-Hyuk;SON Ji-Ho;CHO Eun-Il;LEE Suk-Mo;PARK Chung-Kil
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.29 no.5
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    • pp.629-636
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    • 1996
  • The developments of mariculture fisheries depend on both the natural environmental inputs such as sun, rain, wind, tide and the economic inputs such as ships, fuels, facilities, labor. for the enhancement of mariculture productivity in Deukryang Bay, a new attempt has been made to connect the environmental resources and the economic activity within one system. This study applies EMERGY analysis that evaluates environmental energies, fuels, goods and services in terms of solar emjoelus. In total EMERGY use $(69.65\times10^{20}\;sej/yr)$ the natural environment inputs is $78\%\;(54.60\times10^{20}\;sej/yr)$. This means that the mariculture in Deukryang Bay depends on mainly environmental resources. Net EMERGY yield ratio was 4.63 which indicated high value as a resource, EMERGY investment ratio was 0.28 that means to gain 3.6 times energy from the natural environment than those of economy. If the fisherie's products are made by renewable EMERGY input to Deukryang Bay, the calculated carrying capacity of fishes, crustaceans, shellfish and seaweeds were 1,140, 110, 1,553 and 9,074 ton/yr, respectively. If the quantity of renewable EMERGY input to mariculture grounds in Deukrysng Bay was calculated-based on only shellfish product, shellfish products was estimated as about 1,195 ton/yr.

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Fabrication Method of OPV using ESD Spray Coating (ESD 스프레이를 이용한 OPV 제작 기법)

  • Kim, Jungsu;Jo, Jeongdai;Kim, Dongsoo
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.84.2-84.2
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    • 2010
  • PEMS (printed electro-mechanical system) is fabricated by means of various printing technologies. Passive and active components in 2D or 3D such as conducting lines, resistors, capacitors, inductors and TFT, which are printed with functional materials, can be classified in this category. And the issue of PEMS is applied to a R2R process in the manufacturing process. In many electro-devices, the vacuum process is used as the manufacturing process. However, the vacuum process has a problem: it is difficult to apply toa continuous process as a R2R printing process. In this paper, we propose an ESD (electro static deposition) printing process has been used to apply an organic solar cell of thin film forming. ESD is a method of liquid atomization by electrical forces, anelectrostatic atomizer sprays micro-drops from the solution injected into the capillary, with electrostatic force generated by electric potential of about tens of kV. ESD method is usable in the thin film coating process of organic materials and continuous process as a R2R manufacturing process. Therefore, we experiment the thin films forming of PEDOT:PSS layer and Active layer which consist of the P3HT:PCBM. The result of experiment, organic solar cell using ESD thin film coated method is occurred efficiency of about 1.4%. Also, the case of only used to ESD method in the active layer coating is occurred efficiency of about 1.86% as the applying a spin coating in the PEDOT:PSS layer. We can expect that ESD method is possible for continuous process to manufacture in the organic solar cell or OLED device.

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