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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean hydrogen and new energy society
Journal Basic Information
Journal DOI :
The Korean Hydrogen and New Energy Society
Editor in Chief :
Volume & Issues
Volume 24, Issue 6 - Dec 2013
Volume 24, Issue 5 - Oct 2013
Volume 24, Issue 4 - Aug 2013
Volume 24, Issue 3 - Jun 2013
Volume 24, Issue 2 - Apr 2013
Volume 24, Issue 1 - Feb 2013
Selecting the target year
Fabrication and Performance Evaluation of Tubular Solid Oxide Fuel Cells Stack
Kim, Wanje ; Lee, Seungbok ; Song, Rakhyun ; Park, Seokjoo ; Lim, Takhyoung ; Lee, Jongwon ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 6, 2013, Pages 467~471
DOI : 10.7316/KHNES.2013.24.6.467
In present work, optimized the manufacturing process of anode-supported tubular SOFCs cell and stack were studied. For this purpose, we first developed a high performance tubular SOFC cell, and then made electrical connection in series to get high voltage. The gas sealing was established by attaching single cells to alumina jig with ceramic bond. Through these process, we can obtain such high OVP as around 15V, which means that the electrical connection and gas sealing were optimized. Finally we developed a new tubular SOFC stack which shows a maximum power of 65W @
Simulation of SI-HCCI Transition in a Two-Stroke Free Piston Engine Fuelled with Hydrogen
Hung, Nguyen Ba ; Park, Kyuel ; Lim, Ocktaeck ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 6, 2013, Pages 472~479
DOI : 10.7316/KHNES.2013.24.6.472
A free piston linear engine could be operated under HCCI combustion due to its variable compression ratios. To obtain HCCI combustion, the free piston linear engine needs a high compression ratio to achieve auto-ignition of the fuel/air mixture. In this study, an idea for obtaining a high compression ratio using the transition from SI combustion to HCCI combustion was proposed. The fuel used in this study is hydrogen, which is considered to be an environmentally friendly fuel. Besides, the effects of key parameters such as equivalence ratio (
), load resistance (
) and intake temperature (
) on the SI-HCCI transition were numerically investigated. The simulation results show that the SI-HCCI transition is successful without any significant reduction of in-cylinder pressure as the intake temperature is increased from
=300K (SI mode) to
=450K (HCCI mode), while the load resistance and equivalence ratio are retained respectively at
=0.6 in both SI mode and HCCI mode.
Development of Tubular Solid Oxide Fuel Cells with Advanced Anode Current Collection
Kim, Wanje ; Lee, Seungbok ; Song, Rakhyun ; Park, Seokjoo ; Lim, Takhyoung ; Lee, Jongwon ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 6, 2013, Pages 480~486
DOI : 10.7316/KHNES.2013.24.6.480
In this study, tubular SOFC unit cell with advanced anode current collector was fabricated to improve the cell performance. First, we prepared two types of single cells having the same manufacture processes such as the same electrolyte, electrode coating condition and sintering processes. And then to compare the developed single cell performance with conventional cells, we changed the anode current collecting methods. From the impedance analysis and I-V curve analysis, the cell performance of advanced cell is much higher than that of conventional cell.
Effect of Frictional Resistance Force on a Liquid Pool Spreading Model with Continuous and Instantaneous Release
Kim, Tae Hoon ; Choi, Byung-Il ; Kim, Myungbae ; Do, Kyu Hyung ; Han, Yong-Shik ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 6, 2013, Pages 487~494
DOI : 10.7316/KHNES.2013.24.6.487
In this study, solutions for a liquid pool spreading model with continuous and instantaneous release are discussed based on the model used in the FERC's report. The effects of the release time on the liquid pool volume and radius are investigated for the continuous release. For the continuous release with the frictional resistance force in the liquid pool spreading model, the vaporization time decreases as the release time increases. On the other hand, for the continuous release without the frictional resistance force in the liquid pool spreading model, the vaporization time increases as the release time increases. These phenomena are deeply related to the pool radius. In addition, the effects of the initial pool radius for the instantaneous release in the liquid pool spreading model are discussed. For the case with the frictional resistance force in the liquid pool spreading model, as reducing release time in the model with the frictional resistance force for the continuous release, the solution for a continuous release approaches to that for an instantaneous release. On the contrary to this, the pool volume and radius for the instantaneous release without the frictional resistance force are totally different from those for the continuous release without the frictional resistance force.
A Numerical Investigation of Effects of Methanol Concentration Fluctuation in Active-type Direct Methanol Fuel Cell (DMFC) Systems
Gwak, Geonhui ; Ko, Johan ; Lee, Suwon ; Lee, Jinwoo ; Peck, Donghyun ; Jung, Doohwan ; Ju, Hyunchul ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 6, 2013, Pages 495~509
DOI : 10.7316/KHNES.2013.24.6.495
In this study, we develop a one-dimensional (1-D), two-phase, transient-thermal DMFC model to investigate the effect of methanol concentration fluctuation that usually occurs in active-type direct methanol fuel cell (DMFC) systems. 1-D transient simulations are conducted and time-dependent behaviors of DMFCs are analyzed under various DMFC operating conditions such as anode/cathode stoichiometry, cell temperature, and cathode inlet humidification. The simulation results indicate that the effect of methanol concentration fluctuation on DMFC performance can be mitigated by proper control of anode/cathode stoichiometry, providing a guideline to optimize operating conditions of active DMFC systems.
Performance Characteristics of a Combined Regenerative Ammonia-Water Based Power Generation Cycle Using LNG Cold Energy
Kim, Kyounghoon ; Oh, Jaehyeong ; Jeong, Youngguan ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 6, 2013, Pages 510~517
DOI : 10.7316/KHNES.2013.24.6.510
The ammonia-water based power generation cycle utilizing liquefied natural gas (LNG) as its heat sink has attracted much attention, since the ammonia-water cycle has many thermodynamic advantages in conversion of low-grade heat source in the form of sensible energy and LNG has a great cold energy. In this paper, we carry out thermodynamic performance analysis of a combined power generation cycle which is consisted of an ammonia-water regenerative Rankine cycle and LNG power generation cycle. LNG is able to condense the ammonia-water mixture at a very low condensing temperature in a heat exchanger, which leads to an increased power output. Based on the thermodynamic models, the effects of the key parameters such as source temperature, ammonia concentration and turbine inlet pressure on the characteristics of system are throughly investigated. The results show that the thermodynamic performance of the ammonia-water power generation cycle can be improved by the LNG cold energy and there exist an optimum ammonia concentration to reach the maximum system net work production.
Desulfurization of Biogas Using Micro Bubble in a Biogas Plant
Tak, Bong-Yul ; Tak, Bong-Sik ; Kim, Chan-Gyu ; Min, Gil-Ho ; Jang, Choon-Man ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 6, 2013, Pages 518~523
DOI : 10.7316/KHNES.2013.24.6.518
This paper describes the reduction of a hydrogen sulfide (
) generated from a biogas plant. Micro bubble system is adopted to supply air into the water in the reaction chamber, which can increase the contact area of the supplied air to the reserving water. Two stage reaction chambers having two reaction rooms are designed and manufactured to enhance the reduction rate of a hydrogen sulfide. Sodium hydroxide (NaOH) is also considered to get rid of a hydrogen sulfide. Air volume rate to the water in a reaction chamber is maintained between 0.5 and
. Throughout experimental measurement of the concentration of a hydrogen sulfide by changing the volume of supplied air into the water, reduction rate of a hydrogen sulfide increases as air volume increases. Adding sodium hydroxide to the water with the air supply can reduce effectively a hydrogen sulfide up to 99.5% from biogas. It is noted that a hydrogen sulfide generated by a biogas plant can reduce by supplying micro bubble air and sodium hydroxide effectively.
A Study of Numerical Analysis on Mixed Combustion Characteristics in a Gasoline Direct Injection Engine with Premixed Hydrogen
Bae, Jaeok ; Choi, Minsu ; Suh, Hyunuk ; Jeon, Chunghwan ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 6, 2013, Pages 524~534
DOI : 10.7316/KHNES.2013.24.6.524
Gasoline direct injection(GDI) engine has a high thermal efficiency, but it has a problem to increase carbon emissions such as soot and
. In this study, the objective is to analyze numerically a problem for adding the hydrogen during the intake stroke so as to reduce the injected amount of gasoline in GDI engines. For selection of the base model, the cylinder pressure of simulation is matched to experimental data. The numerical analysis are carried out by a CFD model with the hydrogen addition of 2%, 3% and 4% on the volume basis. In the case of 3% hydrogen addition, the injected gasoline amount is only changed to match the maximum pressure of simulation to that of the base model for additional study. It is found that the combustion temperature and pressure increase with the hydrogen addition. And NO emission also increases because of the higher combustion temperature.
emissions, however, are reduced due to the decrease of injected gasoline amount. Also, as the injected gasoline amount is reduced for the same hydrogen addition ratio, the gross indicated work is no significant, But NO and
emissions are considerably decreased. On the order hand,
emissions of two cases are more decreased and their gross indicated works are higher obtained than those of the base model.
Effect of Bed Insert Geometry on CO Conversion of WGS Catalyst in a Fluidized Bed Reactor for SEWGS Process
Ryu, Hojung ; Kim, Hana ; Lee, Dongho ; Jin, Gyoungtae ; Park, Youngcheol ; Jo, Sungho ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 6, 2013, Pages 535~542
DOI : 10.7316/KHNES.2013.24.6.535
To enhance the performance of SEWGS system by holding the WGS catalyst in a SEWGS reactor using bed inserts, effect of bed insert geometry on CO conversion of WGS catalyst was measured and investigated. Small scale fluidized bed reactor was used as experimental apparatus and tablet shaped WGS catalyst and sand particle were used as bed materials. The cylinder type and the spring type bed inserts were used to hold the WGS catalysts. The CO conversion of WGS catalyst with the change of steam/CO ratio was determined based on the exit gas analysis. Moreover, gas flow direction was confirmed by bed pressure drop measurement for each case. The measured CO conversion using the bed inserts showed high value comparable to previous results even though at low catalyst content. Most of input gas flowed through the bed center side when we charged tablet type catalyst into the cylinder type bed insert and this can cause low
capture efficiency because the possibility of contact between input gas and
absorbent is low in this case. However, the spring type bed insert showed good reactivity and good distribution of gas, and therefore, the spring type bed insert was selected as the best bed insert for SEWGS process.
The Study on the Catalytic Performance and Characterization of La
(B=Mn, Ni, Fe, Ru) for High Temperature Water-gas Shift Reaction with Simuated Coal-derived Syngas
Lee, Seul-Gi ; Kwak, Jaehoom ; Sohn, Jung Min ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 6, 2013, Pages 543~549
DOI : 10.7316/KHNES.2013.24.6.543
In this study,
(M=Mn, Ru, Fe, Ni) were prepared by sol-gel method and water gas shift reaction with simulated coal-derived syngas between
was conducted to evaluate the catalytic activity of prepared catalysts. Physico-chemical properties were characterized by XRD, BET, SEM-EDS and TPR. The formation of perovskite crystallite,
was confirmed and the highest surface area was measured with
. Equilibrium conversion of CO above
was achieved except
. and methanation reaction was carried out as side reaction of water gas shift reaction with
was the most suitable catalyst of water gas shift reaction above
for CO conversion and hydrogen production.
Ni Nanoparticles-hollow Carbon Spheres Hybrids for Their Enhanced Room Temperature Hydrogen Storage Performance
Kim, Jin-Ho ; Han, Kyu-Sung ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 6, 2013, Pages 550~557
DOI : 10.7316/KHNES.2013.24.6.550
A glucose hydrothermal method is described for preparing hollow carbon spheres (HCS), which have a regular morphology and a high Brunauer-Emmett-Teller surface area of 28.6 m2/g. Scanning electron microscopy shows that they have thin shells and diameter between 2 and 8
. The HCSs were modified for the enhanced room temperature hydrogen storage by employing Ni nanoparticles on their surface. The Ni-decorated HCSs were characterized by X-ray diffraction, transmission electron microscopy coupled with an energy dispersive spectroscope, and an inductively coupled plasma spectrometer, indicating that fine and well-distributed Ni nanoparticles can be accomplished on the HCSs. The hydrogen uptake capacity in HCSs with and without Ni loading was evaluated using a high-pressure microbalance at room temperature under a hydrogen pressure upto 9 MPa. As much as 1.23wt.% of hydrogen can be stored when uniformly distributed Ni nanoparticles are formed on the HCSs, while the hydrogen uptake capacity of as-received HCSs was 0.41 wt.%. For Ni nanoparticle-loaded HCSs, hydrogen molecules could be easily dissociated into atomic hydrogen and then chemically adsorbed by the sorbents, leading to an enhanced capacity for storing hydrogen.
Evaluation of Energy Production for a Small Wind Turbine Installed in an Island Area
Jang, Choon-Man ; Lee, Jong-Sung ; Jeon, Wan-Ho ; Lim, Tae-Gyun ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 6, 2013, Pages 558~565
DOI : 10.7316/KHNES.2013.24.6.558
This paper presents how to determine AEP(Annual Energy Production) by a small wind turbine in DuckjeokDo island. Evaluation of AEP is introduced to make a self-contained island including renewable energy sources of wind, solar, and tidal energy. To determine the AEP in DuckjeokDo island, a local wind data is analyzed using the annual wind data from Korea Institute of Energy Research firstly. After the wind data is separated in 12-direction, a mean wind speed at each direction is determined. And then, a small wind turbine power curve is selected by introducing the capacity of a small wind turbine and the energy production of the wind turbine according to each wind direction. Finally, total annual wind energy production for each small wind turbine can be evaluated using the local wind density and local energy production considering a mechanical energy loss. Throughout the analytic study, it is found that the AEP of DuckjeokDo island is about 2.02MWh/y and 3.47MWh/y per a 1kW small wind turbine installed at the altitude of 10 m and 21m, respectively.
Structural Characteristics for the Hybrid Street-Lamp of a Small Wind Turbine and Photovoltaic Power System
Jeon, Hyun-Jun ; Jang, Choon-Man ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 6, 2013, Pages 566~572
DOI : 10.7316/KHNES.2013.24.6.566
In the present study, structure analysis has been performed to understand the deflection and stress distribution for a hybrid street-lamp having a vertical-axis wind turbine and a photovoltaic panel. Modal analysis is also evaluated to avoid resonance gerenerated by sychronism between a turbine and a lamppost. To analyze deflection, stress and frequency, general analysis code(ANSYS-Mechanical 13) is employed in the present work. Throughout structure analysis in the hybrid street-lamp, maximum stress is observed at the connecting position between a turbine blade and a blade supporter. Campbell diagram which is combined the natural frequency of turbine blades and blade passing frequency is presented to analyze a system resonance. It is found that the resonance of the system having a rotating turbine blade and a lamppost can avoid by the optimal selection of geometric parameters of a wind turbine.
An Experimental Study on Expansion of Operation Range by Lean Boosting for a HCCI H
Ahn, Byunghoh ; Lee, Jonggoo ; Lee, Jongmin ; Lee, Jongtai ;
Transactions of the Korean hydrogen and new energy society, volume 24, issue 6, 2013, Pages 573~579
DOI : 10.7316/KHNES.2013.24.6.573
Hydrogen engine with homogeneous charged compression ignition can achieve high efficiency by high compression ratio and rapid chemical reaction rates spatially. However, it needs to expansion of the operation range with over-all load conditions which is very narrow due to extremely high pressure rise rate. The adoption of the lean boosting in a HCCI
engine is expected to be effective in expansion of operation range since minimum compression ratio for spontaneous ignition is decreased by low temperature combustion and increased surround in-cylinder pressure. In order to grasp its possibility by using lean boosting in the HCCI
engine, compression ratio required for spontaneous ignition, expansion degree of the operation range and over-all engine performance are experimentally analyzed with the boosting pressure and supply energy. As the results, it is found that minimum compression ratio for spontaneous ignition is down to the compression ratio(
=19) of conventional diesel engine due to decreased self-ignition temperature, and operation range is extended to 170% in term of the equivalence ratio and 12 times in term of the supply energy than that of naturally aspirated type. Though indicated thermal efficiency is decreased by reduced compression ratio, it is over at least 46%.