• Transactions of the Korean hydrogen and new energy society
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• v.14 no.4
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• pp.348-358
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• 2003

According to Electricity Acceleration Law of Rural Area recently, the needs for replacement of a small scale diesel power generation facility which supplied electricity to 10-50 households Remote Islands has been revealed due to high operating and maintenance cost of Diesel Power Generation. Optimization of electric power system for Small Remote Islands must be made considering the economics, reliability and stability as power sources and estimation of total construction cost of those power stations. For its purpose, an assessment of power generation options such as Photovoltaic, Fuel cell, Wind-hybrid was implemented, economic evaluation of power supply shows the Photovoltaic, Fuel Cell for few household's islands and Diesel, Wind-hybrid for more inhabited islands. Power supplied by Diesel shows the best response to increasing electric demand and system reliability even with its lower economic value. Those who are in charge of power planning have to pay attention to system reliability, stability and operating characteristics of candidate's power supply besides its economics.

• 한국신재생에너지학회:학술대회논문집
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• 2007.06a
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• pp.383-386
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• 2007

This paper describes the design and integration of the wind- fuel cell hybrid system. The hybrid system components included a wind turbine, an electrolyzer (for generation of H2), a PEMFC (Proton Exchange Membrane Fuel Cell), storage system and BOP (Balance of Plant) system. The energy input is entirely provided by a wind turbine. A DC-DC converter controls the power input to the electrolyzer, which produces hydrogen and oxygen form water. The hydrogen used the fuel for the PEMFC. The hydrogen is compressed and stored in high pressure tank by hydrogen gas booster system.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.4
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• pp.346-353
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• 2010

Hydrogen fueled vehicle was evaluated as one of the next-generation technology that will be able to solve the global warming, depletion of fossil fuel and etc. The practical use of hydrogen fueled vehicle, nevertheless, is being delayed more than expected schedule due to various causes. In order to promote the dissemination of hydrogen fueled vehicle, development status and obstacle factors of practical use for hydrogen fueled vehicles were reviewed and the strategy plans for dissemination promotion were proposed. Hydrogen fueled vehicles are included the hydrogen fuel cell, neat and enriched hydrogen fueled engines. The technicalness, economy, safety, cognizance, system, support and etc were considered in the strategy plans.

• Journal of Electrical Engineering and Technology
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• v.4 no.3
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• pp.382-388
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• 2009

Recently, hydrogen energy has been anticipated to change the paradigm of conventional power systems because it can expand sustainable energy utilization and conceptually provide remarkable flexibility to power system operation. Since hydrogen energy can be converted to electric energy through fuel cells, fuel cells are expected to play an important role in the future hydrogen economy. In this paper, a Proton Exchange Membrane Fuel Cell (PEMFC) is modeled as an equivalent circuit and its steady-state characteristics investigated using the model. PEMFCs can be connected to power systems through power conditioning systems, which consist of power electronic circuits, and which are operated as distributed generators. This paper analyzes the effects of the characteristics of the PEMFC internal voltages and investigated the dynamic responses of the PEMFC under fault conditions. The results show that the fault current contribution of the PEMFC is different from those of conventional generators and is closely related to its operating point.

• Journal of the Korean Solar Energy Society
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• v.37 no.2
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• pp.13-22
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• 2017

Two-step water splitting thermochemical cycle with $CeO_2/ZrO_2$ foam device was investigated by using a solar simulator composed of 2.5 kW Xe-Arc lamp and mirror reflector. The hydrogen production of $CeO_2/ZrO_2$ foam device depending on heat recovery of Thermal-Reduction step and Water-Decomposition step was analyzed, and the hydrogen production of $CeO_2/ZrO_2$ and $NiFe_2O_4/ZrO_2$ foam devices was compared. Resultantly, the quantity of hydrogen generation increased by 52.02% when the carrier gas of Thermal-Reduction step is preheated to $200^{\circ}C$ and, when the $N_2/steam$ is preheated to $200^{\circ}C$ in the Water-Decomposition step, the quantity of hydrogen generation increased by 35.85%. Therefore, it is important to retrieve the heat from the highly heated gases discharged from each of the reaction spaces in order to increase the reaction temperature of each of the stages and thereby increasing the quantity of hydrogen generated through this.

• Transactions of the Korean hydrogen and new energy society
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• v.18 no.4
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• pp.382-390
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• 2007

To check the feasibility of SMART(Steam Methane Advanced Reforming Technology) system, an experimental investigation was performed. A fluidized bed reactor of diameter 0.052m was operated cyclically up to 10th cycle, alternating between reforming and regeneration conditions. FCR-4 catalyst was used as the reforming catalyst and calcined limestone(domestic, from Danyang) was used as the $CO_2$ absorbent. Hydrogen concentration of 98.2% on a dry basis was reached at $650^{\circ}C$ for the first cycle. This value is much higher than $H_2$ concentration of 73.6% in the reformer of conventional SMR (steam methane reforming) condition. The hydrogen concentration decreased because the $CO_2$ capture capacity decreased as the number of cycles increased. However, the average hydrogen concentration at 10th cycle was 82.5% and this value is also higher than that of SMR. Based on these results, we could conclude that the SMART system can replace SMR system to generate pure hydrogen without HTS (high tempeature shift), LTS (low temperature shift) and $CO_2$ separation process.

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.214-220
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• 2019

Thermochemical cycles have been predominantly used for energy transformation from heat to stored chemical free energy in the form of hydrogen. The thermochemical cycle based on uranium (UTC), proposed by Oak Ridge National Laboratory, has been considered as a better alternative compared to other thermochemical cycles mainly due to its safety and high efficiency. UTC process includes three steps, in which only the first step is unique. Hydrogen production apparatus with hectogram reactants was designed in this study. The results showed that high yield hydrogen was obtained, which was determined by drainage method. The results also indicated that the chemical conversion rate of hydrogen production was in direct proportion to the mass of $Na_2CO_3$, while the solid product was $Na_2UO_4$, instead of $Na_2U_2O_7$. Nevertheless the thermochemical cycle used for hydrogen generation can be closed, and chemical compounds used in these processes can also be recycled. So the cycle with $Na_2UO_4$ as its first reaction product has an advantage over the proposed UTC process, attributed to the fast reaction rate and high hydrogen yield in the first reaction step.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.7
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• pp.3261-3266
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• 2012

Sodium borohydride($NaBH_4$) known as the material of hydrogen generation and storage can produce the hydrogen via catalytic hydrolysis. This protide chemical could be used in the hydrogen supply system for residential and mobile fuel cells, and thus many researches and developments regarding to these chemicals and decomposition reactions have been implemented. We experimented the hydrolysis of $NaBH_4$ alkaline solution by metal oxide-supported PGM(platinum group metal) catalysts and measured the generation rate of hydrogen which is product of decomposition reaction. We compared oxides as catalyst supports, and the precious metals, Pt and Ru for the catalysts and studied the effects of amounts of catalyst added and $NaBH_4$ concentrations on the hydrogen generation rates and patterns.

• New & Renewable Energy
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• v.3 no.2 s.10
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• pp.60-67
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• 2007

This paper describes the design and integration of the wind-fuel cell hybrid system. The hybrid system components included a wind turbine, an electrolyzer (for generation of H2), a PEMFC (Proton Exchange Membrane Fuel Cell), hydrogen storage tank and BOP (Balance of Plant) system. The energy input is entirely provided by a wind turbine. A DC-DC converter controls the power input to the electrolyzer, which produces hydrogen and oxygen form water. The hydrogen used the fuel for the PEMFC. Hydrogen may be produced and stored in high pressure tank by hydrogen gas booster system. Wind conditions are changing with time of day, season and year. So, wind power is a variable energy source. The main purpose with these WT-FC hybrid system is to store hydrogen by electrolysis of water when wind conditions are good and release the stored hydrog en to supply the fuelcell when wind is low.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.5
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• pp.478-489
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• 2023

In this study, fault diagnosis and detection methods developed to ensure the reliability of polymer electrolyte membrane (PEM) hydrogen electrolysis systems have been proposed. The proposed method consists of model development and data generation of the PEM hydrogen electrolysis system, and data-driven fault diagnosis learning model development. The developed fault diagnosis learning model describes how to detect and classify faults in the sensors and components of the system.