• Transactions of the Korean hydrogen and new energy society
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• v.27 no.4
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• pp.335-340
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• 2016

Hydrogen production through proton exchange membrane water electrolysis (PEMWE) is expeditiously receiving international attention for renewable energy sources as well as energy storage system applications due to its environmentally friendly uses. A series of $Ir_{0.2}Ru_{0.8}O_2$ $Ir_{0.5}Ru_{0.8}O_2$ & $IrO_2$ catalysts were synthesized and electrochemically evaluated by using linear sweep voltammetry (LSV) technique. Furthermore, the PEMWE performances of full cells were evaluated by recording I-V Curves. The developed PEMWE stack was also operated in combination with a proton exchange membrane fuel cell (PEMFC) to demonstrate the discrete regenerative fuel cell (DRFC) performances. Produced hydrogen and oxygen from PEMWE were used as a fuel to operate PEMFC to establish a DRFC system.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.3
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• pp.235-245
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• 2023

Techno-economic analyses on a 5-MW water electrolysis system for hydrogen production, operated in Jeju Island where the portion of renewable energy in the power grid is the highest in Korea, have been performed. The cost of hydrogen production and the economic feasibility of the hydrogen production system have been mainly analyzed based on the levelized-cost-of-hydrogen model. The effects of carbon emission trading and renewable power purchase method have been considered to reduce the cost of green hydrogen production in the case studies. This economic analysis model is expected to be used to derive a business model for green hydrogen production.

• Journal of the Institute of Electronics and Information Engineers
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• v.52 no.3
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• pp.199-205
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• 2015

This study is about ionic water generator filter Recently, a lot of people feel deep interest in health and drinking water. And there are various types of water. Ionic water generator is a system with special function, and can be classified as a medical device and should be manufactured after approval from the Food and Drug Administration. Basically ionized water is different from the packaged and stored water. When the tap water or ground water passes through the various filters of ionic water generator, it turns to the purified water of pH7 ~ 7.5 and we can electrolyze that water into anion and cation by diaphragm. And in negative electrode side, we can get alkaline water with calcium ($Ca^+$), potassium ($K^+$), magnesium ($Mg^+$), sodium ($Na^+$) for body. In general, we can change pH value from 5 to 9 of ionizer by controlling the level of electrolysis voltage in the ionizer. In general, 1stage (pH8), 2stage (pH8.5), 3stage (pH9), 4stage (pH9.5) are used as the alkaline ionized water, -1Stage (pH6.0), -2 stage (pH5.0) are used as the acidic water. But in early stage, the water that passed through filter was weakly alkaline water and that was problem. Therefore, when filter condition is stable, the pH and ORP value of water is different with the early one. the initial setting pH value of the ionizer was confirmed that changes significantly. In order to resolve this problem we need to wash filter for some period time and neutralize by acidification treatment of the filter.

• Journal of the Korean Electrochemical Society
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• v.26 no.4
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• pp.64-70
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• 2023

Global warming is getting worse since a dramatic increase in greenhouse gas emissions recently. As a result, the necessity and implementation of carbon neutrality is required more urgently. To do this, among various new and renewable energies, attention in hydrogen arises. Hydrogen as a carbon-free power source is an abundant resource on Earth and is eco-friendly. Eventually, perfectly eco-friendly hydrogen can be obtained through electrolysis of water. However, the catalyst used in the oxygen evolution reaction is rare and expensive, and has a durability issue. Consequently, the development of a non-precious metal catalyst is necessary. In this review paper, we summarize and introduce Co- and Mo- based catalysts among recently announced oxygen evolution catalysts. This will help understand the design of catalyst to increase the activity and durability of non-precious metal catalysts.

• Korean Chemical Engineering Research
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• v.43 no.3
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• pp.344-351
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• 2005

Hydrogen energy will be considered one of the most important energy carries for the future not only as raw material of petroleum chemical industry but also as the fuel of the fuel cell. The hydrogen production based upon the water electrolysis system combined renewable energy or atomic power energy is being watched as long-term hydrogen sources. Hydrogen from fossil fuel, especially natural gas steam reforming, is the economical mass production method at this time. But the cost of $CO_2$ reduction is added in the economic analysis of hydrogen production processes. Therefore many different results are suggested from these analyses about old processes, and modified schemes are studying for the efficient development. In this review, status for the technology of hydrogen production from natural gas are summarized.

• Transactions of the Korean hydrogen and new energy society
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• v.33 no.6
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• pp.607-615
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• 2022

In this study, economic analysis program was developed for economic evaluation of hydrogen production, storage/delivery, and utilization technologies as well as overseas import of hydrogen. Economic analysis program can be used for the estimation of the levelized cost of hydrogen for hydrogen supply chain technologies. This program include five hydrogen production technology on steam methane reforming and water electrolysis, two hydrogen storage technologies (high compressed gas and liquid hydrogen storage), three hydrogen delivery technologies (compressed gas delivery using tube trailer, liquid hydrogen, and pipeline transportation) and six hydrogen utilization technologies on hydrogen refueling station and stationary fuel cell system. In the case of overseas import hydrogen, it was considered to be imported from five countries (Austraila, Chile, India, Morocco, and UAE), and the transportation methods was based on liquid hydrogen, ammonia, and liquid organic hydrogen carrier. Economic analysis program that was developed in this study can be expected to utilize for planning a detailed implementation methods and hydrogen supply strategies for the hydrogen economy road map of government.

• Transactions of the Korean hydrogen and new energy society
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• v.21 no.6
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• pp.595-603
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• 2010

This paper deals with an economic evaluation of domestic window type photoelectrochemical hydrogen production utilizing solar cells. We make some sensitivity analysis of hydrogen production prices by changing the values of input factors such as the initial capital cost, the solar to hydrogen conversion efficiency, and the system duration time. The hydrogen production price of the window type photoelectrochemical system was estimated as 1,168,972 won/$kgH_2$. It is expected that hydrogen production cost can be reduced to 47,601 won/$kgH_2$ if the solar to hydrogen conversion efficiency is increased to 14%, the system duration time is increased to 20,000 hours, and the initial capital cost is decreased to 25% of the current level. We also evaluate the hydrogen production cost of the water electrolysis using the electricity produced by solar cells. The corresponding hydrogen production cost was estimated as 37,838 won/$kgH_2$. The photoelectrochemical hydrogen production is evaluated as uneconomical at this time, and we need to enhance the solar to hydrogen conversion efficiency and the system duration time as well as to reduce prices of the system facilities.

• Transactions of the Korean hydrogen and new energy society
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• v.34 no.2
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• pp.91-99
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• 2023

Participation in power trading using surplus power is considered a business model active in the domestic energy trade market, but it is limited only if the legal requirements according to the type, capacity, and use of the facilities to be applied for are satisfied. The hydrogen residential demonstration model presented in this paper includes solar power, energy storage system (ESS), fuel cell, and water electrolysis facilities in electrical facilities for private use with low-voltage power receiving system. The concept of operations strategy for this model focuses on securing the energy self-sufficiency ratio of the entire system, securing economic feasibility through the optimal operation module installed in the energy management system (EMS), and securing the stability of the internal power balancing issue during the stand-alone mode. An electric facility configuration method of a hydrogen residential complex demonstrated to achieve this operational goal has a structure in which individual energy sources are electrically connected to the main bus, and ESS is also directly connected to the main bus instead of a renewable connection type to perform charging/discharging operation for energy balancing management in the complex. If surplus power exists after scheduling, participation in power trading through reverse transmission parallel operation can be considered to solve the energy balancing problem and ensure profitability. Consequentially, this paper reviews the legal regulations on participation in electric power trading using surplus power from hydrogen residential models that can produce and consume power, gas, and thermal energy including hybrid distributed power sources, and suggests action plans.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.5 no.1
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• pp.1-8
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• 2009

Nuclear hydrogen production using high temperature heat of a very high temperature reactor(VHTR) is one of the most attractive ways of mass hydrogen production without greenhouse gas emission. In many countries, sulfur-iodine(S-I) thermochemical process and high temperature steam electrolysis(HTSE) process are being investigated. In such processes, corrosion behavior of Intermediate heat exchanger materials are the most critical issues. Especially in a HTSE system, several heat exchangers will be facing hot steam conditions. In this paper, the status of high temperature corrosion researches in hot steam and supercritical water conditions are reviewed in view of the implication to HTSE conditions. Based on the review, test condition and plan of the hot steam corrosion of the candidate materials are formulated and described in some details along with the schematics of the test set-up. The test results and subsequent evaluation will be used in development of a interface system between the HTSE hydrogen production system and the VHTR.

• Transactions of the Korean hydrogen and new energy society
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• v.29 no.3
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• pp.251-259
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• 2018

Metal hydride based hydrogen storage under moderate temperature and pressure gives the safety advantage over the gas and liquid storage methods. Still solid-state hydrogen storage including metal hydride is below the DOE target level for automotive applications, but it can be adapted to stationary or miliary application reasonably. In order to develop a modular solid state hydrogen storage system that can be applied to a distributed power supply system composed of renewable energy - water electrolysis - fuel cell, the heat transfer and hydrogen storage characteristics of the metal hydride necessary for the module system design were investigated using AB5 type metal hydride, LCN2 ($La_{0.9}Ce_{0.1}Ni_5$). The planetary high energy mill (PHEM) treatment of LCN2 confirmed the initial hydrogen storage activation and hydrogen storage capacity through surface modification of LCN2 material. Expanded natural graphite (ENG) addition to LCN2, and compression molding at 500 atm improved the thermal conductivity of the solid hydrogen storage material.