• Journal of Mechanical Science and Technology
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• v.19 no.4
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• pp.1018-1026
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• 2005

The proton exchange membrane (PEM) fuel cell system consisting of stack and balance of plant (BOP) was modeled in a MATLAB/Simulink environment. High-pressure operating (compressor type) and low-pressure operating (air blower type) fuel cell systems were con­sidered. The effects of two main operating parameters (humidity and the pressure of the supplied gas) on the power distribution characteristics of BOP and the net system efficiency of the two systems mentioned above were compared and discussed. The simulation determines an optimum condition regarding parameters such as the cathode air pressure and the relative humidity for maximum net system efficiency for the operating fuel cell systems. This study contributes to get a basic insight into the fuel cell stack and BOP component sizing. Further research using muli­object variable optimization packages and the approach developed by this study can effectively contribute to an operating strategy for the practical use of fuel cell systems for vehicles.

• Proceedings of the KIEE Conference
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• 2008.10c
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• pp.191-193
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• 2008

A fuel cell power system among various alternative power sources has many advantages such as low-polluted, high-efficient, and heat-recyclable, thus it is now able to be up to hundreds MWh-scaled through improving feasibility and longevity of it. During the last few years of the twentieth century, much changed to stimulate new and expanding interest in fuel cell technology. This paper presents optimal design and operational features of stand-alone 500W PEMFC(Proton Exchange Membrane Fuel Cell) system which can be a substitute instead fossil fuel. The stack of PEMFC is composed of 35 laminated graphite, and a unit cell of the stack has electrical characteristics as below; 14W, 0.9V, 15A. The other components of BOP(Balance of Plant) are composed of hydrogen and nitrogen tanks, regulators, 3way 5solenoid valves, mass flow meters, etc.

• Journal of the Korean Electrochemical Society
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• v.6 no.1
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• pp.23-27
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• 2003

In this study investigations have been carried out for the evaluation of small DMFCS under passive operation conditions for use in portable powers. Under passive conditions, a maximum performance was obtained at a methanol concentration of 4 M and at a catalyst loading of $8mg/cm^2$ on both electrodes. By optimizing various parameters, we could achieve the highest performance of $55mW/cm^2$ at 1 attn and at R.T.A monopolar stack consisting of 6 unit cells with active area of $4.5cm^2/cell$ was prepared and it showed a uniform voltage distribution all over the cells and it had a power output of 1 watt and a power density of $37mW/cm^2$ A monopolar stack which consisted of 16 cells and produced a 2.4W power was also fabricated and was tested for operation of a miniature car.

• Journal of Hydrogen and New Energy
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• v.23 no.4
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• pp.323-329
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• 2012

A thermal management system of a proton exchange membrane fuel cell is taken charge of controlling the temperature of fuel cell stack by rejection of electrochemically reacted heat. Two major components of thermal management system are heat exchanger and pump which determines required amount of heat. Since the performance and durability of PEMFC system is sensitive to the operating temperature and temperature distribution inside the stack, it is necessary to control the thermal management system properly under guidance of operating strategy. The control study of the thermal management system is able to be boosted up with hardware in the loop simulation which directly connects the plant simulation with real hardware components. In this study, the plant simulation of fuel cell stack has been developed and the simulation model is connected with virtual data acquisition system. And HIL simulator has been developed to control the coolant supply system for the study of PEMFC thermal management system. The virtual data acquisition system and the HIL simulator are developed under LabVIEWTM Platform and the Simulation interface toolkit integrates the fuel cell plant simulator with the virtual DAQ display and HIL simulator.

• Journal of the Korean Institute of Telematics and Electronics C
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• v.36C no.4
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• pp.31-43
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• 1999

The main goal of this paper is to design a high performance SVP(Stack based Video Processor) for network applications. The SVP is a comprehensive scheme; 'better' in the sense that it is an optimal selection of previously proposed enhancements of a stack machine and a video processor. This can process effectively object-based video data using a S-RISC(Stack-based Reduced Instruction Set Computer) with a semi -general-purpose architecture having a stack buffer for OOP(Object-Oriented Programming) with many small procedures at running programs. And it includes a vector processor that can improve the MPEG coding speed. The vector processor in the SVP can execute advanced mode motion compensation, motion prediction by half pixel and SA-DCT(Shape Adaptive-Discrete Cosine Transform) of MPEG-4. Absolutors and halfers in the vector processor make this architecture extensive to a encoder. We also designed a VLSI stack-oriented video processor using the proposed architecture of stack-oriented video decoding. It was designed with O.5$\mu\textrm{m}$ 3LM standard-cell technology, and has 110K logic gates and 12 Kbits SRAM internal buffer. The operating frequency is 50MHz. This executes algorithms of video decoding for QCIF 15fps(frame per second), maximum rate of VLBV(Very Low Bitrate Video) in MPEG-4.

• Proceedings of the KIEE Conference
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• 1998.07d
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• pp.1543-1545
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• 1998

In order to develop PAFC stack technology using 2.000$cm^3$ electrode-matrix, 10kW stack consisted of 63 single cell was fabricated and operated. The operation installation, and control and data acquision system for the 10kW PAFC stack were designed and equipped. The stack showed the performance of 10kW (275A at 36.5V) and uniform distribution of temperature and voltage between the cells.

• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.27-30
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• 2007

This study considers the feasibility of the concentration control of the methanol solution by oscillating flow in the anode channel of passive type Direct Methanol Fuel Cells(DMFC). DMFC stack performance is largely influenced by the fuel concentration. If the fuel concentration is either lower than 0.5M or more than 2M, its performance deteriorates seriously because of the fuel starvation or the fuel crossover. In this respect the optimization of the fuel concentration is crucially important to maximize the DMFC stack performance. In this work, the effects of oscillating actuation in the fuel supply are studied to control the fuel concentration. Two important nondimensional parameters are introduced, each of which represents either the oscillating frequency or the oscillating amplitude. It is shown how these factors affect the stack performance and the efficiency of the DMFC stack.

• Electrical & Electronic Materials
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• v.5 no.3
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• pp.265-269
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• 1992

미국의 ERC는 용융탄산염형 연료전지의 연구개발을 연방 에너지성의 지원하에 100KW stack의 개발을 진행시키고 있으며 Pacific gas & Electric com.는 100KW stack 운전시험에 성공하면 2MW의 실증 P1-ant를 발주할 게획이다. 그리고 일본은 신에너지 산업기술 총합 개발 기구(NEDO)의 project인 1MW발전 system 개발을 목표로 100KW를 stack 개발, 1MW급 Plant 구성기기 기술 system 기술 개발 진행중에 있으며 '93년에 100KW급 stack의 중간평가 실시와 '93-'94년 1MW급 발전 system의 설계, 건설, 운전 시험을 계획중에 있다. 한편 고체 전해질형 연료전지는 국외에서 1.3KW급 발전에 성공하였으며 10-20KW급 연구 개발이 진행중이다. 따라서 국내에서는 차세대 연료전지인 MCFC와 SOFC에 대하여 많은 노력에 의해서 선진국 기술 수준에 접근하므로서 실용화가 가능하리라고 본다.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.59 no.3
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• pp.317-324
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• 2010

It was used as measuring system to diagnose insulating condition, by which was kept a insulating resistance of inner stack and at the same time was cooled electrochemical heat of reaction of FCEV(fuel cell electric vehicle) stack that used a compressed hydrogen gas reacting with oxygen in accordance with variation on thermal degradation of nonconductive heat transfer fluid. Consequently it was developed a cylindrical multi-terminal capacitive-conductive sensor that could be attached to the internal surface of cooling system pipe to evaluate capacitance and conductivity of heat transfer fluid.

• 한국신재생에너지학회:학술대회논문집
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• 2006.11a
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• pp.105-108
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• 2006

The fuel cell is one of the promising environment-friendly energy sources for the next generation. The fuel cell provides good energy efficiency above 40% without pollution or noise. Different fuel cell types are usually distinguished by the kind of electrolyte. Among these, the proton exchange membrane fuel cell (PEMFC) has advantages of high power density. low operating temperature, relatively quick start-up, and rapid response to varying loads. The bipolar plate is a major component of the PEM fuel cell stack, and it takes a large portion of stack volume, weight and cost. In this study, as alternative materials for bipolar plate of PEM fuel cells, graphite composites were fabricated by compression molding and by machining. Graphite particles mixed with epoxy resin were used as the main substance to provide electric conductivity. Flow channels were fabricated by compression molding with design of experiments (DOE) to evaluate moldability. The cost for compression molding of graphite-composite bipolar plate was compared with machining cost to make the same bipolar plate.