• Title/Summary/Keyword: Stack design

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Design of a Heat Release System for Fuel Cell Vehicles (연료전지 자동차 열방출 시스템의 설계)

  • Kim, Sung-Chul;Park, Min-Su;Jung, Seung-Hun;Yoon, Seok-Ho;Kim, Min-Soo
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.11a
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    • pp.545-548
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    • 2005
  • There is a close relation between the heat generation in the fuel cell stack and the fuel cell performance. In PEM fuel Gell vehicles, the stack coolant temperature is about $65^{\circ}C$, which is far lower than that for general automobile engine. Therefore, it is hard to release heat generated in the stack by using a radiator of limited size because of the reduced temperature difference between the coolant and the ambient air. In this study, indirect stack cooling system using $CO_2$ heat pump was designed and its stack cooling performance in releasing heat to the ambient was investigated. This work focuses on a series of processes that grasp the relation among the fuel cell power, the radiator capacity and the stack temperature. The purpose of this work is to find out a way to properly release sufficient amount of heat through the finite sized radiator, so that the stack power general ion can not be deteriorated due to the stack temperature increase. The optimization between the compressor power consumption and the fuel cel1 output power can be carried out to maximize the performance of fuel cell system.

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The Study of the IGBT and Stack Parallel Operation for the 1.5MVA Medium Power Inverter (1.5MVA급 중용량 인버터용 IGBT 및 Stack 병렬 운전 연구)

  • Park Geon-Tae;Jung Ki-Chan;Kim Yeon-Dal;Jung Myung-Kil;Kim Du-Sik
    • Proceedings of the KIPE Conference
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    • 2004.07a
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    • pp.402-405
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    • 2004
  • In this paper, the parallel operation of the IGBT and power stack for easy capacity enlargement series in the medium power capacity inverter system of the 660V voltage class is described. The parallel operation of the IGBT and power stack for 1.5MVA medium power inverter system's design is applied. The results of the parallel operation are described in this paper. The designed stack capacity for parallel operation is 800kVA class. For 1.5MVA inverter system, the 800kVA stack is applied with 2 parallel configurations. The 800kVA stack is designed with 3 parallel configurations of the IGBT Module. In this paper, the feasibility for easy capacity enlargement series in the medium power inverter by applying the parallel operation of the IGBT and power stack is verified. The experimental results show the good characteristics for the parallel operation of the IGBT and power stack.

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Optimal Sizing of the Manifolds in a PEM Fuel Cell Stack using Three-Dimensional CFD Simulations (3차원 CFD 시뮬레이션을 활용한 고분자전해질 연료전지 스택의 매니폴드 크기 최적화)

  • Jeong, Jeehoon;Han, In-Su;Shin, Hyun Khil
    • Transactions of the Korean hydrogen and new energy society
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    • v.24 no.5
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    • pp.386-392
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    • 2013
  • Polymer electrolyte membrane (PEM) fuel cell stacks are constructed by stacking several to hundreds of unit cells depending on their power outputs required. Fuel and oxidant are distributed to each cell of a stack through so-called manifolds during its operation. In designing a stack, if the manifold sizes are too small, the fuel and oxidant would be maldistributed among the cells. On the contrary, the volume of the stack would be too large if the manifolds are oversized. In this study, we present a three-dimensional computational fluid dynamics (CFD) model with a geometrically simplified flow-field to optimize the size of the manifolds of a stack. The flow-field of the stack was simplified as a straight channel filled with porous media to reduce the number of computational meshes required for CFD simulations. Using the CFD model, we determined the size of the oxidant manifold of a 30 kW-class PEM fuel cell stack that comprises 99 cells. The stack with the optimal manifold size showed a quite uniform distribution of the cell voltages across the entire cells.

Operating characteristics of an air cooling PEMFC for portable application (이동 전원용 공랭식 고분자 연료전지의 제작 및 운전 특성 연구)

  • Sohn Young-Jun;Park Gu-Gon;Yang Tae-Hyun;Yoon Young-Gi;Lee Won-Yong;Yim Sung-Dae;Kim Chang-Soo
    • New & Renewable Energy
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    • v.1 no.1 s.1
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    • pp.72-78
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    • 2005
  • Optimal design and proper operation are important to get aimed output power of a polymer electrolyte membrane fuel cell (PEMFC) stack. An air cooling fuel cell stack is widely used in sub kW PEMFC systems. The purpose of this study is to analyze operating conditions affecting the performance of the air cooling PEMFC which is designed for portable application. In portable applications, air cooling stack is difficult to maintain well balanced operating conditions. The importart parameters are the relative humidity, the temperature of the stack, the utilization of reactant gas and so on. in this study, a 500W air cooling PEMFC was fabricated and tested to evaluate the design performance and to determine optimal operating conditions. Moreover, basic modeling also is carried out. These results can be used 3s design criteria and optimal operating conditions for portable PEMFCs

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Experimental Analyses of Cell Voltages for a Two-cell PEM Stack Under Various Operating Conditions

  • Park, Sang-Kyun;Choi, Jae-Hyuk
    • Journal of Advanced Marine Engineering and Technology
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    • v.35 no.7
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    • pp.881-890
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    • 2011
  • Analyses of performance and behavior of the individual PEM fuel cells (PEMFC) under different operating conditions are of importance optimally to design and efficiently to operate the stack. The paper focuses on experimental analyses of a two-cell stack under different operating conditions, which performance and behavior are measured by the voltage of a cell as well as the stack. Experimental parameters include stoichiometric ratio, temperature of the air supplied under different working stack temperatures and loads. Results showed that the cell voltages are dominantly influenced by the temperature of the air supplied among others. In addition, an inherent difference between the first and the second cell voltage exists because of the tolerances of the cell components and the resulting different over-potentials at different equilibrium states. Furthermore, it is shown that the proton conductivity in the membranes conditioned by the humidity in the cathode channel highly affects the voltage differences of the two cells.

Characteristics of 5 kW Class Proton-Exchange-Membrane Fuel Cell(PEMFC) Stack according to the Long-Term Operation (장기운전에 따른 5 kW급 고분자 전해질 연료전지 스택의 특성)

  • Kim, Jae-Dong;Lee, Jung-Woon;Park, Dal-Ryung
    • Journal of the Korean Institute of Gas
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    • v.11 no.3
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    • pp.40-43
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    • 2007
  • The performance of PEMFC stack can be improved significantly by optimizing the design and operating conditions. As a result, the performance of daily operation showed slight deviation (0.02-0.9%) after accumulated DSS operation for 500 hrs but the stack performance was stable. Therefore, it is confirmed that it would be improved the life-time of stack and operation reliability for the commercialization of PEMFC system.

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Implementation and design of Linux IPv6 Protocol Stack on GSM Phone (GSM Phone 상에서 Linux IPv6 프로토콜 스택 설계 및 구현)

  • Lee, Sang-Woo;Lim, Dong-Hwa;Han, Bosco;Rho, Sun-Ok
    • Journal of KIISE:Information Networking
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    • v.34 no.1
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    • pp.16-26
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    • 2007
  • It is well known that, in the near future, the lifetime of the IPv4 address space will be limited and available 32-bit IP network addresses will not be left my more. In order to solve such IPv4 address space problem in an effective way, the transition to the new version using IPv6 architecture is inevitably required. This paper presents the design and implementation of IPv4/IPv6 dual stack at the GSM Phone based on Linux Kernel 2.4 IPv6 Protocol Stack. It designs appropriately in GSM Phone environment and it is tested by a network of Linux IPv4/IPv6 dual stack on PPP. The test was processed with a test scenario and it was found that the results were successful.

Stack Effect in High-Rise Buildings: A Review

  • Mijorski, Sergey;Cammelli, Stefano
    • International Journal of High-Rise Buildings
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    • v.5 no.4
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    • pp.327-338
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    • 2016
  • This technical paper presents a detailed review of the stack effect phenomenon and of the associated implications pertaining to the design and construction of high-rise buildings in regions of extreme climatic conditions. The present review is focused on both the classical 'chimney' effect as well as on the reverse stack effect, which are respectively related to cold and hot climates. For the purposed of the work here presented, the ASHRAE (2013) design conditions of Astana (Kazakhstan) and Riyadh (Kingdom of Saudi Arabia) were selected. A 230 m tall residential building of rectangular floor plan was numerically modelled in the context of the climatic conditions of the two abovementioned cities and a number of sensitivity analyses were performed, covering parametric changes of: temperature, façade air tightness, site wind speeds and wind directions.

Design of Bytecode Framework (바이트코드 프레임워크 설계)

  • 김영국;김기태;조선문;이갑래;유원희
    • Proceedings of the Korea Contents Association Conference
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    • 2004.05a
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    • pp.330-334
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    • 2004
  • Java bytecode is stack-base code. Stack-base code makes analysis and optimization hardly because use stack access imperative. Therefore, fragment of code that is problem that occur in stack-base code optimization, loss of type information, unnecessary Load and Store can appear. Optimization and analysis of bytecode design bytecode framework by solution way of problem that is difficult. This paper indicates optimization of bytecode and hangup of analysis, and describe research contents about existent byte code optimization technology. This propose byte code framework by the alternative to simplify analysis and optimization of byte code.

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Issues Related to the Modeling of Solid Oxide Fuel Cell Stacks

  • Yang Shi;Ramakrishna P.A.;Sohn Chang-Hyun
    • Journal of Mechanical Science and Technology
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    • v.20 no.3
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    • pp.391-398
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    • 2006
  • This work involves a method for modeling the flow distribution in the stack of a solid oxide fuel cell. Towards this end, a three dimensional modeling of the flow through a Solid Oxide Fuel Cell (SOFC) stack was carried out using the CFD analysis. This paper examines the efficacy of using cold flow analysis to describe the flow through a SOFC stack. It brings out the relative importance of temperature effect and the mass transfer effect on the SOFC manifold design. Another feature of this study is to utilize statistical tools to ascertain the extent of uniform flow through a stack. The results showed that the cold flow analysis of flow through SOFC might not lead to correct manifold designs. The results of the numerical calculations also indicated that the mass transfer across membrane was essential to correctly describe the cathode flow, while only temperature effects were sufficient to describe the anode flow in a SOFC.