Effect of stack configuration on the performance of 10W PEMFC stack

임성대(Yim, Sung-Dae),김병주(Kim, Byung-Ju),손영준(Sohn, Young-Jun),윤영기(Yoon, Young-Gi),양태현(Yang, Tae-Hyun),김창수(Kim, Chang-Soo),김영채(Kim, Young-Chai) 한국신재생에너지학회 2009 한국신재생에너지학회 학술대회논문집 Vol.2009 No.06

A small PEM fuel cell has two different stack configurations such as active and passive stacks. The active stack has a distintion of high power density although it makes system complex by using alr blower and related BOPs resulting in large system volume. On the contrary, passive stack has an advantage of compact system because it doesn't need air supplying devices although it reveals relatively low stack power density. In this study we fabricated two 10W PEMFC stacks with different stack configurations, active and passive stacks, and tested their performance and stability. The active stack consists of 13cells with an active area of 5cm². The passive stack has 12cells with an active area of 16cm². When we compared the stack performance of those stacks, the active stack showed higher power density compared to the passive stack, particularly at high voltage regions. However, at low voltage and high current regions, the passive stack performance was comparable to the active stack. The stack stability was largely dependent on the fuel humidity, particularly for active stack. At low humidity conditions, the active stack performance was decreased continuously and the cell voltage distribution was not uniform showing seriously low cell voltage at center cells mainly due to the cell drying. The passive stack showed relatively stable behavior at low humidity and the stack performance was largely dependent on the atmospheric conditions.

Comparison of a Thermoacoustic Refrigerator Stack Performance: Mylar Spiral, Celcor Substrates and 3D Printed Stacks

N. A. Zolpakar,N. Mohd-Ghazali 대한설비공학회 2019 International Journal of Air-Conditioning and Refr Vol.27 No.3

Although the thermoacoustic refrigeration (TAR) system has been recognized as a potential alternative environmentally cooling system, the low coefficient of performance (COP) has yet to make it marketable. One major factor contributing towards the low COP is the fabrication method applied to the stack component which is the most important component in the TAR. In this paper, comparison of the performance of a (i) 3D printed stack, (ii) a hand fabricated Mylar stack and (iii) an off-the-shelf Celcor substrates stack has been done; these being based on optimized design parameters using Multi-Objective Genetic Algorithm (MOGA). The performance is determined from the temperature attained at the cold end of the stack and the temperature difference across the stack. Experimental results showed that the 3D printed stack has the best performance by achieving a temperature, T c =18.9 ∘ Tc=18.9∘ C at the cold end and a temperature difference of ΔT=18.1 ∘ ΔT=18.1∘ C across the stack, about 60% of the designed temperature difference even though the fabricated 3D printed stack deviated from the optimal design due to fabrication constraint as compared to that of the Mylar stack which was closer to the optimal design. This 3D printing of the stack promises a big potential in the improvement of the TAR performance because of the consistency achievable with the precise dimensions of the stack.

소형 고분자 연료전지 스택의 체결압력에 따른 성능 특성

김병주,임성대,손영준,김창수,양태현,김영채 한국수소및신에너지학회 2009 한국수소 및 신에너지학회논문집 Vol.20 No.6

The effect of gas diffusion layer (GDL) compression caused by different stack clamping pressures on fuel cell performance was experimentally studied in a miniature 5-cell proton exchange membrane fuel cell (PEMFC) stack. Three stacks with different GDL compressions, 15%, 35% and 50%, were prepared using SGL 10BC carbon fiber felt GDL and Gore 57 series MEA. The PEMFC stack performance and the stack stability were enhanced with increasing stack clamping pressure resulting in the best performance and stability for the stack with higher GDL compressions up to 50%. The excellent performance of the stack with high GDL compression was mainly due to the reduced contact resistance between GDL and bipolar plate in the stack, while reduced gas permeability of the excessively compressed GDL in the stack hardly affected the stack performance. The high stack clamping pressure also resulted in excessive GDL compression under the rib areas of bipolar plate and large GDL intrusion into the channels of the plate, which reduced the by-pass flow in the channels and increase gas pressure drop in the stack. It seems that these phenomena in the highly compressed stack enhance the water management in the stack and lead to the high stack stability.

돌노적 설화의 연구

최래옥(Choi Rai-ok) 비교민속학회 2005 비교민속학 Vol.0 No.30

The purpose of this research may be summarized as follows: Through collective research and analysis of Korea wide folktale named “stone Stack tale type(돌노적 설화, 石露積說話)” with ten tales as materials, I studied what is traditional meaning of the poor, the rich, stone stack: and a gold nugget, or a lump of gold on the top of the stone stack. A The story is that 1. beginning part (1-1) Once upon a time there lived a very poor man and his family, and a very rich man next door to poor man. (1-2) This rich neighbor had a big grain stack: that stirred the poor man want to be rich man alike the rich neighbor, pitifully even so the poor man had only a hope to become rich man, but had not ideas to realize a rich man because of what he could not confirm his determination. 2. advanced part (2-1) One day his youngest son proposed a plan to build a stone stack: in his house garden gathering much stones from here and there, from near village, field far mount. The boy said, “ this stone stack we can become rich man as rich neighbor, and get many things by imitation that was modelled on grin stack of rich neighbor.” (2-2) Receiving his idea, parents and family gathered stones hardly, built stone stack earnestly alike the grain stack of rich neighbor. Anyone could not stopped from their resolve to build. (2-3) As time went by the stone stature was completed well, at last the family satisfied through their works during several years beside their stone stature. (2-4) Many neighbors was deeply stirred. 3. last part (3-1) At just time in night rich neighbor found a glittered lump of gold on stone stack of poor man, and in order to get that gold secretly in his greedy he proposed poor man to exchange his grain stack into poor man's stone stack. So the poor man did not know gold, he okayed. (3-2) At the exchange time rich man take a rice bag out of the top of grain stack owing to traditional folk belief that the very first rice bag is a fortune thing in his house, so poor man's new child patriarch take a stone out of stone stack alike rich man deed. (3-3)The exchange event of two stacks, grain stack and stone stack became the exchange event of two men, rich man and poor man. Then what happened? Now the poor man is rich man unhappily, now the rich man is poor man happily. B. Analysis of structure and plot following as- 1. Father, patriarch means that (1) only dream to be rich man by envy mind to rich neighbor. poor situation (2) have no determination. 2. Youngest son, new patriarch means that (1) new idea man for reaching a rich man (2) strong leadership to finnish building a stone stack (3) peace maker in home (4) at last making his family in rich situation. (5) doing neighbors good. 3. Rich neighbor means that (l) from his parents, he is rich (2) unsatisfied himself even so rich (3) greedy (4) decision without deep thoughts 4. Many neighbors means that (1) in first they show the opposition (2) in last agreement (3) common people as beside 5. Stone stack means that (1) the realizing poor man long cherished dream (2) the practise of good creative idea and plan (2) the gathering valueless things as mount change valuable things (3) the result of endurance from hard works (4) making good the field for planting and the road to walking 6. Lump of gold on stone stack means that (1) miracle (2) succeeding (3) God’help (6) all last finishing are good. C In conclusion, this stone stack tale type give us two lessons, how to become rich man and how to fall into poor situation as teacher.

The Violin-Sonata Paradox and the Stack Mechanism

Lee, Chang-Su 한국중앙영어영문학회 2014 영어영문학연구 Vol.56 No.3

Fong and Ginsburg (2013, 2014) propose a new theoretical framework for Agree relations, namely the stack mechanism. Its core idea is the stack. It is a kind of buffer which stores Syntactic Objects with an unvalued feature temporarily. The stack mechanism is argued to be more economical than the probe-goal search of Chomsky (2001) because, with the stack, there is no need for a probe to check all of the labels within its search domain. Fong and Ginsburg (2013) try to make their stack mechanism empirically motivated by demonstrating that it can successfully account for the notorious violin-sonata paradox. Their analysis, however, has two drawbacks: the indetermination of stack order in the case of doubling constituents and the wrong assumption that there is no A'-movement in tough constructions. To solve these problems, this paper suggests the A-over-A Constraint on Stack Order, and shows that Hicks’ (2009) doubling structure is more appropriate for doubling constituents. With these minor modifications, the stack mechanism is still a viable solution for the notorious violin-sonata paradox.

발전소 Stack 발생소음 평가 및 방음대책에 대한 연구

오진우(Jin Woo Oh),이장현(Jang Hyun Lee),이정호(Jung Ho Lee),이수혁(Soo hyuk Lee) 한국소음진동공학회 2015 한국소음진동공학회 학술대회논문집 Vol.2015 No.4

Recently Power Plant like CHP(Combined heat and power plant) and CCPP(Conbined Cycle Power Plant) is increasing. Stack, Blower, Compressor, Pump and so on are noise sources of Power Plant and stack noise affect a wide region because of height. In this study, practical stack noise is measured and main factors of stack noise are analyzed based on measurement. Stack noise has characteristics of high noise level and peak of a low band Frequency. For the reduction of stack noise, I.D fan noise connected stack and structure-borned noise by air-flow at the stack-end shall be reduced by stack silencer. In conclusion stack silencer is adapted at the power plant stack and insertion loss is measured.

센서 운영 체제를 위한 공유 스택 기법의 성능 분석 (pp.53-59)

구본철(Boncheol Gu),허준영(Junyoung Heo),홍지만(Jiman Hong),조유근(Yookun Cho) 한국정보과학회 2008 정보과학회논문지 : 시스템 및 이론 Vol.35 No.1·2

무선 센서 네트워크의 발달에 따라 그 응용분야는 점점 더 복잡해져 가고 있음에도 불구하고, 대부분의 센서 노드 플랫폼은 여전히 심각한 자원 제약을 가지고 있다. 특히 적은 메모리 공간과 메모리 관리 유닛(MMU)의 부재는 스레드의 스택 관리에 있어 메모리 공간 낭비, 스택 오버플로우와 같은 문제를 야기해왔다. 이에 다 수의 스레드가 하나의 스택을 공유 함으로써 기존의 고정 크기 스택에 의해 낭비되는 메모리의 양을 최소화 시킬 수 있는 공유 스택 기법이 제안되었다. 본 논문에서는, 고정 크기 스택기법과 공유 스택 기법의 수학적 분석 모델을 제시하였다. 그 모델을 바탕으로 각각의 스택 오버플로우 확률을 계산하고 공유 스택 기법이 고정 크기 스택보다 더 안정적임을 확인하였다. In spite of increasing complexity of wireless sensor network applications, most of the sensor node platforms still have severe resource constraints. Especially a small amount of memory and absence of a memory management unit (MMU) cause many problems in managing application thread stacks. Hence, a shared-stack was proposed, which allows several threads to share one single stack for minimizing the amount of memory wasted by fixed-size stacks. In this paper, we present the memory usage models for thread stacks by deriving the overflow probability of the fixed-size stack and the shared-stack and also show that the shared-stack is more reliable than the fixed-size stack.

센서 운영 체제를 위한 공유 스택 기법의성능 분석

구본철,허준영,홍지만,조유근 한국정보과학회 2008 정보과학회논문지 : 시스템 및 이론 Vol.35 No.1

In spite of increasing complexity of wireless sensor network applications, most of the sensor node platforms still have severe resource constraints. Especially a small amount of memory and absence of a memory management unit (MMU) cause many problems in managing application thread stacks. Hence, a shared-stack was proposed, which allows several threads to share one single stack for minimizing the amount of memory wasted by fixed-size stacks. In this paper, we present the memory usage models for thread stacks by deriving the overflow probability of the fixed-size stack and the shared-stack and also show that the shared-stack is more reliable than the fixed-size stack. 무선 센서 네트워크의 발달에 따라 그 응용분야는 점점 더 복잡해져 가고 있음에도 불구하고, 대부분의 센서 노드 플랫폼은 여전히 심각한 자원 제약을 가지고 있다. 특히 적은 메모리 공간과 메모리 관리 유닛(MMU)의 부재는 스레드의 스택 관리에 있어 메모리 공간 낭비, 스택 오버플로우와 같은 문제를 야기해왔다. 이에 다 수의 스레드가 하나의 스택을 공유 함으로써 기존의 고정 크기 스택에 의해 낭비되는 메모리의 양을 최소화 시킬 수 있는 공유 스택 기법이 제안되었다. 본 논문에서는, 고정 크기 스택 기법과 공유 스택 기법의 수학적 분석 모델을 제시하였다. 그 모델을 바탕으로 각각의 스택 오버플로우 확률을 계산하고 공유 스택 기법이 고정 크기 스택보다 더 안정적임을 확인하였다.

Technology of Fuel cell stack fault detection by THDA

김억수(Kim, UckSoo),박현석(Park, HyunSeok),강선두(Kang, SunDoo),엄정용(Eom, JeongYong) 한국신재생에너지학회 2011 한국신재생에너지학회 학술대회논문집 Vol.2011 No.11

This technology is applicable to Electrical vehicle that using Energy from Hydrogen Fueled Cell. Electricity & water is got from chemical reaction between H2 & O2 in stack. This technology is used when fault diagnosis of Fuel cell is needed. It is General method that measure each cell's voltage of stack for fault diagnosis. but, this technology is method of measuring entire voltage of stack. For this reason, fault diagnosis system is simplified and cost of system is lower than previous one. In normal stack condition, characteristic graph of voltage-current has linearity. In fault stack condition, it has non-linearity. we use this characteristic to diagnosis of stack fault. In this technology, Specific frequency current is injected into stack & Stack voltage is measured in response. After that, stack voltage difference is analyzed to diagnosis of stack fault. Presently, Development of current injection module & basic program of THDA is finished. in future we will develop the technology of precise measurement technology about entire stack voltage.

Reliable sealing design of metal-based solid oxide fuel cell stacks for transportation applications

Lee, Sanghun,Jang, Young-hoon,Shin, Ho Yong,Lee, Kunho,Bae, Minseok,Kang, Juhyun,Bae, Joongmyeon Pergamon Press 2019 International journal of hydrogen energy Vol.44 No.57

<P><B>Abstract</B></P> <P>Recently, metal-based solid oxide fuel cells (SOFCs) receive much attention as new power converting systems, and reliable sealing is an essential requirement for the metal-based SOFC stacks. In this study, metal-based SOFC stacks with a reliable sealing method are developed for transportation applications. For successful development, bolt-spring and hydraulic compression methods for stack tightening are discussed in terms of their applicability to vehicles. Then, detailed stack designs are developed to obtain sufficient compressive stress on the surfaces of the sealing gaskets based on the finite element method (FEM). To maintain the compression and heat insulation of the stack, a hot box is designed based on the thermogravimetric properties, shrinkage behaviors, and mechanical properties of sealing gaskets of mica and Thermiculite 866LS, and ceramic fiber insulating board. As a result, a 1-cell stack unit is successfully fabricated and tested based on the designs, and a sealing rate of 100 ± 0.78% is achieved at an operating temperature of 800 °C. This study investigates comprehensive stack and sealing design processes, and it has broad implications for reliable stack development.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A metal-based solid oxide fuel cell stack was designed for reliable sealing. </LI> <LI> Bolt-spring and hydraulic compression methods were discussed for vehicles. </LI> <LI> Finite element analysis was conducted for sufficient stress on sealing gaskets. </LI> <LI> A hot box was designed to maintain compression and heat insulation of the stack. </LI> <LI> A sealing rate of 100% of 1-cell stack unit was achieved at a temperature of 800 °C. </LI> </UL> </P>