가정용 연료전지 시스템의 열관리 해석

유상석(Sangseok Yu),이영덕(Youngduk Lee),안국영(Kookyoung Ahn) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11

A PEMFC(proton exchange membrane fuel cell) is a good candidate for residential power generation to be cope with the shortage of fossil fuel and green house gas emission. The attractive benefit of the PEMFC is to produce electric power as well as hot water for home usage. Typically, thermal management of vehicular PEMFC is to reject the heat from the PEMFC to the ambient air. Different from that, the thermal management of PEMFC for RPG is to utilize the heat of PEMFC so that the PEMFC can be operated at its optimal efficiency. In this study, dynamic thermal management system is modeled to understand the response of the thermal management system during dynamic operation. The thermal management system of PEMFC for RPGFC is composed of two cooling circuits, one for controling the fuel cell temperature and the other for heating up the water for home usage. Dynamic responses and operating strategies of the PEMFC system are investigated during load changes.

가정용 연료전지 막 가습기 해석 모델 개발

유상석(Sangseok Yu),김한석(Hanseok Kim),이상민(Sangmin Lee),이영덕(Youngduk Lee),최원석(Wonseok Choi),안국영(Kookyoung Ahn) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5

The performance of proton exchange membrane fuel cell (PEMFC) is seriously changed by the humidification condition which is intrinsic characteristics of the PEMFC. Typically, the humidification of fuel cell is completed by internal or external humidifier. A membrane humidifier is applied to the external humidification of fuel cell used for residential power generation. In this study, a simple static model is constructed to understand the physical phenomena of the membrane humidifier over various parameters. The model is based on the concept of shell and tube heat exchanger but the model is also able to estimate the mass transport through the membrane. Model is constructed in Matlab/Simulink<SUP>®</SUP>□environment to keep consistency with any other components model which we developed. Parametric study of the membrane humidifier is carried out in terms of selected geometric factors and operating factors.

[가솔린엔진] 오일유막의 연료 흡수 및 방출에 관한 연구

유상석(Sang Seok Yu),민경덕(Kyoungdong Min) 한국자동차공학회 1999 한국자동차공학회 춘 추계 학술대회 논문집 Vol.- No.-

An oil layer fuel absorption/desorption modeling was developed. Multi- component fuel model has showed more reasonable condition than single component model. Henry's constant which is related to solubility is the most important variable in the oil layer absorption/desorption mechanism. The oil segments close to the top of the cylinder liner have more significant contribution to the fuel absorption and desorption process than other oil segments. At the warmed-up condition, the effect of the engine speed on the percent fuel absorbed/desorbed is minimal. But at low oil film temperature, percent of fuel absorbed/desorbed is decreased with increasing the engine speed because of low value of molecular diffusion coefficient of fuel. The amount of fuel trapped in the piston crevice is from 2 to 2.3 times larger than that of fuel in the oil film. However, fuel from oil film slowly desorbs into the combustion chamber compared with fuel from the piston crevices when the engine is cold

가정용 연료전지 시스템의 열관리 해석을 위한 시스템 운전 모델 개발

유상석(Sangseok Yu),이영덕(Youngduk Lee),안국영(Kookyoung Ahn) 대한기계학회 2010 大韓機械學會論文集B Vol.34 No.1

이온교환막 연료전지는 전세계적인 에너지 고갈 문제와 온실효과에 대한 대응책의 하나이다. 특히, 이온교환막 연료전지는 전기화학반응에 의해 전기를 생산함과 동시에 열을 발생하기 때문에 가정용으로 적용하기에 적당하다. 가정용 연료전지의 열관리 목적은 연료전지가 최적조건에서 운전할 수 있도록 적절히 온도를 제어해 주는 것으로, 본 연구에서는 부하 변화 시 가정용 연료전지 시스템의 응답 특성과 열관리 특성을 알아보기 위한 해석 모델을 개발하였다. 열관리 해석 모델은 연료전지의 온도를 조절하기 위한 펌프와 열교환기로 구성된 1차측, 주택에 온수를 공급하기 위한 탱크와 펌프 계통의 2차측으로 구성되었다. 부하를 순차적으로 증가시킬 때와 감소시킬 때를 구분하여 열관리 계통의 응답특성을 확인하였다. 결과적으로 탱크의 초기 승온에 많은 시간이 소요되기 때문에 부하를 다단으로 오랜 시간 동안 서서히 증가시키면서 시스템 응답 특성을 확인하였다. 또한, 본 연구에서는 가정용 연료전지의 부하 변화시의 열관리 특성을 고려한 운전 전략에 대해서도 조사하였다. A PEMFC(proton exchange membrane fuel cell) is a good candidate for residential power generation to be coped with the shortage of fossil fuel and green house gas emission. The attractive benefit of the PEMFC is to produce electric power as well as hot water for home usage. The thermal management of PEMFC for RPG is to utilize the heat of PEMFC so that the PEMFC can be operated at its optimal efficiency. In this study, thermal management system of PEMFC stack is modeled to understand the dynamic response during load change. The thermal management system of PEMFC for RPGFC is composed of two cooling circuits, one for controling the fuel cell temperature and the other for heating up the water for home usage. The different operating strategy is applied for each cooling circuit considering the duty of those two circuits. Even though the capacity of PEMFC system (1kW) is enough to supply hot domestic water for residence, heat-up of reservior takes some hours. Therefore, in this study, time schedule of the simulation reflects the heat-up process. Dynamic responses and operating strategies of the PEMFC system are investigated during load changes.

차량용 연료전지 냉각 계통의 제어 알고리즘 비교

유상석(Sang Seok Yu),한재영(Jae Young Han),김성수(Sung Soo Kim) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.5

단순모델을 이용한 막 가습기 열 및 물질 전달 특성 해석

유상석(Sangseok Yu),이영덕(Youngduk Lee),배호준(Hojune Bae),황준영(Joonyoung Hwang),안국영(Kookyoung Ahn) 대한기계학회 2009 大韓機械學會論文集B Vol.33 No.8

The performance of proton exchange membrane fuel cell (PEMFC) is seriously changed by the humidification condition which is intrinsic characteristics of the PEMFC. Typically, the humidification of fuel cell is carried out with internal or external humidifier. A membrane humidifier is applied to the external humidification of residential power generation fuel cell due to its convenience and high performance. In this study, a simple static model is constructed to understand the physical phenomena of the membrane humidifier in terms of geometric parameters and operating parameters. The model utilizes the concept of shell and tube heat exchanger but the model is also able to estimate the mass transport through the membrane. Model is constructed with FORTRAN under Matlab/Simulink<SUP>®</SUP>□ environment to keep consistency with other components model which we already developed. Results shows that the humidity of wet gas and membrane thickness are critical parameters to improve the performance of the humidifier

학교체육에 대한 고등학교 남학생의 인식 분석

유상석(Yu Sang Seog) 한국사회체육학회 2003 한국사회체육학회지 Vol.20 No.1

The purpose of this paper is to understand high school male students` perception toward physical education. Understanding on students` thought on physical education is a first step to develop and implement quality physical education. Questionnaire was consisted of 8 items and was administerd to 250 high school male students. In general students tends to showed positive value on physical education and positive attitude toward participation in physical activity. Students who like physical education expressed positive attitude for future participation of physical activity, whereas students who dislike physical education expressed negative attitude. However, many students thought that their physical education did not reflect student`s need properly. And large portion of students showed neutral attitude about the justification of physical education as core of curriculum. This may resulted in stereo-typed attitude toward physical education. This stereo-typed attitude should be resolved very soon, otherwise, the school physical education might be loose it`s status in school curriculum. The enhancement of teaching expertise of physical educator is the most effective approach to resolve the problem of prevailed stereo-typed attitude.

수소 연료전지 자동차의 열관리

유상석(Sangseok Yu) 한국자동차공학회 2016 오토저널 Vol.38 No.4

대면적 셀 고분자 막전해질 연료전지의 열관리를 위한 2 차원 수치 해석 모델

유상석(Sangseok Yu),이영덕(Youngduk Lee),안국영(Kookyoung Ahn) 대한기계학회 2008 大韓機械學會論文集B Vol.32 No.5

A two-dimensional thermal model of proton exchange membrane fuel cell with large active area is developed to investigate the performance of fuel cell with large active area over various thermal management conditions. The core sub-models of the twodimensional thermal model are one-dimensional agglomerate structure electrochemical reaction model, one-dimensional water transport model, and a two-dimensional heat transfer model. Prior to carrying out the simulation, this study is contributed to set up the operating temperature of the fuel cell with large active area which is a maximum temperature inside the fuel cell considering durability of membrane electrolyte. The simulation results show that the operating temperature of the fuel cell and temperature distribution inside the fuel cell can affect significantly the total net power at extreme conditions. Results also show that the parasitic losses of balance of plant component should be precisely controlled to produce the maximum system power with minimum parasitic loss of thermal management system.

교수전문성 제고를 통한 사회체육 지도자의 경쟁력 강화

유상석(Yu Sang Seog) 한국사회체육학회 2003 한국사회체육학회지 Vol.20 No.1

No one deny the importance of strengthening sport educator`s competitiveness through enhancement of teaching expertise. The direction of expertise, curriculum for expertise, and approaches for expertise varies depends on one`s value toward expertise of sport educator. However, this can not be a reason to explain why college curriculums could not reflect it`s own characteristics. Social needs for dept of sport and leisure studies is to provide effective sport educator who can reflects diversity of participants in sport program. Thus, it is necessary to enhance the teaching expertise of sport educator. First step is to develop curriculum based on analysis of social needs. Second step is to analyze body of knowledge for enhancement of teaching expertise. Third step is to provide enough opportunities to practice teaching in simulation or real setting. And last step is to implement in-service program for sport educator to keep developing expertise.