가정용 연료전지 시스템의 계통연계 시 수용가 및 배전계통에서의 고조파 영향 평가

박찬엄(Chan-Eom Park),정진수(Jin-Soo Jung),한운기(Woon-Ki Han) 대한전기학회 2011 전기학회논문지 Vol.60 No.6

Recently, due to the use of fossil fuels for electric power production, carbon emissions increased excessively. Thereby, in order to replace fossil fuels, many studies about fossil fuels such as solar and fuel cell energy source are progressing. Fuel cell system has high energy conversion efficiency. Also, fuel cell system is environmentally friendly system because the carbon emission is almost not occur. Therefore, the fuel cell system is considered as the core technology of in the fields of the future energy and environmental. Fuel cell system has an effect on distribution power system because another power source of other than large power plants. So, fuel cell system can be degradation reason of power quality in the power system. In this paper, we constructed the system for an assessment on harmonics effect. The system is composed with power source, harmonics generation and linear load, fuel cell system. we also performed assessment on harmonics effect in customer and the distributed power system during grid connection of residential fuel cell system. An assessment cases are divided into three. A Case 1 is state that residential load and fuel system are connected to grid, Case 2 is state that residential load and harmonics load are connected to grid, and Case 3 is state that all loads are connected to grid. As a output of fuel cell system is increase, analysis results based on assessment system showed that power quality became more aggravation as effect of harmonics.

정전용량형 연료센서를 이용한 항공기 연료량측정시스템 구현

양준모,양성욱,이상철,이용식 항공우주시스템공학회 2018 항공우주시스템공학회지 Vol.12 No.6

The amount of fuel, which afects aircraft endurance, neds to be measured acurately. This paper deals with the implementation of a fuel quantiy measurement system that consists of capacitve fuel sensor, DAQ board, and Labview software. The main circuit of the implemented system for measuring fuel quantiy is simulated with Pspice to identify parameters, which are related to the change of fuel quantiy. After simulation, we established that Vrms changes with the variation of fuel amount. The Vrms, which is the output of fuel sensor, is transmited to the Labview software via the DAQ board of the implemented fuel quantiy measurement system. The fuel quantiy is also calculated using this software. The present simulation results indicated that the acuracy of the implemented fuel quantiy measurement system improved with the filter aplication. 항공기 항속시간에 영향을 미치는 요소인 연료량은 정확한 측정이 필요하다. 본 논문에서는 정전용량형 연료센서, DAQ 보드, Labview 소프트웨어로 구현된 연료량측정시스템을 다루었다. 연료량에 따라 변화하는 파라미터를 확인하기 위해 Pspice를 이용하여 구현된 시스템의 주회로가 시뮬레이션 되었다. 시뮬레이션을 통해 연료량에 따라 변화하는 파라미터인 Vrms를 찾아내었다. 연료 센서의 출력인 Vrms는 구현된 연료량측정시스템의 DAQ 보드를 통해 Labview 소프트웨어로 전송되고, 이 소프트웨어를 사용하여 연료량이 계산된다. 그 결과, 필터가 적용되지 않은 연료량측정시스템보다 정확도가 향상되었다.

가정용 연료전지 시스템의 단독운전 시 부하설비의 전압 및 전력품질 평가

박찬엄(Chan-Eom Park),정진수(Jin-Soo Jung),한운기(Woon-Ki Han),송영상(Young-Sang Song),임현성(Hyun-Sung Lim),김춘삼(Choon-Sam Kim),임덕규(Duk-Gyu Lim) 대한전기학회 2013 전기학회논문지 Vol.62 No.12

Recently, due to the excessive use of fossil fuels, many studies about the fossil fuels such as solar and fuel cell energy source are progressing. Fuel cell system has high energy conversion efficiency. Also, fuel cell system is environmentally friendly system because the carbon emission is almost not occur. Therefore, the fuel cell system is considered as the core technology of in the fields of the future energy and environmental. Fuel cell system has an effect on distribution power system because another power source of other than large power plants. So, fuel cell system can be reason of power quality in the power system. In this paper, we constructed the system for an assessment on Islanding. The system is composed with power source, Impedance coordination load and linear load, fuel cell system. we are performed assessment on voltage and power quality in customer and the distributed power system during the Islanding of residential fuel cell system. In addition, no change in the impedance of power system, we made a islanding condition only using the actual load, As a variation of generation and load current under islanding, an analysis results based on assessment system showed that the power qualities of distribution system became more aggravation as effect of voltage sag and voltage swell phenomena.

산소분리기술을 사용한 연료전지/순산소연소 발전시스템 해석

박성구(Park, Sung-Ku),김동섭(Kim, Tong-Seop),손정락(Sohn, Jeong-Lak),이영덕(Lee, Young-Duk) 한국신재생에너지학회 2008 한국신재생에너지학회 학술대회논문집 Vol.2008 No.10

This study aims to devise and analyze a power generation system combining the solid oxide fuel cell and oxy-fuel combustion technology. The fuel cell operates at an elevated pressure, a constituting a SOFC/gas turbine hybrid system. Oxygen is extracted from the high pressure cathode exit gas using ion transport membrane technology and supplied to the oxy-fuel power system. The entire system generates much more power than the fuel cell only system due to increased fuel cell voltage and power addition from oxy-fuel system. More than one third of the power comes out of the oxy-fuel system. The system efficiency is also higher than that of the fuel cell only system. Recovering most of the generated carbon dioxide is major advantage of the system.

암모니아에 의한 차량 연료 시스템 부품 부식성 검토

장진영(Jinyoung Jang),우영민(Youngmin Woo),이영재(Youngjae Lee),김종남(Jongnam Kim) 한국자동차공학회 2012 한국자동차공학회 학술대회 및 전시회 Vol.2012 No.11

In this research, Ammonia was assessed using ammonia as a fuel for combustion engine. Since ammonia has similar physical property with LPG(liquid petroleum gas), LPG fuel system was plan to use an ammonia fuel system. However, Ammonia-LPG fuel system reactivity resulted in system failure should be checked. For ammonia-LPG fuel system reactivity test, reactor was made and parts of LPG fuel system was assessed. Through the reactor test, O-rings used in parts of fuel injector and tank were corroded. And fuel pump and floater indicating fuel lever were affected. For using LPG fuel system as ammonia fuel system, O-rings should be changed Kaliz O-ring and fuel pump and floater also should be replaced.

미래병사체계를 위한 휴대형 연료전지 기술개발 동향 및 발전방안

이유화 한국산학기술학회 2020 한국산학기술학회논문지 Vol.21 No.6

A portable power supply system for soldiers must be able to supply electric energy corresponding to the power consumption of combat support troops, and have a carrying load in a range that does not impair the combatant's ability to execute operations. In particular, as the total required power of combat equipment increases with the advances in the future soldier system, a portable, lightweight power supply system with high efficiency is essential. A fuel cell has a high energy-to-weight density compared to lithium batteries, which are used mainly as a military power source system. Therefore, it is capable of miniaturization and lightweight, making active R&D to a portable power supply system. In this paper, the characteristics of the fuel cell applied as a portable power supply system, and the R&D trends of domestic and foreign military portable fuel cell systems were investigated. The current status of domestic technology compared to the level of foreign development was analyzed. In addition, future technology development plans are presented based on the consideration factors when developing a portable fuel cell (power supply stability, portability, and cost reduction) so that it can be used when establishing a plan on the development of a portable fuel cell system for the future soldier system. 병사용 휴대형 전원은 전투원의 작전 수행 능력을 해치지 않는 범위의 휴대 하중을 지님과 동시에 전투장비의 소비전력에 대응하는 전기에너지를 공급할 수 있어야 한다. 특히 미래병사체계의 경우 전투장비의 고성능화에 따라 장비의 총 요구전력이 증가하고 있으므로 경량 고효율 특성을 가지는 휴대형 전원 개발이 필수적이다. 연료전지는 군용 전원으로 주로 적용되던 종래의 리튬 전지에 비해 중량 대비 에너지밀도가 높아 경량 소형화가 가능하여 휴대형 전원 시스템으로 활발한 연구개발이 진행되고 있다. 본 논문에서는 휴대형 전원으로 적용되는 연료전지의 특성을 살펴보고, 국내·외 군용 휴대형 연료전지 개발 현황을 조사한 후, 국외 선진 기술국의 개발 수준 대비 국내 기술 현황에 대해 분석한다. 또한, 미래병사체계용 전원으로의 적용을 위한 휴대형 연료전지 개발 시 고려해야할 주요 요소를 전력 공급 안정성, 휴대 용이성, 비용 절감 세 가지로 분류하고, 이와 관련된 기술을 중심으로 발전방안을 제시하여 향후 연료전지 기반 개인병사체계용 휴대형 전원 기술 발전방안 수립 시 활용할 수 있도록 한다.

Design and development of a fuel cell-powered small unmanned aircraft

Kim, Taegyu,Kwon, Sejin Elsevier 2012 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.37 No.1

<P><B>Abstract</B></P><P>The design, construction, and flight test of a fuel cell-powered small unmanned aircraft are described. A fuel cell system featuring a polymer electrolyte membrane fuel cell combined with a hydrogen generator, which serves as a new power source alternative to the existing batteries, is proposed. The hydrogen generator uses a catalytic hydrolysis reaction to extract hydrogen from an alkaline solution of sodium borohydride, and constructed with a reactor, pump, separator, and fuel cartridge. Considering the performance characteristics of the fuel cell, the hybrid power management of a fuel cell and a battery was contrived. The fuel cell stack, hydrogen generator, and power management system were evaluated at the various load conditions. A high efficiency unmanned aircraft was designed and fabricated to validate the possibility of the proposed fuel cell system, and a small flight control system was developed for a high endurance test flight. Wind-tunnel tests were conducted before the flight tests under actual flight conditions. The possibility for the utilization of a fuel cell in a small aircraft was validated through the fuel cell powered flight test. The fuel cell aircraft flew for 2 h without incidents in the fuel cell system.</P> <P><B>Graphical abstract</B></P><P><ce:figure id='dfig1'></ce:figure></P><P><B>Highlights</B></P><P>► Small aircraft using PEMFC combined with NaBH<SUB>4</SUB> hydrogen generator was developed. ► Hybrid power management of a fuel cell and a battery was evaluated. ► High efficiency aircraft was designed and wind-tunnel tests were conducted. ► The fuel cell aircraft flew for 2 hours without incidents in the fuel cell system.</P>

항공기 시스템 열관리 모델링 및 엔진 연료윤활계통 열 부하 특성 분석

김영진(Youngjin Kim),손창민(Changmin Son) 한국추진공학회 2015 한국추진공학회 학술대회논문집 Vol.2015 No.11

본 연구에서는 대형 상업용 항공기에 적용 가능한 시스템 레벨 열관리 아키텍쳐를 구성하고, Fuel Thermal Management System 중에서 연료시스템에 대한 모델링을 수행하였다. 상용프로그램인 AMESim을 이용하여 모델링을 수행하였으며, 높은 바이패스 비를 가지는 two-spool, 터보팬 엔진을 대상으로 임무 프로파일에 따른 엔진 연료와 윤활계통과의 열 부하 특성을 확인하였다. 연료시스템의 각 구성품별 시간 변화에 대한 연료의 온도변화 및 연료펌프에서 low Pressure pump와 high pressure pump 사이의 열전달 특성에 따른 low pressure pump 출구의 연료 온도변화 특성을 확인하였다. 연료의 열부하량은 엔진으로 유입되는 연료량에 크게 좌우되며, 연료량이 증가하는 Take Off 및 Climb 구간보다는 연료량이 급격히 감소하는 Descent, Flight Idle, Ground Idle 구간에서 증가하는 것으로 나타났다. 또한, low pressure pump와 high pressure pump 사이의 열전달이 반영되었을 경우 Cruise, Descent 구간에서 low pressure pump의 후단에서의 연료 온도는 각각 11.7%, 30.9% 증가하는 것으로 나타났다. In the present study, an architecture of system level thermal management of a commercial aircraft is built for modeling and simulation of fuel system, which is a key part of Fuel Thermal Management System. The study shows thermal interactions between fuel and engine lubrication oil through the mission profile for a high bypass ratio, two-spool turbofan. For the system modeling, a commercial tool, AMESim is used. Fuel temperature is monitored as it flow through each sub-components of fuel system during the mission. As the low and high pressure pumps are installed in the same housing, it is important to investigate the effect of thermal interaction between low pressure pump and high pressure pump. Heat load in fuel system strongly depends on fuel flow rate and is significantly increased for the periods of take off and climb with increase of fuel flow rate rather than for the periods of descent, flight idle and ground idle. Due to the thermal interaction in pump housing, fuel temperature at the outlet of low pressure pump was increased 11.7%, and 30.9% than the case without thermal interaction for cruise and descent, respectively.

Safety integrity level (SIL) determination for a maritime fuel cell system as electric propulsion in accordance with IEC 61511

Ahn, Junkeon,Noh, Yeelyong,Joung, Taehwan,Lim, Youngsub,Kim, Juneyoung,Seo, Youngkyun,Chang, Daejun Elsevier 2019 INTERNATIONAL JOURNAL OF HYDROGEN ENERGY - Vol.44 No.5

<P><B>Abstract</B></P> <P>This study investigates the safety integrity levels for an electric propulsion system based on a molten carbonate fuel cell in a liquefied hydrogen tanker. The electric propulsion system necessitates multiple electronic and electric elements; thus, the functional safety of the system should be considered. Additionally, a maritime fuel cell system is nonconventional propulsion machinery. This system should follow a risk-based ship design framework, and IEC 61511 is a suitable standard for evaluating the functional safety of the system. Hazardous operability studies provide basic information for determining the safety integrity. In this work, a safety layer matrix and calibrated risk graph are generated, and a layer of protection analysis is conducted for a molten carbonate fuel cell stack. Eight guidewords are used to describe accidental scenarios and compare the results of the three methods in an unbiased manner. The most severe consequences are fire and explosion caused by overflows or a control failure in the stack, and the safety integrity levels are mutually different.</P> <P><B>Highlights</B></P> <P> <UL> <LI> A maritime fuel cell system consumes the boil-off hydrogen gas in a LH<SUB>2</SUB> tanker. </LI> <LI> The functional safety of a fuel cell should be considered as SIL. </LI> <LI> HAZOP is the proper technique to address potential hazards in fuel cell stack. </LI> <LI> Even for identical risks, three SIL methods produce different results. </LI> <LI> IEC 61511 is useful for determining the SILs for a maritime fuel cell system. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

목재펠릿시스템의 대체투자 가능성 분석 - 시설과채 사례 -

김성섭(Seongsup Kim),김태후(Taehoo Kim),서상택(Sangtaek Seo) 한국농촌지도학회 2018 농촌지도와 개발 Vol.25 No.3

This study aim ed to analyze the replacem ent investm ent of the diesel fuel system w ith the pallet fuel system in the Korean farm ing sector. Equivalent annual annuity approach w as used to resolve a discrepancy of useful life in capital goods and to facilitate investm ent analyses in an independent perspective. D ata w as obtained from previous studies on econom ic analysis of greenhouse tom ato, paprika and cucum ber. Results show ed that the replacem ent w ith the pallet fuel system w as acceptable irrespective of the rem aining period of useful life for the diesel fuel system . In addition, sensitivity analysis w ith governm ent support level, repair cost, and light and heat energy cost show ed robustness in the possibility of replacem ent w ith the pallet fuel system w hile the speed of replacem ent w as accelerated w ith an increase in the am ount of diesel fuel used and price of diesel fuel, and a decrease in price of the pallet fuel. The result im plied that the replacem ent investm ent rather than a new investm ent w as appropriate for existing greenhouse farm ers and the pallet fuel system w as acceptable to replace existing diesel fuel system in producing greenhouse tom ato, paprika and cucum ber.