• Title, Summary, Keyword: Fuel efficiency

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Dynamic Analysis of PEM fuel cell system (PEM 연료전지시스템의 동특성 해석)

  • Kim Beomsoo;Jeon Soonil;Lim Wonsik;Park Yeong-il
    • 한국신재생에너지학회:학술대회논문집
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    • pp.353-356
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    • 2005
  • We developed a dynamic model of PEM fuel cell system which can analyze its transient response to dynamic load current. System components such as compressor, air cooler, humidifier, and stack were modeled based on their dynamic equations and performance maps by using Matlab Simulink platform. Through this simulation model, dynamic characteristics of fuel cell system including oxygen excess rat io, stack voltage, and system efficiency were shown. In addition to that, we briefly analyzed the humidity effect on cathode pressure and system efficiency, expecting that this model can be further used to optimize fuel cell system parameters just like operating pressure and temperature, humidity and oxygen excess ratio.

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Performance Variation of a Combined Cycle Power Plant by Coolant Pre-cooling and Fuel Pre-heating (냉각공기 예냉각과 연료예열에 의한 복합발전 시스템의 성능변화)

  • Kwon, Ik-Hwan;Kang, Do-Won;Kim, Tong-Seop;Kim, Jae-Hwan
    • The KSFM Journal of Fluid Machinery
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    • v.15 no.3
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    • pp.57-63
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    • 2012
  • Effects of coolant pre-cooling and fuel pre-heating on the performance of a combined cycle using a F-class gas turbine were investigated. Coolant pre-cooling results in an increase of power output but a decrease in efficiency. Performance variation due to the fuel pre-heating depends on the location of the heat source for the pre-heating in the bottoming cycle (heat recovery steam generator). It was demonstrated that a careful selection of the heat source location would enhance efficiency with a minimal power penalty. The effect of combining the coolant pre-cooling and fuel pre-heating was also investigated. It was found that a favorable combination would yield power augmentation, while efficiency remains close to the reference value.

Experimental Study on Fuel Consumptions of LPG Vehicle Depending on the Atmospheric Temperature, Vaporizer Gas Leakage, Engine Oil and Engine Loads (대기온도, 증발기 누출, 엔진오일 및 엔진부하에 따른 LPG 차량의 연비실험에 관한 연구)

  • Kim, Chung-Kyun;Lee, Il-Kwon
    • Journal of the Korean Institute of Gas
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    • v.13 no.5
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    • pp.1-6
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    • 2009
  • This paper presents the fuel consumption effects of LPG vehicle depending on the atmospheric temperature, LP gas leakage of vaporizer, viscosity of engine oil and engine load conditions. The fuel consumption test results show that when the temperature of engine temperature rises, the fuel consumption efficiency increases in general. The fuel consumption efficiency for an atmosphere temperature of $24.2^{\circ}C$ is 13.6% high compared to that of $1^{\circ}C$. No leak vaporizer on fuel consumption efficiency is 5.3% high compared to that of the LP gas leak vaporizer. The fuel economy of new engine oils is just 1.1% high compared to that of used oils with a LPG vehicle mileage of 9,500km. This is not an influential factor compared with an atmospheric temperature and a LP gas leakage. The more important factors on the fuel consumption efficiency are driving conditions such as a rapid braking, abrupt start and fast acceleration. The test results indicate that the normal start is 32.3% high compared to that of an abrupt start and the fast acceleration is 10.8% high compared with that of an abrupt start. And the fuel consumption efficiency for a rapid braking is 18.3% higher than that of an abrupt start. These indicate that the driving condition is very important to reduce the fuel consumption rate.

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A Study on Fuel Saving Measure by Fuel Efficiency Analysis Associated with Weight. (중량에 따른 연료효율 분석을 통한 연료 절감 방안 연구)

  • Lee, Jun-Oh;Jeon, Je-hyung;Park, Jeongmin
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.26 no.4
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    • pp.142-148
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    • 2018
  • In recent years, Korea's aviation industry has been developing rapidly due to the emergence of low-cost airlines. In order to survive in such competition, airlines are making various efforts to save the operation cost as much as possible. Fuel costs account for more than 25% of operating costs. For airlines, reducing aircraft fuel costs is an important part of improving profitability. In this study, analyzing the difference weight between flightplan and W&B Manifest for calculated the fuel that was unnecessarily loaded. As a method to calculate the unnecessary fuel was used by Airbus company flight planning program.

Numerical Analysis of Supersonic Combustion Flows according to Fuel Injection Positions near the Cavity (공동주위 분사위치에 따른 초음속 연소 유동해석)

  • Jeong Eunju;Jeung In-Seuck
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • v.y2005m4
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    • pp.368-373
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    • 2005
  • To achieve efficient combustion within a manageable length, a successful fuel injection scheme must provide rapid mixing between the fuel and airstreams. The aim of the present numerical research is to investigate the mixing enhancement combustion phenomena according to fuel injector location near the cavity in supersonic flow. Fuel injector location changes the actual length to depth ratio of the cavity in the supersonic combustor. Therefore fuel injector location near the cavity effects different fuel/air mixing efficiency and combustion efficiency.

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Flow analysis of the Hydrogen Recirculation System for Fuel Cells (연료전지 수소 재순환 시스템의 유동해석)

  • Kim, Jae-Choon;Lee, Yong-Taek;Chung, Jin-Taek;Kim, Yong-Chan;Hwang, In-Chul
    • 유체기계공업학회:학술대회논문집
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    • pp.759-764
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    • 2005
  • In this paper, numerical analysis of hydrogen recycle system has been conducted in order to enhance the efficiency of automotive fuel cell. Generally, the excess hydrogen is provided in the automotive fuel cell. Since the non-reaction hydrogen reduces automotive fuel cell efficiency, reuse of the non-reaction hydrogen can be helpful to improve the fuel cell performance. In case of PEM FC, the water vapor is provided to hydrogen from the cathode so that the mixture experiences phase change depending on the changes of pressure and temperature. The internal flow of the mixture in the hydrogen recirculation system of fuel cell was investigated for real flow conditions. The variation of performance, properties and mass fractions of mixture, hydrogen and water-vapor were investigated. This study was performed based on 80KW level automotive fuel cell's recycling system.

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Power System Development of Unmanned Aerial Vehicle using Proton Exchange Membrane Fuel Cell (고분자 전해질 연료전지를 이용한 무인비행체 동력시스템 설계)

  • Jee, Yeong-Kwang;Sohn, Young-Jun;Park, Gu-Gon;Kim, Chang-Soo;Choi, Yu-Song;Cho, Sung-Baek
    • Transactions of the Korean hydrogen and new energy society
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    • v.23 no.3
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    • pp.250-255
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    • 2012
  • In this paper, the development and performance analysis of a fuel cell-powered unmanned aerial vehicle is described. A fuel cell system featuring 1 kW proton exchange membrane fuel cell combined with a highly pressurized fuel supply system is proposed. For the higher fuel consumption efficiency and simplification of overall system, dead-end type operation is chosen and each individual system such as purge system, fuel supply system, cooling system is developed. Considering that fluctuation of exterior load makes it hard to stabilize fuel cell performance, the power management system is designed using a fuel cell and lithium-ion battery hybrid system. After integration of individual system, the performance of unmanned aerial vehicle is analyzed using data from flight and laboratory test. In the result, overall system was properly operated but for more duration of flight, research on weight lighting and improvement of fuel efficiency is needed to be progressed.

Experimental Study on the Direct Contact Thermal Screw Drying of Sawdust for Wood-Pellet Fuel

  • Lee, Hyoung-Woo
    • Journal of the Korean Wood Science and Technology
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    • v.35 no.2
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    • pp.23-28
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    • 2007
  • Wood fuel must be dried before combustion to minimize the energy loss. Sawdust of Japanese red pine was dried in a direct contact thermal screw dryer to investigate the drying characteristics of sawdust as a raw material for bio-fuel. Average drying rate and energy efficiency was 1.4%/min and 69.23% at $100^{\circ}C$, respectively, and those at $120^{\circ}C$ was 2.1%/min and 71.03%, respectively.

The development of fuel processor for compact fuel cell cogeneration system (소형 열병합 연료전지 연계형 연료처리시스템 개발)

  • Cha, Jung-Eun;Jun, Hee-Kwon;Park, Jung-Joo;Ko, Youn-Taek;Hwang, Jung-Tae;Chang, Won-Chol;Kim, Jin-Young;Kim, Tae-Won;Kim, In-Ki;Jeong, Young-Sik;Kal, Han-Joo;Yung, Wang-Rai;Jung, Woon-Ho
    • 한국신재생에너지학회:학술대회논문집
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    • pp.323-327
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    • 2009
  • To extract hydrogen for stack, fuels such as LPG and LNG were reformed in the fuel processor, which is comprised of desulfurizer, reformer, shift converter, CO remover and steam generator. All elements of fuel processor are integrated in a single package. Highly active catalysts (desulfurizing adsorbent, reforming catalyst, CO shift catalyst, CO removal catalyst) and the various burners were developed and evaluated in this study. The performance of the developed catalysts and the commercial ones was similar. 1 kW, 5 kW class fuel processor systems using the developed catalyst and burner showed efficiency of 75 %(LHV, for LNG). The start-up time of the 1 kW class fuel processor was less than 50 minutes and its volume including insulation was about 30 l. The start-up time of 3 kW and 5 kW class fuel processors with the volume of 90 l and 150 l, respectively, was about 60 minutes. In the case of LPG fuel, efficiency, volume and start-up time of 1kW class fuel processor showed 73 %(LHV), < 60 l and < 60 min, respectively. Advanced fuel processor showed more highly efficiency and shorter start-up time due to the improvement of heat exchanger and operating method. 1 kW and 3 kW class fuel processors have been evaluated for reliability and durability including with on/off test of developed catalysts and burner.

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High Efficiency Power Conversion System of Non Isolated Type Applied in Fuel Cell Generator Used to Fire Prevention Installation (소방 방재설비용 연료전지 발전시스템의 비절연형 고효율 전력변환기 설계)

  • Kwak, Dong-Kurl
    • Journal of the Microelectronics and Packaging Society
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    • v.13 no.3
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    • pp.19-26
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    • 2006
  • In this paper, author proposes to a fuel cell generation system used to fire prevention installation at emergency. The proposed system is used with a power source of fire prevention installation in preparation for breaking of commercial power supply at emergency. A part of most power loss of the fuel cell generation system is power converter. And the major losses of power converter are switching losses of power semiconductor switches used to power conversion. This parer is designed with a high efficiency power converter of non isolated type in order to increase efficiency of fuel cell power system. The controlling switches used in power conversion system are operated with soft switching, which is applied to partial resonant method to reduce switching loss. The result is that the fuel cell power system gets to high efficiency. Some computer simulated results and experimental results are confirmed to the validity of the analytical results.

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