• 제목, 요약, 키워드: Fuel efficiency

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

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

  • 권익환;강도원;김동섭;김재환
    • 한국유체기계학회 논문집
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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.

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

  • 김청균;이일권
    • 한국가스학회지
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    • v.13 no.5
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    • pp.1-6
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    • 2009
  • 본 논문에서는 LPG 차량의 연비효과에 미치는 대기온도, 증발기의 가스누출, 엔진오일의 점도, 엔진의 부하조건을 실험적으로 고찰하고자 한다. 연비에 대한 시험결과에 의하면, 엔진의 온도가 상승할수록 연비효과도 함께 점차 높아지고 있다. 대기온도가 $24.2^{\circ}C$일 때의 연비는 $1^{\circ}C$일 때보다 13.6% 정도 높게 나타난 것을 알 수 있다. LP가스 누출이 없는 증발기의 연비는 가스누출이 있는 경우에 비해 5.3%나 좋아지는 것으로 확인되었다. 반면에 엔진오일을 새로 교환한 경우의 연비는 9,500km를 주행한 오일에 비해 1.1% 정도 향상된 것으로 나타났으며, 이것은 대기온도나 증발기의 누설조건에 비해 상대적으로 낮은 영향을 미치는 것으로 관찰되었다. 연비에 더 많은 영향을 미치는 요소는 급제동, 급출발, 급가속과 같은 운전조건으로 판단된다. 연비시험 결과에 의하면, 정상출발은 급출발에 비해 32.3%나 연비가 향상되었고, 급가속은 급출발보다 10.8%나 우수한 연비조건을 보여주고 있다. 또한, 급제동은 급출발보다 18.3%나 우수한 연비상태를 나타내고 있다. 결국 비정상적인 주행조건은 정상적인 운전패턴에 비해 연비가 나쁜 것으로 나타났으므로, 연비를 높이기 위해서는 차량의 주행조건을 정상상태로 유지하는 것이 대단히 중요함을 알 수 있다.

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

  • 이준오;전제형;박정민
    • 한국항공운항학회지
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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.

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

  • 정은주;정인석
    • 한국추진공학회:학술대회논문집
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    • v.y2005m4
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    • pp.368-373
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    • 2005
  • 효과적인 초음속 연소를 수행하기 위해 연료와 공기의 빠른 혼합을 이룰 수 있는 연료 분사 기술이 요구된다. 본 수치적 연구의 목적은 초음속 유동장내에서 공동 주위 연료분사 위치에 따른 연료/공기 혼합 및 연소 현상을 살펴보고자 한다. 연료 분사 위치는 연소기내에서 영향을 미치는 공동의 길이-깊이비를 변화시킨다. 따라서 같은 형상의 공동이라 하더라도 공동 주위 유동 특성이 달라지므로 연소기 내부의 연료/공기 혼합과 연소 현상에 영향을 끼치게 된다.

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

  • 김재춘;이용택;정진택;김용찬;황인철
    • 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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고분자 전해질 연료전지를 이용한 무인비행체 동력시스템 설계 (Power System Development of Unmanned Aerial Vehicle using Proton Exchange Membrane Fuel Cell)

  • 지영광;손영준;박구곤;김창수;최유송;조성백
    • 한국수소및신에너지학회논문집
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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
    • 목재공학
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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.

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

  • 차정은;전희권;박정주;고윤택;황정태;장원철;김진영;김태원;김인기;정영식;갈한주;윤왕래;정운호
    • 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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소방 방재설비용 연료전지 발전시스템의 비절연형 고효율 전력변환기 설계 (High Efficiency Power Conversion System of Non Isolated Type Applied in Fuel Cell Generator Used to Fire Prevention Installation)

  • 곽동걸
    • 마이크로전자및패키징학회지
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    • v.13 no.3
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    • pp.19-26
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    • 2006
  • 본 논문은 예비 전력공급설비의 일환으로 비상시 소방 방재설비에 적용되는 연료전지 발전시스템에 대해 연구된다. 제안된 시스템은 비상시 상용 전력공급의 차단에 대비하여 소방 방재설비들의 전력공급원으로 이용된다. 연료전지 발전시스템에서 가장 손실이 큰 부분은 전력변환부이다. 또한 전력변환부의 손실은 전력변환을 위해 사용된 전력용 반도체 스위치의 스위칭 손실로 주어진다. 본 논문에서는 이러한 연료전지 발전시스템의 출력을 최대한 활용하기 위하여 부분공진의 기법이 적용된 고효율의 전력변환기가 제안된다. 또한 연료전지 발전시스템에 적용된 고효율 전력변환기는 비절연형으로 설계되고 사용된 제어스위치들은 새로운 소프트 스위칭 회로토폴로지에 의해 무손실로 동작되어 시스템의 효율을 증대시킨다. 다양한 컴퓨터 시뮬레이션과 특성실험을 통해 이론적 해석의 타당성이 입증된다.

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