• Journal of Forest and Environmental Science
• /
• 제36권4호
• /
• pp.298-310
• /
• 2020

Fuel management can play enormous role in fire management in tropical dry forests. However, unlike the temperate forests, knowledge on implications of different fuel management methods in tropical forests is often inadequate. In this study, the implications of prescribed burning and hand thinning treatments on implementation cost, fuel loading and post-treatment fire behaviour were tested and compared in degraded forests and teak plantations in two forest reserves of different levels of dryness in Ghana. The study found that prescribed burning was less expensive (62.02 US Dollars ha-1) than hand thinning (95.37 US Dollars ha-1). The study also indicated that the two fuel management methods were able to reduce fuel loading in degraded forests and teak plantations. However, prescribed burning was more effective in reducing fuel loading than hand thinning. While the relative change of fuel reduction was 13% higher in prescribed burning than the hand thinning in degraded forest, it was 41% higher in prescribed burning than hand thinning in teak plantations. The fire behaviour of post-treatment experimental fire was also lower in prescribed burning than the hand thinning and control plots. Fuel management, therefore, has a great potential in fire management in degraded forests and teak plantations in Ghana.

• 한국분무공학회지
• /
• 제22권4호
• /
• pp.203-209
• /
• 2017

The International maritime organization(IMO), in an effort to slow down the global warming, proposes reduction in ship's speed as a way to lower the rate emissions from ships. In addition, since ship's fuel cost have been increased, the shipping volumes, fuel-saving technology are being required urgently. Therefore, in this present study, a method of reducing the fuel cost that can improve the performance of the diesel engine was tried by introducing a predetermined amount (0.1~0.3% of the mass amount of fuel used) of hydrogen fuel additive. The experimental conditions of the test engine were 1500rpm and torque BMEP-10b ar. The engine performances (power output, fuel consumption rate, p-max, exhaust temperature) were compared before and after addition of hydrogen fuel additives. This experimental study confirmed reducing at least 2% fuel consumption and 2.19% NOx emission.

• International Journal of Automotive Technology
• /
• 제8권6호
• /
• pp.781-790
• /
• 2007

Hybrid electric vehicles(HEV) combined with more than one power sources have great potential to improve fuel economy and reduce pollutant emissions. The Integrated Starter Generator(ISG) HEV researched in this paper is a two energy sources vehicle, with a conventional internal combustion engine(ICE) and an energy storage system(batteries). In order to investigate the potential of diesel engine hybrid electric vehicles in fuel economy improvement and emissions reduction, a Dynamic Programming(DP) based supervisory controller is developed to allocate the power requirement between ICE and batteries with the objective of minimizing a weighted cost function over given drive cycles. A fuel-economy-only case and a fuel & emissions case can be achieved by changing specific weighting factors. The simulation results of the fuel-economy-only case show that there is a 45.1% fuel saving potential for this ISG HEV compared to a conventional transit bus. The test results present a 39.6% improvement in fuel economy which validates the simulation results. Compared to the fuel-economy-only case, the fuel & emissions case further reduces the pollutant emissions at a cost of 3.2% and 4.5% of fuel consumption with respect to the simulation and test result respectively.

• 신재생에너지
• /
• 제4권3호
• /
• pp.5-14
• /
• 2008

The target for the reduction of $CO_2$ emissions, as specified in the Kyoto Protocol, can only be achieved by an extended use of renewable fuels and the increasing of the energy efficiency. The energy generation from waste gases with a reasonable content of methane like biogas can significantly contribute to reach this target. A further reduction of greenhouse gas emissions is possible by increasing the electrical efficiency using progressive technologies. Fuel cells can be highly energy conversion devices. Utilizing biogas as the fuel for fuel cell systems offers an option that is technically feasible, potentially economically attractive and greenhouse gas neutral. High temperature fuel cells that are able to operate with carbon monoxide in the feed are well suited to these applications. Furthermore, because they do not require noble metal catalysts, the cost of high-temperature fuel cells has the greatest potential to become competitive in the near future compared to other types of fuel cells.

• 한국항공운항학회지
• /
• 제21권1호
• /
• pp.39-44
• /
• 2013

The amount of greenhouse gas (GHG) emissions has been increasing steadily over the last 4 years, averaging 6.8 percent a year, due to the growth of low cost carriers and the increased demand for air transportations. For the aviation GHG reduction, various fuel saving activities are implemented in many areas such as high-efficiency aircraft and bio-fuel development in the technical part and low carbon flight procedures, short cut route development in the operational approach. Among the various reduction technologies, we focused on low carbon flight procedures that are crucial to GHG reduciton and suggested a reduction effect according to target implementation rate using by fuel saving estimation data in each aircraft type.

• 한국신재생에너지학회:학술대회논문집
• /
• 한국신재생에너지학회 2011년도 춘계학술대회 초록집
• /
• pp.89.1-89.1
• /
• 2011

According to green growth's policy, green-home dissemination's projects are promoting. Among them, stationary fuel cell systems are receiving attention due to high efficiency and clear energy. But it need absolutely to develop cost down technologies and improve system durability for commercialization of the fuel cell system. To achieve this objectives, in 2009, the Korean Government and "Korea Institute of Energy Technology Evaluation and Planning(KETEP)" launched into the strategic development project of BOP technology for practical applications and commercializations of stationary fuel cell systems, named "Technology Development on Cost Reduction of BOP Components for 1kW Stationary Fuel Cell Systems to Promote Green-Home Dissemination Project". This paper introduces a summary of improved BOP performances that has been achieved through the 2nd year development precesses(2010.06~2011.05) base on 1st year development precesses(2009.06~2010.05). The major elements for fuel cell systems are cathode air blowers, burner air blowers, preferential oxidation air blowers, fuel blowers, cooling water pumps, reformer water pumps, heat recovery pumps, mass flow meters, electrical valves, safety valves and a low-voltage inverter. Key targets of those elements are the reduction of cost, power consumption and noise. Invert's key targets are development the low -voltage technologies in order to reduce the number of unit cell in fuel cell system's stack.

• 한국수소및신에너지학회논문집
• /
• 제17권3호
• /
• pp.279-285
• /
• 2006

Recirculation for the unreacted fuel is necessary to improve the overall efficiency of the fuel cell system and to prevent fuel starvation since the fuel cell for a vehicle application is a closed system. In case of the automotive fuel cell, the ejector which does not require any parasitic power is good for the performance improvement and easy operation. It is essential to design the customized ejector due to the lack of the commercial ejector corresponding to the operating conditions of the fuel cell systems. In this study, the design methodology for the ejector customized to an automotive fuel cell is proposed. The model based sensitivity analysis prevents the time-consuming redesign and reduces the cost of developing ejector. As a result, the customized ejector to meet the desired performance within overall operating range has developed for the PEMFC automotive system.

• Journal of Advanced Marine Engineering and Technology
• /
• 제39권6호
• /
• pp.620-625
• /
• 2015

IMO MEPC에서는 지구온난화를 늦추기 위해서, 선박에서 배출되는 GHG(Green House Gas)인 $CO_2$를 줄이기 위한 방안으로 선속을 다운시켜 운항할 것을 제안한바 있으며, 해운회사에서도 연료비 절감을 위해서 자발적으로 감속운항(Low steaming)을 하고 있어, 국제항해에 종사하고 있는 대부분의 컨테이너선들이 감속운항을 하고 있다. 또한, 날로 증가되고 있는 해운 물동량 증가로 선박의 연료비 부담이 증가되고 있어 연료비 절감 기술개발이 절실히 요구되고 있다. 따라서 본 연구에서는 디젤엔진의 성능을 향상시킬 수 있는 연료첨가제(유용성 칼슘계 유기금속화합물)를 일정량 투입(사용 연료량의 0.025%) 하여 연료비를 절감하는 방법을 시도하였다. 실험의 정확도를 위해서 육상 발전소에 설치된 2행정 대형 디젤엔진을 실험 대상으로 하였다. 실험 엔진의 부하는 저, 중 및 고 부하(50, 75, 100%)로 나누어서 실시하였으며, 연료첨가제의 투입 전과 투입 후의 엔진성능(출력, 연료소비율, 최고연소압력(P-max), 배기온도)을 비교 분석 하였다. 본 실험을 통해서 연료첨가제를 투입함으로써 저부하(50%) 에서 2% 이상의 연료비 절감 효과를 확인 할 수 있었으며, 최고연소압력은 상승하는 반면에 배기온도는 하강함을 알 수 있었다.

• Corrosion Science and Technology
• /
• 제21권5호
• /
• pp.412-417
• /
• 2022

Proton exchange membrane fuel cells (PEMFCs) provide zero emission power sources for electric vehicles and portable electronic devices. Although significant progresses for the widespread application of electrochemical energy technology have been achieved, some drawbacks such as catalytic activity, durability, and high cost of catalysts still remain. Pt-based catalysts are regarded as the most efficient catalysts for sluggish kinetics of oxygen reduction reaction (ORR). However, their prohibitive cost limits the commercialization of PEMFCs. Therefore, we proposed a NiCo@Au core shell structure as Pt-free ORR electrocatalyst in PEMFCs. NiCo alloy was synthesized as core to introduce ionization tendency and autoxidation reaction. Au as a shell was synthesized to prevent oxidation of core NiCo and increase catalytic activity for ORR. Herein, we report the synthesis, characterization, electrochemical properties, and PEMFCs performance of the novel NiCo@Au core-shell as a catalyst for ORR in PEMFCs application. Based on results of this study, possible mechanism for catalytic of autoxidation core@anti-oxidation shell in PEMFCs is suggested.

• 전기화학회지
• /
• 제14권2호
• /
• pp.71-76
• /
• 2011

Fe-tetramethoxyphenylporphyrin on carbon black (Fe-TMPP/C) is examined and compared with carbon (C) and Pt-coated carbon (Pt/C) for oxygen reduction reaction in a two chambered microbial fuel cell (MFC). The Fe-TMPP/C is prepared by heat treatment and characterized using SEM, TEM, and XPS. The electrochemical properties of catalysts are characterized by voltammerty and single cell measurements. It is found that the power generation in the MFC with Fe-TMPP/C as the cathode is higher than that with Pt/C. The maximum power of the Fe-TMPP/C is 0.12 mW compared with 0.10 mW (Pt/C) and 0.02 mW (C). This high output with the Fe-TMPP/C indicates that MFCs are promising in further practical applications with low cost macrocycles catalysts.