• 한국신재생에너지학회:학술대회논문집
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• 2005.11a
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• pp.60-75
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• 2005

천연가스차량이 배출하는 미연 탄화수소 중 약 80%이상이 메탄으로 구성 되어있다. 메탄은 그 자체로 유독성 물질은 아니지만 이산화탄소와 더불어 지구온난화를 유발하는 온실가스로 향후 강력한 규제가 예상되는 물질로 이를 저감하는 기술 개발이 이루어져야하나 연료 특성상 이를 줄이는데 어려움이 있다. 최근 연구에 의하면 천연가스엔진에 수소를 일정량(15%이상) 첨가할 경우 배출가스 및 성능 이 상당량 개선되는 결과를 보이고 있다. 이는 종래 천연가스 연소의 문제점인 지연된 화염 전파 속도를 수소 연료를 첨가함에 따라 화염 전파속도를 촉진시켜 적정한 연소를 야기 시켜 미연탄화수소 배출이 줄어들고 열효율도 향상되는 결과를 보이고 있다. 이와 같이 수소와 천연가스연료의 각각의 장점을 활용한 Hy-thane 엔진을 개발할 경우 무공해엔진에 근접한 초 저공해 동력장치 개발이 가능하며 이에 대한 상용화 측면에서 산업용 발전기, GEHP, 차량용 엔진 등 활용도가 크기 때문에 그 개발이 절실히 필요하다고 할 수 있다. 따라서 본 과제에서는 이중연료를 사용하는 수소-천연가스 기관을 개발하고 이를 효과적으로 제어할 수 있는 제어시스템을 개발하여, 기관효율 향상과 배기가스저감을 이루었다.

• Proceedings of the KIEE Conference
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• 2007.07a
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• pp.1037-1038
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• 2007

프리피스톤 기관은 크랭크가 없는 엔진을 동력원으로 리니어 발전기를 구동시켜 전기에너지를 생성하는 시스템으로 기존 왕복 구동식 기관에 비해 기계적 손실이 작고, 팽창 에너지를 최대한 활용할 수 있는 고효율 기관으로 평가되고 있다. 또한 프리피스톤 기관은 가솔린, 디젤, 수소, 천연가스와 같은 청정 연료를 사용할 수 있기 때문에, 최근 에너지 수급 문제 및 대체 에너지원으로 활용할 수 있다는 장점을 가지고 있다. 프리피스톤 기관에 적용되는 리니어 발전기의 경우 기존 회전형 발전기보다 효율은 다소 떨어지는 단점은 있으나, 동력 변환을 하지 않는 리니어 엔진에 적용할 경우에는 효율적 이득을 볼 수 있다. 본 논문에서는 리니어 발전기의 성능 측정을 위한 시험 장치를 구성하고, 프리피스톤용 기관에 적용되는 평판형 및 원통형 타입의 리니어 발전기의 손실 및 효율 특성을 비교하였다.

• Journal of Hydrogen and New Energy
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• v.29 no.4
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• pp.363-369
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• 2018

This paper considers the alternative way to mitigate cost for REC instead of Photovoltaic (PV) panels with Energy Storage System (ESS). This study starts from an economic analysis of a 1 megawatt PV system without ESS. Several assumptions have been applied in consideration of the current domestic situation. Based on this result, the economic efficiency of PV with ESS improved. However, the reliance on government subsidies was very high. The alternative way to cover the fluctuation power from renewable energy was reviewed with economical and technical way. In case the natural gas engine applied to PV, the IRR and Levelized Cost of Electricity (LCOE) can be improved without ESS. And if small amount of additional REC, the IRR can be improved up to investment level.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.35 no.7
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• pp.693-699
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• 2011

Internal combustion engines running on syngas, which can be obtained from biomass or organic wastes, are expected to be one of the suitable alternatives for power generation, because they are environment-friendly and do not contribute to the depletion of fossil fuels. However, syngas has variable compositions and a lower heating value than pure natural gas, owing to which the combustion conditions need to be adjusted in order to achieve stable combustion. In this study, a gas that has the same characteristics as syngas, such as low heating value (LHV), was produced by mixing $N_2$ with compressed natural gas (CNG). In addition, this study investigates the combustion characteristics of syngas when it is mixed with hydrogen in a ratio ranging from 10% to 30% with a constant LHV of total gas.

• Journal of ILASS-Korea
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• v.25 no.4
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• pp.170-177
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• 2020

Stoichiometric combustion in spark ignition (SI) engines has an advantage of meeting future stringent emission regulations. However, the drawback of the combustion is a lower thermal efficiency than that of lean burn. In this study, energy losses in a natural gas stoichiometric SI engine generator were analyzed to establish a strategy for improving the generating efficiency (GE). The energy losses were investigated based on dynamometer and load bank experiments. As the intake manifold pressure increased in the dynamometer experiment, the brake thermal efficiency (BTE) increased mainly due to the reduction in the pumping and mechanical losses. In the load bank experiment, the generating power and GE increased with the increased intake manifold pressure. The generating power and GE were lower than the brake power and BTE due to the cooling fan power and the losses in the generator.

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.3
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• pp.269-274
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• 2009

Recently, the construction of Liquefied Natural Gas Carriers(LNGC) is being promoted larger and larger depending on long voyage. In 1950 years, $5,000m^3$ class of LNGC had been changed to $71,500m^3$ class in 1973. and to $210,000-266,000m^3$ class in 2007. Especially, the system of main engines and cargo control, Re-liquefaction of natural gases have become possible in LNGC. This research deals with the LNG projects, world markets of energy and developing tendency of liquefied natural gas carriers.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2016.10a
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• pp.219-220
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• 2016

A power management system (PMS) has been an important part in a ship integrated control system. To evaluate a PMS for a liquefied natural gas carrier (LNGC), this research proposes a real-time hardware-in-the-loop simulation (HILS), which is composed of major component models such as turbine generator, diesel generator, governor, circuit breaker, and 3-phase loads on MATLAB/Simulink. In addition, FPGA based control console and main switchboard (MSBD) are constructed in order to develop an efficient control and a similar real environment in an LNGC PMS. A comparative study on the performance evaluation of PMS functions is conducted using two test cases for sharing electric power to consumers in an LNGC. The result shows that the proposed system has a high verification capability for the operating function and failure insertion evaluation as a PMS simulator.