• Title/Summary/Keyword: Alternative Gas

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The Combustion Characteristics of Biodiesel Fuel as an Alternative Fuel for IDI Diesel Engine (간접분사식 디젤기관에서 바이오디젤연료의 연소 특성)

  • 유경현;윤용진;오영택
    • Transactions of the Korean Society of Automotive Engineers
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    • v.11 no.1
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    • pp.72-78
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    • 2003
  • Recently, lots of researchers have been attracted to develope various alternative fuels and to use renewable fuels as a solution of environmental problems from automobile. The use of biodiesel fuel is an effective way of substituting diesel fuel in the long nun. It is a domestically produced, renewable fuel that can be manufactured from vegetable oils, used vegetable oils, or animal fats. In this study, the usability of biodiesel fuel derived from rice ban oil, one of the oxygenated fuels as an alternative fuel for diesel engines was investigated in IDI diesel engine. Emissions were characterized with neat biodiesel fuel and with a blend of biodiesel fuel and conventional diesel fuel. Since the biodiesel fuel includes oxygen of about 11%, it could influence the combustion process strongly. So, the use of biodiesel fuel resulted in lower emissions of carbon monoxide and smoke emissions with some increase in emissions of oxides of nitrogen. It is concluded that biodiesel fuel can be utilized effectively as a renewable fuel for IDI diesel engine.

Performance analysis of a hermetic reciprocating compressor using the alternative refrigerants, HFC134a and HC600a (대체냉매(HFC134a, HC600a)용 밀폐형 왕복동 압축기의 성능해석에 관한 연구)

  • Kim, Jeong-U
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.22 no.7
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    • pp.966-979
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    • 1998
  • Thermodynamic and dynamic analysis has been conducted to investigate performance variations induced by substitution of alternative refrigerants, HFC134a or HC600a for CFC12 in hermetic reciprocating compressors. For the thermodynamic analysis, mass and energy conservation laws are applied to the cylinder volume and Helmholtz resonator modeling method is adopted to describe gas pulsations at suction and discharge system. The modeling of the dynamics of the compressor mechanism has been performed with lumped mass method to analyse the bearing loads and friction losses at each bearing. To verify the correctness of this analysis, results of the performance simulation have been compared to those of calorimetric measurrements of compressor operating with CFC12. Analysis of the various losses, noise and reliability as well as performance has been conducted to present the design guideline for the compressor development with alternative refrigerants. It is found that compressors with alternative refrigerants, HFC 134a or HC600a give better COPs than those with CFC12 under the same operating conditions and especially, compressors with HC600a show better reliability and noise characteristics also.

Estimation and Adjustment of Time Point in Manifestation of Gas Safety Project Effects using Sigmoid Functions (시그모이드 함수를 이용한 가스안전사업 효과의 발현시점 추정과 조정)

  • Hyeon Kyo Lim;Geon Yeong Bak
    • Journal of the Korean Society of Safety
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    • v.38 no.1
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    • pp.70-77
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    • 2023
  • Gas has replaced coal or petroleum as primary fuel because of its convenience. However, gas has risk of fire, explosion, or poisoning. To reduce gas-related accidents, many strategic projects have been being carried based on 'Gas Safety Management Basic Plans' on a domestic scale. In spite of those projects, the gas-related accident rate did not decrease over past decades. Thus, this study was conducted to analyze the effectiveness of ongoing projects, and to find out ways to make improvements. Conventional statistical analyses on accident data published by gas-related institutions were not useful to determine meaningful attributes to predict future. Whereas, accident case analyses adopted in the present study discovered differences in the type of people and their unsafe acts for each gas type. Meanwhile, the overall average priority of projects was not high in the aspect of System Safety Precedence. If the current trend is maintained, with sigmoid functions, it can be estimated that mean annual accident rate will decrease by only 2.0% in the next two decades. To improve the current trend, the present study made conclusions as followings: (1) safety projects should be designed with careful consideration of accident traits including gas type, unsafe acts, and persons involved and (2) alternative strategies should include system considerations such as minimum hazard design and safety devices prior to mere education or training. To summarize briefly, the present state related with gas accidents highlights the necessity of a system-based multidisciplinary approach.

A Study on the Safety Improvement of City Gas Pressure Regulators in Apartment Housing (공동주택 등에 설치하는 도시가스 압력조정기의 안전성 향상에 관한 연구)

  • Youngman Yun;Yongchai Kwon;Kyungho Kim;Jihyun Jang
    • Journal of the Korean Institute of Gas
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    • v.27 no.2
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    • pp.86-94
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    • 2023
  • This study was conducted with the purpose of preparing an alternative to improving the safety of civil pressure regulators installed instead of gas governors to supply city gas to apartment houses. First, problems were derived and solutions were presented by investigating the safety standards and installation status of domestic pressure regulators. In addition, using the DNV Phast-Safeti program, a quantitative risk assessment solution, risks such as gas leakage contained in pressure regulators installed in apartment houses and surrounding gas facilities were evaluated in terms of individual risks and societal risks, and measures were derived to reduce the risks in the installation and management of the pressure regulators.

PERSPECTIVES OF NUCLEAR HEAT AND HYDROGEN

  • Lee, Won-Jae;Kim, Yong-Wan;Chang, Jong-Hwa
    • Nuclear Engineering and Technology
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    • v.41 no.4
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    • pp.413-426
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    • 2009
  • Nuclear energy plays an important role in world energy production by supplying 6% of the world's current total electricity production. However, 86% of the energy consumed worldwide to produce industrial process heat, to generate electricity and to power the transportation sector still originates in fossil fuels. To cope with dwindling fossil fuels and climate change, it is clear that a clean alternative energy that can replace fossil fuels in these sectors is urgently required. Clean hydrogen energy is one such alternative. Clean hydrogen can play an important role not only in synthetic fuel production but also through powering fuel cells in the anticipated hydrogen economy. With the introduction of the high temperature gas-cooled reactor (HTGR) that can produce nuclear heat up to $950^{\circ}C$ without greenhouse gas emissions, nuclear power is poised to broaden its mission beyond electricity generation to the provision of nuclear process heat and the massive production of hydrogen. In this paper, the features and potential of the HTGR as the energy source of the future are addressed. Perspectives on nuclear heat and hydrogen applications using the HTGR are discussed.

Economic Analysis of Heat Pump System in Educational Building -Focused on the High School of Twenty Four Classes- (교육용 건축물의 히트펌프 냉난방시스템에 대한 경제성 분석 -24학급 규모의 고등학교를 중심으로-)

  • Park, Ryul;Park, Min-Yong;Kim, Jong-Min
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.15 no.10
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    • pp.879-887
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    • 2003
  • Buildings with heating and cooling systems have been increased, since the requirement of thermal comfort for residents is grown. Heating and cooling systems, have been changed from two separate systems to one multi-function system which includes both heating and cooling. Especially, heat pump heating and cooling system has been adopted for general classrooms in schools since education environment improvement project has been launched. This research suggests the best option for the heat pump heating and cooling system in educational buildings through economic assessments for four alternative systems based on electric heat pump (EHP) and gas engine driven heat pump (GHP), which are most widely used for elementary, middle and high schools. The model buildings are in the Y high school which has 24 classes of new construction building, which will be built soon. Annual energy consumption for alternative systems uses BECS 3.10, which can be used for system simulation.

The characteristic analysis and model of PEM fuel cell for residential application (가정용 고분자 연료전지의 모델과 특성해석)

  • Cho, Y.R.;Kim, N.H.;Han, K.H.;Joo, K.D.;Yun, S.Y.;Baek, S.H.
    • Proceedings of the KIEE Conference
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    • 2005.04a
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    • pp.277-279
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    • 2005
  • The imbalance of energy demand and supply caused by rapid industrialization around the world and the associated environmental issues require and alternative energy source with possible renewable fuels. Political instability and depletion of cruel oils are other factors that cause fluctuation of oil price. Securing a new alternative energy source for the next century became an urgent issue that our nation is confronting with. As a matter of fact, the fuel cell technology can be widely used as next generation energy regardless of regions and climate. Specially, the ability of expansion and quick installation enable one to apply it for distributed power, where the technology is already gaining remarkable attentions for the application. Particularly, leading industrialized nations are focusing on the PEM fuel dell with anticipation that this technology will find their place of applications in the vehicles and homes. In this study, demonstrate the multi physics modeling of a proton exchange membrane(PEM) fuel cell with interdigitated flow field design. The model uses current balances, mass balance(Maxwell-Stefan diffusion for reactant, water and nitrogen gas) and momentum balance(gas flow) to simulate the PEM fuel cell behavior.

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The Effect of Fuel Composition on Emissions and Combustion of CNG Engine at Partial Load (부분부하에서 연료 조성이 천연가스 엔진의 연소 및 배기에 미치는 영향)

  • Kim, Hyung-Min;Lee, Ki-Hyung;Kim, Bong-Gyu
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.3288-3293
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    • 2007
  • Compressed natural gas has good potential for alternative vehicle fuel due to its economical and clean characteristics. However, the composition of natural gas based on production location is known to affect performance and emissions of CNG engine. Thus, the objective of this paper is to clarify the effect of fuel composition on combustion and emissions of CNG engine. This paper presents combustion characteristics obtained from running a 2.5L, 4-cylinder CNG engine retrofitted IDI diesel engine with engine dynamometer. BSFC, emissions, fuel consumption and combustion pressure were measured under steady state operating conditions especially at partial load for CNG engine. Based on the experimental results, we found that CNG composition affects engine performance, fuel conversion efficiency and burning rate.

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An Experimental Study on Measurement of Oxygen Concentration in the Cathode Channel of PEMFC by Using GC (GC를 이용한 고분자전해질형 연료전지의 공기극 채널 내 산소 농도 분포에 관한 실험적 연구)

  • Ha Taehun;Kim Han-Sang;Min Kyoungdoug
    • 한국신재생에너지학회:학술대회논문집
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    • 2005.06a
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    • pp.384-387
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    • 2005
  • Fuel cell has been well known as a clean alternative power for vehicles. Recently, an experimental technique has been developed measurement of species and distributions by using gas chromatograph. In this study, cathode channel oxygen distributions as various conditions were investigated using gas chromatograph and cell visualization. And discussed relation between flooding and oxygen concentrations. As a result of experiment, oxygen consumpt ion is affected wi th flooding. Flooding is observed in channel near hydrogen inlet, and oxygen consumption is low at that region.

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Design of Gas Burner for Cooking (조리기기용 가스버너 설계)

  • Shim, S.H.;Kim, S.J.;Keel, S.I.;Yun, J.H.;Kim, I.K.;Han, I.H.;Lee, D.R.
    • 한국연소학회:학술대회논문집
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    • 2000.12a
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    • pp.202-211
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    • 2000
  • Characteristics of the fuel injection and entrainment of the primary air of gas burner have been investigated. Primary air flow rates that entrained by gas streams play major role to control the performance of the partially premixed combustion. Pressure distributions of mixing tube assembly are studied as major parameter for increasing the primary air flow rates. Buoyancy-effect burner is proposed as one alternative to improve the pressure distribution. Buoyancy effect caused by metal ring placed around the flame holes reduces pressure of the entrance of the mixing tube and that, entrained air flow rates are increased.

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