• Title/Summary/Keyword: Fuel Cell system

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Development of High-Efficient Small Euel Cells : I. Synthesis of Organic-Inorganic Nanocomposite Electrolyte Membranes (고효율 소형 연료전지의 개발 : I.유기-무기 나노복합 전해질막의 합성)

  • Park, Yong-Il;Moon, Joo-Ho;Kim, Hye-Kyung;Kim, Suk-Hwam
    • Journal of the Korean Ceramic Society
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    • v.42 no.1
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    • pp.50-55
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    • 2005
  • New fast proton-conducting organic-inorganic nanocomposite membranes were successfully fabricated using polymer matrix obtained through proper oxidation of thiol ligands in (3-Mercaptopropyl) trimethoxysilane (MPTS) and hydrolysis/condensation reaction of (3-glycidoxypropyl) trimethoxysilane (GPTS). The obtained nanocomposite membranes showed relatively hirh proton-conductivity over $10^{-2}S/cm$ at $ 25^{circ}C$. The proton conductivities of the fabricated composite membranes increased up to $3.6{\times}10^{-1}$ S/cm cm by increasing temperature and relative humidity to $70^{circ}C$ and 100 $100RH\%$. The high proton conductivity of the composites Is due to the proton conducting path through the GPTS-derived 'pseudo-polyethylene oxide 'network in which sulfonic acid ligands work as a proton donor.

Development of an educational wind turbine control equipment (교육용 풍력터빈제어 실습장치 개발)

  • Huh, Jun-Young;Park, Sung-Su
    • The Journal of Korean Institute for Practical Engineering Education
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    • v.3 no.2
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    • pp.75-82
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    • 2011
  • Recently the technology of green growth became more important role among the problems of running out of fossil fuels and global warming. To procure a new growth power combined with energy and green growth, a lot of investment for wind power, photovoltaics system, fuel cell and biofuel expanded day by day. Among these, wing power has a merit of a highly economic and no discharge of toxic substance. These days government and industrial companies actively support the development of wind power technology with lots of investment, but domestic related education and equipment still stay in research level when it is compared with foreign advanced countries which lead the wind power technology. Therefore to expand the base of basic skill required in the related industrials and to advance technology, we are in the situation to be needed a development of a new curriculum and educational equipment which is analogous with the actual industrial system. In this paper a development of a new educational equipment for the learning of turbine control is introduced. This educational equipment has been developed for students to get easy understanding for the theory of wind turbine control. And finally to demonstrate the effect of the use of the developed equipments and curriculum a questionnaire carried out.

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Performance Improvement of Isolated High Voltage Full Bridge Converter Using Voltage Doubler

  • Lee, Hee-Jun;Shin, Soo-Cheol;Hong, Seok-Jin;Hyun, Seung-Wook;Lee, Jung-Hyo;Won, Chung-Yuen
    • Journal of Electrical Engineering and Technology
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    • v.9 no.6
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    • pp.2224-2236
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    • 2014
  • The performance of an isolated high voltage full bridge converter is improved using a voltage doubler. In a conventional high voltage full bridge converter, the diode of the transformer secondary voltage undergoes a voltage spike due to the leakage inductance of the transformer and the resonance occurring with the parasitic capacitance of the diode. In addition, in the phase shift control, conduction loss largely increases from the freewheeling mode because of the circulating current. The efficiency of the converter is thus reduced. However, in the proposed converter, the high voltage dual converter consists of a voltage doubler because the circulating current of the converter is reduced to increase efficiency. On the other hand, in the proposed converter, an input current is distributed when using parallel input / serial output and the output voltage can be doubled. However, the voltages in the 2 serial DC links might be unbalanced due to line impedance, passive and active components impedance, and sensor error. Considering these problems, DC injection is performed due to the complementary operations of half bridge inverters as well as the disadvantage of the unbalance in the DC link. Therefore, the serial output of the converter needs to control the balance of the algorithm. In this paper, the performance of the conventional converter is improved and a balance control algorithm is proposed for the proposed converter. Also, the system of the 1.5[kW] PCS is verified through an experiment examining the operation and stability.

Optimal Sizing Method of Distributed Energy Resources for a Stand-alone Microgrid by using Reliability-based Genetic Algorithm (신뢰도 기반의 유전자알고리즘을 활용한 독립형 마이크로그리드 내 분산형전원 최적용량 산정 방법)

  • Baek, Ja-Hyun;Han, Soo-Kyung;Kim, Dae-Sik;Han, Dong-Hwa;Lee, Hansang;Cho, Soo-Hwan
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.66 no.5
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    • pp.757-764
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    • 2017
  • As the reduction of greenhouse gases(GHGs) emission has become a global issue, the microgrid markets are growing rapidly. With the sudden changes in the market, Korean government suggested a new business model called 'Self-Sufficient Energy Islands'. Its main concern is a stand-alone microgrid composed of Distributed Energy Resources(DERs) such as Renewable Energy Sources(RESs), Energy Storage System(ESS) and Fuel Cell, in order to minimize the emission of GHGs. According to these trend, this paper is written to propose an optimal sizing method of DERs in a stand-alone microgrid by using Genetic Algorithm(GA), one of the representative stochastic methods. It is to minimize the net present cost with the variables, size of RESs and ESS. In the process for optimization, the sunless days are considered as additional constraints. Through the case study analysis, the size of DERs installed in a microgrid system has been computed using the proposed method in MATLAB. And the result of MATLAB is compared with that of HOMER(Hybrid Optimization of Multiple Energy Resources), a well-known energy modeling software.

Visualization of Virtual Slave Manipulator Using the Master Input Device (주 입력장치를 이용한 가상 슬레이브 매니퓰레이터의 시각화)

  • 김성현;송태길;이종열;윤지섭
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2003.11a
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    • pp.388-394
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    • 2003
  • To handle the high level radioactive materials such a spent fuel, the master-slave manipulators (MSM) are widely used as a remote handling device in nuclear facilities such as the hot cell with sealed and shielded space. In this paper, the Digital Mockup which simulates the remote operation of the Advanced Conditioning Process(ACP) is developed. Also, the workspace and the motion of the slave manipulator, as well as, the remote operation task should be analyzed. The process equipment of ACP and Maintenance/Handling Device are drawn in 3D CAD models using IGRIP. Modeling device of manipulator is assigned with various mobile attributes such as a relative position, kinematics constraints, and a range of mobility, The 3D graphic simulator using the external input device of space ball displays the movement of manipulator. To connect the external input device to the graphic simulator, the interface program of external input device with 6 DOF is deigned using the Low Level Tele-operation Interface(LLTI). The experimental result shows that the developed simulation system gives much-improved human interface characteristics and shows satisfactory response characteristics in terms of synchronization speed. This should be useful for the development of work's education system in the virtual environment.

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An Effective Multiplication Factor Calculation of Uniform Lattices of $UO_2-PuO_2$ Fueled System ($UO_2-PuO_2$ 노심에서의 유효증배계수계산)

  • Sang Keun Lee;Ji Bok Lee;Chang Saeng Rim;Chang Kun Lee;Chang Hyun Chung
    • Nuclear Engineering and Technology
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    • v.14 no.3
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    • pp.138-147
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    • 1982
  • A theoretical basis for analysis of plutonium-hearing fuel in a thermal nuclear power reactor has been established. The analysis of UO$_2$-PuO$_2$ fueled, light water moderated uniform lattice experiments has been performed. A unit cell program, KARATE, which is based on the theoretical models of GAM and THERMOS with some modifications, has been developed to generate a few-group cross-sections. These cross-sections are subsequently used in the diffusion theory code, KIDD, to compare the calculated values of the effective multiplication factor with the measured. The average value of the effective multiplication factor for 41 selected critical experiments is estimated to be 0.9997 with standard deviation of 0.43%. This illustrates the fact that KARATE/KIDD system can be effectively used for the analysis of uniform lattices of UO$_2$-PuO$_2$fuels.

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Effects of Plasma Treatment on Mechanical Properties of Jute Fibers and Their Composites with Polypropylene (황마섬유 및 황마-폴리프로필렌 복합체의 특성에 미치는 플라즈마 처리영향)

  • Huh, Yang Il;Bismark, Mensah;Kim, Sungjin;Lee, Hong Ki;Nah, Changwoon
    • Elastomers and Composites
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    • v.47 no.4
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    • pp.310-317
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    • 2012
  • A jute fiber surface was modified with argon gas in a cylinder type RF plasma generator to enhance the interfacial bond strength and to optimize the plasma treatment condition. The plasma power, gas pressure, and treat time were varied to figure out any effect of those parameters on the morphology and mechanical strength of jute fibers, and the interfacial bond strength for a model composite with polypropylene resin. As the severity of plasma treatment was increased, the surface of jute fibers became rougher. Gas pressure was less effective in roughening of the surface compared with those of treat time and plasma power. Approximately 25% drop in tensile strength of jute fibers was observed for the parameters of treat time and plasma power, while little deterioration was found for gas pressure, with increasing the severity. Based on the interfacial shear strength (IFSS), the optimum plasma treatment condition was determined to be treat time of 30 s, plasma power of 40 W, and gas pressure of 30 mTorr.

Development of the Interconnection Evaluation System for Dispersed Generations in Distribution Systems (분산전원의 배전계통 연계 평가 시스템의 개발에 관한 연구)

  • Kang Min-Kwan;Park Jae-Ho;Oh Yong-Taek;Hong Sang-Eun;Rho Dae-Seok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.7 no.1
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    • pp.12-20
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    • 2006
  • Recently, new dispersed sources (DSG) such as Photovoltaic, Wind Power, fuel cell etc. are interconnected with distribution systems as national projects for alternative energy preparing for oil crisis. This paper deals with the optimal evaluation algorithms in the case where new dispersed sources are operated in distribution systems. It is very difficult and complicated to handle the interconnection issues for proper voltage managements, because professional skills and enormous amounts of data for the evaluations are required. The typical evaluation algorithms mainly depending on individual ability and quality of data acquired, inevitably cause the different results f3r the same issue, so unfair and subjective evaluations are unavoidable. In order to overcome these problems, this paper proposes reasonable and general algorithms based on the standard model system and proper criterion, which offers the fair and objective evaluations in any case.

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Thermodynamic Analysis on Hybrid Turbo Expander - Heat Pump System for Natural Gas Pressure Regulation (히트펌프를 적용한 터보팽창기 천연가스 정압기지의 열역학적 분석)

  • Sung, Taehong;Kim, Kyoung Hoon;Han, Sangjo;Kim, Kyung Chun
    • Journal of the Korean Institute of Gas
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    • v.18 no.4
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    • pp.13-20
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    • 2014
  • In natural gas distribution system, gas pressure is regulated correspond to requirement using throttle valve which is releasing huge pressure energy as useless form. The waste pressure can be recovered by using turbo machinery devices such as a turbo expander. In this process, excessive temperature drop occurs due to Joule-Thompson effect during the expansion process. Installing natural gas boiler before or after the turbo expander prevents temperature drop. Fuel cell or gas engine hybrid system further improve the efficiency, but 1~2% of total transporting natural gas is used for operating the hybrid system. In this study, a heat pump system is proposed as a preheating device which can be operated without using transporting natural gas. Thermodynamic analysis on evaporating and condensing temperatures and refrigerants is conducted. Results show that R717 is proper refrigerant for the hybrid system with high COP and low turbine work within the defined operating conditions. In domestic usage in Korea, the heat pump system has more economic feasibility owing to natural gas being imported with a high price of LNG form.

Recent Progress in Air-Conditioning and Refrigeration Research : A Review of Papers Published in the Korean Journal of Air-Conditioning and Refrigeration Engineering in 2013 (설비공학 분야의 최근 연구 동향 : 2013년 학회지 논문에 대한 종합적 고찰)

  • Lee, Dae-Young;Kim, Sa Ryang;Kim, Hyun-Jung;Kim, Dong-Seon;Park, Jun-Seok;Ihm, Pyeong Chan
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.26 no.12
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    • pp.605-619
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    • 2014
  • This article reviews the papers published in the Korean Journal of Air-Conditioning and Refrigeration Engineering during 2013. It is intended to understand the status of current research in the areas of heating, cooling, ventilation, sanitation, and indoor environments of buildings and plant facilities. Conclusions are as follows. (1) The research works on the thermal and fluid engineering have been reviewed as groups of fluid machinery, pipes and relative parts including orifices, dampers and ducts, fuel cells and power plants, cooling and air-conditioning, heat and mass transfer, two phase flow, and the flow around buildings and structures. Research issues dealing with home appliances, flows around buildings, nuclear power plant, and manufacturing processes are newly added in thermal and fluid engineering research area. (2) Research works on heat transfer area have been reviewed in the categories of heat transfer characteristics, pool boiling and condensing heat transfer and industrial heat exchangers. Researches on heat transfer characteristics included the results for general analytical model for desiccant wheels, the effects of water absorption on the thermal conductivity of insulation materials, thermal properties of Octadecane/xGnP shape-stabilized phase change materials and $CO_2$ and $CO_2$-Hydrate mixture, effect of ground source heat pump system, the heat flux meter location for the performance test of a refrigerator vacuum insulation panel, a parallel flow evaporator for a heat pump dryer, the condensation risk assessment of vacuum multi-layer glass and triple glass, optimization of a forced convection type PCM refrigeration module, surface temperature sensor using fluorescent nanoporous thin film. In the area of pool boiling and condensing heat transfer, researches on ammonia inside horizontal smooth small tube, R1234yf on various enhanced surfaces, HFC32/HFC152a on a plain surface, spray cooling up to critical heat flux on a low-fin enhanced surface were actively carried out. In the area of industrial heat exchangers, researches on a fin tube type adsorber, the mass-transfer kinetics of a fin-tube-type adsorption bed, fin-and-tube heat exchangers having sine wave fins and oval tubes, louvered fin heat exchanger were performed. (3) In the field of refrigeration, studies are categorized into three groups namely refrigeration cycle, refrigerant and modeling and control. In the category of refrigeration cycle, studies were focused on the enhancement or optimization of experimental or commercial systems including a R410a VRF(Various Refrigerant Flow) heat pump, a R134a 2-stage screw heat pump and a R134a double-heat source automotive air-conditioner system. In the category of refrigerant, studies were carried out for the application of alternative refrigerants or refrigeration technologies including $CO_2$ water heaters, a R1234yf automotive air-conditioner, a R436b water cooler and a thermoelectric refrigerator. In the category of modeling and control, theoretical and experimental studies were carried out to predict the performance of various thermal and control systems including the long-term energy analysis of a geo-thermal heat pump system coupled to cast-in-place energy piles, the dynamic simulation of a water heater-coupled hybrid heat pump and the numerical simulation of an integral optimum regulating controller for a system heat pump. (4) In building mechanical system research fields, twenty one studies were conducted to achieve effective design of the mechanical systems, and also to maximize the energy efficiency of buildings. The topics of the studies included heating and cooling, HVAC system, ventilation, and renewable energies in the buildings. Proposed designs, performance tests using numerical methods and experiments provide useful information and key data which can improve the energy efficiency of the buildings. (5) The field of architectural environment is mostly focused on indoor environment and building energy. The main researches of indoor environment are related to infiltration, ventilation, leak flow and airtightness performance in residential building. The subjects of building energy are worked on energy saving, operation method and optimum operation of building energy systems. The remained studies are related to the special facility such as cleanroom, internet data center and biosafety laboratory. water supply and drain system, defining standard input variables of BIM (Building Information Modeling) for facility management system, estimating capability and providing operation guidelines of subway station as shelter for refuge and evaluation of pollutant emissions from furniture-like products.