• 한국신재생에너지학회:학술대회논문집
• /
• 2010.11a
• /
• pp.74.2-74.2
• /
• 2010

전세계는 $CO_2$ 규제강화와 에너지의 효율적 사용에 대한 사회적, 경제적 요구가 증대되면서 친환경 에너지 설비와 지능형 전력망(smart grid)가 크게 예상되고 있다. 이에 따라 기존 내연기관에 근거한 발전산업 및 자동차 산업은 필연적으로 청정에너지 기반의 전기에너지로 점진적으로 대체될 것으로 판단된다. 따라서, 청정 발전 시스템의 보급 확대와 기존 에너지의 효율적 사용을 위해서 2차전지 기반의 전력저장 기술과 연료전지 기반의 분산발전 기술이 향후 미래에너지 산업의 근간이 되는 중요한 기술들로 부상하게 되었다. 아연/공기전지는 현재는 연료전지 개념의 1차전지에 기술수준이 머물러 있지만 향후 미래에는 기존의 리튬이온전지의 낮은 에너지밀도를 극복할 수 있는 미래 2차전지 기술의 하나로 평가받고 있다. 본 연구에서는 이러한 연료전지 개념의 아연/공기전지에 대하여 기존의 수소연료전지 기반의 분산발전 분야에 적용한다면 약 1/10 이하의 가격으로 조기에 시장진입이 가능할 것으로 판단하여 사전 타당성 연구 및 대면적화를 위한 기초 설계인자 연구를 수행하였다. 연구결과, 소형 단전지부터 약 800cm2까지의 대면적 단전지까지 대면적화를 위한 기초연구를 실시하였으며, 4개의 cell로 구성된 최고출력 90W급 전해질 순환형 미니스택 시스템을 구성하여 발전시스템으로서의 가능성과 문제점 등을 도출하였다. 이러한 시험결과를 바탕으로 25개의 cell로 구성된 약 1kW 급 스택을 설계하여 향후 소형 발전시스템을 제작하고자 하였다.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2012.05a
• /
• pp.58.2-58.2
• /
• 2012

Heavy hydrocarbon reforming is a core technology for "Dirty energy smart". Heavy hydrocarbons are components of fossil fuels, biomass, coke oven gas and etc. Heavy hydrocarbon reforming converts the fuels into $H_2$-rich syngas. And then $H_2$-rich syngas is used for the production of electricity, synthetic fuels and petrochemicals. Energy can be used efficiently and obtained from various sources by using $H_2$-rich syngas from heavy hydrocarbon reforming. Especially, the key point of "Dirty energy smart" is using "dirty fuel" which is wasted in an inefficient way. New energy conversion laboratory of KAIST has been researched diesel reforming for solid oxide fuel cell (SOFC) as a part of "Dirty energy smart". Diesel is heavy hydrocarbon fuels which has higher carbon number than natural gas, kerosene and gasoline. Diesel reforming has difficulties due to the evaporation of fuels and coke formation. Nevertheless, diesel reforming technology is directly applied to "Dirty fuel" because diesel has the similar chemical properties with "Dirty fuel". On the other hand, SOFC has advantages on high efficiency and wasted heat recovery. Nippon oil Co. of Japan recently commercializes 700We class SOFC system using city gas. Considering the market situation, the development of diesel reformer has a great ripple effect. SOFC system can be applied to auxiliary power unit and distributed power generation. In addition, "Dirty energy smart" can be realized by applying diesel reforming technology to "Dirty fuel". As well as material developments, multidirectional approaches are required to reform heavy hydrocarbon fuels and use $H_2$-rich gas in SOFC. Gd doped ceria (CGO, $Ce_{1-x}Gd_xO_{2-y}$) has been researched for not only electrolyte materials but also catalysts supports. In addition, catalysts infiltrated electrode over porous $La_{0.8}Sr_{0.2}Ga_{0.8}Mg_{0.2}O_3-{\delta}$ and catalyst deposition at three phase boundary are being investigated to improve the performance of SOFC. On the other hand, nozzle for diesel atomization and post-reforming for light-hydrocarbons removal are examples of solving material problems in multidirectional approaches. Likewise, multidirectional approaches are necessary to realize "Dirty energy smart" like reforming "Dirty fuel" for SOFC.

• Journal of Power Electronics
• /
• v.5 no.2
• /
• pp.99-103
• /
• 2005

In this paper, a novel circuit topology of a three-winding coupling inductor-assisting a high-frequency PWM boost chopper type DC-DC power converter with a high boost voltage conversion ratio and low switch voltage stress is proposed for the new energy interfaced DC power conditioner in solar photovoltaic and fuel cell generation systems. The operating principle in a steady state is described by using its equivalent circuits under the practical condition of energy processing of a lossless capacitive snubber. The newly-proposed power MOSFET boost chopper type DC-DC power converter with the three-winding coupled inductor type transformer and a single lossless capacitor snubber is built and tested for an output power of 500W. Utilizing the lower voltage and internal resistance power MOSFET switch in the proposed PWM boost chopper type DC-DC power converter can reduce the conduction losses of the active power switch compared to the conventional model. Therefore, the total actual power conversion efficiency under a condition of the nominal rated output power is estimated to be 81.1 ％, which is 3.7％ higher than the conventional PWM boost chopper DC power conversion circuit topology.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.57 no.10
• /
• pp.1738-1743
• /
• 2008

Environmental issue is one of the key factors to industry area using fossil fuels, because it accelerates the global warming. So it is supposed to reduce greenhouse gases around the developed nations of the world at times go. This issue is especially for the power industry. Under this background, MicroGrid system that consists of Distributed Energy Resources (DER) system, such as natural power system (wind, solar) and fuel-cell, co-generation, also known as CHP (Combined heat and power), has been developed greatly during the last 10 years. This paper adopts optimal model using GAMS to develop methods for conducting an integrated assessment of MicroGrid system.

• Proceedings of the KIPE Conference
• /
• 2010.07a
• /
• pp.200-201
• /
• 2010

본 논문에서는 동특성이 매우 느린 용융탄산염 연료전지 (Molten Carbonate Fuel Cell, MCFC) 스택이 계통 사고 시 추가적인 UPS (Uninterruptible Power Supply) 없이 비상부하로 전력 공급이 가능하고, 사고 제거 후 즉시 정격전력 발전하여 계통으로 주입할 수 있는 비상부하 추종형 백업 시스템을 제안한다. 제안된 MCFC 발전 시스템용 비상부하 추종형 백업 시스템은 3상 인버터로 구성된 PCS (Power Conditioning System) 출력단에 3상 PWM 컨버터를 연결한 구조이고, 비상부하 추종 및 부하량 조절이 가능한 추가적인 제어 알고리즘으로 PWM 컨버터를 제어한다. 제안된 비상부하 추종형 백업 시스템의 회로와 제어 알고리즘의 타당성을 컴퓨터 시뮬레이션을 통하여 검증한다.

• 한국신재생에너지학회:학술대회논문집
• /
• 2008.10a
• /
• pp.369-371
• /
• 2008

Environmental issue is one of the key factors to industry area using fossil fuels, because it accelerates the global warming. So it is supposed to reduce greenhouse gases around the developed nations of the world at times go. This issue is especially for the power industry. Under this background, CHP system that consists of Distributed Energy Resources (DER) system, such as natural power system (wind, solar) and fuel-cell, co-generation, also known as CHP (Combined heat and power), has been developed greatly during the last 10 years. This paper adopts optimal model using GAMS to develop methods for conducting an integrated assessment of MicroGrid system.

• Journal of Electrochemical Science and Technology
• /
• v.11 no.2
• /
• pp.99-116
• /
• 2020

The article provides information on ceramic / nanostructured materials which are suitable for solid oxide fuel cells (SOFCs) working between 500 to 1000℃. However, low temperature solid oxide fuel cells LTSOFCs working at less than 600℃ are being developed now-a-days with suitable new materials and are globally explored as the "future energy conversion devices". The LTSOFCs device has emerged as a novel technology especially for stationary power generation, portable and transportation applications. Operating SOFC at low temperature (i.e. < 600℃) with higher efficiency is a bigger challenge for the scientific community since in low temperature regions, the efficiency might be less and the components might have exhibited lower catalytic activity which may result in poor cell performance. Employing new and novel nanoscale ceramic materials and composites may improve the SOFC performance at low temperature ranges is most focused now-a-days. This review article focuses on the overview of various ceramic and nanostructured materials and components applicable for SOFC devices reported by different researchers across the globe. More importance is given for the nanostructured materials and components developed for LTSOFC technology so far.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
• /
• v.23 no.6
• /
• pp.96-103
• /
• 2009

Wind power, Solar power and Fuel cell is the representative of new and renewal energy sources. In this paper, the frictional noise made by vehicles tire on roads is considered and researched as alternative electrical generation source. The amplitude and waveform of generated electricity with various types of vehicles according to their velocity, weight and distances between vehicles and sensor are measured and analyzed. As a result, all difference effects mentioned above which make the frictional noise affect quality and quantity of generated electricity. Maximum 0.53[V] and 0.028[W] electricity was generated by truck with 100[km/h] velocity on the express way.

• Journal of the Korean Solar Energy Society
• /
• v.39 no.6
• /
• pp.93-112
• /
• 2019

In this paper, a very new web-based software for renewable energy system (RES) design and economic evaluation was introduced. This solution would provide the precise RES estimation service including not only photovoltaic (PV), wind turbine (WT) and fuel cell (FC) individually but also energy storage system (ESS) as combined forms with PV or WT. The three reasons why we ought to develop it are: First, the standardized tool suitable to the domestic environment for estimating power generation from RES facilities and economic evaluation is required. Secondly, the standardized tool is needed to spread domestic RES supply policy and to promote the new industry in the micro-grid field. The last, the reliability of economic evaluation should be enhanced more for new facilities. To achieve those aims, the weather database of one hundred locations have established and the RES facility database has also constructed. For the energy management, mathematical models for PV, WT, ESS and FC were developed. As a final phase, the analytical process to evaluate economics has performed with field data verification.

• Journal of the Korea Organic Resources Recycling Association
• /
• v.21 no.1
• /
• pp.39-44
• /
• 2013

This study evaluated the effect of fluid flow on the power density in a horizontal-flow microbial fuel cell (MFC). The maximum power densities in four types of flow induced by different channel types in the anode chamber were investigated. The fluid flow at each channel was analyzed using tracer tests. Results of polarization curves showed that the maximum power densities of case 1, 2, 3 and 4 were 95.7, 129.1, 190.9 and 114.2 mW/m2, respectively. Case 3 with a set of guide walls where flow had an S type-like shape showed the highest power density. Based on the Morrill Dispersion Index (MDI) value of case 4, microbial activity would be enhanced since the reactor allows even distribution of substrate but the overflow occurrence would not guarantee stable performance. Therefore, case 3 could be an effective reactor type for MFC because of high electricity generation and stable performance.