• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.44-46
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• 2008

Air-breathing polymer electrolyte membrane fuel cells (PEMFC) are highly promising particularly for small-power applications up to tens watts class. A distinctive feature of the air-breathing PEMFC is its simple system configuration in which axial fans operate for dual purposes, supplying both oxidant and coolant in a single manner. In the present study, a nominal 80W air-breathing PEMFC system is developed and investigated to determine the optimal operating strategy through parametric studies (i.e., reactant humidity, and fanblowing flow rate). The cell voltage distributions are examined as a function of time to evaluate the system performance under various operating conditions.

• Proceedings of the SAREK Conference
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• 2008.06a
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• pp.1184-1189
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• 2008

This paper is a study about characteristics of the SSC-1 nozzle, which is used in a fire extinguishing system in a ship. Through this paper, we can find that the traces and elements’ distributions obtained from experiments are as the same as the simulation analysis results of CFD program. At the point of 100mm, the $\alpha$ is 34.9 in the CFD analysis, and it is 32.5 in the experiment. This shows that there is no big different between the CFD analysis and the experiment result. And the average elements velocity is similar to the SMD.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.59 no.2
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• pp.225-231
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• 2010

As growth of operational complexity in power systems, necessity of information integration between automation systems such as EMS, SAS, DAS and renewable energy sources has been increased. This paper proposes a new information integration architecture between power automation systems based on web service technique. Loosely coupled feature of web service system can provide more flexible and reliable way to exchange information. Communication testing on the demonstration system has been performed to establish the feasibility of the proposed architecture.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.125-129
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• 2006

This paper presents the isolation and performance evaluation of PV systems installed at Tibet area of China in order to identity the key factors that determines system operation at a severe climate conditions and promote the cooperation of PV technology between Korea and China. The installed systems consist of 100kW on-grid connected PV systems, BOS(balance of systems), data acquisition and transmission equipments. The Korea side supplied the solar cell, BOS like as inverter, control box and monitoring system. And the Chinese side assembled solar module by using Koreans solar cells, constructed site and built control house.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.249-252
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• 2006

Wind turbine gearbox is a complex mechanical system that includes gear trains, shafts, bearings, and gearbox housings. All these component are interacting with each other therefore changing certain design parameter will affect other components. RomaxDesigner enables a reduction in development period by simulating the full gearbox system. The gear pairs, bearings and shafts are represented as analysis objects and the complex components are modelled by means of reduced stiffness matrices. The software allows durability analysis and advanced contact analysis including the effects of system misalignments in gear and bearing. In this paper the 2MW wind turbine gearbox was model led and a study on optimum design was conducted

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.323-324
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• 2006

In the present paper a forecasting system of wind power generation for Walryong Site, Jejudo is presented, which has been developed and evaluated as a first step toward establishing Korea Forecasting Model of Wind Power Generation. The forecasting model, KIER forecaster is constructed based on statistical models and is trained with wind speed data observed at Gosan Weather Station nearby Walryong Si to. Due to short period of measurements at Walryong Site for training statistical model, Gosan wind data were substituted and transplanted to Walryong Site by using Measure-Correlate-Predict technique. Three-hour advanced forecast ins shows good agreement with the measurement at Walryong site with the correlation factor 0.88 and MAE(mean absolute error) 15% under.

• 한국신재생에너지학회:학술대회논문집
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• 2006.06a
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• pp.73-76
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• 2006

본 연구에서는 독일 율리히 연구소에서 도입된 면적 200mm*200mm의 연료극 지지체 평판형 SOFC 셀 및 금속 분리판 40장을 적층하여 5kW급 SOFC 스택을 제작하고 연속운전을 수행하여 운전특성을 분석했다. 본 연구를 통해 도입된 5kW급 SOFC 스택은 외국에서 시도된 적이 없는 평판형 SOFC스택의 가압운전을 시도해 보는 것으로서, 스택의 임계압력 특성을 확인하고, 이를 바탕으로 가스터빈-연료전지 하이브리드 시스템에서의 SOFC 스택 가압 운전기술을 확보하는 것이다 이러한 목적을 위해 본 연구에서는 상압형 5kW급 SOFC 스택 운전시스템에 대한 구성과 설계, 전반적인 운전 특성평가 (40셀 스택 운전 열 사이클 시험 연료 전환 $(H_2{\rightarrow}pre-reformed\;gas)$, 1200시간 연속운전 등)가 이뤄졌다.

• Journal of the Semiconductor & Display Technology
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• v.17 no.1
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• pp.84-87
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• 2018

As the propeller end speed increases, the propeller surface is damaged in the process of bubble formation and dropout. It is intended to prevent the corrosion of the propeller by modifying the shape of the end through the winglet structure to mitigate the cavitation phenomenon. In the case of conventional SUS materials, the cost of production is so high that plastic materials are used to prevent corrosion. This paper aims to mitigate the cavitation by deforming the shape of the end through the winglet structure by using the SMC composite material of the propeller using the existing SUS.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.2
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• pp.149-155
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• 2023

Photovoltaic power generation is the most familiar power generation facility among new and renewable energies, and its supply began to expand about 10 years ago, and at this point, interest in solutions and technologies for system maintenance management is increasing. In particular, it is necessary to take measures to maximize the overall efficiency of the solar power generation system, whether or not there is an abnormality in the solar power generation system, and when to replace parts. The PV inverter, one element of the photovoltaic power generation system, is a power conversion system that relies on power switching devices, and DC-Link capacitors are used according to the configuration of DC/DC converters and DC-AC inverters. These DC capacitors also affect system safety (Safety) through renewable energy facilities due to the decrease in power generation of PV inverters, power loss, and increase in harmonics (THD, total distortion of AC output current) due to aging and deterioration due to long-term use. factors can be analyzed. Therefore, in this paper, the PV inverter operating characteristics according to the DC capacitor capacity state currently operating in the photovoltaic power generation system were considered, and research contents were proposed to secure the safety and reliability of renewable energy facilities.

• Journal of Energy Engineering
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• v.22 no.2
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• pp.112-119
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• 2013

The thermal performance for test system with evacuated tubular solar collector is experimentally investigated to obtain the basis data for developing new type solar collector. For this purpose, the test system was designed using CATIA and then after being manufactured, the system was tested using evacuated tubular solar collector. Numerical analysis, furthermore, was performed using ANSYS Fluent V.13 for glass evacuated tubular solar collector. The results showed that as setting temperature difference(${\Delta}T$) of system was increased, total operating(working) time was almost same in all cases, even though operating count was decreased. The results of numerical analysis showed that as temperature of solar absorber in glass evacuated tubular solar collector was high, the drop-rate of temperature of center part was increased.