• Solar Energy
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• v.18 no.3
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• pp.9-14
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• 1998

The present solar energy concentrator is a 2-dimensional system that incorporates with a tubular absorber. A new design theory is developed on the basis of the generalized edge-ray principle. The result shows the increase of concentration ratio for the same acceptance angle as the basic CPC by a factor of $C_{new}=C_{cpc}\{1+(d/{\pi}r)\;sin^2{\theta}_c\}$. For example, if ${\theta}_c=30^{\circ}$, the new design offers the concentration of $2.0{\sim}2.72$, whereas $C_{cpc}=2$. The new system also provide a thin and light-weight design.

• Annual Conference of KIPS
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• 2013.05a
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• pp.1044-1045
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• 2013

신재생에너지자원 사용의 확대와 더불어 그 안전성에도 관심이 고조되고 있다. 이에 따라 신재생에너지의 개발과 보급을 위한 데이터를 축적하고 관리, 활용할 수 있는 체계가 필요하다. 본 연구에서는 신재생에너지자원을 보다 효율적으로 활용하기 위한 WebGIS 기반의 시스템을 개발한다. 공간 데이터의 관리, 공간정보 서비스 인프라를 구축하기 위해서 기 구축된 시스템에 OGC의 표준을 적용하고, 평가를 위한 공간정보를 연계하여 신재생에너지자원의 개발 및 보급을 위한 경제성평가 모듈의 신뢰성을 향상시켰다. 이를 통해 신재생에너지 자원평가, 최적지 선정 및 잠재량 등에 대한 정밀한 분석 및 평가가 가능하며, Web기반의 시스템 개발을 통해 신재생에너지 정보의 활용성 증대, 신재생에너지에 대한 인식제고를 위한 도구로써 활용될 수 있다.

• New & Renewable Energy
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• v.19 no.4
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• pp.53-60
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• 2023

The Computational Fluid Dynamics (CFD) model is a method of studying the flow phenomenon of fluid using a computer and finding partial differential equations that dominate processes such as heat dispersion through numerical analysis. Through CFD, a lot of information about flow disorders such as speed, pressure, density, and concentration can be obtained, and it is used in various fields from energy and aircraft design to weather prediction and environmental modeling. The simulation used for fluid analysis in this study utilized Gexcon's (FLACS) CODE, such as Norway, through overseas journals, for the accuracy of the analysis results through many experiments. It was analyzed that a technology for treating two or more catalysts with physical properties under low-temperature atmospheric pressure conditions could not be found in the prior art. Therefore, it would be desirable to establish a continuous plan by reinforcing data that can prove the effectiveness of producing efficient synthetic oil (renewable oil) through the application that pyrolysis under low-temperature and atmospheric pressure conditions.

• Journal of the Korean Solar Energy Society
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• v.36 no.4
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• pp.11-20
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• 2016

For accurate wind resource assessment and wind turbine performance test, it is essential to secure wind data covering a rotor plane of wind turbine including a hub height. In general, we can depict wind speed profile by extrapolating or interpolating the wind speed data measured from a meteorological tower where multiple anemometers are mounted at different heights using a power-law of wind speed profile. The most important parameter of a power-law equation is a vertical wind profile exponent which represents local characteristics of terrain and land cover. In this study, we calculated diurnal vertical wind profile exponents of 8 locations in Jeju Island who possesses excellent wind resource according to the GUM (Guide to the Expression of Uncertainty in Measurement) to evaluate its uncertainty. Expanded uncertainty is calculated by combined standard uncertainty, which is the result of composing type A standard uncertainty with type B standard uncertainty. Although pooled standard deviation should be considered to derive type A uncertainty, we used the standard deviation of vertical wind profile exponent of each day avoiding the difficult of uncertainty evaluation of diurnal wind profile variation. It is anticipated that the evaluated uncertainties of diurnal vertical wind profile exponents at 8 locations in Jeju Island are to be registered as a national standard reference data and widely used in the relevant areas.

• Journal of Hydrogen and New Energy
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• v.29 no.3
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• pp.251-259
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• 2018

Metal hydride based hydrogen storage under moderate temperature and pressure gives the safety advantage over the gas and liquid storage methods. Still solid-state hydrogen storage including metal hydride is below the DOE target level for automotive applications, but it can be adapted to stationary or miliary application reasonably. In order to develop a modular solid state hydrogen storage system that can be applied to a distributed power supply system composed of renewable energy - water electrolysis - fuel cell, the heat transfer and hydrogen storage characteristics of the metal hydride necessary for the module system design were investigated using AB5 type metal hydride, LCN2 ($La_{0.9}Ce_{0.1}Ni_5$). The planetary high energy mill (PHEM) treatment of LCN2 confirmed the initial hydrogen storage activation and hydrogen storage capacity through surface modification of LCN2 material. Expanded natural graphite (ENG) addition to LCN2, and compression molding at 500 atm improved the thermal conductivity of the solid hydrogen storage material.

• Journal of the Korean Solar Energy Society
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• v.39 no.6
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• pp.137-151
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• 2019

This study estimated the available renewable market potential based on Levelized Cost Of Electricity and then assessed the renewable derived energy self-sufficiency for the unit of local government in South Korea. To calculate energy self-sufficiency, 1 km gridded market renewable generation and local government scale of final energy consumption data were used based on the market costs and statistics for the recent three years. The results showed that the estimated renewable market potentials were 689 TWh (Install capacity 829 GW, 128 Mtoe), which can cover 120% of power consumption. 55% of municipalities can fully replace the existing energy consumption with renewable energy generation and the surplus generation can compensate for the rest area through electricity trade. However, it was confirmed that, currently, 47% of the local governments do not fully consider all renewable energy sources such as wind, hydro and geothermal in establishing 100% renewable energy. The results of this study suggest that energy planning is decentralized, and this will greatly contribute to the establishment of power planning of local governments and close the information gap between the central government, the local governments, and the public.

• Journal of the Korean Solar Energy Society
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• v.37 no.5
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• pp.85-99
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• 2017

New and Renewable Energy Equipment Certification program has been integrated into the KS(Korean Industrial Standards) certification system as of July 29, 2015. This study is to determine whether the KS certification requirement has had a positive effect on corporate performance (e.g. quality improvement, financial result, customer satisfaction) within those that had already acquired the New and Renewable Energy Equipment KS certification. As a result, among the requirements for the KS certification, quality management, product management, and product testing have a positive impact on product quality improvement, and product testing has shown a positive influence on customer satisfaction. Although requisite for the KS certification did not have a significant effect on financial outcome such as increase in revenue, it has shown to have positive consequence to some extent on those firms that newly obtained the certification.

• Journal of Hydrogen and New Energy
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• v.2 no.1
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• pp.23-28
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• 1990

A search program which use only free energies of formation has been developed to find new thermochemical cycles as means of producing hydrogen and oxygen from water. The searching procedures are described and some closed thermochemical cycles from this program are presented here.

• Journal of Hydrogen and New Energy
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• v.17 no.3
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• pp.279-285
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• 2006

Recirculation for the unreacted fuel is necessary to improve the overall efficiency of the fuel cell system and to prevent fuel starvation since the fuel cell for a vehicle application is a closed system. In case of the automotive fuel cell, the ejector which does not require any parasitic power is good for the performance improvement and easy operation. It is essential to design the customized ejector due to the lack of the commercial ejector corresponding to the operating conditions of the fuel cell systems. In this study, the design methodology for the ejector customized to an automotive fuel cell is proposed. The model based sensitivity analysis prevents the time-consuming redesign and reduces the cost of developing ejector. As a result, the customized ejector to meet the desired performance within overall operating range has developed for the PEMFC automotive system.

• Journal of Hydrogen and New Energy
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• v.18 no.1
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• pp.60-66
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• 2007

In terms of the vehicle efficiency, a fuel cell hybrid system has advantages compared to a conventional internal combustion engine and a fuel cell alone-powered system. The efficiency of the fuel cell hybrid vehicle mainly depends on the maximum power of the fuel cell and therefore it is important to decide the design value of the fuel cell maximum power. In this paper, to estimate the performance of the fuel cell hybrid mini-bus in the design phase the simulator based on the models for the fuel cell stack, the electric battery, the fuel cell balance of plant, the controller, and the vehicle itself is proposed. Additionally, the hybrid mini-bus efficiencies with several different fuel cell powers are simulated for a city driving schedule and are compared on another. Consequently, the proposed simulation scheme is useful to determine the best design value of the fuel cell hybrid vehicles.