• KSBB Journal
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• v.20 no.6
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• pp.393-400
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• 2005

Hydrogen($H_2$) as a clean, and renewable energy carrier will be served an important role in the future energy economy. Several biological $H_2$ production processes are known and currently under development, ranging from direct bio-photolysis of water by green algae, indirect bio-photolysis by cyanobacteria including the separated two stage photolysis using the combination of green algae and photosynthetic microorganisms or green algae alone, dark anaerobic fermentation by fermentative bacteria, photo-fermentation by purple bacteria, and water gas shift reaction by photosynthetic or fermentative bacteria. In this paper, biological $H_2$ production processes, that are being explored in fundamental and applied research, are reviewed.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2013.10a
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• pp.914-916
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• 2013

Renewable energy from the environment in a variety of ways to obtain various forms of energy. Recent functional polymer composites (EAP) to take advantage of the pressure and vibration of physical energy into electrical energy storage, to take advantage of current collector technology is attracting attention. EAP, a type of IPMC (Ionic exchange Polymer Composite) got a hydrophilic properties, marine power plants is being studied as a source of energy. Studies using IPMC marine power plant because there is a constraint on the time, IPMC in real time, which can measure the power generated by the system is required, Due to the nature of the power plant to be floating in the sea through the power cable and data transmission measurement system is hard drive self-generation and wireless data transmission system is required. In this study, IPMC marine power plant is to develop a system of monitoring. IPMC for several power plants to build individual current-voltage measurement system, CAN communication with the main system to collect all the information and wireless data transmission to occur, and Generation of electricity using solar energy to building systems in real-time without an external power supply to drive the measuring system is to develop a monitoring system.

• The Journal of the Korea institute of electronic communication sciences
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• v.17 no.4
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• pp.595-606
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• 2022

Korea has the characteristics of traditional power system such as large-scale power generation and large-scale power transmission systems, including 20 GW large-scale power generation complexes in several regions with unit generator capacity exceeding 1.4 GW, 2-3 ultra-high-voltage transmission lines that transport power from large-scale power generation complexes, and 6 ultra-high-voltage transmission lines that transport power from non-metropolitan areas to the metropolitan area. Due to the characteristics of the power system, the penetration level for renewable energy is low, but due to frequency stability issue, some generators are reducing the output of generators. In the future, the issue of maintaining the stability of the power system is expected to emerge as the most important issue in accordance with the policy of expanding renewable energy. When non-inertial inverter-based renewable energy, such as solar and wind power, surges rapidly, the means to improve the power system stability in an independent system is to install a natural inertial resource synchronous condenser (SC) and a virtual inertial resource BESS in the system. In this study, we analyzed the effect of renewable energy on power system stability and the BESS effect to maintain the minimum frequency through a power system simulation. It was confirmed that the BESS effect according to the power generation constraint capacity reached a maximum of 122.81 %.

• Journal of Astronomy and Space Sciences
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• v.24 no.1
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• pp.69-78
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• 2007

The international EARTHSHINE mission is to measure 1% anomaly of the Earth global albedo and total solar irradiance using Amon-Ra instrument around Lagrange point 1. We developed a new ray truing based integrated end-to-end simulation tool that overcomes the shortcomings of the existing end-to-end performance simulation techniques. We then studied the in-orbit radiometric performance of the breadboard Anon-Ra visible channel optical system. The TSI variation and the Earth albedo anomaly, reported elsewhere, were used as the key input variables in the simulation. The output flux at the instrument focal plane confirms that the integrated ray tracing based end-to-end science simulation delivers the correct level of incident power to the Amon-Ra instrument well within the required measurement error budget of better than ${\pm}0.28%$. Using the global angular distribution model (ADM), the incident flux is then used to estimate the Earth global albedo and the TSI variation, confirming the validity of the primary science cases at the L1 halo orbit. These results imply that the integrated end-to-end ray tracing technique, reported here, can serve as an effective and powerful building block of the on-line science analysis tool in support of the international EARTHSHINE mission currently being developed.

• The Journal of the Convergence on Culture Technology
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• v.9 no.5
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• pp.523-528
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• 2023

The applicability as a material to improve solar cell performance was reviewed by synthesizing a phosphor that emits red wavelengths by a liquid synthesis method using a metal salt aqueous solution and a polymer medium as a starting material. An aqueous solution was prepared using nitrate of metals such as Ca, Zn, Al, and Eu, and a precursor impregnated with starch, a natural polymer, was sintered to synthesize CaZnAlO:Eu phosphor powder. The surface structure and composition analysis of the synthesized CaZnAlO:Eu phosphor powder were analyzed by scanning electron microscope(SEM) and energy-dispersed X-ray spectroscopy(EDS). The crystal structure of CaZnAlO:Eu phosphor particles was analyzed by an X-ray diffraction analyzer (XRD). As a result of measuring the photoluminescence(PL) characteristics of the phosphor, it was confirmed that a red phosphor with a light emitting wavelength of 650-780nm was successfully synthesized. According to SEM and EDS analysis, the synthesized Ca₁₄Zn₆Al_9.93O₃₅:Eu³⁺_0.07 phosphor powder has a uniform particle size, and Eu ions used as an activator are present. The synthesized CZA:Eu³⁺ phosphor can be used as a material that can increase the light absorption efficiency of the solar cell by converting ultraviolet or visible light down conversion into a wavelength in the near-infrared region.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.12 no.4
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• pp.202-209
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• 2002

The stochiometric mix of evaporating materials for the $CuInSe_2$single crystal thin films was prepared from horizontal furnace. To obtain the single crystal thin films, $CuInSe_2$compound crystal was deposited on thoroughly etched semi-insulating GaAs(100) substrate by the Hot Wall Epitaxy (HWE) system. The source and substrate temperature were $620^{\circ}C$ and $410^{\circ}C$, respectively. The crystalline structure of single crystal thin films was investigated by the photoluminescence and double crystal X-ray diffraction (DCXD). The carrier density and mobility of $CuInSe_2$single crystal thin films measured from Hall effect by van der Pauw method. From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the $CuInSe_2$single crystal thin film, we have found that the values of spin orbit splitting $\Delta$So and the crystal field splitting $\Delta$Cr. From the photoluminescence measurement on $CuInSe_2$single crystal thin film, we observed free exciton ($E_x$) existing only high quality crystal and neutral bound exciton ($A^{\circ}$, X) having very strong peak intensity. Then, the full-width-at-half-maximum (FWHM) and binding energy of neutral donor bound exciton were 7 meV and 5.9 meV, respectivity. By haynes rule, an activation energy of impurity was 59 meV.

• The Journal of the Korea institute of electronic communication sciences
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• v.15 no.1
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• pp.71-78
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• 2020

In the case of power generation using renewable energy, power production may not be smooth due to the influence of the weather. The energy storage system (ESS) is used to increase the efficiency of solar and wind power generation. ESS has been continuously fired due to a lack of battery protection systems, operation management, and control system, or careless installation, leading to very big casualties and economic losses. ESS stability and battery protection system operation management technology is indispensable. In this paper, we present a battery level calculation algorithm and a failure prediction algorithm for ESS optimization and stable operation. The proposed algorithm calculates the correct battery level by accumulating the current amount in real-time when the battery is charged and discharged, and calculates the battery failure by using the voltage imbalance between battery cells. The proposed algorithms can predict the exact battery level and failure required to operate the ESS optimally. Therefore, accurate status information on ESS battery can be measured and reliably monitored to prevent large accidents.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.20 no.2
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• pp.8-15
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• 2006

To reduce costs and address other practical concern related to architectural lighting, we have been involved in various aspects of advanced daylighting design and control. If we look toward future building trends, we see that the advanced has already successfully deployed such complex lighting control systems. This paper takes a broad view of what advanced manufacturers have done to develop energy efficient lighting control technologies such as sensors, lumen maintenance, time of day scheduling, peak demand reduction and so forth. First of all strategies, daylighting controls would also need to be commissioned to respond to the specific daylighting signature of the zone. To translate the daylight in term of the amount of energy savings, an electric lighting system is designed and automatic on-off control system integrated with the contribution of daylighting has been applied to the operating of the artificial lighting. The lighting analysis program, Lumen-Micro predicts the optimal layout of conventional fluorescent and incandescent lighting fixtures to meet the designed lighting level and calculates unit power density, which translates the demanded amount of lighting energy.

• Journal of the Korean Society of Marine Environment & Safety
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• v.29 no.2
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• pp.127-138
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• 2023

A variety of decarbonized energy sources are being developed globally to realize carbon neutrality (Net Zero) by 2050 as a measure to address the global climate crisis. As the Korean government has also established a Renewable Energy 3020 policy and promoted energy development plans using solar or wind power, large-scale offshore development projects not present before in coastal waters, such as offshore wind farms, are being promoted. From ships' point of view, offshore facilities present obstacles to safe navigation, and with the installation of marine facilities, ship collisions or contact accidents between ships and marine facilities may occur in the narrowed water areas. In addition, there are concerns about environmental pollution and human casualties caused by marine accidents. Accordingly, we review overseas and domestic offshore wind farm development plans, analyze whether institutional devices are in place to ensure the safe passage of ships in wind farm areas, and study the safe operation of large-scale offshore wind farms and safe passage of ships along the Korean coast by comparing overseas legislative cases with domestic laws and presenting a proposal to illuminate the legal blind sectors.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.13 no.3
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• pp.1288-1295
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• 2012

Korea Ministry of Knowledge Economy has estimated that wind power (WP) will be occupied 37% in 2020 and 42% in 2030 of the new energy sources, and also green energies such as photovoltaic (PV) and WP are expected to be interconnected with the distribution system because of Renewable Portfolio Standard (RPS) starting from 2012. However, when a large scale wind power plant (over 3[MW]) is connected to the traditional distribution system, protective devices (mainly OCR and OCGR of re-closer) will be occurred mal-function problems due to changed fault currents it be caused by Wye-grounded/Delta winding of interconnection transformer and %impedance of WP's turbine. Therefore, when Double-Fed Induction Generator (DFIG) of typical WP's Generator is connected into distribution system, this paper deals with analysis three-phase short, line to line short and a single line ground faults current by using the symmetrical components of fault analysis and PSCAD/EMTDC modeling.