• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.84.1-84.1
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• 2010

Currently, new and renewable energy come into the spotlight, such as solar energy, wind power, fuel cell, hybrid car etc., due to the energy resource is being depleted. Especially, in order to solve like this problem, the study of solar cell manufacturing systems are being extensively researched such as vacuum process. But the major fault of the vacuum process are its expensive production price. On the order hand, Roll-to-roll printing system, the new technology of solar cell manufacturing, has low production price compare with the vacuum process. Also roll-to-roll printing system can decrease the 95% of waste water and 99.9% of harmful gasses than the vacuum process. So we addressed the roll to roll printing system for the flexible solar cell by using printing technology. This roll-to-roll printing system is comprised of various modules, such as web handling module, fine pattern printing module, dry/curing module, uniform coating module and laminating module etc.

• Journal of the Korean Solar Energy Society
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• v.26 no.2
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• pp.43-51
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• 2006

New renewable energy information becomes one of the greatest issues all over the world because of serious environment problems and limited fossil resources. The new renewable energy source information system is treated seriously for efficient management and distribution as dealing with these energy problems. However, it is difficult to manage and utilize new renewable energy information because gathering and surveying information is progressed individually in each research field. Therefore this paper will establish ISP(Information Strategy Planning) and propose the basic management system based-on GIS to analyze new renewable energy such as solar energy, wind power, small hydro, biomass, geothermal etc. and build the integration management system. The proposed integration management system can provide spatial analysis using thematic map, data search, data import/export and interpolation about users' queries.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.12
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• pp.1873-1878
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• 2017

Both the introduction of the Renewable Energy Portfolio Standard (RPS) system into the electric energy market in 2012 and a decrease in the cost of constructing photovoltaic (PV) power plants have been increasing the number of MW PV plants in South Korea. Jeju Island is located at the center of three nations, South Korea, China and Japan, and its provincial government declared in 2012 that the island will be a clean region where greenhouse gases are not emitted by 2030. The Jeju provincial government is now doing its best to install PV plants and wind farms to realize a carbon-free island. In this study we investigated contribution of MW PV plants to the power of the electric grid during summer peak times on Jeju Island. Mt. Halla the highest mountain in South Korea, is located at the center of Jeju Island, and we divided the island into four regions and carried out analyses of a total of 24 PV plants. The average contribution of the PV plants in the respective region to electric power of Jeju Island during summer peak times was investigated and compared with those of the other regions. The best average contribution during the 12.5% maximum load period was obtained from the PV plants in the western region, and the value was 33% during 2015 and 2016.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.25 no.10
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• pp.1302-1309
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• 2021

Recently, the Korean Government announced the Korean New Deal as a national development strategy to overcome the economic recession from the pandemic crisis and lead the global action against structural changes. In the Korean New Deal, the Green New Deal related with the energy aims to achieve net-zero emissions and accelerates the transition towards a low-carbon and green economy. To this end, the government plans to promote an increased use of renewable energy in the society at large. This paper introduces a binary power generation using unused low-grade thermal energy to accelerate the transition towards a low-carbon and green economy and examines a control system based on Neural Network which is capable maintenance at low-cost by an unmanned automated operation in actual power generation environment. It is expected that the realization of binary power generation accelerates introduction of renewable energy along with solar and wind power.

• Journal of the Korea Concrete Institute
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• v.17 no.4 s.88
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• pp.551-558
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• 2005

The setting and hardening of concrete is accompanied with nonlinear temperature distribution caused by development of hydration heat of cement. Especially at early ages, this nonlinear distribution has a large influence on the crack evolution. As a result, in order to predict the exact temperature history in concrete structures it is required to examine thermal properties of concrete. In this study, the convection heat transfer coefficient which presents thermal transfer between surface of concrete and air, was experimentally investigated with variables such as velocity of wind, curing condition and ambient temperature. At initial stage, the convection heat transfer coefficient is overestimated by the evaporation quantity. So it is essential to modify the thermal equilibrium considered with the boiling effect. From experimental results, the convection heat transfer coefficient was calculated using equations of thermal equilibrium. Finally, the prediction model for equivalent convection heat transfer coefficient including effects of velocity of wind, curing condition, ambient temperature and boiling effects was theoretically proposed. The convection heat transfer coefficient in the proposed model increases with velocity of wind, and its dependance on wind velocity is varied with curing condition. This tendency is due to a combined heat transfer system of conduction through form and convection to air. From comparison with experimental results, the convection heat transfer coefficient by this model was well agreed with those by experimental results.

• Journal of Agricultural Extension & Community Development
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• v.11 no.2
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• pp.251-265
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• 2004

The agricultural sector's economic structure in Korea is regarded to encounter major barriers on the way toward revitalizing its economic prosperity. Among many, the energy-related problem is one of prime nuclei embedded in the country's agricultural sector. The ought-to-come structural changes in the country's agricultural energy system hinge upon the central government's policy direction as well as efforts of local governments and local farming community members. The indirect aids via 'cross subsidy' of electricity tariff rate and 'tax-exempt price' of oil fuels are two notable causes of the unsustainable energy consumption pattern in the country's agricultural sector. As measures, demand-side management(DSM) and energy-efficiency promotions are regarded to be the most attractive methods for energy conservation and economic productivity as well. Development of renewable energy sources are also receiving a great deal of attention for the long-term alternatives to the country's existing oil-based agricultural production mode. This study examines the contributive potential of DSM approaches and renewables-based technologies. With the critical evaluation on the concurrent adversities of the country's agricultural energy system, various sources of renewable energy-solar power, wind power, biomass, etc.-are examined for the purpose of technological and economical viability. As sufficient potentials of renewable energy sources are being estimated, both the system production cost and the installation cost for the county's rural areas are expected to lower in the long term. DSM options are also evaluated to be fruitful even in the short term. Both the public and civil arenas must galvanise each side's effort in order to promote these policy options and community potentials.

• Journal of the Korea Convergence Society
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• v.2 no.2
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• pp.47-56
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• 2011

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.

• Journal of Mechanical Science and Technology
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• v.19 no.10
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• pp.1856-1863
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• 2005

In this study, a visual sensor system for weld seam tracking the I-butt weld joints in GMA welding was constructed. The sensor system consists of a CCD camera, a diode laser with a cylindrical lens and a band-pass-filter to overcome the degrading of image due to spatters and arc light. In order to obtain the enhanced image, quantitative relationship between laser intensity and iris opening was investigated. Throughout the repeated experiments, the shutter speed was set at 1/1000 second for minimizing the effect of spatters on the image, and therefore the image without the spatter traces could be obtained. Region of interest was defined from the entire image and gray level of the searched laser stripe was compared to that of weld line. The differences between these gray levels lead to spot the position of weld joint using central difference method. The results showed that, as long as weld line is within $\pm15^{o}$ from the longitudinal straight line, the system constructed in this study could track the weld line successfully. Since the processing time is no longer than 0.05 sec, it is expected that the developed method could be adopted to high speed welding such as laser welding.

• Journal of the Korean Institute of Gas
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• v.21 no.6
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• pp.23-29
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• 2017

Solar and wind energy among the renewable energy produce irregular power because resource is difficult to control. When connected to grid have unstable. However, when the fuel cell system is connected to grid more stable because regular frequency and output power based on controllable hydrogen energy. To using fuel cell system in the household, it is important that the safety performance of power conditioning system(PCS) and it is important that evaluation method of electromagnetic compatibility(EMC). In this study, we consider that introduce power-frequency magnetic field immunity test before analyzed that compare with the EMC of the international standards and KGS AB 934 PC53. Also, we conduct that actual assessment and study on available the quantitative analysis as using complementary indicator.

• 한국신재생에너지학회:학술대회논문집
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• 2009.06a
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• pp.121-125
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• 2009

There have been many developed systems for harnessing the solar energy such as solar water heaters, solar thermal power systems, PV systems, daylighting and solar hydrogen systems. all of them are capable of reducing $CO_2$ emission. However, the efficiency of those systems which work without a solar tracker is lower. This paper is a step by step procedure for fabrication and a performance test of a solar tracking system. The system developed in this study consists of motion controllers, motor drives, step-motors, feedback devices and application. CdS sensors are introduced into the solar tracking system for playing a primary role in poor conditions for tracking due to a gear backlash and a strong wind. Mini-dish was used as a concentrator for collecting sun light. The solar position data, in terms of azimuth and elevation, sunrise and sunset times was compared with those of KASI(Korea Astronomy & Space Science Institute). The results presented in this article provide the high accuracy of the present system in solar tracking and indicate a potential for energy savings.