• Communications for Statistical Applications and Methods
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• v.29 no.6
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• pp.709-719
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• 2022

Recently, as the importance of environmental protection has emerged, interest in new and renewable energy is also increasing worldwide. In particular, the solar energy sector accounts for the highest production rate among new and renewable energy in Korea due to its infinite resources, easy installation and maintenance, and eco-friendly characteristics such as low noise emission levels and less pollutants during power generation. However, although climate prediction is essential since solar power is affected by weather and climate change, solar radiation, which is closely related to solar power, is not currently forecasted by the Korea Meteorological Administration. Solar radiation prediction can be the basis for establishing a reasonable new and renewable energy operation plan, and it is very important because it can be used not only in solar power but also in other fields such as power consumption prediction. Therefore, this study was conducted for the purpose of improving the accuracy of solar radiation. Solar radiation was predicted by a total of three weather variables, temperature, humidity, and cloudiness, and solar radiation outside the atmosphere, and the results were compared using various models. The CatBoost model was best obtained by fitting and comparing the Boosting series (XGB, CatBoost) and RNN series (Simple RNN, LSTM, GRU) models. In addition, the results were further improved through Time series cross-validation.

• IE interfaces
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• v.25 no.4
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• pp.441-449
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• 2012

Solar PV(photovoltaic) is paid great attention to as a possible renewable energy source to overcome recent global energy crisis. However to be a viable alternative energy source compared with fossil fuel, its market competitiveness should be attained. Grid parity is one of effective measure of market competitiveness of renewable energy. In this paper, we forecast the grid parity timing of solar PV energy in Korea using two factor learning curve model. Two factors considered in the present model are production capacity and technological improvement. As a result, it is forecasted that the grid parity will be achieved in 2019 in Korea.

• Advances in Energy Research
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• v.4 no.1
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• pp.1-28
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• 2016

A grid-connected photovoltaic (PV) system comprised of multicrystalline silicon (mc-Si) modules was installed in a cold climate region in the U.S. This roof-mounted stationary PV system is a real-world application of PV for building energy generation in International Energy Conservation Code (IECC) Climate Zone 5 (and possibly similar climate zones such as 6, 7 and 8), and it served the purposes of research, demonstration, and education. The importance of this work is highlighted by the fact that there has been less emphasis on solar PV system in this region of the U.S. because of climate and latitude challenges. The system is equipped with an extensive data acquisition system capable of collecting performance and meteorological data while visually displaying real-time and historical data through an interactive online interface. Experimental data was collected and analyzed for the system over a one-year period with the focus of the study being on measurements of power production, energy generation, and efficiency. The annual average daily solar insolation incident upon the array was found to be $4.37kWh/m^2$. During the first year of operation, the PV system provided 5,801 kWh (1,264 kWh/kWp) of usable AC electrical energy, and it was found to operate at an annual average conversion efficiency and PR of 10.6 percent and 0.79, respectively. The annual average DC to AC conversion efficiency of the inverter was found to be 94 percent.

• Journal of the Korean Vacuum Society
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• v.16 no.3
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• pp.161-166
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• 2007

Photovoltaic (PV) technology permits the transformation of solar light directly into electricity. For the last five years, the photovoltaic sector has experienced one of the highest growth rates worldwide (over 30% in 2006) and for the next 20 years, the average production growth rate is estimated to be between 27% and 34% annually. Currently the cost of electricity produced using photovoltaic technology is above that for traditional energy sources, but this is expected to fall with technological progress and more efficient production processes. A large scale production of solar grade silicon material of high purity could supply the world demand at a reasonably lower cost. A shift from crystalline silicon to thin film is expected in the future. The technical limit for the conversion efficiency is about 30%. It is assumed that in 2030 thin films will have a major market share (90%) and the share of crystalline cells will have decreased to 10%. Our research at Sungkyunkwan University of South Korea is confined to crystalline silicon solar cell technology. We aim to develop a technology for low cost production of high efficiency silicon solar cell. We have successfully fabricated silicon solar cells of efficiency more than 16% starting with multicrystalline wafers and that of efficiency more than 17% on single crystalline wafers with screen printing metallization. The process of transformation from the first generation to second generation solar cell should be geared up with the entry of new approaches but still silicon seems to remain as the major material for solar cells for many years to come. Local barriers to the implementation of this technology may also keep continuing up to year 2010 and by that time the cost of the solar cell generated power is expected to be 60 cent per watt. Photovoltaic source could establish itself as a clean and sustainable energy alternate to the ever depleting and polluting non-renewable energy resource.

• Journal of the Korean Solar Energy Society
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• v.31 no.4
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• pp.27-33
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• 2011

To find effective way of the production of distilled water for drought and flood with solar radiation, three boxes were made same base each 1000mm ${\times} $1000mm and tops are 45 degree. Individual boxes contained the sea water, rain water and surface water were placed at the same location and same time. Condensation of each box has been compared. On clear day production of distilled water in the box with sea water was 36% and 32% less than boxes with rain water and surface water. The maximum condensation reached when the temperature of the top and bottom parts are equal. As concentration of sea water increased production of distilled water was decreased. In the box with sea water, the surface temperature was lower than 3cm below the surface. Optimum collector area for producing distilled water 2000ml of these three boxes were $3.75m^2$

• New & Renewable Energy
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• v.17 no.2
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• pp.40-49
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• 2021

This paper explains the development process of methane decomposition to hydrogen and carbon black using solar thermal energy. It also demonstrates the advantages and disadvantages of five different reactors for each development stage, including the reactor's experimental results. Starting with the initial direct heating type reactor, the indirect heating type reactor was developed through five modifications. The 40-kWth solar furnace installed at the Korea Institute of Energy Research was used for the experiment. In the experiment using the developed indirect heating reactor, an 89.0% methane to hydrogen conversion rate was achieved at a methane flow rate of 40 L/min, obtained at about twice the flow rate compared to previous advanced studies.

• Solar Energy
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• v.18 no.1
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• pp.3-18
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• 1998

Since entered into force in 1994, United Nations Framework Convention on Climate Change(UNFCCC) would require all the member nations to adopt national programme for mitigating climate change and industrialized countries to undertake specific commitments of carbon dioxide emission reduction. Considering all the situation, it may be safe to assume that Korea would undertake such commitment early in the next century. Unfortunately, however, we are in the position that is very disadvantageous in preparing national strategies for carbon dioxide reduction mainly due to our rigid energy-intensive economic structure and poor geographic conditions. Solar energy is regarded as most available renewable energy resource in Korea and hence development of solar energy technology would serve as one of most effective alternatives for energy conservation and renewable energy utilization. In this regard, the presenting paper discuss the perspectives on solar energy development in relation to carbon dioxide reduction strategies. Such technologies of solar cell mass production and solar heating were considered to be most advantageous among many solar energy solutions discussed in this paper.

• Journal of Biosystems Engineering
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• v.16 no.4
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• pp.399-407
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• 1991

In Korea, the cultivation area under the plastic greenhouse was 1,746 ha in 1975, and 36,656 ha in 1989, it shows that the greenhouse cultivation area was increased by 21 times during last 14 years. The greenhouse cultivation area of 90~93% has been kept warm with double layers of plastic film and thermal curtain knitted with rice straw, and the rest area of 7~10% has been heated by fossil fuel energy. The use of rice straw thermal curtain is inconvenient to put it on and off, on the other hand the use of fossil fuel heating system results in the increase of production cost. To solve these problems, at first the heating load and the storable solar energy in greenhouse during the winter season were predicted to design solar utilization system, secondly a solar thermal storage system filled with latent heat storage materials was developed in this study. And then finally the thermal performance of greenhouse-solar energy storage system was analyzed theoretically and experimentally.

• Journal of the Korean Society of Industry Convergence
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• v.27 no.2_1
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• pp.277-285
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• 2024

Hydrogen is considered a key energy source to achieve carbon neutrality through the global goal of 'net zero'. Due to limitations in producing green hydrogen domestically, Korean companies are interested in importing green hydrogen produced overseas. The Middle East has high-quality solar energy resources and is attracting attention as a region producing green hydrogen using renewable energy. To build a green ammonia plant, optimization of the production facility configuration and economic feasibility analysis are required. It is expected that it will contribute to reviewing the economic feasibility of constructing overseas hydrogen production plants through preliminary economic feasibility analysis.

• Transactions of the Korean hydrogen and new energy society
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• v.15 no.4
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• pp.324-332
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• 2004

According to the rapid depletion of the fossil fuels, the electricity and hydrogen will gradually take charge of the future energy supply. Especially, in order to control the supply and demand of electricity, energy storage medium is necessary and this could be solved by the combination of water electrolysis and fuel cell. Although electricity can be generated from such alternative energies as hydropower, nuclear, solar, and wind-power resources, alternative energy storage medium is also required since regenerative energies, solar and wind-powers, are intermittent energy resources. In this regard, hydrogen production from water electrolysis was recognized as a superb method for electricity storage. In this work, the current development and economic status of alkaline, solid polymer, and high temperature electrolysis were reviewed, and then the practical use of water electrolysis technology were discussed.