• Current Photovoltaic Research
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• v.6 no.2
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• pp.62-67
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• 2018

Multi-wire busbar-type bifacial n-type Si solar cells have been used for the fabrication of monofacial and bifacial photovoltaic (PV) module, where bifacial module was equipped with transparent backsheet while monofacial module was prepared using white backsheet. The comparison of six-day accumulated power production obtained from outdoor test under gray cement ground conditions using 60cell monofacial and bifacial PV modules suggested the bifacial gain of over 20% could be achieved. Furthermore, the outdoor evaluation tests of bifacial modules with different ground conditions such as cement (reference), green paint, white paint and green artificial grass, were performed. It turned out white paint showed the best albedo and thus the highest power production, while green paint and artificial grass showed less power generation than cement ground.

• New & Renewable Energy
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• v.5 no.3
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• pp.26-31
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• 2009

Using MBE growth method, GaAs/AlGaAs solar cell structure was grown. Deposited electrodes are Au/Ni/Ge for n-type and Au/Pt/Ti for p-type electrodes were deposited by E-beam evaporator. Indoor light concentrators were devised and fabricated in order to concentrate artificial solar rays. Also mirror and prism and Fresnel lens concentration system with solar simulator were devised and fabricated. Results of solar cell characteristics were measured with shutting system which can control the amount of light. Maximum power density was 2.13 W/$cm^2$ and maximum concentration was 124 sun, when mirror with Fresnel lens was used at $7854\;mm^2$ of shutter hole.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.28 no.7
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• pp.52-58
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• 2010

• Journal of the Korean Solar Energy Society
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• v.32 no.6
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• pp.11-21
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• 2012

In the normal office building, the energy consumption to maintain the reasonable intensity of illumination for the work by using the artificial illumination occupies 30% or greater of the whole building electric energy consumption. If the dependability of the artificial illumination is dropt by positively using the natural lighting from the outside, the large amount of electrical energy can be saved, in addition the more nice visual environment for work can be created. Daylight is lighting source that most closely match visual response of the human, because sunlight and skylight achieve the harmony. For this reason, the daylight of small amount than amount of the artificial lighting source also can give the same effect in work activities of human. In addition, if there is daylight at the window of the building, the energy can be saved by controlling the artificial lighting. In this paper, in the building using the photovoltaic power generation analyze the correlation between the amount of energy generated by photovoltaic and indoor illumination and this was proved through the simulation with Relux 2010. In addition, the amount of daylight inflow in the room and distribution was drawn by the equation and the ratio for the sectional dimming control of each lighting equipment was predicted and the energy saving amount according to this was calculated. As a result, the indoor illumination was satisfied with recommended illumination value of the office and consumption power could be reduced approximately with 20~70%.

• International journal of advanced smart convergence
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• v.12 no.2
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• pp.182-186
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• 2023

In this study, we measured the power and temperature of the floating horizontal solar cell in a coastal lagoon and compared with those of ground solar cell and water platform solar cell. Because the bottom surface of the floating horizontal solar cell was contacting the water, cooling effect was expected stronger than other cells. As a result of the measurement, the power of floating horizontal cell was 11.7% higher than that of the ground cell and 15% higher than that of the water platform cell. During the measurement, it was observed that water waves were continuously flowed on the top surface of floating horizontal cell by the wind, and it could be assumed that the cooling effect occurred not only on the bottom surface of the cell but also on the top surface. In order to analyze the cooling effect and power increasing of the horizontal cell in the wave situation, we measured power and temperature of the cell while generating artificial waves in a laboratory equipped with Zenon lamp as a solar simulator. At the height of thewater surface, the power of the cell with waves was 3.7% higherthan without waves and temperature was 4.6℃ lower. At 1 cm and 2 cm below the watersurface, power of the cell with waves was decreased by 14% and 11% than without waves while temperature was same . At 3 cm below the water surface, there was no effect of waves.

• 한국태양에너지학회:학술대회논문집
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• 2009.04a
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• pp.170-175
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• 2009

Apartment housing block has been spreaded according to rapid economic development and urbanization in Korea. A parking lot is located at underground, artificial ground is inevitably created in apartment housing block. Artificial ground creates different thermal environment compared to natural ground, because the composition and coverage of artificial ground are diverse. In this study, the effect of the artificial ground on building thermal environment will be disscussed by simulation. Considering the result of simulation, surface albedo is more important for building energy performance. A purpose of this study is to examine how the characteristic of surface effect to thermal environment, and to develop design method for sustainable outdoor space.

• 한국태양에너지학회:학술대회논문집
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• 2011.04a
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• pp.282-286
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• 2011

The artificial increase in the solar intensity incident on solar cells using lenses or mirrors can allow solar cells to generate equivalent power with a lower cost. In application areas of Fresnel lenses as solar concentrators, several variations of design were devised and tested. Some PV systems still use commercially available flat Fresnel lenses as concentrators. In this study, we designed and optimized flat Fresnel lens and the 'light pipe' to develop 500X concentrated solar PV system. We performed rigorous ray tracing simulation of the flat Fresnel lens and light-pipe. The light-pipe can play imporatant roles of redistributing solar energy at the solar cell and increase the mechanical tolerance so that it can increase the lifetime of the high-concentration solar PV system and decrease the cost of manufacturing. To investigate the sensitivity of the solar power generated by the concentrated solar PV according to the performance of lens and light pipe, we performed raytracing and executed a simulation of electrical performance of the solar cell when it is exposed to the non-uniform illumination. We could conclude that we can generate 95 % or more energy compared with the energy that can be generated by perfectly uniform illumination once the total energy is given the same.

• Atmosphere
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• v.29 no.5
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• pp.537-550
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• 2019

To analyze the observation environment of solar radiation stations operated by the Korea Meteorological Administration (KMA), we analyzed the skyline, Sky View Factor (SVF), and solar radiation due to the surrounding topography and artificial structures using a Digital Elevation Model (DEM), 3D camera, and solar radiation model. Solar energy shielding of 25 km around the station was analyzed using 10 m resolution DEM data and the skyline elevation and SVF were analyzed by the surrounding environment using the image captured by the 3D camera. The solar radiation model was used to assess the contribution of the environment to solar radiation. Because the skyline elevation retrieved from the DEM is different from the actual environment, it is compared with the results obtained from the 3D camera. From the skyline and SVF calculations, it was observed that some stations were shielded by the surrounding environment at sunrise and sunset. The topographic effect of 3D camera is therefore more than 20 times higher than that of DEM throughout the year for monthly accumulated solar radiation. Due to relatively low solar radiation in winter, the solar radiation shielding is large in winter. Also, for the annual accumulated solar radiation, the difference of the global solar radiation calculated using the 3D camera was 176.70 MJ (solar radiation with 7 days; suppose daily accumulated solar radiation 26 MJ) on an average and a maximum of 439.90 MJ (solar radiation with 17.5 days).

• The Korean Journal of Applied Statistics
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• v.31 no.1
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• pp.139-153
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• 2018

This paper investigates solar power forecasting based on several time series models. First, we consider weather variables that influence forecasting procedures as well as compare forecasting accuracies between time series models such as ARIMAX, Holt-Winters and Artificial Neural Network (ANN) models. The results show that ten models forecasting 24hour data have better performance than single models for 24 hours.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.70-70
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• 2013

As the costs of carbon-footprinetd fuels grow continuously and simultaneously atmospheric carbon dioxide concentration increases, solar fuels are receiving growing attention as alternative clean energy carriers. These fuels include molecular hydrogen and hydrogen peroxide produced from water, and hydrocarbons converted from carbon dioxide. For high efficiency solar fuel production, not only light absorbers (oxide semiconductors, Si, inorganic complexes, etc) should absorb most sunlight, but also charge separation and interfacial charge transfers need to occur efficiently. With this in mind, this talk will introduce the fundamentals of solar fuel production and artificial photosynthesis, and then discuss in detail on photoelectrochemical (PEC) water splitting and CO2 conversion. This talk largely divides into two section: PEC water oxidation and PEC CO2 reduction. The former is very important for proton-coupled electron transfer to CO2. For this oxidation, a variety of oxide semiconductors have been tested including TiO2, ZnO, WO3, BiVO4, and Fe2O3. Although they are essentially capable of oxidizing water into molecular oxygen, the efficiency is very low primarily because of high overpotentials and slow kinetics. This challenge has been overcome by coupling with oxygen evolving catalysts (OECs) and/or doping donor elements. In the latter, surface-modified p-Si electrodes are fabricated to absorb visible light and catalyze the CO2 reduction. For modification, metal nanoparticles are electrodeposited on the p-Si and their PEC performance is compared.