• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.214-219
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• 2011

Today, various activities to save energy are being conducted around the world. Even in our country, carbon reduction policy is being conducted for low carbon green growth and with this movement, effort to replace energy sources by recognizing the problems on environment pollution and resource exhaustion due to the indiscrete usage of fossil fuel is being made. Therefore, active study on renewable energy is in progress as part of effort to replace the energy supply through fossil fuel and solar ray industry has rapidly developed receiving big strength of renewable energy policies. The conclusion of this study measuring the surface temperature change of single crystal and polycrystalline PV module in green roof system and non-green roof system aspect are as follows. There was approximately $4^{\circ}C$ difference in PV module temperature in green roof system and non-green roof system aspect and this has the characteristic to decrease 0.5% when the temperature rises by $1^{\circ}C$ when the front side of the module is $20^{\circ}C$ higher than the surrounding air temperature following the characteristic of solar cells. It can be concluded that PV efficiency will be come better when it is $4^{\circ}C$ lower. Also, in result of temperature measurement of the module back side, there was $5^{\circ}C$ difference of PV module installed on the PV module back side and green roof system side on the 5th, $3^{\circ}C$ on the 4th, $2^{\circ}C$ on the 5th to show decreasing temperature difference as the air temperature dropped, but is judged that there will be higher temperature difference due to the evapotranspiration latent heat effect of green roof system floor side as the temperature rises. Based on this data, it is intended to be used as basic reference to maximize efficiency by applying green roof system and PV system when building non-green roof system flat roof.

• 한국태양에너지학회:학술대회논문집
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• 2011.11a
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• pp.364-369
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• 2011

Recently, the cases of BIPV(Building-integrated Photovoltaic) have been increased with interest in renewable energy application for buildings. PV System in building can perform a variety of roles as an energy supplier, exterior materials, aesthetic element and etc. To apply PV modules in buildings, various factors should be considered, such as the installation angle and orientation of PV module, shading, and temperature. The temperature of PV modules that are attached to building surfaces especially is one of the most important factors, as it affects both the electrical efficiency of a PV module and the energy load in a building. BIPV modules designed as finished material for spandrels are presented in this paper. The purpose of this study is to analysis on the thermal performance characteristics of BIPV modules. This study dealt with different types of BIPV modules depending on the backside material, such as clear glass and backsheet. The analysis of monitoring data shows that the PV module temperature was closely related to the solar radiation on the BIPV module surface, and the BIPV used at the backside also had an effect on the PV module temperature that in turn determines its thermal performance.

• Journal of the Korean Solar Energy Society
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• v.35 no.4
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• pp.67-75
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• 2015

PV module is conventionally connected in series with some solar cell to adjust the output of module. Some bypass diodes in module are installed to prevent module from hot spot and mismatch power loss. However, bypass diode in module exposed outdoor is easily damaged by surge voltage. In this paper, we study the thermal and electrical characteristics change of module with damaged bypass diode to easily find module with damaged bypass diode in photovoltaic system consisting of many modules. Firstly, the temperature change of bypass diode is measured according to forward and reverse bias current flowing through bypass diode. The maximum surface temperature of damaged bypass diode applied reverse bias is higher than that of normal bypass diode despite flowing equal current. Also, the output change of module with and without damaged bypass diode is observed. The output of module with damaged bypass diode is proportionally reduced by the total number of connected solar cells per one bypass diode. Lastly, the distribution temperature of module with damaged bypass diode is confirmed by IR camera. Temperature of all solar cells connected with damaged bypass diode rises and even hot spot of some solar cells is observed. We confirm that damaged bypass diodes in module lead to power drop of module, temperature rise of module and temperature rise of bypass diode. Those results are used to find module with a damaged bypass diode in system.

• Journal of the Korean Solar Energy Society
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• v.32 no.4
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• pp.51-58
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• 2012

This study aims to analyze characteristics of Cell surface temperature and generated power performance for improving PV(Photovoltaic) system condition according to the cell opening ratio of transparent crystal PV system at Spandrel of curtain-wall. For this purpose, alternatives were classified for eight different cases that opening ratio of transparent crystal PV system varied from 0% to 70%, which was used by simulation tool, EnergyPlus. As results, it turned out that increasing opening ratio of transparent crystal PV system led higher PV surface temperature, back-sheet type was thus the most advantageous for decreasing surface temperature, annual generating efficiency, and annual accumulated generating power. Consequently, blocking off air space from outside insolation can advantageously keep to be better condition for generated power performance.

• Journal of the Korean Solar Energy Society
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• v.30 no.5
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• pp.63-68
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• 2010

To guarantee life time more than 20 years for manufacturer without stopping photovoltaic(PV) system, it is really important to test the module in realistic time and condition compared to outside weather. In here, we tested PV modules in highly stressed condition compared to IEC standards. In IEC 61215 and IEC 61646 standards, damp-heat, thermal cycle(TC200) and mechanical test are main test items for evaluating long-term durability of PV module in controlled temperature and humidity condition. So in this paper, we have lengthened the test time for TC200 and damp-heat test and increased the loading stress on surface of module. Through this test, we can get some clue of proper the method for measuring realistic life cycle of PV modules and suggested the minimum time for PV test method. The detail description is specified as the following paper.

• 한국태양에너지학회:학술대회논문집
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• 2008.11a
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• pp.42-47
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• 2008

In this paper, we analyze the electrical characteristics of PV depending on distance among solar cells before and after lamination process. From the result, the PV module's maximum power increases about 3.37% when solar cells's distance is 10mm. And the maximum power increases up to 8.42% when solar cells's maximum distance is 50mm. It is assumed that PV module's surface temperature decreases because of increasing distance between solar cells that would give high power generation. Also, short distance between solar cell and frame result in contamination on glass. When considering reduced maximum power caused by contaminant, from that. we can fabricated PV module of lower cost with high performance.

• The Transactions of the Korean Institute of Electrical Engineers P
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• v.67 no.1
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• pp.33-36
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• 2018

The purpose of this study is to improve the efficiency of anti-pollution film for PV module. The anti-pollution coating process was performed on a glass substrate, which is the same material as the glass substrate for the PV module. We coated the anti-pollution film on the glass substrate by spray coating. After coating process, annealing process was performed during 1 hour at $200^{\circ}C$, $300^{\circ}C$, and $400^{\circ}C$. And then we analyzed the surface characteristics according to the annealing temperature of the film. Annealing process can also improve the durability of the coated film. And then we analyzed the anti-pollution characteristics, particle size of anti-pollution film, light transmittance. The particle size of anti-pollution film was analyzed with FE-SEM. The light transmittance was analyzed with UV-Visible spectroscopy including integrating sphere.

• Journal of Environmental Science International
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• v.23 no.11
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• pp.1943-1951
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• 2014

In order to clarify the characteristics of Photo-Volatic(PV) power generation over the Korean peninsula with complex terrain, special meteorological observation campaign was carried out for one year from 25 May 2011. Analysis is based on the comparison between observed meteorological elements and PV values generated at rated capacity 200 kW power plants. Solar radiation observed at $15^{\circ}$ inclined surface is 11 % larger than that observed at horizontal surface due to low elevation angel of the sun during winter season. The PV power generation tend to be more similar the variation of inclined surface irradiance than horizontal surface irradiance. Increasing air temperature often induce disturbance of the PV power generation. However, the higher the air temperature in winter season, the higher PV power generation because the PV module may be more activated at higher air temperature. PV generating efficiency tends to be conversed the value of 15%.

• Advances in nano research
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• v.13 no.5
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• pp.475-485
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• 2022

Crystalline silicon photovoltaic cells have advantages of zero pollution, large scale and high reliability. A major challenge is that sunlight wavelength with photon energy lower than semiconductor band gap is converted into heat and increase its temperature and reduce its conversion efficiency. Traditional cooling PV method is using water flowing below the modules to cool down PV temperature. In this paper, the idea is proposed to reduce the temperature of the module and improve the energy conversion efficiency of the module through the modulation of the solar spectrum. A spectrally selective nanofilm reflector located directly on the surface of PV is designed, which can reflect sunlight wavelength with low photon energy, and even enhance absorption of sunlight wavelength with high photon energy. The results indicate that nanofilm reflector can reduce spectral reflectivity integral from 9.0% to 6.93% in 400~1100 nm wavelength range, and improve spectral reflectivity integral from 23.1% to 78.34% in long wavelength range. The nanofilm reflector can reduce temperature of PV by 4.51℃ and relatively improved energy conversion efficiency of PV by 1.25% when solar irradiance is 1000 W/m². Furthermore, the nanofilm reflector is insensitive in sunlight's angle and polarization state, and be suitable for high irradiance environment.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2008.06a
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• pp.13-14
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• 2008

In this paper, we analyze the electrical characteristics of PV depending on distance among solar cells before and after lamination process. From the result, the PV module's maximum power increases about 3.37% when solar cells's distance is 10mm. And the maximum power increases up to 8.42% when solar cells's maximum distance is 50mm. It is assumed that PV module's surface temperature decreases because of increasing distance between solar cells that would give high power generation. Also, short distance between solar cell and frame result in contamination on glass. When considering reduced maximum power caused by contaminant, from that, we can fabricated PV module of lower cost with high performance.