• Journal of the Korean Society for Geothermal and Hydrothermal Energy
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• v.14 no.3
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• pp.8-14
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• 2018

PV module power is calculated on PV module surface temperature adjustment by irradiation on the summer and autumn in NOCT(Nominal Operating Cell Temperature) conditions. The summer and autumn periods were selected because of large variation in outdoor air temperature and irradiation. This study was performed to understand relationship between PV module surface temperature and photovoltaic power using field measurement. As a results, it was determined that the amount of irradiation was proportional to the amount of photovoltaic power in the field measurement. However, it was also identified that the PV power generation decreased by increased PV module surface temperatures due to irradiation.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.312.1-312.1
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• 2013

PID (Potential Induced Degradation)는 높은 시스템 전압을 갖는 PV모듈에서 발생하는 현상으로 PV모듈의 출력을 급격하게 감소시키는 현상을 말한다. PV시스템의 높은 전압은 태양전지와 PV모듈의 프레임 사이에 전위차를 발생시키고 이로 인하여 누설전류가 흐르게 된다. 누설전류는 태양전지 표면에 전하를 축적 시켜 발전 효율을 감소시키게 된다. 이러한 누설전류는 온도와 습도가 높을수록 많이 발생하는 것으로 알려져 있다. 본 논문에서는 PV모듈을 구성하는 재료가 PID에 의한 출력변화에 어떠한 영향을 주는지에 관한 연구를 수행하였다. PID가 쉽게 발생하는 태양전지를 이용하여 일반적으로 PV모듈을 제작 할 때 사용되는 전 후면 재료를 이용하여 각각의 출력변화에 대한 연구를 수행하였다. PV모듈의 전 후면 재료를 각각 다르게 하여 이에 따른 PID 발생 정도를 출력 변화로 확인하였으며 PID의 원인이 되는 누설전류에 어떠한 변화를 주는지 분석하였다. PV모듈의 후면 재료는 PV모듈 내부로의 수분 침투와 관련하여 PID 발생에 영향을 주고 전면재료인 저철분 강화유리는 PV모듈 내부에 전하를 공급하여 누설전류가 발생하게 하는 역할을 하는 것으로 판단된다.

• Journal of the Architectural Institute of Korea Structure & Construction
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• v.35 no.8
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• pp.177-184
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• 2019

Recently, electric power usages and peak loads from buildings are increasing due to higher outdoor air temperatures and/or abnormal climate during the summer period. As one of the eco-friendly measures, a renewable energy system has been received much attention. Particularly, interest on a photovoltaic (PV) system using solar energy has been rapidly increasing in a building sector due to its broad applicability. In using the PV system, one of important factors is the PV efficiency. The normal PV efficiency is determined based on the STC(Standard Test Condition) and the NOCT(Nominal Operating Cell Temperature) performance test. However, the actual PV efficiency is affected by the temperature change at the module surface. Especially, higher module temperatures generally reduce the PV efficiency, and it leads to less power generation from the PV system. Therefore, the analysis of the relation between the module temperature and PV efficiency is required to evaluate the PV performance during the summer period. This study investigates existing algorithms for calculating module surface temperatures and analyzes resultant errors with the algorithms by comparing the measured module temperatures.

• Proceedings of the KIPE Conference
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• 2011.07a
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• pp.275-276
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• 2011

본 논문에서는 일사량 및 표면온도에 따라 변화하는 태양전지의 출력 특성을 고려하여 설치되는 태양광 발전 인버터의 운전 허용 범위에 대해 살펴본다. 또한 대용량 발전 시 직렬 모듈 수를 높이는 구성과 기존 센트럴 인버터의 최소 MPP 전압의 증가에 대한 효율성을 검증하기 위해 (주)카코 뉴에너지에서 제공하는 PV Array Sizing Tool과 Matlab Simulink를 통해 태양전지 어레이의 동작 범위를 파악하고, 새로운 대용량 인버터 개발 원리의 타당성을 제시한다.

• Journal of the Korean Solar Energy Society
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• v.29 no.6
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• pp.88-93
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• 2009

This study was conducted to improve the power of PV module using a surface cooling system One of the unique characteristics of PV module is power drop as a module surface temperature increases due to the characteristics of crystalline silicon used in a solar cell. To overcome the output power reduction by temperature effect, module surface cooling using water circulation was performed. By cooling effect, module surface temperature drops maximally $20.3^{\circ}C$ predicting more than 10% power enhancement. Maximum deviation of voltage and current between a control and cooled module differed by 5.1 V and O.9A respectively. The maximum power enhancement by cooling system was 12.4% compared with a control module. In addition, cooling system can wash the module surface by water circulation so that extra power up of PV module can be achieved by removing particles on the surface which interfere solar radiation on the cells. Cooling system, besides, can reduce the maintenance cost and prevent accidents as a safety precaution while cleaning works. This system can be applied to the existing photovoltaic power generation facilities without any difficulties as well.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.309-313
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• 2009

This study was conducted to improve the power of PV module using a surface cooling system. One of the unique characteristics of PV module is power drop as a module surface temperature increases due to the characteristics of crystalline silicon used in a solar cell. To overcome the output power reduction by temperature effect, module surface cooling using water circulation was performed. By cooling effect, module surface temperature drops maximally $20.3^{\circ}C$ predicting more than 10% power enhancement. Maximum deviation of voltage and current between a control and cooled module differed by 5.1V and 0.9A respectively. The maximum power enhancement by cooling system was 12.4% compared with a control module. In addition, cooling system can wash the module surface by water circulation so that extra power up of PV module can be achieved by removing particles on the surface which interfere solar radiation on the cells. Cooling system, besides, can reduce the maintenance cost and prevent accidents as a safety precaution while cleaning works. This system can be applied to the existing photovoltaic power generation facilities without any difficulties as well.

• 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.

• Journal of Energy Engineering
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• v.21 no.3
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• pp.243-248
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• 2012

In this study, The report analysed the characteristics of power drop and damage of surface in solar cell through high temperature and humidity test. The solar cells were tested during the 1000hr in $85^{\circ}C$ temperature and 85% humidity conditions, that excerpted standard of PV Module(KS C IEC-61215). An analysis of the cell surface through EL(Electroluminescence), the cell has partly change of surface in yearly. Single-crystalline Solar cell efficiency is decreased from 17.7% to 15.6% and decreasing rate is 11.9%. On the other hand, Poly-crystalline Solar cell efficiency is decreased from 15.5% to 14.0% and decreasing rate is 9.3%. A comparison of the fill factor for analysis of electro characteristic in yearly, Single-crystalline Solar cell efficiency is decreased from 78.7% to 78.1% and decreasing rate is 4.7%. On the other hand, Poly-crystalline Solar cell efficiency is decreased from 78.1% to 76.7% and decreasing rate is 1.8%. Single-crystalline has more bigger power drop than poly-crystalline by the silicon purity and silicon atom arrangement. Also, FF decreasing rate has more bigger drop than efficiency decreasing rate for the reason that the damage of surface by exterior environmental factor is the more influence in cell than other reason that is decreasing FF by damage of p-n junction.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.11
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• pp.971-975
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• 2013

In general, the solar photovoltaic power increases with higher solar insolation. However, the solar cell generation efficiency reduces because the solar cell surface is heated by solar insolation. According to advanced research, with a $1^{\circ}C$ increase in the solar cell surface temperature, the generation efficiency decreases by ~0.5%. To solve this problem, we conducted experiments in which we attempted to reduce the solar cell surface temperature using a water jet spray. In this study, we found the long-term experimental results of increases in solar power generation. The experimental results show a comparison of the site with and without cooling and cleaning equipment being installed. The results of the long-term experiments show that solar photovoltaic power generation is increased by at least 13% up to 19% with cooling and cleaning.

• Korean Journal of Materials Research
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• v.29 no.11
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• pp.703-708
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• 2019

In this study, we investigate the relationship between the peeling behavior of the backsheet of a photovoltaic(PV) module and its surface temperature in order facilitate removal of the backsheet from the PV module. At low temperatures, the backsheet does not peel off whereas, at high temperatures, part of the backsheet remains on the surface of the PV module after the peeling process. The backsheet material remaining on the surface of the PV module is confirmed by X-ray diffraction(XRD) analysis to be poly-ethylene(PE). Differential scanning calorimetry(DSC) is also performed to investigate the interfacial characteristics of the layers of the PV module. In particular, DSC provides the melting temperature($T_m$) of laminated ethylene vinyl acetate(EVA) and of the backsheet on the PV module. It is found that the backsheet does not peel off below the $T_m$ of ethylene of EVA, while the PE layer of the backsheet remains on the surface of the PV module above the $T_m$ of the PE. Thus, the backsheet is best removed at a temperature between the $T_m$ of ethylene and that of PE layer.