• KIEAE Journal
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• v.9 no.4
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• pp.37-42
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• 2009

Photovoltaic-thermal(PVT) collectors are a combination of photovoltaic modules with solar thermal collectors, forming one device that receives solar radiation and produces electricity and heat simultaneously. The PVT collectors can produce more energy per unit surface area than side by side PV modules and solar thermal collectors. There are two types of water type PVT collectors, depending on the existence of glass cover over PV module; glass-covered(glazed) PVT module, which produces relatively more thermal energy but has lower electrical yield, and uncovered(unglazed) PVT module, which has relatively lower thermal energy with somewhat higher electrical performance. In this paper, the experimental performance of two types of the water-based PVT combined collectors, glazed and unglazed, was analyzed. The electrical and thermal performances of the PVT combined collectors were measured in outdoor conditions, and the results were compared.

• Proceedings of the KIPE Conference
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• 2003.07b
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• pp.692-695
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• 2003

Generally, photovoltaic system is composed with several solar cell modules. For increasing power of photovoltaic systems, serial and parallel connection needed. A Desirable characteristic of a parallel supply system is that individual converters share the load current equally and stably. The current sharing(CS) can be implemented using two approaches. The first one, known as a droop method, relies on the high output impedance of each converter. and The second approach, known as active current-sharing techniques. In this paper, using droop method at parallel connection with it's convenience and simplicity.

• 한국신재생에너지학회:학술대회논문집
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• 2008.10a
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• pp.121-123
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• 2008

The PV modules are affected by heat. The hotter the PV module, the lower the power output, then the life time will be short. If the cell temperature rises above a certain limit the encapsulating materials can be damaged, and this will degrade the performance of the PV module. This is called the ‘hot spot’ formation. This paper presents that the PV module temperature can be estimated by using a thermal analysis program, and demonstrates the thermal characteristics of the PV module.

• Current Photovoltaic Research
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• v.2 no.3
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• pp.140-145
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• 2014

The globally used PV qualification tests and reports the pass/fail only. Therefore, the reliability of new PV materials and parts can't be compared quantitatively with the reliability of the PV parts and materials in the market. Global PV materials and parts companies test and compare their materials, parts, and modules using the failure-to-test (FTT). However, it takes a long accelerated stress test (AST) until failure. It also needs to test the new and existing materials and parts. Therefore, it requires excessive equipment time and cost. In order to reduce the time and cost, a new reliability enhancement methodology has been developed. It tests the PV materials, parts, and modules in the global market and stores them in the PV reliability database. It reduces the time and cost of the comparison and enhancement of PV reliability. An example of the reliability enhancement of the PV encapsulant, EVA is presented.

• Proceedings of the KIPE Conference
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• 2013.07a
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• pp.467-468
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• 2013

In this paper, a switching control strategy of bidirectional converter for energy storage system in photovoltaic hybrid modules is proposed. The bidirectional converter for energy storage system (ESS) with battery is connected with DC link in parallel which is located between current source flyback converters(CSFC) and unfolding bridge. Because CSFC generates rectified sinusoidal current, the bidirectional converter requires suitable control strategy. Therefore, a theoretical analysis of the proposed switching control strategy is presented. And, validity is confirmed through simulation results.

• Journal of the Korean Solar Energy Society
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• v.35 no.2
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• pp.63-71
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• 2015

Soiling is the accumulation of dirt on photovoltaic (PV) modules and can reduce the performance of the PV power plant depending on the site location. Nevertheless, the reason which can not be the great interest to researchers of PV reliability is the phenomenon of performance loss caused by external environmental factors, not the internal degradation of the PV module. In this paper, we provide the phenomenon, history, research overview and mitigation method in order to help understanding of the soiling.

• Proceedings of the SAREK Conference
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• 2009.06a
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• pp.792-797
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• 2009

The excess heat that is generated from PV modules can be removed and converted into useful thermal energy. A photovoltaic-thermal(PVT) module is a combination of photovoltaic module with a solar thermal collector, forming one device that receives solar radiation and produces electricity and heat simultaneously. In general, two types of PVT can be classified: glass-covered PVT module, which produces high-temperature heat but has a slightly lower electrical yield, and uncovered PVT module, which produces relatively lower temperature heat but has a somewhat higher electrical performance. In this paper, the experimental performance of two types of the PVT combined module(water type), glazed(glass-covered) and unglazed, was analyzed. The electrical and thermal performance of the PVT combined modules were measured in outdoor conditions, and the results were compared.

• Journal of Power Electronics
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• v.19 no.5
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• pp.1259-1269
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• 2019

PV system performance is dependent on different irradiations and temperature values in addition to the capability of the employed PV inverter / maximum power point tracker (MPPT) circuit or algorithm. Therefore, it would be appropriate to use a PV simulator capable of producing identical repeatable conditions regardless of the weather to evaluate the performance of inverter / MPPT circuits and algorithms. In accordance with this purpose, a photovoltaic (PV) array simulator is presented in this paper. The simulator is designed to generate current-voltage (I-V) and power-voltage (P-V) curves of a PV panel. Series connected cascaded modules constitute the basic part of the simulator. This feature also allows for the modeling of PV arrays since the number of modules can be increased and high voltage values can be reached with the simulator. In addition, the curves obtained at the simulator output become similar to the actual curves of sample PV panels with an increase in the number of modules. In order to show the validity of the proposed simulator, it was simulated for various situations such as panels under full irradiance and partial shading conditions. After completing simulations, experiments were realized to support the simulation study. Both simulation and experimental results show that the proposed simulator will be very useful for researchers to carry out PV studies under laboratory conditions.

• Current Photovoltaic Research
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• v.7 no.1
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• pp.21-27
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• 2019

Lifetime of Si photovoltaics modules are about 25 years and a large amount of waste modules are expected to be discharged in the near future. Therefore, the extraction and collection of valuable metals out of discharged Si modules will be one of the important technologies. In this study, we demonstrated that supercritical $CO_2$ extraction method can be effectively used to remove Cu, one of the abundant elements in the module, as well as its oxide form, $Cu_2O$. Especially, we proved that the addition of hexane as co-solvent is effective for the removal of both materials. The optimal ratio of $CO_2$ and hexane was 4:1 at a fixed temperature and pressure of $250^{\circ}C$ and 250 bar, respectively. In addition, it was proven that the removal of $Cu_2O$ was preceded via reduction of $Cu_2O$ to Cu.

• New & Renewable Energy
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• v.17 no.2
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• pp.24-31
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• 2021

Renewable energy has become more popular with the increase in the use of solar power. Consequently, the disposal of defective and old solar panels is gradually increasing giving rise to a new problem. Furthermore, the efficiency and power output decreases with aging. Researchers worldwide are engaged in solving this problem by developing eco-module technologies that restore and reuse the solar panels according to the defect types rather than simple disposal. The eco-module technology not only solves the environmental problem, but also has economic advantages, such as extending the module life. Replacement of encapsulants contributes to a major portion of the module maintenance plan, as the degradation of encapsulants accounts for 60% of the problems found in modules over the past years. However, the current International Electrotechnical Commission (IEC) standard testing was designed for the commercialization of solar modules. As the problem caused by long-term use is not considered, this method is not suitable for the quality assurance evaluation of the eco-module. Therefore, to design a new accelerated test, this paper provides an overview of EVA degradation and comparison with the IEC and accelerated tests.