• 한국수소및신에너지학회논문집
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• 제32권6호
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• pp.477-482
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• 2021

Hydrogen production, hydrogen production cost, and utilization rate were calculated assuming four cases of hydrogen production system in combination of photovoltaic power generation (PV), water electrolysis system (WE), battery energy storage system (BESS), and power grid. In the case of using the PV and WE in direct connection, the smaller the capacity of the WE, the higher the capacity factor rate and the lower the hydrogen production cost. When PV and WE are directly connected, hydrogen production occurs intermittently according to time zones and seasons. In addition to the connection of PV and WE, if BESS and power grid connection are added, the capacity factor of WE can be 100%, and stable hydrogen production is possible. If BESS is additionally installed, hydrogen production cost increases due to increase in Capital Expenditures, and Operating Expenditure also increases slightly due to charging and discharging loss. Even in a hydrogen production system that connects PV and WE, linking with power grid is advantageous in terms of stable hydrogen production and improvement of capacity factor.

• Current Photovoltaic Research
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• 제4권4호
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• pp.159-163
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• 2016

Piled snow upon PV module interferes with Photoelectric Effect process through photovoltaic directly. As a result of this phenomenon, its generation efficiencies keep decreasing or are stuck at zero power generating status. In addition, PV facilities have been installed on those places such as water surface, roof-top, and other isolated places, dealing with conditions of "Securing high REC weighted value", "Difficulty of securing land" and so forth. Through this study, we are able to actualize the function of heating over PV modules when it snows. We adopted laminating method through heating film and modules, guaranteeing warranty more than for 25 years. Also we are trying remote control systemically, not by hardware control, to run parallel with automatic driving and monitoring system which enable to control operation time, insolation, amount of snowfall automatically. We applied analysis of actual proof to both snow removal PV system and general PV power system, and these led to bear power consumption analysis while snow-removing, and its comparison after finishing the task as "One stone, two birds." In the long run, we could carry out economic analysis against snow removal system, and this helps to verify the most maximized control method for snow removal conditons on a basis of weather information. this study shall let prevent people from negligent accidents, and improve power generation problems as mentioned from the top. Ultimately, we expect to apply this system to heavy snowfall regions in winter season in spite of its limited system installaion in Korean territory, initially.

• Current Photovoltaic Research
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• 제8권4호
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• pp.124-128
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• 2020

Output power of photovoltaic (PV) modules installed outdoors decreases every year due to environmental conditions such as temperature, humidity, and ultraviolet irradiations. In order to promote the installation of PV modules, the reliability must be guaranteed. One of the important factors affecting reliability is intermetallic compounds (IMC) layer formed in ribbon solder joint. For this reason, various studies on soldering properties between the ribbon and cell have been performed to solve the reliability deterioration caused by excessive growth of the IMC layer. However, the IMC layer of the PV module interconnected by multi-wires has been studied less than using the ribbon. It is necessary to study soldering characteristics of the multi-wire module for improvement of its reliability. In this study, we analyzed the growth of IMC layer of the PV module with multi-wire and the degradation of output power through damp-heat test. The fabricated modules were exposed to damp-heat conditions (85 ºC and 85 % relative humidity) for 1000 hours and the output powers of the modules before and after the damp-heat test were measured. Then, the process of dissolving ethylene vinyl acetate (EVA) as an encapsulant of the modules was performed to observe the IMC layer. The growth of IMC layer was evaluated using OM and FE-SEM for cross-sectional analysis and EDS for elemental mapping. Based on these results, we investigated the correlation between the IMC layer and output power of modules.

• Advances in Energy Research
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• 제5권1호
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• pp.31-55
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• 2017

In the present study, PV/T collector was modeled via analysis of governing equations and physics of the problem. Specifications of solar radiation were computed based on geographical characteristics of the location and the corresponding time. Temperature of the collector plate was calculated as a function of time using the energy equations and temperature behavior of the photovoltaic cell was incorporated in the model with the aid of curve fitting. Subsequently, operational range for reaching to maximal efficiency was studied using Genetic Algorithm (GA) technique. Optimization was performed by defining an objective function based on equivalent value of electrical and thermal energies. Optimal values for equipment components were determined. The optimal value of water flow rate was approximately 1 gallon per minute (gpm). The collector angle was around 50 degrees, respectively. By selecting the optimal values of parameters, efficiency of photovoltaic collector was improved about 17% at initial moments of collector operation. Efficiency increase was around 5% at steady condition. It was demonstrated that utilization of photovoltaic collector can improve efficiency of solar energy-based systems.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.164-168
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• 2011

This study of PV modules in the external environment, learn about the mechanical strength characteristics, the module will investigate the aluminum frame. Positive support in the module by wind loads if uniformly distributed load acting on the front glass of the module size and elongation(${\omega}$), and accordingly, depending on the bend is sealed inside the solar cell, micro-cracks that will occur. At this point the most damage-prone parts in a module, this module is part of the center of a strong wind load is applied by the destruction of the environment does not occur in the module frame to secure the reliability and to evaluate changes in the structure.

• Current Photovoltaic Research
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• 제9권3호
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• pp.106-109
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• 2021

In order to perform photovoltaic (PV) operation and management (O&M) efficiently, individual PV module monitoring is becoming more important. In this research, we developed wireless IoT sensor which can monitor individual photovoltaic modules. This IoT sensor can detect the output voltage, current and module temperature of individual modules and provide monitored data by wireless communication. Measured voltage error was 1.23%, and it shows 16.6 dBM, 0.42sec and 7.1 mA for voltage, transmittance output, response time and mean power consumption, respectively. IoT sensors were demonstrated in the test field with real climate environment condition and each of 5 sensors showed precise results of voltage, current and temperature. Also, sensors were compared with commercial power-optimizers and showed result difference within 5%.

• 한국태양에너지학회 논문집
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• 제38권1호
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• pp.45-55
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• 2018

Environmentally benign lead-free solder coated ribbon (e. g. SnCu, SnZn, SnBi${\cdots}$) has been intensively studied to interconnect cells without lead mixed ribbon (e. g. SnPb) in the crystalline silicon(c-Si) photovoltaic modules. However, high melting point (> $200^{\circ}C$) of non-lead based solder provokes increased thermo-mechanical stress during its soldering process, which causes early degradation of PV module with it. Hence, we proposed low-temperature conductive paste (CP) based tabbing method for lead-free ribbon. Modules, interconnected by the lead-free solder (SnCu) employing CP approach, exhibits similar output without increased resistivity losses at initial condition, in comparison with traditional high temperature soldering method. Moreover, 400 cycles (2,000 hour) of thermal cycle test reveals that the module integrated by CP approach withstands thermo-mechanical stress. Furthermore, this approach guarantees strong mechanical adhesion (peel strength of ~ 2 N) between cell and lead-free ribbons. Therefore, the CP based tabbing process for lead free ribbons enables to interconnect cells in c-Si PV module, without deteriorating its performance.

• 한국태양에너지학회 논문집
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• 제24권2호
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• pp.9-15
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• 2004

3kW grid connected PV(photovoltaic) systems have been constructed for evaluating and analyzing performance of PV system at FDTC(field demonstration test center) in Korea, PV systems installed in FDTC have been operating and monitored since November 2002. As climatic and irradiation conditions have been varied through long-term field test, data acquisition system has been constructed for measuring performance of PV system to observe the overall effect of environmental conditions on their operation characteristics. The performance of PV systems has been evaluated and analyzed for component perspective(PV array and power conditioning system) and global perspective(system efficiency, capacity factor, and electrical power energy) by field test. By the results, it is very important to develop optimal design technology of grid connected PV system.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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• pp.1157-1158
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• 2006

The key of this study is the technical development to maximize electric energy production through PV generation system. Under a conventional MPPT control method, both input voltage and input current coming out from PV array had to be feed backed. Then, the system has complex structure and may fail to track Maximum Power Point of PV array when weather conditions changed urgently. A PV output senseless MPPT control for PV generation system is possible to solve the mentioned above. The best advantage is that the current flowing into load is the only one considerable factor. In case of a huge photovoltaic generation system, it can be operated much more safely than a conventional system. In this paper, a novel PV output senseless MPPT control for the PV generation system was proposed and applied to the manufactured system and the experimental results were shown. Authors are sure that it is the most useful method to maximize power from photovoltaic system with only a feedback of load current.

• 한국재료학회지
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• 제29권11호
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• pp.720-726
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• 2019

Recently, research on cost reduction and efficiency improvement of crystalline silicon(c-Si) photovoltaic(PV) module has been conducted. In order to reduce costs, the thickness of solar cell wafers is becoming thinner. If the thickness of the wafer is reduced, cracking of wafer may occur in high temperature processes during the c-Si PV module manufacturing process. To solve this problem, a low temperature process has been proposed. Conductive paste(CP) is used for low temperature processing; it contains Sn57.6Bi0.4Ag component and can be electrically combined with solar cells and ribbons at a melting point of $150^{\circ}C$. Use of CP in the PV module manufacturing process can minimize cracks of solar cells. When CP is applied to solar cells, the output varies with the amount of CP, and so the optimum amount of CP must be found. In this paper, in order to find the optimal CP application amount, we manufactured several c-Si PV modules with different CP amounts. The amount control of CP is fixed at air pressure (500 kPa) and nozzle diameter 22G(outer diameter 0.72Ø, inner 0.42Ø) of dispenser; only speed is controlled. The c-Si PV module output is measured to analyze the difference according to the amount of CP and analyzed by optical microscope and Alpha-step. As the result, the optimum amount of CP is 0.452 ~ 0.544 g on solar cells.