• KIEAE Journal
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• v.13 no.5
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• pp.111-118
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• 2013

This study aims to investigate advantages of complex installation of green roof and PV system in a public building, to analyze the impact of green roof on the efficiency of PV power generation, and to consider the correlation between green roof and PV power generation. When the temperature and power generation of the modules installed in the green roof and non-green roof of the public building were measured for 3 days, the average temperature of the green roof was 23.6 degrees, and it was 36.1 degrees in the non-green roof which increased by nearly 53%. Overall, the module temperature in the green roof was lower. On the other hand, in relation to the PV generation depending on temperature reduction during the same period, the mono-crystalline module and the poly-crystalline module in the green roof showed an increase in generation at nearly 222.2W and 341.6W, and the efficiency rose by 5.5% and 6.2%, respectively, compared to the modules in the non-green roof. Therefore, it is analyzed that green roof has a positive influence on PV power generation. Finally shows the efficiency of the installed on the Green Roof PV system (complex Installation) higher than on the concrete roof PV system. Thus, the complex PV systems as well as the usual benefits of green roofs will provide greater synergies.

• Journal of the Korean Solar Energy Society
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• v.25 no.1
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• pp.57-64
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• 2005

The present society have been polluted the earth environment by the rapid industrial growth. So, the meaning of sustainable development is doing more important. Therefore the technology skills of sustainable architecture techniques have been studied many-side of energy as like energy saving and substitutive energy. But, See the studies until now, there have been just one system either energy saving or substitutive energy. So, the paper studies about energy saving system with substitutive energy system(the double-skin facade system with PV modules) and presents the performance of system through the analysis of reduction of the energy load, the solar radiation on the slope angle of PV module, the blind effect in system.

• ETRI Journal
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• v.42 no.1
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• pp.118-128
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• 2020

A semitransparent photovoltaic-thermal (PV/T) air collector can produce electricity and heat simultaneously. To maximize the thermal and overall efficiency of the semitransparent PV/T air collector, its availability should be maximum; this can be determined through a Markov analysis. In this paper, a Markov model is developed to select an optimized number of semitransparent PV modules in service with five states and two states by considering two parameters, namely failure rate (λ) and repair rate (μ). Three artificial neural network (ANN) models are developed to obtain the minimum cost, minimum temperature, and maximum thermal efficiency of the semitransparent PV/T air collector by setting its type appropriately and optimizing the number of photovoltaic modules and cost. An attempt is also made to achieve maximum thermal and overall efficiency for the semitransparent PV/T air collector by using ANN after obtaining its minimum temperature and available solar radiation.

• Proceedings of the KIPE Conference
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• 2011.11a
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• pp.44-45
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• 2011

Research on photovoltaic (PV) generation is taking a lot of attention due to its infinity and environment-friendliness with decrease of price per PV cell. While central inverters connect group of PV modules to utility grid in which maximum power point tracking (MPPT) for each module is difficult, micro inverter is attached on each module so that MPPT for individual modules can be easily achieved. Moreover, energy generation and consumption efficiency can be much improved by employing direct current (DC) distribution system. In this paper, a digitally controlled PV micro converter interfacing PV to DC distribution system is proposed. Boundary conduction mode (BCM) is utilized to achieve zero voltage switching (ZVS) of active switch and eliminate reverse recovery problem of passive switch. A 120W prototype boost PV micro converter is implemented to verify the feasibility and experimental results show higher than 98% efficiency at peak power and 97.29% of European efficiency.

• Journal of the Korean Solar Energy Society
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• v.32 no.3
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• pp.26-32
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• 2012

A current compensation method to reduce the mismatch loss in PV systems is proposed as a way to increase the power generation efficiency. A dc-dc converter is used to supply currents to irregular modules in a PV string and is powered from the string output. The converter's voltage conversion ratio is adjusted so that all the modules in the string are operated at the maximum power point. The power rating and size of the converter can be reduced since only the current difference between the regular and irregular module may be supplied. The compensated string shows very little voltage mismatch compared to other regular strings. The validity of the proposed method is verified through a simulation and experiments in a prototype PV system.

• 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.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.10
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• pp.760-765
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• 2013

PID (potential induced degradation) of PV module is the degradation of module due to the high potential difference between the front surface of solar cells and ground when PV modules operate under high humidity and temperature conditions. PID is generally derived from the positive sodium ions in front glass that are accumulated on P-type solar cells. Therefore, some papers for the electrical characteristic of only front components as glass, EVA sheet, solar cell under PID generation condition were revealed. In this paper, we analyzed the different outputs of module with PID by considering the all parts of module including the back side elements such as glass, back sheet. Mini modules with one solar cell were fabricated with the various parts on front and back sided of module. To generate PID of module in a short time, the all modules were applied.1,000 V in $85^{\circ}C$, 85% RH. The outputs, dark IV curves and EL images of all modules before and after experiments were also measured to confirm the main components of module for PID generation. From the measured results, the outputs of all modules with front glass were remarkably reduced and the performances of modules with back and front glass were greatly deteriorated. We suggest that the obtained data could be used to reduce the PID phenomenon of diverse modules such as conventional module and BIPV (building integrated photovoltaic) module.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.303-308
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• 2009

In 2008, the global photovoltaic(PV) market reached 5.6GW and the cumulative PV power installed totalled almost 15GW compared to 9GW in 2007. Due to a favourable feed-in-tariff, Korea emerged in 2008 as the 4th largest PV market worldwide. PV power installation rose 495.5 percent to 268MW in 2008 compare to 45MW in 2007. However many PV systems are not installed in suitable part which is concerned about geometrical factor. It is generally recognized that the actual output of PV system in field is a function of orientation, tilt angle, irradiance, temperature, soiling and various system-related losses. Thus this paper shows that a experimental result of PV modules(A group) with uniform azimuth angle and PV modules(B group) with non-uniform azimuth angle. As a result, the electrical output of B group is decreased 48.8% as compared with electrical output of A group.

• KIEAE Journal
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• v.7 no.6
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• pp.17-22
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• 2007

The integration of PV modules into building facades or roof could raise their temperature that results in the reduction of PV system's electrical power generation. Hot air can be extracted from the space between PV modules and building envelope, and used for heating in buildings. The extraction of hot air from the space will enhance the performance of BIPV systems. The solar collector utilizing these two aspects is called PV/T(photovoltaic/thermal) solar collector. This paper compares the experimental performance of two different types of air type PV/T collector units: the base case of a collector unit with 10cm gap for forced ventilation and the other unit with copper pin attached to PV module to enhance its thermal performance. The experimental results shows that the base case unit had the overall efficiency of 41.9% and the improved unit with copper pin attached to PV module had 50.1% efficiency. For these air type PV/T units, the forced ventilation of the air space improved the electrical performance as well as the thermal performance.

• Current Photovoltaic Research
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• v.7 no.4
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• pp.111-120
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• 2019

The output power of a crystalline silicon (c-Si) photovoltaic (PV) module is not directly the sum of the powers of its unit cells. There are several losses and gain mechanisms that reduce the total output power when solar cells are encapsulated into solar modules. Theses factors are getting high attention as the high cell efficiency achievement become more complex and expensive. More research works are involved to minimize the "cell-to-module" (CTM) loss. Our paper is aimed to focus on electrical losses due to interconnection and mismatch loss at PV modules. Research study shows that among all reasons of PV module failure 40.7% fails at interconnection. The mismatch loss in modern PV modules is very low (nearly 0.1%) but still lacks in the approach that determines all the contributing factors in mismatch loss. This review paper is related to study of interconnection loss technologies and key factors contributing to mismatch loss during module fabrication. Also, the improved interconnection technologies, understanding the approaches to mitigate the mismatch loss factors are precisely described here. This research study will give the approach of mitigating the loss and enable improvement in reliability of PV modules.