• Progress in Superconductivity and Cryogenics
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• v.13 no.1
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• pp.22-26
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• 2011

As new one of superconducting power supplies, we proposed an HTS flux pump utilized a solar energy system. As an eternal electric energy can be converted by the solar system, the solar energy system is promisingly applied as an energy source in the power applications. Especially, since the solar energy system played a role in conventional utility power, total power consumption of the flux pump system are provided by solar energy. That means its operating efficiency is remarkably improved compared with developed flux pumps. A solar energy system is comprised of solar panel, photo-voltaic (PV) controller, converter and battery. The HTS flux pump consists of an electromagnet, two thermal heaters and a Bi-2223 magnet. In this paper, we describe the possibility the fusion technology between superconducting power supply and solar energy system. As a fundamental step, the fabrication, structure and experimental results are explained.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.2
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• pp.152-158
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• 2015

Unlike photovoltaic systems installed on land, photovoltaic systems applied to the offshore plant have the characteristic that is installed in a limited space. For single point mooring plant, it is advantageous in terms of a reliable power supply to be installed in different directions of photovoltaic panels, because it is not possible to identify the position of the sun by rotation of the plant itself. Differences of installation angle between photovoltaic panels make a difference of the intensity of radiation irradiated on each photovoltaic panel, and it brings loss of generation quantity due to the partial shading. In order to provide a photovoltaic system suitable for offshore plant, the modeling which contains multiple photovoltaic panels controlled by single controller is performed. Then, it was examined how the output characteristics of the photovoltaic system change about the difference of the intensity of radiation that varies depending on the altitude of the sun. Finally, through the simulation, a development model of the photovoltaic system which is suitable for offshore plant is suggested.

• KIEAE Journal
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• v.4 no.2
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• pp.65-72
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• 2004

Ecological architecture enables people to recycle and reuse architectural resources within the category of ecosystem and also to minimize the effect on environment in a whole process, including architectural planning, usage and exhaustion to use sustainable energies. Rammed earth wall construction method utilized in EcoCenter located in Crystalwaters ecological village in Austrailia is a good example, which maximizes its advantages and also covers its limits to use soil and wood as structural resources. In a case of wood, they used non-treated timber to minimize environmental load and utilized used materials in openings. In the roofs, aluminum coated steel which is plated with zinc collects rain effectively even though it is not regenerable. Nontoxic finishes and insulation in floor and ceiling with used papers are able to minimize its environmental load. Solar energy system applied in EcoCenter enables them to market extra energy with electricity companies as well as support needs of its own buildings to utilize photovoltaic panel system with PV panels. Passive solar system is planned effectively in heating and cooling to apply regenerative walls in a use of rammed earth wall construction and natural ventilation systems through openings.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.64 no.12
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• pp.1709-1717
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• 2015

In remote islands PV (Photo Voltaic) panel with BESS (Battery Energy Storage System) supplies electric power to the customers in parallel operation with EG (Engine Generator) to save fuel consumption and to mitigate environmental load. BESS operates in voltage control mode when it supplies power to the load alone, while it operates in current control mode when it supplies power to the load in parallel with EG. This paper proposes a smooth mode change scheme from current control to voltage control of BESS by adding proper initial value to the integral part of voltage control, and a smooth mode change scheme from voltage control to current control by tracking the EG output voltage to the BESS output voltage using PLL (Phase-Locked Loop). The feasibility of proposed schemes was verified through computer simulations with PSCAD/EMTDC, and the feasibility of actual hardware system was verified by experiments with scaled prototype. It was confirmed that the proposed schemes offer a seamless operation in the stand-alone power system in remote islands.

• New & Renewable Energy
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• v.20 no.1
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• pp.61-69
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• 2024

This study investigates the barriers to the deployment of solar thermal and ground source heat pump (GSHP) from the perspective of consumers and businesses, as well as evaluates priorities for improving the barriers via expert AHP evaluation. From a consumer's perspective, the overall satisfaction with solar thermal is significantly lower than that with PV and needs to be improved at the installation and use stages. GSHP needs to be improved at the prior-information search stage. From a business perspective, the non-distinction between heat and electricity in mandatory installations in public buildings, the difficulty in assessing the value of heat, and high initial costs impede the deployment. Based on the result of AHP analysis, the priorities for improving the barriers to the wide utilization of solar thermal are evaluated in the order of economic feasibility, policy, acceptability, and technology, where high installation cost is shown to be the greatest barrier. Barriers for GSHP are evaluated in the order of policy, acceptability, economic feasibility, and technology, where policy means improvement is evaluated as the most important factor in promoting the deployment of GSHP.

• Current Photovoltaic Research
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• v.8 no.3
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• pp.67-78
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• 2020

A novel energy production system which has fascinated a wide consideration because of its several benefits that are called floating photovoltaic technology (FPVT). The FPVT system that helps to minimize the evaporation of water as well as an increase in energy production. For the research purposes, both electrical and mechanical structure requires studying of these systems for the development of FPVT power plants. From different points of views, numerous researches have been directed on FPVT systems that have evaluated these systems. The present research article give a logical investigation and up to date review that shows the different features and components of FPVT systems as an energy production system is offered. This articles reviewing the FPVT that gets the attention of the scientists who have the investigational stage and involuntary inspection of FPVT systems in addition to influence of implementing these systems on the water surface. Also, a comprehensive comparison has been constructed that shows the cons and pros of various types of solar systems that could be installed in various locations. In this review, it has been found that solar energy on the roof of a dwelling house generally has a power of 5 to 20 kW, while the inhabitants of commercial buildings generally have a power of 100 kW or more. The average power capacity of a floating solar panel is 11% more of the average capacity of a solar panel installed on the ground. Studies show that 40% of the water in open reservoirs is lost through evaporation. By covering only 30% of the water surface, evaporation can be reduced by 49%. The global solar panel market exceeds 100 GW and the capacity of 104 GW will bring the annual growth rate to 6%. In 2018, the world's total photovoltaic capacity reached 512 GW, an increase of 27% compared to the total capacity and about 55% of the renewable resources newly created that come from photovoltaic systems. It has been also predicted by this review that in 2025 the Solar technology including the FPVT system will increase by 7.38% that is 485.4 GW more of today installed power worldwide.

• Journal of the Korean Solar Energy Society
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• v.30 no.6
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• pp.73-80
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• 2010

This study was conducted to estimate the relative performance of modules with changed characteristics due to long term exposure to the outdoor environment, with a specially made test device for simultaneous measurement of real time power output from the photovoltaic array, taking into account the inclined panel, direct irradiation, power being generated, temperature as well as the optimal analysis timing. In terminology description, M is an abbreviation of module and Group A, Group B are 10 modules series connection (1~10 of M), (11~20 of M) for each of them respectively. The overall mean voltage difference of M-18 with the lowest power output and M-14 with the highest output is-2.13V and it was identifiable that voltage difference was more concentrated to Group B. In addition, in case of M-2 and M-7, M-8, when compared with M-14, the overall mean voltage difference was -0.92V, -1.56 and -0.91V respectively showing the more concentration to Group A. When the temperature of module went up by $1^{\circ}C$, the mean voltage was reduced by 0.35V. For current, Group A was lower than Group B by-0.022A and the ratio of each group was 49.68% and 50.32% respectively, presumably the module with deteriorated properties were more concentrated to Group A relatively. From the comparison of relations with the comprehensive accumulation, M-2, M-7, M-8, M-16 and M-18 were those with deterioration of performance to the worst, thereby requiring precision examination. In comparative efficiency, M-14 was the most excellent one as 12.19% while M-18 as 10.53% was identified that its efficiency was comparatively rapidly reduced.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.10a
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• pp.35.1-35.1
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• 2011

New photovoltaic (PV) materials and manufacturing approaches are needed for meeting the demand for lower-cost solar cells. The prototypal thin-film photovoltaic absorbers (CdTe and $Cu(In,Ga)Se_2$) can achieve solar conversion efficiencies of up to 20% and are now commercially available, but the presence of toxic (Cd,Se) and expensive elemental components (In, Te) is a real issue as the demand for photovoltaics rapidly increases. To overcome these limitations, there has been substantial interest in developing viable alternative materials, such as $Cu_2ZnSnS_4$ (CZTS) is an emerging solar absorber that is structurally similar to CIGS, but contains only earth abundant, non-toxic elements and has a near optimal direct band gap energy of 1.4~1.6 ev and a large absorption coefficient of ${\sim}10^4\;cm^{-1}$. The CZTS absorber layers are grown and investigated by various fabrication methods, such as thermal evaporation, e-beam evaporation with a post sulfurization, sputtering, non-vacuum sol-gel, pulsed laser, spray-pyrolysis method and electrodeposition technique. In the present work, we report an alternative method for large area deposition of CZTS thin films that is potentially high throughput and inexpensive when used to produce monolithically integrated solar panel modules. Specifically, we have developed an aqueous chemical approach based on chemical bath deposition (CBD) with a subsequent sulfurization heat treatment. Samples produced by our method were analyzed by scanning electron microscopy, X-ray diffraction, transmission electron microscopy, absorbance and photoluminescence. The results show that this inexpensive and relatively benign process produces thin films of CZTS exhibiting uniform composition, kesterite crystal structure, and good optical properties. A preliminary solar cell device was fabricated to demonstrate rectifying and photovoltaic behavior.

• Journal of the Korean Solar Energy Society
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• v.33 no.2
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• pp.35-41
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• 2013

Dye-sensitized solar cell (DSC) allows light transmission and the application of various colors that make it especially suitable for building-integrated PV (BIPV) application. In order to apply DSC module into windows, it has to be panelized: DSC module should be protected with reinforced glass to the entire surface. Up to date, it seems to be common to make double glazing with DSC modules with air gaps between the glasses and the DSC modules. Few research has been conducted on the characteristics of various glazing types with DSC modules. This study aims to analyze the electrical performance of DSC modules according to panelizing method for glazing unit with DSC modules. The prototype of the DSC glazing that applied silicone filler between DSC modules and glasses was developed. The electrical performances of this type of DSC glazing with the filler and rather conventional double glazing with DSC modules were compared. Their performances were measured using a solar simulator that is suitable for DSC performance testing. The results indicated that the electrical performance of the filler type DSC glazing improved by 7% compared to that of the conventional DSC double glazing type.

• Journal of the Korea institute for structural maintenance and inspection
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• v.23 no.5
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• pp.75-83
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• 2019

In order to fulfill the obligation to voluntarily reduce greenhouse gas emissions under the Paris Climate Agreement, the proportion of coal and nuclear power generation is reduced worldwide and national efforts are being made to spread renewable energy including solar power generation. Korea also intends to increase the proportion of renewable energy generation to 30~35% by 2040 by introducing laws and regulations. In addition, while the country is trying to apply solar power generation to sidewalks and roads, there is no research related to it in Korea. Therefore, as a precedent study to develop solar power generation roads, solar power generation concrete blocks applicable to sidewalks and plazas were developed and the applicability was evaluated by constructing them on the site. As a result of indoor experiment, compressive strength was measured by 25.5~35.7MPa and flexural strength was measured by 5.1~10.5MPa, which showed that all domestic standards were satisfied. However, the higher the unit cement amount, the lower the strength was measured according to the mixing of the broken fine aggregate. The absorption rate was 5.7%, which satisfied the domestic standard of 7% or less. As a result of the freeze-thawing test, the reduction rate of the compressive strength after 100 cycles was up to 6.3%. As a result of measuring the settlement amount after construction, the maximum of 2.498mm was measured and irregular settlement occurred in the overall area, which is because the resolution of the sand layer was poor during construction. Maintenance techniques of sidewalk concrete block and solar panel need to be established more efficiently through long-term operation in the further.