• Title/Summary/Keyword: Direct solar

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Photoreactivation Study of Wastewater Treatment Effluent Disinfected by UV-disinfection for Water Reuse (용수재이용을 위한 하수처리 유출수의 UV 소독 후 광회복 조사)

  • 윤춘경;정광욱;함종화;전지홍
    • Magazine of the Korean Society of Agricultural Engineers
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    • v.45 no.3
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    • pp.84-93
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    • 2003
  • Photoreactivation of microorganism following UV-disinfection is one of the research topics of interest in assessing the UV-disinfection performance. Apparent photoreactivation was examined under fluorescent lamp and solar radiation as well as in darkness. Total coliform, fecal coliform, and Escherichia coli were used as indicator microorganisms, and their concentration was monitored with time after UV-disinfection. Under the darkness, their initial concentration of 10∼30 MPN/100 mL increased to the level of 100 MPN/100 mL after 24 hours, which implied that part of damaged microorganisms by UV-disinfection might be repairable with time. Under the fluorescent lamp, photoreactivation was more apparent that their concentration increased up to 1,000 MPN/100 mL which might significantly impair the water uses specially in reuse of reclaimed wastewater. However, their concentration further decreased down to below 2 MPN/100 mL under the solar radiation primarily due to additional disinfection by solar radiation rather than photoreactivation. Samples not disinfected by UV-disinfection also demonstrated substantial decrease of their concentration under solar radiation from about 5,000 MPN/100 mL to less than 30 MPN/100 mL in 24 hours. But direct reuse of effluent without disinfection is not recommended because natural decay by solar radiation may take time and be affected by climatic conditions. The result suggests that photoreactivation of pathogenic microorganisms may not be concerned in agricultural reuse of reclaimed wastewater because solar radiation may provide further disinfection after UV-disinfection.

Deposition of Solar Selective Coatings for High Temperature Applications (고온용 태양 선택흡수막의 제작)

  • Lee, Kil-Dong
    • Journal of the Korean Solar Energy Society
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    • v.28 no.1
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    • pp.33-42
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    • 2008
  • Zr-O ($Zr-ZrO_2$) cermets solar selective coatings with a double cermets layer film structure were prepared using a DC (direct current) magnetron sputtering method. The typical film structure from surface to bottom substrate were an $Al_2O_3$ anti-reflection layer on a double Zr-O cermets layer on an Al metal infrared reflection layer. Optical properties of optimized Zr-O cermets solar selective coating had an absorptance of ${\alpha}\;=\;0.95$ and thermal omittance of ${\epsilon}\;=\;0.10\;(100^{\circ}C)$. The absorbing layer of Zr-O cermets coatings on glass and silicon substrate was identified as being amorphous by using XRD. AFM showed that ZF-O cermets layers were very smooth and their surface roughness were approximately $0.1{\sim}0.2 nm$. The chemical analysis of the cermets coatings were determined by using XPS. Chemical shift of photoelectron binding energy was occurred due to the change of Zr-O cermets coating structure deposited with increase in oxygen flow rate. The result of thermal stability test showed that the Zr-O cermets solar selective coating was stable for use at temperature below $350^{\circ}C$.

A Study on the Improvement of Coloring in Dye-sensitized Solar Cell (염료감응형 태양전지의 착색 특성 개선 연구)

  • Seo, Hyun-Woong;Kim, Mi-Jeong;Son, Min-Kyu;Lee, Kyoung-Jun;Hong, Ji-Tae;Kim, Hee-Je
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.11a
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    • pp.297-300
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    • 2007
  • In this study, we have attempted a new method to enhance the coloring of dye on the $TiO_2$ surface in the dye sensitized solar cell. In the conventional coloring process in a dye sensitized solar cells, dye is absorbed by the covalent bond between TiO2 and dye molecule while the photo-electrode coated with $TiO_2$ layer is soaked in dye solution for about 12-24 hours. But this process takes long time, so we have researched more effective and faster way than the conventional process by applying electric field. Three kinds of electric power such as direct voltage, alternating voltage and pulse voltage were applied to the transparent conducting oxide during the coloring process. As a result, we achieved improved power, fill factor and efficiency of dye-sensitized solar cell in case of applying direct voltage and pulse voltage. In contrast, alternating voltage tend to reduce the dye adsorption on the $TiO_2$ surface and hence the efficiency. We measured the absorption spectra of dye by UV-VIS spectrophotometer before and after soaking the $TiO_2$ in the dye and found no characteristic change in the dye was observed. In this study, we researched on shortening time of coloring process which spent much time in the whole process.

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Calculation Method for the Transmitted Solar Irradiance Using the Total Horizontal Irradiance (수평면 전일사를 이용한 창 투과 일사량 계산 방법)

  • Jeon, Byung-Ki;Lee, Seung-Eun;Kim, Eui-Jong
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.29 no.4
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    • pp.159-166
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    • 2017
  • The growing global interest in energy saving is particularly evident in the building sector. The transmitted solar irradiance is an important input in the prediction of the building-energy load, but it is a value that is difficult to measure. In this paper, a calculation method, for which the total horizontal irradiance that can be easily measured is employed, for the measurement of the transmitted solar irradiance through windows is proposed. The method includes a direct and diffuse split model and a variable-transmittance model. The results of the proposed calculation model are compared with the TRNSYS-simulation results at each stage for the purpose of validation. The final results show that the CVRMSE over the year between the proposed model and the reference is less than 30 %, whereby the ASHRAE guideline was achieved.

Full-scale Mock-up Measurement of a Double Glazed Window System Equipped with Sunlight Controls (광기능성 창호시스템의 동절기 채광특성에 관한 목업연구)

  • Kim, Gon
    • Journal of the Korean Solar Energy Society
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    • v.28 no.4
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    • pp.35-42
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    • 2008
  • Besides genuine skin and clothes, it is called that building is third skin for us. That means the skin of buildings is the most important factor for our man-made environment. The issues in designing the building envelope include the insulation, infiltration, ventilation and bridging in windows. Getting light into the space safely and providing views to outdoor, additionally, are key things with the building envelope design. A deep-rooted preference for full view is still alive with large area of glass. Balcony expansion is legalized in apartment houses, which causes lots of environmental problems. Without balcony space, the adjacent space to unshaded window is exposed to the direct sun. A window can have many layers and the inner space can be utilized with an automatic blind system. Recently, the refurbished version of a double-glazed window system has been developed for the purpose of minimizing energy loss occurred around windows. For the better daylight control with equipped blind system, a set of adjustment technique of blind slats was tested in a mock-up building and recommended the detail operation. Not surprisingly, the optimized blind system can be oriented to enhance the uniformity in light distribution and direct glare from the sky as well..

Basic Design and Dynamic Simulation of Large Scale Solar Thermal Power Plant (대규모 태양열발전 기본설계 및 동특성 계산)

  • Kim, Jong-Kyu;Kang, Yong-Heack;Kim, Jin-Soo;Yoon, Hwan-Ki;Yu, Chang-Kyun;Lee, Sang-Nam
    • Journal of the Korean Solar Energy Society
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    • v.27 no.1
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    • pp.55-61
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    • 2007
  • This paper describes the procedure and calculation results of basic design and transient variation of performance of 1 MWe large scale solar thermal power plant (STPP) by using the commercial software of THERMOFLEX and TRNSYS, respectively. In order to simulate the transient variation of STPP, the results of basic design are necessary. The design standard of the STPP is 1 MWe generation with solar only at high DNI condition and then 0.6 MWe output power for 1 hour using stored energy when the DNI becomes lower unable to operate normally. The results of basic design show the important design data of flow rates, water/steam conditions at each equipments and the estimated efficiency of STPP. In addition, dynamic simulation results of STPP are predicted and plotted for one year and three different days weather data of Daejeon.

Development of an equipment preventing overheated in a car using the solar cell

  • Han, Jong-Soo;Seo, Chang-Jun
    • 제어로봇시스템학회:학술대회논문집
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    • 2003.10a
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    • pp.938-941
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    • 2003
  • In this paper we develop an equipment which prevents vehicles from overheating their inside due to exposure to direct sunlight in summer. Overheating of inside vehicle may give rise to accidents, for instances, dying from suffocation, the deformation of its internal equipment and the explosion from the cracks of its internal parts etc.. The equipment is operated under no starting engine. We adjust the overheating of the inside vehicle by operating the equipment. This equipment checks the temperature of the inside vehicle using temperature sensor. If the temperature increases more than reference temperature(a condition which can be given by the driver), the equipment will operate until the temperature of the inside decreases to the given temperature. Its power is obtained from solar cell. So the equipment keeps away overheating accidents as well as provides the drivers with optimized condition. And also it increases the ability of original car battery through solar cell.

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A review of zinc oxide photoanode films for dye-sensitized solar cells based on zinc oxide nanostructures

  • Tyona, M.D.;Osuji, R.U.;Ezema, F.I.
    • Advances in nano research
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    • v.1 no.1
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    • pp.43-58
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    • 2013
  • Zinc oxide (ZnO) is a unique semiconductor material that exhibits numerous useful properties for dye-sensitized solar cells (DSSCs) and other applications. Various thin-film growth techniques have been used to produce nanowires, nanorods, nanotubes, nanotips, nanosheets, nanobelts and terapods of ZnO. These unique nanostructures unambiguously demonstrate that ZnO probably has the richest family of nanostructures among all materials, both in structures and in properties. The nanostructures could have novel applications in solar cells, optoelectronics, sensors, transducers and biomedical sciences. This article reviews the various nanostructures of ZnO grown by various techniques and their application in DSSCs. The application of ZnO nanowires, nanorods in DSSCs became outstanding, providing a direct pathway to the anode for photo-generated electrons thereby suppressing carrier recombination. This is a novel characteristic which increases the efficiency of ZnO based dye-sensitized solar cells.

Controller Design of Stand-Alone Photovoltaic System with Charge-Discharge Controller for Remote lsland Power Supply

  • Kang, Ki-Hwan;Yu, Gwon-Jong;Song, Jinsoo;Jeong, Young-Seok;Kang, Ki-Hwan;Lee, Byoung-Ku;Choe, Gyu-Ha
    • Proceedings of the KIPE Conference
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    • 1998.10a
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    • pp.972-977
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    • 1998
  • This paper deals with stand-alone Photovoltaic system(SPVS) with charge and discharge controller. Main power source of SPVS are generally solar cell and battery. Therefore SPVS can be classified into variable types in accordance with connection method between battery and solar cell array. Mainly used one of them is direct connection type which has advantages such as simple structure and simple controller. However most big drawback of this system is energy loss by voltage disharmony between solar cell array and battery. Therefore SPVS with charge and discharge controller which can operate solar cell array at maximum power point is designed and experimented with a laboratory prototype.

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Design of Stand-Alone Photovoltaic System with Charge-Discharge Controller (충방전 제어기를 이용한 독립형 태양광 발전시스템의 설계)

  • 김홍성;유권종;송진수;이병구;정영석;강기환;최규하
    • Proceedings of the KIPE Conference
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    • 1998.07a
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    • pp.103-108
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    • 1998
  • This paper deals with stand-alone Photovoltaic system(SPVS) with charge and discharge controller. Main power source of SPVS are generally solar cell and battery. Therefore SPVS can be classified into variable types in accordance with connection type between battery and solar cell. Mainly used one of them is direct connection type which has advantages such as simple structure and simple controller. However most big drawback of this system is energy loss by voltage disharmony between solar cell and battery. Therefore SPVS with charge and discharge controller which can operate solar cell at maximum power point is designed and analyzed by simulation in this paper.

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