• KIEAE Journal
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• 제15권4호
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• pp.5-11
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• 2015

Purpose: Recently, renewable energy system has been widely used to reduce the energy consumption and CO2 emission of building. A photovoltaic/thermal(PVT) system is a kind of efficient energy uses, which is combined with photovoltaic module and solar thermal collector. PVT system removes heat from PV module by through thermal fluid to raise the performance efficiency of the PV system. However, though PVT system has the merit of the improved efficiency in theoretical approach, there have been few performance analysis for PVT system using the dynamic energy simulation. In this study, in order to establish the optimum design method of this system, simulation was conducted by using individual system modules. Method: For the dynamic simulation, TRNSYS17 was used and local weather data was utilized. Furthermore, the system performance in various installation condition was calculated by case studies. Result: As a result, the amount of electric generation and heat production in each case was found by the simulation. The gap of system performance was also evident according to the installation condition.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2012년도 춘계학술발표대회 논문집
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• pp.445-450
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• 2012

BIPV/T (Building Intergrated PhotoVoltaic/Thermal) is combined system produces electricity and thermal energy. The heat from PV modules should be removed for better electrical performance, and can be converted into useful thermal energy. The efficiency of the PV system's performance will raise by the system removes heat from the PV. The test system is installed to top floor of the experimental house in the KEPCO Research Institute. The planned experiment is following. (1) Supplying heat energy to top floor. (2) Supplying heat and cool energy to thermal storage in the bottom of the top floor. (3) Supplying heat energy to EHP for improved performance. The experimental performance is executed from 13th February to 13th March, 2012. The solar generation of electricity is 4.04kWh under the horizontal solar radiation is $1000W/m^2$ and the air temperature is $25^{\circ}C$.

• Journal of the Korean Solar Energy Society
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• 제25권2호
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• pp.1-8
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• 2005

On-off differential controller is one of the very important components which affect the system performance of the active solar thermal system. In this study, analyses were made regarding the influence of "on-off" setting temperature on the system efficiency and on the electrical consumption by circulation pump. This study was performed by experiment as well as the computer simulation using TRNSYS program. The simulation system was developed in this study was verified the its reliability by the experimental results. As a results, the turn off temperature(${\Delta}T_{off}$) is much more influence than the turn on temperature(${\Delta}T_{on}$) on the system efficiency. It is more clear and sensitivity in winter season. Finally the optimum on-off setting value and the system on-off pattern according to the several different kind of system was also represented.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• 제24권12호
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• pp.57-63
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• 2010

The efficiency of LED package is increasing by applying the high power, and a existing lighting is changing as the LED lighting. However, many problems have appeared by heat. Therefore, in order to solve thermal problems, LED lighting is designing in several ways, but the advantages of LED lighting is fading due to increase the prices and volumes. In this study, we try to improve the thermal performance by formation of via holes. The junction temperature and thermal resistance in the FR4-PCB with via-holes of 0.6[mm] was excellent in experiment and FR4-PCB with Via-holes of 0.6[mm] was excellent in simulation without solder. Further, the thermal resistance and the optical properties can be improved through a formation of via-holes.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2011년도 추계학술발표대회 논문집
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• pp.158-163
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• 2011

Recently, more attention has been paid to DSC(Dye-sensitized Solar Cell) with the potential of glazing applications. The aim of the study is to analyze thermal and electrical performance according to composition of glazing with DSC. For this study, the electrical and thermal performance of glazing with DSC modules were measured and their result were compared. The measurement were performed according to the KS L2525 and with a solar simulator of DSC modules. The result show that the U-value of the DSC double glazings with clear glass and low-e glass were 2.78 $W/m^2K$ and 1.70 $W/m^2K$, respectively. The electrical measurement indicated that the electrical efficiency of the DSC double glazings with clear glass and low-e glass decreaced by 9.9% and 13.3%, respectively, compared to the DSC medules electrical performance.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• 제28권2호
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• pp.137-141
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• 2015

The purpose of this study is examining thermal dissipation materials for the lighting and radiate efficiency improvement of 8W LED and confirming the properness of the thermal dissipation materials for LED heat sink. Solid Works flow simulation on 8W class COB was done based on the material characteristics of thermal conductive polymer materials. According to the result of simulation, Al had better thermal dissipation performance than PET. Highest temperature was $7.6^{\circ}C$ higher while lowest temperature was $7.8^{\circ}C$ lower. The test on the heat sinks made by the materials, highest temperature was $4.1^{\circ}C$ higher and lowest temperature was $3.9^{\circ}C$ lower. It is possible to confirm that Al heat sink has better thermal dissipation efficiency because it has better dispersion of heat generated at junction temperature and less heat cohesion. The weight of PET heat sink was reduced than Al heat sink by 46.9% by the density difference between Al and PET. In conclusion, thermal dissipation performance of thermal conductive polymer is lower than Al material however, it is possible to lighting heat sink because thermal conductive polymer has better formability, has lower specific weight and enables various design options.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.133-133
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• 2010

We studied the thermal and electric effect of 2D and 3D p-n photovoltaic diode structures with and without surface texturing. By analyzing the numerical simulation results of I-V characteristics and lattice temperature distributions, we systematically studied the effect of different texturing structures and different doping concentration on the characteristics of the silicon p-n photovoltaic devices. The, efficiency of the device with the surface texturing shows more than ~ 2% enhancement compared to the reference devices without texturing. The tendency of the efficiency of doping concentration has been studied with boron doping of $10^{14}{\sim}10^{17}cm^{-3}$ and phosphorus doping of $10^{15}cm^{-3}$. In addition to that, the study of changing phosphorus doping of $10^{15}{\sim}10^{18}cm^{-3}$ with boron doping of $10^{14}cm^{-3}$ has been examined. It has been shown that the texturing structure not only improves the light trapping but also plays an important role in the heat radiation.

• Journal of the Korean Society of Manufacturing Process Engineers
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• 제20권3호
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• pp.113-121
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• 2021

In this study, the thermal characteristics of cold and hot water mattress units equipped with thermoelectric modules were investigated via numerical analyses. Cold and hot water mattress products that are currently in existence use manual methods requiring refrigerants to be added to the hot water boiler. However, the cold and hot water mattress units using thermoelectric modules can provide improved efficiency via energy savings and actively resolving environmental pollution problems. To determine the efficiency of the thermoelectric module, the mattress was modeled and its efficiency was analyzed for the cooling and heating processes using two 100-W-class and one 200-W-class thermoelectric modules, respectively. From the results of this study, it was confirmed that when two 100-W-class modules were used, the application area was larger than when a single 200-W-class module was used, with uniform temperature distribution and improved performance compared to existing products in terms of electrical energy.

• Proceedings of the KIEE Conference
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• 대한전기학회 1998년도 추계학술대회 논문집 학회본부 C
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• pp.947-949
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• 1998

In this paper, the NO was oxidized $NO_2$ by using the non-thermal plasma and NOx removal characteristics were measured by showering NaOH water-solution to $NO_2$. The NO oxidation increased in the order of DC, AC, and Pulse. NOx oxidation for two stage with applied voltage was better than that for one stage with applied voltage. NO oxidation didn't depend on applied voltage. While NO oxidation was going on, NOx removal efficiency was 20-25%, however, significantly depended on the injection method of air and $H_2O$ + air. When NaOH water-solution density of 20% was showered to flue gases, NOx removal efficiency increased to 64%.

• Proceedings of the KIEE Conference
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• 대한전기학회 2007년도 제38회 하계학술대회
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• pp.1291-1292
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• 2007

Recently, there were many researches for efficiency improvement of DSC. Among of these works, research of surface treatment is still a prerequisite for electron diffusion, light-harvesting and surface state of DSC.[1] Using of the surface treatment, it can be raise up porosity of $TiO_2$ nano-crystalline structure on photo-electrode. There are chemical, physical, electrical and optical methods which raise up its porosity. In this paper, we have designed and manufactured MOPA-type ultrasonic circuit (100W, frequency and duty variable). Manufactured ultrasonic circuit to use to force cavity density and power into $TiO_2$ paste. Then, we have optimized forcing time, frequency and duty of ultrasonic irradiation for surface treatment of photo-electrode of DSC. In I-V characteristic test of DSC, ultrasonic and thermal treated DSC shows 19% improved its efficiency against monolithic DSC. And it shows stability of light-harvesting from drastically change of light irradiation test.