• 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.

• Proceedings of the KIEE Conference
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• 2005.07b
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• pp.1684-1686
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• 2005

As photovoltaic(PV) power generation systems become more common, it will be necessary to investigate islanding detection method for PV systems. Islanding of PV systems can cause a variety of problems and must be prevented. However, if the real and reactive power of load and PV system are closely matched, islanding detection by passive methods becomes difficult. Also, most active methods lose effectiveness when there are several PV systems feeding the same island. The active frequency drift positive feedback method(AFDPF) enables islanding detection by forcing the frequency of the voltage in the island to drift up or down. In this paper the research for the minimum value of chopping fraction gain applied digital phase-locked-loop(DPLL) to AFDPF considering output power quality and islanding prevention performance are performed by simulation and experiment in IEEE Std 929-2000 islanding test.

• Proceedings of the KIPE Conference
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• 2016.11a
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• pp.73-74
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• 2016

본 논문은 포워드-플라이백 컨버터와 태양광 단일 전원 비대칭 다단식 H-bridge 다중 레벨 인버터를 적용한 태양광 전력 조절 시스템에 관한 논문이다. 이는 기존에 연구되었던 대칭형 다단식 H-Brdige 다중 레벨 인버터나 플라이백 컨버터를 사용한 태양광 전력 조절 시스템의 단점을 보완 한 것이다. 대칭형 다단식 멀티 레벨 인버터는 각 H-Bridge 구조 마다 독립된 전원이 필요하지만, 포워드-플라이백(Foward-Flyback) 컨버터를 접목시켜 단일 태양광 전원으로 하나의 다단식 H-Brdige 인버터를 구성 할 수 있고, 또한 기존의 플라이백 컨버터를 포워드-플라이백 컨버터로 대체 하면서 기존 대비 대용량 설비가 용이하고 효율적인 태양광 전력 조절 시스템을 설계 할 수 있다. 제안한 시스템의 가능성을 확인하기 위하여, PSIM 시뮬레이션을 통해 계통 연계형 1kW급 태양광 시스템의 최대 전력 추종 제어(Maximum Power Point Tracking)와 인버터의 $V_{dc}$ 전압 제어를 확인하였다.

• Journal of the Korean Solar Energy Society
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• v.30 no.2
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• pp.10-15
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• 2010

The experimental study was conducted to optimize the system dissipating properly heat from the in-situ solar panel installed on the roof. For this purpose, six 12-Watt panels, which were consisted of the different design conditions such as containing phase change material(PCM), changing the array of the aluminum fin and honeycomb at the back of the panel, were tested. PCM, which had $44^{\circ}C$ melting point, was chosen in this study. In order to enhance absorbing and expelling heatin PCM, profiled aluminum fin was placed either inward oroutward from the panel. Furthermore, Aluminum honeycomb is imbedded in the back container to find if it would improve the thermal conductivity of PCM. During the experiment, there were ranged to $26^{\circ}C\sim32^{\circ}C$ for outdoor temperature and $700W/m^2\sim1000W/m^2$ for irradiance. As a result, the solar panel, combined with honeycomb and outward fins with PCM instead of placing the fins inward, is showing the best performance in terms of controling panel temperature and its efficiency.

• The Journal of Sustainable Design and Educational Environment Research
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• v.17 no.3
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• pp.1-8
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• 2018

We suggest improvement direction of energy-saving design based on analysis of current situation in school facilities. School facilities have large area among public buildings. While the number of students is decreasing, the number of school and energy consumption is increasing year after year. School facilities have excellent heat insulation property, but it requires further examination about excessive heat insulation plan. School facilities are using gas heat pump actively for cooling and heating, but has difference in use ratio of ground source heat pump by region. Thus School facilities requires active using of ground source heat pump and BIPV(Building Integrated Photovoltaic System).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.8
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• pp.461-465
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• 2016

n-type silicon shows the better tolerance towards metal impurities with a higher minority carrier lifetime compared to p-type silicon substrate. Due to better lifetime stability as compared to p-type during illumination made the photovoltaic community to switch toward n-type wafers for high efficiency silicon solar cells. We fabricated the front electrode of the n-type solar cell with AgAl paste. The electrodes characteristics of the AgAl paste depend on the contact junction depth that is closely related to the firing temperature. Metal contact depth with p+ emitter, with optimized depth is important as it influence the resistance. In this study, we optimize the firing condition for the effective formation of the metal depth by varying the firing condition. The firing was carried out at temperatures below $670^{\circ}C$ with low contact depth and high contact resistance. It was noted that the contact resistance was reduced with the increase of firing temperature. The contact resistance of $5.99m{\Omega}cm^2$ was shown for the optimum firing temperature of $865^{\circ}C$. Over $900^{\circ}C$, contact junction is bonded to the Si through the emitter, resulting the contact resistance to shunt. we obtained photovoltaic parameter such as fill factor of 76.68%, short-circuit current of $40.2mA/cm^2$, open-circuit voltage of 620 mV and convert efficiency of 19.11%.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.88.1-88.1
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• 2010

Organic dyes, because of their many advantages, such as high molar extinction coefficients, convenience of customized molecular design for desired photophysical and photochemical properties, inexpensiveness with no transition metals contained, and environment-friendliness, are suitable as photosensitizers for the Dye-sensitized Solar Cell (DSSC). The efficiency of DSSC based on metal-free organic dyes is known to be much lower than that of Ru dyes generally, but a high solar energy-to-electricity conversion efficiency of up to 8% in full sunlight has been achieved by Ito et al. using an indoline dye. This result suggests that smartly designed and synthesized metal-free organic dyes are also highly competitive candidates for photosensitizers of DSSCs with their advantages mentioned above. Recently, the performance of DSSC based on metal-free organic dyes has been remarkably improved by several groups. We had reported the novel organic dye with double electron acceptor chromophore, which was a new strategy to design an efficient photosensitizer for DSSC. To verify the strategy, we synthesized organic dyes whose geometries, electronic structures and optical properties were derived from preceding density functional theory (DFT) and time-dependent density functional theory (TD-DFT) calculations. In this paper, we successfully synthesized the chromophore containing multi-acceptor push-pull system from triphenylamine with thiophene moieties as a bridge unit. Organic dyes with a single electron acceptor and double acceptor system were also synthesized for comparison purposes. The photovoltaic performances of these dyes were compared, and the recombination dark current curves and the incident photon-to-current (IPCE) efficiencies were also measured in order to characterize the effects of the multi-anchoring groups on the open-circuit voltage and the short-circuit current. In order to match specifications required for practical applications to be implemented outdoors, light soaking and thermal stability tests of these DSSCs, performed under $100mWcm^{-2}$ and $60^{\circ}C$ for 1000h.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.3
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• pp.201-206
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• 2022

Energy harvesting is a concept introduced in 1954 by Bell Labs in the US while conducting research on solar cells that convert sunlight into energy. Such energy harvesting technology is a technology that collects wasted or unused energy in daily life and recycles it as electric power. In particular In the case of a photovoltaic power generation system, energy harvesting can be applied by storing electricity generated by using a battery to reduce power consumption generated by the inverter in the form of loss of power generation in cloudy weather compared to sunny days. Therefore, in this paper, energy harvesting technology is applied in the low sunlight section such as sunrise, sunset, and cloudy weather to improve the amount of power generation by recovering the power that is below the minimum operating voltage of the inverter and dissipated. Accordingly, the research contents were verified through the development of systems and algorithms according to the amount of solar power generation and the development of systems and algorithms using low power generated in sunset, sunrise, and other environments.

• Journal of the Korean Solar Energy Society
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• v.30 no.4
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• pp.29-35
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• 2010

This study has been carried out empirical research on Transparent Thin-film BIPV modules, BIPV modules installed on the exterior of the building are applied a laminated module 1kWp, double-glazing module 3kWp and triple-glazing module 1kWp. Applied to the total capacity of BIPV modules are 5kWp. In this study, design and construction process of BIPV systems is presented. In addition, through monitoring of the BIPV system, the temperature and the power characteristics of each module were analyzed. During the measurement period, the module temperature measurement results, the maximum surface temperature of $51.5^{\circ}C$ triple-glazing BIPV module showed the highest, followed by double-glazing BIPV module $49.1^{\circ}C$, $44.7^{\circ}C$ laminated modules, respectively. Power output results, the daily average double-layer modules showed 4.10kWh/day, triple-glazing module 1.57kWh, respectively 1.81kWh laminated modules. In particular, the power efficiency of triple-glazing BIPV module was lower than the power efficiency of the laminated BIPV module. This phenomenon is considered to be affected by the module temperature. In the future, BIPV modules in this study the relationship between module temperature and power characteristics plans to identify.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.36 no.4
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• pp.403-407
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• 2023

In this paper, in order to investigate the efficiency of solar power generation system operation, we have studied operation cases such as generation amount, utilization rate, and generation time, and the following conclusions were obtained. The amount of power generation in 2017 was 1,311.48 MWh, and the amount of power generation in 2018 was 1,226.03 MWh. In 2021, 1,184.28 MWh was generated, and 90.30% compared to 2017, and the amount of power generation decreased by 1.94% every year. The deterioration of photovoltaic modules could be seen as one cause of the decrease in power generation. 1,977.74 MWh was generated in the spring, and 1,621.77 MWh was generated in the summer. In addition, 1,478.87 MWh was generated in the fall, and 1,110.55 MWh was generated in the winter, showing a lot of power generation in the order of spring, summer, fall, and winter. From 2017 to 2022, the seasonal utilization rate, daily power generation time, and daily power generation were investigated, and it could be seen that the spring utilization rate varies from 19.29% to 16.99%. It could be seen that the daily generation time in winter decreased from 2.67 hours to 2.13 hours, and in spring it generated longer than spring from 4.63 hours to 4.08 hours. In addition, the daily power generation in winter also decreased from 2.67 MWh to 2.13 MWh, and in spring it decreased from 4.63 MWh to 4.08 MWh, but it could be seen that it is more than in winter.