• 한국태양에너지학회:학술대회논문집
• /
• 2012.03a
• /
• pp.177-181
• /
• 2012

본 연구는 고온고습 시험을 통하여 Cell 레벨에서의 표면관찰 및 효율저하를 분석하였다. 고온고습 시험 조건은 KS C IEC-61215에서 제시한 PV module하의 조건을 이용하여 온도 $85^{\circ}C$, 습도 85% 조건하에 1000시간 동안 수행하였다. 고온고습 시험에 따라 효율에 직접적인 영향을 줄 수 있는 이상 유 무를 Cell 표면을 통해 분석한 결과, 고온고습 시험 수행 중 부분적으로 변색되는 것을 확인하였다. 고온고습 시험 전 단결정 Cell의 효율은 17.74% 였으며, 1000시간 수행 후 15.63%으로 11.89%의 감소율을 보였다. 다결정 Cell의 시험 전 효율은 15.46%, 1000시간 수행 후 효율은 14.02%로 9.31%의 감소율을 보였다. 경년 시 나타나는 전기적 특성을 분석하기 위해 FF(Fill Factor)값을 분석한 결과, 고온고습 시험 전 단결정 Cell은 78.71%에서 75.01%로 4.7%의 감소율을 보였으며, 다결정 Cell은 78.10 %에서 76.66%로 1.84%의 감소율을 보였다. 효율 및 FF값에서 단결정 Cell이 다결정 Cell보다 감소율이 큰 것으로 분석되었으며, 이는 단결정 Cell이 외부 환경에서 더욱 크게 작용하여 효율저하에 영향을 주었다고 판단된다.

• Journal of Biosystems Engineering
• /
• v.28 no.1
• /
• pp.53-58
• /
• 2003

This study was carried out to design, construct, and test a greenhouse monitoring system fur the environment and status of control devices in a greenhouse from a remote site using internet. The measuring items selected out of many environmental factors were temperature, humidity, solar radiation, CO$_2$, SOx, NOx concentration, EC, pH of nutrient solution, the state of control devices, and the image of greenhouse. The developed greenhouse monitoring system was composed of the network system and the measuring module. The network system consists of the three kinds of monitors named the Croup Monitor. the Client Monitor and the Server Monitor. The results of the study are summarized as follows. 1. The measuring module named the House Monitor. which is used to watch the state of the control device and the environment of the greenhouse, was developed to a embedded monitoring module using one chip microprocessor 2. For all measuring items. the House Monitor showed a satisfactory accuracy within the range of ${\pm}$0.3%FS. The House Monitors were connected to the Croup Monitor by communication method of RS-485 type and could operate under power and communication fault condition within 10 hours. The Croup Monitor was developed to receive and display measurement data received from the House Monitors and to control the greenhouse environmental devices. 3. The images of the plants inside greenhouse were captured by PC camera and sent to the Group Monitor. The greenhouse manager was able to monitor the growth state of plants inside greenhouse without visiting individual greenhouses. 4. Remote monitoring the greenhouse environment and status of control devices was implemented in a client/server environment. The client monitor of the greenhouse manager at a remote site or other greenhouse manager was able to monitor the greenhouse environment and the state of control devices from the Server Monitor using internet.

• Journal of agriculture & life science
• /
• v.46 no.5
• /
• pp.143-152
• /
• 2012

This study was performed to reduce the operating cost of a greenhouse by securing electric energy required for greenhouse operation. Therefore, it experimentally reviewed the performance analysis of photovoltaic system in terms of maximum amount of generated electric power based on the amount of horizontal solar radiation during daytime. That is to say, the maximum solar radiation at 300, 400, 500, 600, 700, 800 and 900 W. $m^{-2}$, respectively. The amount of momentary electric power of the photovoltaic system at any was about 970 W and we found that the momentary efficiency of the photovoltaic system that was used for this experiment was 97%. In the case of this system, we found that electric power will be generated when amount of horizontal solar radiation is more than 200 W. $m^{-2}$, at minimum. If the amount of horizontal solar radiation is increased, the maximum power generation is also increased. At that time, the maximum efficiencies were 30, 78, 86 and 90%, respectively. However, when the amount of insolation was about 800 W. $m^{-2}$, the maximum power generation tended to be lower than 700 W. $m^{-2}$. The efficiency which caused the maximum electric power was decreased to less than 97% of the momentary generated electric power. When the total amounts of horizontal solar radiation per day were 3.24, 8.10, 10, 90, 12.70, 14.33, 19.53 and $21.48MJ{\cdot}m^{-2}$ respectively, the total amounts of power energy were 0.03, 0.40, 3.60, 4.37, 4.71, 4.70 and 4.91 kWh. And it represented that the total amounts of power energy were either decreased or increased a bit on the border between some solar radiations. The temperature at the back of the array tended to be higher than the temperature at the front but it demonstrated an increased when the amount of solar radiation increased. In the case of this system, the performance of the module in terms of degradation has not been shown yet.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.38 no.9
• /
• pp.757-762
• /
• 2014

A solar heat and power hybrid system can simultaneously generate electricity and thermal energy. In this study, several experiments were carried out with a solar heat and power hybrid unit. Then, a method to increase the photovoltaic efficiency and amount of thermal energy was suggested based on a comparative analysis. The experiment was conducted using only the photovoltaic system as a reference case, with the photovoltaic-thermal air system as a hybrid case. A numerical increase in the photovoltaic efficiency per $1^{\circ}C$ was suggested based on a comparative data analysis of these two cases. In this experiment, the surface temperature on the air hybrid system was $13.52^{\circ}C$ lower than that in the reference case, and the photovoltaic efficiency was increased by 5.09. The amount of thermal energy produced was 15.69 Wt per $1^{\circ}C$ difference between the ambient and outlet temperatures. In this paper, therefore, a photovoltaic efficiency increase of 0.34 per $1^{\circ}C$ is proposed for the air hybrid system based on the analysis of the experimental data.

• Journal of Bio-Environment Control
• /
• v.18 no.3
• /
• pp.177-184
• /
• 2009

For the purpose of reducing the cost for greenhouse operation by acquiring the electric power necessary for it, this study installed a solar photovoltaic system on the roof of the building adjacent to green-houses and experimentally examined the quantity of power generation based on weather conditions. The results of the study are as per the below: The maximum, average and minimum temperature while the experiment was conducted was $0.4{\sim}34.1,\;-6.1{\sim}22.2$, and $-14.1{\sim}16.7^{\circ}C$ respectively, and the solar radiation was $28.8MJ{\cdot}m^{-2}$ (maximum), $14.9MJ{\cdot}m^{-2}$ (average), and $0.6MJ{\cdot}m^{-2}$ (minimum). The quantity of electric power didn't increase in proportion to the quantity of solar radiation and instead, it was almost consistent around 750W. Daily maximum, average and minimum consumption of electric power was 5.2kWh, 2.5kWh and 0kWh respectively. Based on the average electric power consumption of the system used for this experiment, it was sufficient in case the capacity and the working time of a hot blast heater are small, but it was short in case they are big. In case the capacity of the hot blast heater is big, the average electric power quantity will be sufficient for array area $21m^2$, about three times of the present area. In summer when the temperature of the array becomes high, the generation of electric power didn't increase in proportion to the quantity of solar radiation, but this experiment result shows a high correlation between two factors (coefficient of correlation 0.84).

• Journal of the Korean Solar Energy Society
• /
• v.39 no.6
• /
• pp.55-65
• /
• 2019

With the rapid development of the national industry, the importance of electrical safety was recognized because of a lot of new electrical equipment are installing and the electrical accidents have been occurring annually. Today, the electrical equipments is inspect by using the portable Infrared thermal imaging camera. but the most negative element of using the camera is inspected for only state of heating, the reliable diagnosis is depended with inspector's knowledge, and real-time monitoring is impossible. This paper present the infrared thermal imaging safety diagnosis system. This system is able to monitor in real time, predict the state of fault, and diagnose the state with analysis of thermal and power data. The system consists of a main processor, an infrared camera module, the power data acquisition board, and a server. The diagnostic algorithm is based on a mathematical model designed by analyzing the Pearson's Correlation Coefficient between temperature and power data. To test the prediction algorithm, the simulations were performed by damaging the terminals or cables on the switchboard to generate a large amount of heat. Utilizing these simulations, the developed prediction algorithm was verified.

• Journal of Power Electronics
• /
• v.4 no.1
• /
• pp.46-55
• /
• 2004

This paper presents a high-frequency ZVS-PWM boost chopper-fed DC-DC converter with a single active auxiliary edge resonant snubber in the load-side which can be designed for power conditioners such as solar photovoltaic generation, fuel cell generation, battery and super capacitor energy storages. Its principle operation in steady-state is described in addition to a prototype setup. The experimental results of ZVS-PWM boost chopper-fed DC-DC converter proposed here, are evaluated and verified with a practical design model in terms of its switching voltage and current waveforms, the switching v-i trajectory, the temperature performance of IGBT module, the actual power conversion efficiency and the EMI of radiated and conducted emissions. And then discussed and compared with the hard switching scheme from an experimental point of view. Finally, this paper proposes a practical method to suppress parasitic oscillation due to the active auxiliary resonant switch at ZCS turn off mode transition with the aid of an additional lossless clamping diode loop, and reduced the EMI conducted emission in this paper.

• Proceedings of the KIPE Conference
• /
• 2003.07a
• /
• pp.223-226
• /
• 2003

This paper presents a high-frequency ZVS-PWM boost chopper-fed DC-DC converter with a single active auxiliary edge-resonant snubber which is used for power conditioner such as solar photovoltaic generation and fuel cell generation. The experimental results of boost chopper fed ZVS-PWM DC-DC converter are evaluated. In audition to its switching voltage and current waveforms, and the switching v-i trajectory of the power devices are discussed and compared with the conventional hard switching DC-DC converter treated here. The temperature performance of IGBT module,, efficiency, and EMI noise characteristics of this ZVS-PWM DC-DC converter using IGBTs are measured and evaluated from an experimental point of view.

• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.1384-1385
• /
• 2011

This paper presents the active maximum power point tracking(MPPT) control of the photovoltaic(PV) module integrated converter(MIC) system considering the shadow influence. Conventional perturbation and observation(PO) and incremental conductance(IC) are the method finding MPP by the continued self-excitation vibration. The MPPT control is unable to be performed by rapid output change affected by the shadow. To solve this problem, the active MPPT in which the step value changes by output change is presented. In case there are the solar radiation, a temperature and shadow influence, the presented algorithm treats and compares the conventional control algorithm and output error. In addition, the validity of the algorithm is proved through the output error response characteristics.

• KIEAE Journal
• /
• v.13 no.6
• /
• pp.105-111
• /
• 2013

This study aims to suggest the PV lightshelf and to evaluate the power performance of the photovoltaic systems easily mounted on the windows. For the study, the suggested systems consist of two parts as fixed and movable PV modules. Also, tempered glass and polycarbonate are used on the surface protection materials for solar cells of PV lightshelf. By using polycarbonate, the weight of PV lightshelf is lighter about 20%. The field tests are performed for five days by using real size models. The voltage, current and electric powers are measured as basic performances of PV lightshelf. Also, the irradiation, brightness and module surface temperature are measured as outside conditions. As results, the power performance of tempered glass PV lightshelf shows about 11(%) higher thant that of polycarbonate PV lightshelf. And the power performance shows about 5(%) higher in a horizontal system. This results could be used to develop the effective PV lightshelf in next study.