Power Generation Prediction of Building-Integrated Photovoltaic System with Colored Modules Using Machine Learning

The building-integrated photovoltaic (BIPV) system is provoking mention as a technology for generating the energy consumed in cities with renewable sources. As the number of BIPV systems increases, performance diagnosis through power-generation predictions becomes more essential. In the case of a colored BIPV module that has been installed on a wall, it is more difficult to predict the amount of power generation because the shading loss varies based on the entrance altitude of the irradiance. Recently, artificial intelligence technology that is able to predict power by learning the output data of the system has begun being used. In this paper, the power values of colored BIPV systems that have been installed on walls are predicted, and the system output values are compared. The current-voltage (I–V) curve data are measured to predict the power required changing the intensity of the irradiance, and the linear regression model is derived for the changes in the voltage and current at a maximum power operating point and during irradiance changes. To improve the power prediction accuracy by considering the shading loss of colored BIPVs, a new model is proposed via neural network machine learning (ML). In addition, the accuracy of the proposed prediction models is evaluated by comparing the metrics such as RMSE, MAE, and R2. As a result of testing the linear regression model and the proposed ML model, the R2 values for the voltage and current values of the proposed ML model were 5% higher for voltage and 2% higher for current. From this result, the proposed ML model of the RMSE about real power improved by more than 50% (0.0754 kW) compared to the simulation model (0.1581 KW). The proposed model demonstrates high-accuracy power estimations and is expected to help diagnose the performance of BIPV systems with colored modules

Higenamine이 기니피그 대동맥 및 결장뉴 평활근의 수축성에 미치는 영향

Higenamine isolated from Aconiti tuber is known to have positive inotropic action through the adrenergic ~-receptors. However, the effects of higenamine on the vascular smooth muscle and taenia coli have not yet been elucidated. The actions of higenamine were investigated on the activated aortic strips of guinea-pigs and rabbits by norepinephrine, high K-Tyrode's solution and electrical field stimulation, and also on the spontaneous contractions of guinea-pig taenia coli. Electrical activities and mechanical contractions were simultaneously recorded using the conventional suction-electrode method and single sucrose gap technique. All experiments were performed in tris-buffered Tyrode's solution which was aerated with 100% O2 and kept at 35°C. Higenamine suppressed dose-dependently the norepinephrine-induced contraction. Propranolol potently antagonized the inhibitory effects of higenamine on rabbit aorta, while less potently on guinea-pig aorta. Higenamine seemed to suppress profoundly the component of intracellular Ca2+ mobilization in the contraction curve of norepinephrine in guinea-pig aorta. Higenamine did not seem to suppress the component of Ca2 + influx through the potential-sensitive Ca2 + channel in K-contracture of guinea-pig aorta. Higenamine suppressed both passive resting tension and active tension (phasic contraction) driven by electrical field stimulation (A.C. 60 Hz, 5-7 V/cm, duration 10 sec, interval 3 min) in guinea-pig aorta. Propranolol also rapidly suppressed both passive resting and active tensions. Higenamine dose-dependently suppressed the frequency and amplitude of spontaneous contraction, resulting in complete abolishment of it above 10-6 M concentration in guinea-pig taenia coli. Propranolol almost completely antagonized its effect. Higenamine reduced dose-dependently both burst frequency and spike frequency, and depolarized membrane potential in guinea-pig taenia coli. Propranolol almost completely blocked its effect. In conclusion the inhibitory action of higenamine to the norepinephrine-induced contraction might be produced by the depression of intracellular Ca2+ mobilization and Ca2+-influx through ~-adrenoceptors in guinea-pig aorta. The Ca2+-influx through the potential-sensitive Ca2+ channel might not be suppressed by higenamine in guinea-pig aorta. The inhibitory effects of higenamine on the spontaneous contractions of guineapig taenia coli result from the decrease of burst frequency and spike frequency through the ~-adrenoceptors

Origin of Bypass Diode Fault in c-Si Photovoltaic Modules: Leakage Current under High Surrounding Temperature

Bypass diodes have been widely utilized in crystalline silicon (c-Si) photovoltaic (PV) modules to maximize the output of a PV module array under partially shaded conditions. A Schottky diode is used as the bypass diode in c-Si PV modules due to its low operating voltage. In this work, we systematically investigated the origin of bypass diode faults in c-Si PV modules operated outdoors. The temperature of the inner junction box where the bypass diode is installed increases as the ambient temperature increases. Its temperature rises to over 70 °C on sunny days in summer. As the temperature of the junction box increases from 25 to 70 °C, the leakage current increases up to 35 times under a reverse voltage of 15 V. As a result of the high leakage current of the bypass diode at high temperature, melt down of the junction barrier between the metal and semiconductor has been observed in damaged diodes collected from abnormally functioning PV modules. Thus, it is believed that the constant leakage current applied to the junction caused the melting of the junction, thereby resulting in a failure of both the bypass diode and the c-Si PV module

Analytical Study of the Electrical Output Characteristics of c-Si Solar Cells by Cut and Shading Phenomena

Cut solar cells have received considerable attention recently as they can reduce electrical output degradation when the c-Si solar cells (crystalline-silicon solar cells) are shaded. Cut c-Si solar cells have a lower short-circuit current than normal solar cells and the decrease in short-circuit currents is similar to the shading effect of c-Si solar cells. However, the results of this study’s experiment show that the shadow effect of a c-Si solar cell reduces the V o c (open circuit voltage) in the c-Si solar cell but the V o c does not change when the c-Si solar cell is cut because the amount of incident light does not change. In this paper, the limitations of the electrical power analysis of the cut solar cells were identified when only photo current was considered and the analysis of the electric output of the cut c-Si solar cells was interpreted with a method different from that used in previous analyses. Electrical output was measured when the shaded and cut rates of c-Si solar cells were increased from 0% to 25, 50 and 75%, and a new theoretical model was compared with the experimental results using MATLAB

A Study of the Electrical Output and Reliability Characteristics of the Crystalline Photovoltaic Module According to the Front Materials

In recent years, various types of installations such as floating photovoltaic (PV) and agri-voltaic systems, and BIPV (building integrated photovoltaic system) have been implemented in PV systems and, accordingly, there is a growing demand for new PV designs and materials. In particular, in order to install a PV module in a building, it is important to reduce the weight of the module. The PV module in which low-iron, tempered glass is applied to the front surface, which is generally used, has excellent electrical output and reliability characteristics; however, it is heavy. In order to reduce the weight of the PV module, it is necessary to use a film or plastic-based material, as opposed to low-iron, tempered glass, on the front surface. However, if a material other than glass is used on the front of the PV module, various problems such as reduced electrical output and reduced reliability may occur. Therefore, in this paper, a PV module using a film instead of glass as the front surface was fabricated, and a characteristic analysis and reliability test were conducted. First, the transmittance and UV characteristics of each material were tested, and one-cell and 24-cell PV modules were fabricated and tested for electrical output and reliability. From the results, it was found that the transmittance and UV characteristics of the front material were excellent. In addition, the electrical output and reliability test results confirmed that the front-surface film was appropriate for use in a PV module

Immunoblotting for protein expression of osteogenic molecules in MC3T3-E1 cells (A) and ADSC (B).

<p>Relative ratios of Runx2, Type I collagen, ALP, MMP3 to β-actin were measured with Image J software. Data are representative of at least two experiments. Values are the mean ± standard deviation. Statistical difference as compared to corresponding control group. ^#p<0.05, ^*p<0.01.</p