Current Issue : January - March Volume : 2018 Issue Number : 1 Articles : 5 Articles
Renewable energy generation and electric vehicles (EVs) have attracted much attention in\nthe past decade due to increasingly serious environmental problems as well as less and less fossil\nenergy reserves. Moreover, the forms of energy utilization are changing with the development of\ninformation technology and energy technology. The term ââ?¬Å?energy hubââ?¬Â has been introduced to\nrepresent an entity with the capability of energy production, conversion and storage. A residential\nquarter energy-hub-optimization model including a concentrating solar power (CSP) unit is proposed\nin this work, with solar energy and electricity as its inputs to supply thermal and electrical demands,\nand the operating objective is to minimize the involved operation costs. The optimization model\nis a mixed integer linear programming (MILP) problem. Demand side management (DSM) is next\nimplemented by modeling shiftable electrical loads such as EVs and washers, as well as flexible\nthermal loads such as hot water. Finally, the developed optimization model is solved with the\ncommercial CPLEX solver based on the YALMIP/MATLAB toolbox, and sample examples are\nprovided for demonstrating the features of the proposed method....
Solar collector technologies operate with better performance when the Sun beam direction\nis normal to the capturing surface, and for that to happen despite the relative movement of the Sun,\nsolar tracking systems are used, therefore, there are rules and standards that need minimum accuracy\nfor these tracking systems to be used in solar collectorsââ?¬â?¢ evaluation. Obtaining accuracy is not an\neasy job, hence in this document the design, construction and characterization of a sensor based on\na visual system that finds the relative azimuth error and height of the solar surface of interest, is\npresented. With these characteristics, the sensor can be used as a reference in control systems and\ntheir evaluation. The proposed sensor is based on a microcontroller with a real-time clock, inertial\nmeasurement sensors, geolocation and a vision sensor, that obtains the angle of incidence from the\nsunraysââ?¬â?¢ direction as well as the tilt and sensor position. The sensorââ?¬â?¢s characterization proved how\na measurement of a focus error or a Sun position can be made, with an accuracy of 0.0426ââ??¦ and an\nuncertainty of 0.986%, which can be modified to reach an accuracy under 0.01ââ??¦. The validation of\nthis sensor was determined showing the focus error on one of the best commercial solar tracking\nsystems, a Kipp & Zonen SOLYS 2. To conclude, the solar tracking sensor based on a vision system\nmeets the Sun detection requirements and components that meet the accuracy conditions to be used\nin solar tracking systems and their evaluation or, as a tracking and orientation tool, on photovoltaic\ninstallations and solar collectors....
This work proposes a new analytical model to extract the 1-Diode/2-Resistor solar\ncell/panel equivalent circuit parameters. The methodology is based on a reduced amount of\nexperimentally measured information: short-circuit current, the slope of the I-V curve at that point,\nthe open-circuit voltage, and the current and voltage levels, together with the slope of the I-V curve at\nthe instantaneous operation point. This procedure is specially designed to analyze the performance\nof autonomous photovoltaic systems, which are most of the primary sources for spacecraft power.\nResults show good agreement with experimental data. Furthermore, this methodology allows for\nfast and accurate I-V curve maximum power point (MPP) identification....
Fluorinated oligomer gel is suitable to the electrolyte of dye sensitized solar\ncell. This article studied mainly in the scope of electric conductivity, including\nionic liquid in the electrolyte. It was found that the ratio of mixing with dimetyl\nsulfoxide and the concentration of LiI affect the conductivity. The behavior\nis different depending on the type of ionic liquid. Although the mixing\nionic liquid enhances the conductivity, the short circuit current density of assembled\nsolar cell with it was suppressed so much....
Photovoltaic (PV) devices are spectrally selective, and their performance is influenced\nby unavoidable spectral variations. In addition, multijunction-based concentrating photovoltaic\n(CPV) devices show a strong spectral dependence due to the series connection of various junctions\nwith different absorption bands, and also due to the use of concentrator optics. In this work,\nthe accuracy of a new set of analytical equations that quantify the spectral impact caused by the\nchanges in air mass (AM), aerosol optical depth (AOD) and precipitable water (PW) is discussed.\nFour different CPV devices based on lattice-matched and metamorphic triple-junction solar cells\nand a poly(methyl methacrylate) (PMMA) and silicon-on-glass (SoG) Fresnel lenses are considered.\nA long-term outdoor experimental campaign was carried out at the Centre for Advanced Studies on\nEnergy and Environment (CEAEMA) of the University of JaÃ?©n, Spain. Results show a high accuracy\nin the estimations of the spectral factor (SF), with an average mean absolute percentage error (MAPE)\nwithin 0.91% and a mean relative error (MRE) within âË?â??0.32%....
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