National Institute of Technology, Karnataka

About: National Institute of Technology, Karnataka is a education organization based out in Mangalore, Karnataka, India. It is known for research contribution in the topics: Computer science & Corrosion. The organization has 5017 authors who have published 7057 publications receiving 70367 citations.

Optimum location and influence of tilt angle on performance of solar PV panels

Abstract: With the growing demand of economically feasible, clean, and renewable energy, the use of solar photovoltaic (PV) systems is increasing. The PV panel performance to generate electrical energy depends on many factors among which tilt angle is also a crucial one. Among hundreds of research work performed pertinent to solar PV panels performance, this work critically reviews the role of tilt angles and particularly locating the optimum tilt angle using different methods. The past data collected for analysis can be categorized mainly into mathematical model based, experimental based, simulation based, or combination of any of these. Single-axis tracking, dual-axis tracking, simple glass cover, hydrophobic glass cover, soiled glass, clean glass, partial shadow, use of phase-change material, computational fluid dynamic analysis, etc., are the novel methods found in the literature for analysis and locating the optimum tilt angle. For illustration purpose, few figures are provided in which the optimum tilt angle obtained on monthly, seasonally, and annual basis is shown. Research works are growing in the field of computations and simulations using online software and codes. Pure mathematical-based calculations are also reported but the trend is to combine this method with the simulation method. As the PV panel performance is found to be affected by number of parameters, their consideration in any single study is not reported. In future, work is required to carry out the experiment or simulation considering the effect of soiling, glass material, temperature, and surrounding ambience on the location of optimum tilt angle. As a whole, the optimum tilt angles reported for locations exactly on the equator line, i.e., 0° latitude, ranges between − 2.5° and 2.5°, for locations just above the equator line, i.e., latitude 2.6°–30° N ranges between 5° and 28°, for 40°–70° N, it is 29°–40°, and for 71°–90° N, it is 41°–45°. For locations at 2.6°–30° S, optimum tilt angles range between − 4° and − 32°, 30°–46° S, it is − 33° to − 36°, 47°–65° S, it is − 34° to − 50°, and for 66°–90° S it is − 51° to − 62°.

Photocatalytic activity of ZnO-WO3 for diclofenac degradation under visible light irradiation

Abstract: Diclofenac is known to be a persistent pharmaceutical compound, and their effective removal from water sources has been a rising concern. This study reports the visible light irradiated photocatalytic degradation of diclofenac using ZnO-WO3 mixed oxide catalysts, prepared by the hydrothermal method with variation in molar ratios of tungsten precursor. The prepared catalysts were characterized using a different technique, and the photocatalytic activity has been tested under visible light irradiation. Adsorption isotherm studies were performed to elucidate the preferential adsorption nature of the mixed oxide catalyst. The interaction of diclofenac and the prepared mixed oxides is based on the positively charged ZnO-WO3 surface and anionic diclofenac at solution pH 6. The adsorption and photodegradation kinetics is best expressed by the Langmuir isotherm model and pseudo-first-order kinetic model, respectively. Results indicated that all the prepared catalysts exhibited better catalytic activity than the bare ZnO under the visible light irradiation. The catalyst prepared with a molar ratio of 10:1 is proven to be an efficient catalyst and achieved 76%mineralization of diclofenac during the irradiation. The effect of operating variables like pH, initial diclofenac concentration, and catalyst loading was investigated and reported. The ZnO-WO3 mixed oxide catalysts were showed better stability, and the results revealed that the photocatalytic efficiency was retained up to 80% over the repeated reaction cycles. Several intermediate compounds formed during the photocatalytic reaction have been analyzed using LC–MS, and their degradation pathways have been found to primarily follows hydroxylation, dechlorination and decarboxylation reactions.