Numerical Study of the Effect of Temperature on the Performance of a Silicon Heterojunction Solar Cell (HIT) in the Presence of Excitons
Ousmane Ngom,
Modou Faye,
Mamadou Mbaye,
Cheikh Mbow,
Bassirou Ba
Issue:
Volume 8, Issue 4, July 2019
Pages:
56-67
Received:
10 July 2019
Accepted:
18 August 2019
Published:
6 September 2019
Abstract: In this article, a detailed study of the physical phenomena in the base of a silicon heterojunction solar cell (HIT) is elaborated. To carry out this work we have established a mathematical model which is in the form of a system of two continuity equations. The latter are subjected to physical conditions of nature to define our field of study. This system of continuity equations is solved using a computational program in a digital programming language. Numerical analysis is used in this study because the mathematical system describing the transport phenomena of load carriers (electrons and excitons) in a silicon heterojunction photovoltaic cell is very complex. Thus, to facilitate numerical resolution, the dimensional parameters of the physical system are rendered dimensionless. The resulting dimensionless equations are discretized by the finite volume method. They are then implemented in a calculation program by an iterative line-by-line relaxation method of the Gauss-Siedel type. In addition, with a low density coupling coefficient b=10-16cm3s-1 that depends on the material’s properties, the influence of temperature on the diffusion lengths, on the carrier and photocurrent densities, and on the internal quantum yield is studied. This study is carried out using polychromatic illumination with ultraviolet, visible and infrared wavelengths.
Abstract: In this article, a detailed study of the physical phenomena in the base of a silicon heterojunction solar cell (HIT) is elaborated. To carry out this work we have established a mathematical model which is in the form of a system of two continuity equations. The latter are subjected to physical conditions of nature to define our field of study. This...
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Reduction of Friction by Electric Action on Oils
Anatoly Vasilievich Dunaev
Issue:
Volume 8, Issue 4, July 2019
Pages:
68-75
Received:
23 June 2019
Accepted:
22 August 2019
Published:
10 September 2019
Abstract: In the well-known research, testing tribometer TRB-S-DE, in the operation of hundreds of cars confirmed the effectiveness of low-cost and a significant reduction in friction and improvement of working properties of interfaces of components operating in motor and gear oils under electrical stress on the oil. Thus, by 2007 the Kharkiv Academy of railway transport proved the efficiency of processing of motor and hydraulic oils in a constant field up to 1000 V/cm. And by 2013, the Academy has provided heavy machinery Donbass several models of devices for such processing of motor and hydraulic oils. However, Lyubimov D. N. with colleagues provided a more simple method of processing oil - supply voltage converters +12V /+ 50V on the dipstick, or other isolated parts washed by the oil. This was tested at Tallinn University on the Timken friction machine, at the Helsinki diagnostic centre by two tests of the car on a drum stand (fuel economy up to 22.4%) and a bench test of the engine with fuel economy of 3.7%. And in St.-Petersburg Polytechnic University, Shabanov A. Yu. in bench trials of the engine the VAZ-2108, measuring 276 parameters, convincingly showed a varied effect of the filing of charges in oil: mechanical losses decreased by 5.5%, fuel consumption by 4.3%, the exhaust gas temperature by 6-10°C, the content of co and CH by 19%, but NOx increased by 6.53%. The effective efficiency of the engine increased by 4.62%, and the power-by 1%. That is, the savings in gasoline and diesel engines are close. Therefore, in Russia, Lyubimov D. N. converters are already used at 330 facilities. In tests of the Nanocenter at the Moscow Institute GOSNITI on the tribometer ТRB-S-DE voltage of +12...33 V and +48 V was applied to the electrodes of iron, graphite, copper, aluminum, zinc and tin, mounted in oil with finger groups steel pin-on-disc. Tests at a sliding speed of 100 cm/s were carried out at a stepped loading to a pressure of 220 MPa. A 3.5 - fold reduction in friction and wear was obtained at low loads, less - at medium and without effect in the nominal mode. In 2018, on 29 modern Russian and imported cars, the supply voltage even on steel parts in engines, in transmission units provided fuel savings of at least 3, in different conditions 10-18, mainly 7-8%. Tribological treatment Pustovoi I. F. by serpentine composition «Fe-do» of the four units of the car's Ford F-150 and emission of charges in their oils have reduced the fuel consumption from 15 to 10-11 l/100 km. Recent testing demonstrated the effectiveness of applying a voltage of 100 V.
Abstract: In the well-known research, testing tribometer TRB-S-DE, in the operation of hundreds of cars confirmed the effectiveness of low-cost and a significant reduction in friction and improvement of working properties of interfaces of components operating in motor and gear oils under electrical stress on the oil. Thus, by 2007 the Kharkiv Academy of rail...
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