Wyniki wyszukiwania - BazTech

1

Electrical performance analysis and optimization of monofacial and bifacial crystalline silicon solar cells

Manikandan A. V. M., Prince Shanthi

Optica Applicata

|

2023

|

Vol. 53, nr 3

327--351

EN

This paper presents the investigations and performance analysis of monofacial and bifacial crystalline silicon solar cells with PC1D simulation software. The fundamental limitation in the monofacial solar cell’s performance is its inability to absorb all the incoming solar radiation since the albedo effect (ground-reflected light that can be captured by the rear of the solar cell) is often neglected. So, the efficiency of the monofacial cell will be lower due to poor and incomplete optical absorption. Bifaciality helps to enhance the capturing of light in the solar cell, which means that the rear of the cell is exposed to solar radiation to produce electrical power. The primary focus of our work is to determine which solar cell offers better device performance and conversion efficiency by analyzing various parameters of the solar cell like surface texturing, emitter doping, bulk doping, minority carrier lifetime, bulk and surface recombination rates, front and rear reflectance, among other parameters. The other parameters are maintained at an optimal range to achieve the highest conversion efficiency. Our work has shown that the bifacial solar cell can be as efficient as 28.15%, which is much better than the 22.65% efficiency of the monofacial solar cell.

2

A three-way catalyst system for a five-stroke engine

Noga Marcin

Technical Transactions

|

2019

|

Vol. 116, iss. 3

149--183

EN

This paper presents the results of research on the development of an exhaust gas aftertreatment system for a turbocharged five-stroke engine. This engine was designed and constructed at Cracow University of Technology. A characteristic feature of the five-stroke engine is the use of an additional expansion process to increase overall efficiency. A challenge for a catalytic converter is the fact that it has a low exhaust gas temperature. Two three-way catalytic converters were tested – one with a ceramic support and the second with a metal support. The results of the tests showed that the reactor with a ceramic support obtains an acceptable conversion efficiency starting with an exhaust gas temperature of 280°C. For the metal-support reactor, a few percent increase in torque and a decrease in the brake-specific fuel consumption of the engine was obtained; however, the converter itself did not show signs of operation even with an exhaust gas temperature of over 380°C. The performed analyses highlighted directions of further development works in this area.

PL

W artykule przedstawiono efekty badań nad opracowaniem układu oczyszczania spalin dla turbodoładowanego silnika pięciosuwowego, który został zaprojektowany i wykonany na Politechnice Krakowskiej. Cechą charakterystyczną silnika pięciosuwowego jest zastosowanie dodatkowego rozprężania spalin w celu zwiększenia sprawności ogólnej. Wyzwanie dla reaktora katalitycznego stanowi niska temperatura spalin. Badaniom poddano dwa reaktory trójfunkcyjne, z rdzeniem ceramicznym i z rdzeniem metalowym. Wyniki przeprowadzonych prób wskazały, że reaktor ceramiczny uzyskuje akceptowalną sprawność konwersji od temperatury spalin 280°C. Dla reaktora metalowego uzyskano kilkuprocentowy wzrost momentu obrotowego i obniżenie jednostkowego zużycia paliwa silnika, jednak sam reaktor nie wykazywał oznak działania nawet przy temperaturze spalin powyżej 380°C. Przeprowadzone analizy wskazały kierunki dalszych prac rozwojowych w przedmiotowym obszarze.

3

Characterization of a green and environmentally friendly sensitizer for a low cost dye-sensitized solar cell

Hosseinnezhad M., Jafari R., Gharanjig K.

Opto-Electronics Review

|

2017

|

Vol. 25, No. 2

93--98

EN

Clean and cheap device, namely dye-sensitized solar cells (DSSCs) were fabricated using a natural dye extracted from Sambucus ebulus. We prepared five sample solutions with various pH in the extraction process to improve power conversion efficiency. The UV-visible absorption investigation of sample solutions and on photoanode show the dyes from J-type aggregation on a photoanode substrate. Redox proper-ties of all sample solutions certify thermodynamically a charge transfer from excited state to conduction band TiO2. The optical properties of various dye solutions were investigated and results showed dark-ness and bluish tint effect of dye solutions extracted in basic environment rather than those extracted in acidic condition. Moreover, in comparison to the basic condition, the dye solutions extracted in acidic environment were more saturated and colorimetrically less different from that one which extracted in neutral condition. Photophysical and photoelectrochemical performance of natural extraction dyes have been studied in dye-sensitized solar cell devices. The results show the rather high conversion efficiency of 0.57%, 1.15%, 1.02%, 0.35% and 0.15% of each individual dye extraction, respectively.

4

The effect of magnetic field on the efficiency of a silicon solar cell under an intense light concentration

Zoungrana M., Zerbo I., Soro B., Savadogo M., Tiedrebeogo S., Bathiebo D. J.

Advances in Science and Technology. Research Journal

|

2017

|

Vol. 11, no 2

133--138

EN

This work put in evidence, magnetic field effect the electrical parameters of a silicon solar cell illuminated by an intense light concentration: external load electric power, conversion efficiency, fill factor, external optimal charge load. Due to the high photogeneration of a carrier in intense light illumination mode, in addition of magnetic field, we took into account the carrier gradient electric field in the base of the solar cell. Taking into account this electric field and the applied magnetic field in our model led to new analytical expressions of the continuity equation, the photocurrent and the photovoltage. In this work, we used the electric power curves versus junction dynamic velocity (Sj) to determine, according to magnetic field, the maximum electric power Pelmax and we calculate the solar cell conversion efficiency (η). We also used the J-V characteristics to determine the solar cell short circuit density current (Jcc) and the open circuit voltage (Vco) under magnetic field and we calculate the fill factor (FF). Finally, we used simultaneously the J-V characteristics and equipower curves to determine the optimal external load resistance. The results of this study have showed that the maximum electric power and the conversion efficiency are higher than those of monofacial and bifacial silicon solar cells illuminated by conventional light but they decreased with the increase of magnetic field.

5

Effect of incidence angle varying from 0 rad to Π/2 rad and intensity of radio waves on the performance of a silicon solar cell

Zerbo I., Zoungrana M., Saria M., Ouedraogo A., Bathiebo D. J.

Advances in Science and Technology. Research Journal

|

2017

|

Vol. 11, no 4

68--75

EN

In this work, a one dimensional approach is presented for modelling the effect of the incidence angle, varying from 0 rad to π/2 rad, and the intensity of radio waves on the performance of a polycrystalline silicon solar cell under constant multispectral illumination. By solving the continuity equation in steady state, we derived the expression of the density of excess minority carriers, the photocurrent density, the photovoltage, the electric power and their dependence on the incidence angle and the intensity of the electromagnetic field is analyzed. Using the electric power curves versus junction dynamic velocity we determined the electric power lost at the junction, the maximum electric power and we calculated the conversion efficiency for various incidence angle and intensity of the electromagnetic field. The leakage photocurrent density, deduced from the photocurrent density curves versus junction dynamic velocity, and the electric power lost at the junction allowed us to calculate the shunt resistance of the solar cell according to the incidence angle and the intensity of the electromagnetic field. The numerical data show the negative effect of radios waves on the performance of a silicon solar cell.

6

Characteristics of nanostructure dye-sensitized solar cells using food dyes

Hosseinnezhad M., Rouhani S.

Opto-Electronics Review

|

2016

|

Vol. 24, No. 1

34--39

EN

Dye-sensitized solar cells (DSSCs) were prepared using various food dyes. Food dyes are economically superior to organometallic dyes since they are nontoxic and inexpensive. The spectrophotometric evaluation of chosen food dyes in solution and on a TiO2 substrate show that the dyes form J-aggregation on the photoelectrode substrate. Oxidation of potential measurements for used food dyes ensured an energetically permissible and thermodynamically favorable charge transfer throughout the continuous cycle of a photo-electric conversion. The performance of dye-sensitized solar cells based on food dyes was studied. The results illustrate that the dye containing carboxylic acid and sulfonic acid as the acceptor group gave the maximum conversion efficiency 4.20%.

7

Photocurrent response of phloxin B-cetyltrimethylammonium bromide photogalvanic cell device

Genwa K. R., Shraddha S.

Materials Science Poland

|

2015

|

Vol. 33, No. 3

612--619

EN

Photocurrent and photovoltage generation using phloxin B dye in aqueous and micellar medium at different concentrations have been studied in a photogalvanic cell. The photopotential and photocurrent generated were 1135.0 mV and 260.0 μA, respectively. The observed solar energy conversion efficiency with CTAB surfactant was 0.64 % and maximum power of the cell was 66.72 mW. The output of the cell was sensitive to various parameters, like dye concentration, reductant concentration, pH, light intensity, electrode area and diffusion length. Current-potential characteristics studied by I-V curve of the cell and the mechanism of cell photovoltage generation have been presented in the paper.

8

Energia z biomasy - efektywność, sprawność i przydatność energetyczna. Cz. 1

Roszkowski A.

Problemy Inżynierii Rolniczej

|

2013

|

R. 21, nr 1

97--124

PL

W pracy dokonano przeglądu i analizy czynników decydujących o efektywności energetycznej różnych rodzajów biomasy. Wykazano obiektywne trudności, wynikające ze zróżnicowania definicji i klasyfikacji biomasy, braku ustalonych metod analitycznych określających jej cechy oraz kwantyfikujących ilościowo i jakościowo przydatność, uwarunkowania i ograniczenia wykorzystania w głównych technologiach pozyskiwania bioenergii z biomasy (lub z jej udziałem). Uwzględniono biomasę pochodzenia leśnego i rolniczego (uprawy energetyczne, produkty główne, dodatkowe i odpadowe, tłuszcze roślinne i zwierzęce, substraty do wytwarzania biogazu). Wykazano uzależnienie wskaźników efektywności energetycznej od wielkości uzyskiwanych plonów w warunkach rzeczywistych, technologii pozyskiwania biomasy, nakładów energii na niezbędne pomocnicze operacje technologiczne i uzyskiwane sprawności konwersji na określone postacie energii. Rosnące zapotrzebowanie, zwłaszcza na energię elektryczną i paliwa transportowe (określane też jako biomasa płynna), wywołuje dążenie do wykorzystywania różnych źródeł energii odnawialnej, w tym i biomasy, co nie zawsze odpowiada wymogom dodatniej efektywności energetycznej, zachowania środowiska naturalnego i produkcji żywności. Ograniczenia pozyskiwania energii z biomasy wymuszają konieczność modyfikowania obowiązujących regulacji prawnych i ekonomicznych tak w UE, jak i w Polsce. Wymuszanie uprawy roślin energetycznych na obszarach o ograniczonej przydatności do produkcji żywności spowoduje prawdopodobny spadek plonów z 10-12 t·ha-1 do 3-10 t·ha-1. Najbardziej „pewnym” rodzajem bioenergii wydają się być gazy otrzymywane z przetwarzania odpadów organicznych, osadów i szlamów ściekowych, wysypisk i innych źródeł biologicznych, głównie ze względu na ich uciążliwość dla środowiska, a nie uzyskiwanie bezpośrednich korzyści energetycznych. W części II pracy zostaną omówione oddziaływania podstawowych czynników technologicznych i innych na sprawność i efektywność pozyskiwania energii z biomasy.

EN

The study reviewed and analysed factors deciding on the energetic effectiveness of different biomass kinds. Objective difficulties were showed as resulted from diversification of biomass definition and classification, lack of fixed analytical methods to determine its features qualifying and quantifying the usability, conditions and limitations of use in main technologies of gaining the energy from biomass (or with its share). Biomass of the forest and agricultural origin was considered (such as the energy crops, products of main, additional and residuary character, plant and animal fats, substrates for biogas generation, etc.). Dependence of energetic effectiveness indices on the following factors was revealed: crop yields under real conditions, technology of gaining biomass, energy inputs on necessary auxiliary technological operations and obtained efficiency of the conversion into particular forms of energy. Increasing demand, especially for electric energy and transport fuels (named also as the liquid biomass), results in a tendency to using different resources of renewable energy, biomass inclusive, what does not always fulfill the requirements of positive energetic effectiveness, environment protection and food production. Limitations in gaining the energy from biomass make necessary the modifications of legal and economic regulations, valid either in the EU and Poland. Extortion of energy crop cultivation on the areas of limited usability to food production shall probably cause a drop of crop yielding from 10-12 t·ha-1, down to 3-10 t·ha-1. The most “sure” kind of bioenergy seems to be the gas, gained by processing of organic wastes, sewage sludges, landfill sites and other biological sources, because of their environmental nuisance, and not for achieving direct energetic benefits. The influence of basic technological and other factors on the effectiveness and efficiency of gaining the energy from biomass will be discussed in the II-nd part of this study.

9

Energia z biomasy - efektywność, sprawność i przydatność energetyczna. Cz. 2

Roszkowski A.

Problemy Inżynierii Rolniczej

|

2013

|

R. 21, nr 2

55--68

PL

W części I pracy przedstawiono problematykę dotyczącą energetycznych uwarunkowań wykorzystania i ocen dostępnych źródeł biomasy oraz jej składu chemicznego i biochemicznego, w tej części omówiono oddziaływanie podstawowych czynników technologicznych i innych na sprawność i efektywność pozyskiwania energii z biomasy oraz przedstawiono wnioski wynikające z obu części pracy.

EN

The 1st part of this study presented problems concerning energetic conditions of using and the evaluation of attainable biomass sources, their chemical and biochemical composition. This part discussed the effects of basic technological and other factors on effectiveness and efficiency of energy generation from biomass. The conclusions resulted from both parts of study were also presented here.

10

Energy sustainability of two parallel sewage sludge-to-energy pathways: Effect of sludge volatile solids content on net energy efficiency

Cao Y., Pawłowski A.

Environment Protection Engineering

|

2012

|

Vol. 38, nr 2

77--87

EN

Previously, we conducted a preliminary evaluation on two parallel sewage sludge-to-energy pathways from the perspective of energy conversion efficiency. One pathway combined anaerobic digestion with fast pyrolysis while its counterpart was simplified to only use the pyrolysis. In this study, their energetic performances were evaluated as a function of the volatile solids (VS) content and in terms of net energy efficiency. Both pathways, when used to convert sludge with higher VS content, can achieve higher net energy efficiency. The combined pathway could achieve higher net energy efficiency than the simplified pathway, but its relative advantage is not impressive when converting sludge with low VS content; for example, the difference in normalized net energy production between the two pathways was only 0.76 MJ/kg for sludge with 50% VS content.

11

Modelowanie zależności temperaturowej parametrów ogniw słonecznych ze studniami kwantowymi

Prażmowska J., Paszkiewicz R., Tłaczała M.

Elektronika : konstrukcje, technologie, zastosowania

|

2008

|

Vol. 49, nr 1

91-93

PL

Za pomocą symulacji komputerowych oraz wykorzystania odpowiedniego algorytmu zoptymalizowano strukturę ogniwa p-i-n ze studniami GaAs oraz barierami AlxGa1-xAs w obszarze "i". Jako wynik otrzymano strukturę p-i(GaAs/Al0.1Ga0.9As)-n z dwoma studniami kwantowymi. W dalszej części pracy badano wpływ temperatury na parametry ogniwa zoptymalizowanego, takie jak: prąd zwarcia, napięcie rozwarcia, maksymalny prąd i napięcie oraz sprawność konwersji. Wzrost temperatury nie wprowadził spodziewanego polepszenia sprawności konwersji przyrządu. Wyniki porównano ze strukturami odniesienia p-i-n, w których zastosowano obszar "i" GaAs lub AI01Ga09As. Wszystkie symulacje wykonano za pomocą programu SimWindows program v. 1.5.0

EN

Within intrinsic layer of ordinary p-i-n solar cell GaAs wells and AlxGa1-xAs barriers were inserted. Solar cells structure was optimized by means of computer simulations assuming dedicated algorithm. In a result p-i(GaAs/AI0.1Ga0.9As)-n structure with two quantum wells was obtained. Influence of temperature of solar cell device on its parameters like: short-circuit current, open-circuit voltage, maximum current and voltage, and conversion efficiency was investigated. Temperature increase did not contributed significantly to the expected extension of investigated device's conversion efficiency. Two reference p-i-n solar cell structures with intrinsic layer composed of GaAs and AI0.1Ga0.9As were also examined for comparison purposes. All simulations were carried out by using SimWindows program v. 1.5.0.

12

Solar cells conversion efficiency enhancement techniques

Prażmowska J., Paszkiewicz R., Korbutowicz R., Wosko M., Tłaczala M.

Optica Applicata

|

2007

|

Vol. 37, nr 1-2

93-99

EN

In order to enhance the conversion efficiency of GaAs p-i-n solar cells GaAs/AlxGa1-xAs QW within intrinsic region or gradation of Al fraction of AlxGa1-xAs emitter and base region were applied. The influence of AlAs Bragg reflectors on the performance of MQWSC was studied theoretically by using SimWindows software.

13

Parameters comparison of p-i-n and quantum well solar cells

Prażmowska J., Korbutowicz R., Paszkiewicz R., Tłaczała M.

Optica Applicata

|

2007

|

Vol. 37, nr 4

371-376

EN

Double gallium arsenide quantum wells (2QW) were inserted within AlxGa1-xAs barriers of the intrinsic layer of an ordinary solar cell. Structure parameters have strong influence on device performance and should be precisely controlled in order to obtain the enhancement of conversion efficiency. Computer simulations of solar cells were carried out by SimWindows program v. 1.5.0. Some parameters of optimized quantum well solar cells (QWSC) and reference p-i-n solar cell structures, like: series resistance Rs, shunt resistance Rsh, emission coefficients (n1 and n2), diffusion and recombination components of current (Jd and Jr) were compared.