Research Article
Renewable Energy Resources and Technologies
Sepideh Rahmati Dehkordi; Mehdi Jahangiri
Abstract
In Iran, due to the problems and constraints of fossil fuels and the need to maximize the use of solar potential, one of the best ways is the application of photovoltaic systems integrated with buildings. Due to the significant dependence of solar cell performance on the availability of radiation, it ...
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In Iran, due to the problems and constraints of fossil fuels and the need to maximize the use of solar potential, one of the best ways is the application of photovoltaic systems integrated with buildings. Due to the significant dependence of solar cell performance on the availability of radiation, it is necessary for architects to have an accurate assessment of the amount of electricity produced in different conditions. Therefore, in the present work, using HOMER software, the energy-econo-Enviro (3E) potential of a Building Integrated Photovoltaic (BIPV) in Abadan was studied. The effect of slope and azimuth of solar cells as well as cloudiness and system losses were investigated using sensitivity analysis. The results showed that the PV-grid system was the most economical option and after the azimuth angle of zero degree, the positive azimuth angle was the most economical. The results also showed that the slope of 30 degree and the angle of azimuth equal to zero was appropriate, for which the price per kWh of generated electricity was calculated to be $0.09. For the use of solar cells in the vertical wall of the building, the southwest direction was the most suitable and based on the results, it was suggested that the western wall of the building should be in the form of “inclined PVs with windows”. The authors of this paper hope that the results of the present work can be used by architects and energy decision-makers as a guide in developing the BIPV use in Iran.
Research Article
Renewable Energy Resources and Technologies
Marziyeh Gharibian; Bahram Hosseinzadeh Samani; Alireza Shirneshan; Sajad Rostami
Abstract
To investigate the possibility of using fuel for plant origin in a diesel generator, safflower methyl ester was prepared and used as a biodiesel. In this research, biodiesel was produced through a transesterification reaction using a hydrodynamic reactor, which increased the reaction efficiency and reduced ...
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To investigate the possibility of using fuel for plant origin in a diesel generator, safflower methyl ester was prepared and used as a biodiesel. In this research, biodiesel was produced through a transesterification reaction using a hydrodynamic reactor, which increased the reaction efficiency and reduced fuel production time. Upon increasing the reaction time from 30 seconds to 60 seconds, the reaction performance increased by 5.5 %. Then, its important features complied with ASTM D-6751 standard. The performance and pollution indices of the diesel generator engine were tested with compounds B0, B20, B50, B80 and B100. The results of short-term engine tests showed that by increasing the share of biodiesel to 20 %, CO emissions were reduced by 21 % compared to pure diesel fuel, but the amount of NOX increased by 0.82 % compared to diesel. Also, the use of 20 % volume of biodiesel in the fuel composition increased the thermal efficiency of braking, braking power, and braking torque of fuel, compared to diesel. Also, the specific fuel consumption of B20 was reduced by 2 %, which is very important economically. Finally, the TOPSIS analysis illustrated that B50 fuel outperformed pure diesel fuel and other listed fuel combinations.
Research Article
Renewable Energy Resources and Technologies
Mohamed A. Barakat; Tamer Mohamed Ismail; Sayed Ibrahim Abdel-Mageed; Khaled Ramzy
Abstract
The greenhouse problem has a significant effect on our communities, health, and climate. So, the capturing techniques for CO2 remain the focus of attention these days. In this work, a Chemical Looping Combustor (CLC) was designed and fabricated with the major geometric sizes at the Faculty of Engineering, ...
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The greenhouse problem has a significant effect on our communities, health, and climate. So, the capturing techniques for CO2 remain the focus of attention these days. In this work, a Chemical Looping Combustor (CLC) was designed and fabricated with the major geometric sizes at the Faculty of Engineering, Suez Canal University. The system involves two interconnected fluidized beds. Nickel powder with 150 µm diameter as well as brown coal and liquefied petroleum gas were used as oxygen carrier, solid fuel, and gaseous fuel, respectively. The temperature distributions along the fuel reactor for LPG flow rates of 11 and 18 LPM with and without using nickel powder as well as using preheated reactor were discussed and evaluated. The effects of brown coal diameter change with and without using nickel powder were studied. The CO and CO2 concentrations at combustion gases with and without using nickel powder were conducted for LPG and brown coal fuels. A mathematical model was used to simulate the combustion in CLC using combustion and energy code. The obtained results showed that using nickel powder improved the combustion process and in case of using LPG, the flame color changed to blue which is the color of the complete combustion flame. The CO was reduced by 48.4 % and CO2 was augmented by 66.5 %. In case of using brown coal as solid fuel, CO was reduced by 53.7 % and CO2 was increased by 71.9 %. Finally, there is good agreement between the experimental and numerical results based on the determination coefficient.
Review Article
Renewable Energy Resources and Technologies
Toyese Oyegoke; Emo Obadiah; Francis Adah; John E. Oguche; Geoffrey T. Timothy; Ismail A. Mantu; Abubakar D. Ado
Abstract
In recent times, limitations and adverse effects of fossil fuels have significantly attracted researchers' attention to green fuels worldwide, especially in developed nations. As a way of assessing this actualization of biorefineries establishment in developing nations, this report surveys the works ...
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In recent times, limitations and adverse effects of fossil fuels have significantly attracted researchers' attention to green fuels worldwide, especially in developed nations. As a way of assessing this actualization of biorefineries establishment in developing nations, this report surveys the works done by various researches towards this great course in terms of promoting and gaining the attention of both government and private investors about the technical and economic feasibility of embracing the use of biofuels, a case of bioethanol in Nigeria. Different classes of feedstocks were reviewed for the laboratory-scale, process scale-up, pilot plant, and techno-economic studies regarding ascertaining the technical and economic feasibility of local setup of a functional biorefinery in Nigeria, which would be beneficial environmentally and economically. The literature survey unveiled that the Bioethanol yield obtained from sugarcane-juice (72.7 %), banana-stems (84.0 %), and cassava (92.0 %) were found to be of highest potential amongst other sugar-based, lignocellulosic, and starch-based feedstock, respectively. The survey further unveils that the volume of process scale-up and economic feasibility studies does not correlate well with the laboratory-scale studies. The bulk of the research works on bioethanol has given preferential attention to laboratory studies. Only a few studies have looked into the commercialization (i.e., scale-up) of the laboratory findings and the economic implications. Presently, only sugarcane and a few cassavas are reported in the literature so far. It is, therefore, necessary for further studies to give attention to the investigation of the commercializing locally developed technologies and the exploration of their economic benefits.
Research Article
Renewable Energy Resources and Technologies
Aloys Martial Ekoe A. Akata
Abstract
Photovoltaic energy has the potential to become one of the major energy sources used in the households in the tropical region of Africa, where the solar radiation intensity is abundant and almost constant over the year. Solar photovoltaic systems present many advantages when they are integrated in the ...
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Photovoltaic energy has the potential to become one of the major energy sources used in the households in the tropical region of Africa, where the solar radiation intensity is abundant and almost constant over the year. Solar photovoltaic systems present many advantages when they are integrated in the building structure envelope and have a significant influence on the indoor air temperature of dwelling buildings due to the thermal resistance modification. In this paper, a simplified model of the photovoltaic system integrated on the roof of a residential building according to the building construction customs and materials has been designed and modeled. The heat transfer is studied in several situations: with and without a Building Integrated Photovoltaic (BIPV) system and for a building with and without false ceiling. The BIPV system installed over an effective area of 35 m2 increases the building indoor air temperature of approximately 5 °C which is corrected by the heat insulation optimization of the false ceiling made up with building local materials. The final indoor air temperature obtained is in good agreement with the ASHRAE standards and can, therefore, be applied to tropical regions.
Research Article
Advanced Energy Technologies
Mohsen Babaiee; Mohammad Zarei-Jelyani; Shaghayegh Baktashian; Rahim Eqra
Abstract
A mechanical technique was applied to the copper current collector of lithium-ion battery anode to improve interface adhesion between Cu foil and anode film. The mechanical and electrochemical performances of graphite anodes coated on Bare Cu Foil (BCF) and Modified Cu Foil (MCF) were evaluated. The ...
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A mechanical technique was applied to the copper current collector of lithium-ion battery anode to improve interface adhesion between Cu foil and anode film. The mechanical and electrochemical performances of graphite anodes coated on Bare Cu Foil (BCF) and Modified Cu Foil (MCF) were evaluated. The BCF and MCF anodes exhibited adhesion strengths of 1.552 and 1.617 MPa, respectively. The electrochemical studies of BCF and MCF anodes showed that the initial discharge capacity of graphite anode coated on the MCF (323.6 mAh g-1) was about 8 % higher than the BCF anode (299.9 mAh g-1). The BCF anode capacity reached 227.9 mAh g-1 after 100 charge/discharge cycles at 0.5C rate, while this value was 247.7 mAh g-1 for MCF anode. The results of electrochemical impedance spectra demonstrated that the diffusion coefficient of lithium-ion for MCF anode was about 56 % higher than that for BCF anode. On the other hand, the surface modification of the copper current collector reduced the charge transfer resistance of anode from 28.5 Ω to 23.2 Ω.
Research Article
Renewable Energy Resources and Technologies
Babak Tohidi; Majid Delshad; Hadi Saghafi
Abstract
A new interleaved high step-up converter with Zero Voltage Transition (ZVT) is proposed for operation in this paper. The main advantages of the proposed converter are low input current ripple and low voltage stress on the power switches, high efficiency, low total component count, and eliminating reverse ...
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A new interleaved high step-up converter with Zero Voltage Transition (ZVT) is proposed for operation in this paper. The main advantages of the proposed converter are low input current ripple and low voltage stress on the power switches, high efficiency, low total component count, and eliminating reverse recovery problem of power diodes. Due to the soft switching operation of the switches and diodes in the converter, the efficiency has been enhanced. Also, the switches do not have capacitive turn on loss due to ZVT operation. The proposed converter uses only one power switch to provide ZVT conditions for all switches and the clamp capacitor transfers its energy to the lifting capacitor, which causes increase in voltage gain of the converter. Because of the interleaved structure, the converter has a low input ripple current and this advantage makes it very suitable for solar applications. The proposed converter is analysed and a 580W prototype is made to verify theoretical analyses.
Research Article
Renewable Energy Resources and Technologies
Hemad Zareiforoush; Adel Bakhshipour; Iraj Bagheri
Abstract
Drying process is an important post-harvest stage of food crops production which accounts for about 20 % of the world’s energy consumption in the industrial sector. One of the effective ways to reduce the share of fossil fuel consumption in the food drying process is to develop new drying systems ...
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Drying process is an important post-harvest stage of food crops production which accounts for about 20 % of the world’s energy consumption in the industrial sector. One of the effective ways to reduce the share of fossil fuel consumption in the food drying process is to develop new drying systems based on the use of renewable energy sources. In this research, a novel solar-assisted multi-belt conveyor dryer was developed and its performance was analysed. The required thermal energy for drying process was supplied by the combination of solar-gas water heaters and four solar-powered infrared (IR) lamps. The experimental factors included the speed and temperature of the drying air and the power of IR lamps. The performance characteristics were drying time, Overall Specific Energy (OSE), Non-Solar Specific Energy (NSE), Overall Energy Efficiency (OEE), and Solar-Assisted Energy Efficiency (SEE). The optimization process of the drying system was carried out using Response Surface Methodology (RSM) by defining two general modes for the energy sources of the drying system, namely overall mode and solar-assisted mode. Based on the results, the lowest OSE (17.30 MJ/kg water evaporated) was obtained when the speed and temperature of the drying air were equal to 7 m/s and 40 °C, respectively, without using IR power. The lowest NSE (2.71 MJ/kg water evaporated) was achieved by applying the treatment of 7 m/s * 40 °C * 300 W. The maximum OEE was equal to 13.92 % whilst the maximum SEE was obtained as 88.71 %. Both of the mentioned maximum values were obtained at the speed and temperature combination of 7 m/s and 40 °C and their difference was applying 300 W IR power to gain maximum SEE and no IR utilization for the maximum OEE. According to RSM analysis, the optimum working conditions for the drying system included the treatment of 7 m/s * 39.96 ºC * 300 W. Under this condition, the drying time, NSE, and SEE values were equal to 180.95 min, 1.062 MJ/kg water evaporated, and 84.63 %, respectively.
Research Article
Renewable Energy Resources and Technologies
Shiva Shadpour; ALi Pirouzi; Mohsen Nosrati; Hoda Hamze
Abstract
Long mixing time, high power consumption, and small mass transfer coefficients are common problems in the photobioreactor design for microalgae culture which have a great effect on system efficiency and performance, CO2 stabilization, and biomass production. In this study, a special design of the triangular ...
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Long mixing time, high power consumption, and small mass transfer coefficients are common problems in the photobioreactor design for microalgae culture which have a great effect on system efficiency and performance, CO2 stabilization, and biomass production. In this study, a special design of the triangular external loop airlift photobioreactor was studied. The bioreactor's geometry was such that the angle between hypotenuse and the horizontal side ( ) could vary. This configuration created an effective gas-liquid countercurrent flow in the downcomer section. In the present research, hydrodynamic and mass transfer of the reactor were investigated on the microalgae productivity under different design and operating parameters. The optimum conditions for the enhancement of Chlorella vulgaris productivity were explored by analyzing the mixing time ( ), volumetric power consumption (P/V), mass transfer coefficients ( ), bubble diameter (d), and gas holdup ( ) as responses. The results showed that the hypotenuse angle of = 59o and the superficial gas velocities of the = 0.0050 m.s-1 for the downcomer and = 0.008 m.s-1 for the riser of the reactor were the best conditions to achieve the highest biomass productivity. The responses’ values obtained in the optimum condition were as follows: = 19.67 (h-1), = 23.79 (h-1), = 23.76 (h-1), = 0.41, and = 62.83 , which had a smaller deviation than the actual values. The highest concentration of Chlorella vulgaris ( 1.4 g.l-1) achieved in this work was obtained in a shorter span of time (11th day of cultivation) based on the growth curve in optimized conditions.
Research Article
Advanced Energy Technologies
Ghasem Alahyarizadeh; Maryam Amirhoseiny; Majid Khorsandi
Abstract
The performance characteristics of InGaN Double-Quantum-Well (DQW) Laser Diodes (LDs) with different barrier structures were studied numerically by Integrated System Engineering Technical Computer-Aided Design (ISE TCAD) software. Three different kinds of structures of barriers including quaternary AlInGaN ...
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The performance characteristics of InGaN Double-Quantum-Well (DQW) Laser Diodes (LDs) with different barrier structures were studied numerically by Integrated System Engineering Technical Computer-Aided Design (ISE TCAD) software. Three different kinds of structures of barriers including quaternary AlInGaN and AlInGaN/AlGaN superlattice barriers were used and compared with conventional GaN in InGaN-based laser diodes. Replacing the traditional GaN barriers with quaternary AlInGaN increased holes and electrons flowing in the active region and thus, the radiative recombination enhanced the output power. However, it did not reduce the threshold current due to hole and electron overflowing. To investigate the ways of greatly reducing the threshold current, the structure consisting of AlInGaN/AlGaN superlattice barriers was proposed. The simulation showed that electrical and optical characteristics such as output power, Differential Quantum Efficiency (DQE), and slop efficiency were significantly enhanced for LDs containing superlattice barriers compared to the basic structure. This is while the threshold current was considerably reduced. The enhancement was mainly attributed to the improvement of hole injection and also the blocking hole and electron overflowing caused by the reduction of polarization charges at the interface between the barriers, the well, and the Electron Blocking Layer (EBL).