by Vidyasagar C. C, Gururaj Hosamani and Prakash Kariyajjanavar
Original Research
Dye-sensitized solar cells (DSSCs) are a low cost and promising alternative to standard silicon photovoltaic cells; there is growing interest in near-infrared sensitization of semiconductor anode materials, which converts to high power conversion efficiencies (PCEs). In this work, the effect of ion implantation and annealing temperature has been studied to provide an effective approach for developing visible-light driven Cu-ZnO anode materials for solar cells. Synthesis of ZnO and Cu doped ZnO nanoparticles via microwave combustion method without using any fuel is proposed. The crystal structure, optical properties, surface morphology and electrical properties were characterized by X-ray diffraction (XRD), UV-Vis spectroscopy, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX) and Keithley Source meter. The results revealed that the change in lattice parameters, decrease in the band gap and absorption peak shifting towards near-infrared region are due to the change in concentration and annealing temperature. The change in crystal defects leads to an abrupt change in bond length, unit volume and lattice strain in the Cu-ZnO crystals. Optical absorbance of copper phthalocyanine pigment (Imperon Blue-15) sensitized Cu-ZnO films were found to be at 600 nm to 700 nm region.
American Journal of Energy Research. 2019, 7(1), 31-40. DOI: 10.12691/ajer-7-1-4
Pub. Date: October 28, 2019
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by Hagninou Elagnon Venance Donnou, Aristide Barthélémy Akpo, Gbènoukpo Fidèle Nonfodji and Basile Bruno Kounouhewa
Original Research
The variability of onshore wind energy potential has been investigated over Cotonou coast (Benin) under an unstable atmosphere. Data on the speed and the wind direction at 10 m above the ground recorded every 10 min, have been used over the period from June 2011 to April 2014. The power law based on atmospheric stability was used to determine the vertical wind profile. The Weibull function was used to characterize the frequency distribution of the wind speed and to calculate the wind energy potential. The results indicate that the annual average of the wind speed for a typical day time varies from 3.8 ± 0.40 m.s-1(10 m) to 7.25 ± 0.58 m.s-1(60 m) during the convective diurnal cycle. The mean parameters k and c of Weibull were evaluated respectively from 1.65 (December) to 2.21 (August) and from 4.3 (December) to 9.1 m.s-1 (August). The most frequent wind speeds at the study site are between 2.5 ± 0.56 m.s-1 in December to 7 ± 0.24 m.s-1 in August from 10 to 60 m. The average wind speeds giving the maximum energy vary from 6.91 ± 0.56 m.s-1 in December at 10 m to 12.20 ± 0.24 m.s-1 in August at 60 m. Finally, the wind energy potential has been evaluated. As a result, the largest quantity of energy are generally collected between 13:00 UTC and 18:00 UTC. During the months of March, July and August, the daily energy peaks are observed between 14:00 UTC and 18:00 UTC with the values of the order of 650 to 770 W.m-2 at 60 m. The average annual energy potential has been estimated at 130.43 W.m-2(10 m) and 332.67 W.m-2 (60 m). In view of these results, the site of Cotonou could be suitable for the installation of small and large wind turbines in order to supply the southern Benin with power energy.
American Journal of Energy Research. 2019, 7(1), 19-30. DOI: 10.12691/ajer-7-1-3
Pub. Date: July 04, 2019
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by Yirgalem Damtew and Gashaw Getenet
Original Research
Energy generated by the force of water in hydropower can provide a more sustainable, non-polluting alternative to fossil fuels, along with other renewable sources of energy, such as wind, solar and tidal power, bio-energy and geothermal energy. Small-scalehydroelectricity in Ethiopia is well suited for “off-grid” rural electricity applications. Micro-hydropower which is hydro energy in a ‘small’ scale provides electricity to small communities by converting hydro energy into electrical energy. The purpose of this paper is to assess the micro-hydroelectric potential of different rivers in North Shoa Zone, Ethiopia, especially rural communities, 5Km far from main grid. From the 22 woreda towns found in north shoa zone only 9 of them with 11 rivers were assessed. Based on the head and flow rate measurements all the studied rivers have the potential to generate electric power, with the result ranges between 5.51 kW to 52.19 kW. These results were estimated for 80% hydropower generation, which are more than 5kW. Therefore, all of the assessed river sites are sufficient for micro-hydro power generation with through study on proper site location and socio-economic aspects.
American Journal of Energy Research. 2019, 7(1), 15-18. DOI: 10.12691/ajer-7-1-2
Pub. Date: February 12, 2019
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by Abubakar A. Bukar, M. Ben Oumarou, Babagana M. Tela and Abubakar M. Eljummah
Original Research
The essence of a gasification process is the conversion of solid carbon fuels into carbon monoxide and hydrogen mainly; by a complex thermo chemical process. Other products of the biomass conversion are gases which contain carbon dioxide, methane and nitrogen. The history of gasification dates back to the seventeenth century. Since the conception of the idea, gasification has passed through several phases of development. Authors across the world have conducted studies and researches on the design of gasifiers, performed modeling and simulation of biomass gasification. Various energy crisis and technological advancements have influenced the development of gasifiers for different fuels, configurations and applications other than wood and charcoal. The economic success of a biomass gasification plant depend on the understanding of the basic principles involved, knowledge of the steps to be taken while designing and the hitch free running of the plant. This paper reviews the fundamentals and basic formulae adopted while designing a biomass gasifier for energy production. Aspects such as: the elemental composition, ash content and energy density of the biomass were considered. The gasification process physical and chemical characteristics were reviewed too. Design considerations were reviewed with special emphasis on the reactor and blower such as: the type of reactor, cross-sectional area of the reactor, height of the reactor, thickness of the fuel bed, fan airflow and pressure, insulation for the reactor, location of firing the fuel, size and location of the char chamber, intended uses as well as safety considerations.
American Journal of Energy Research. 2019, 7(1), 1-14. DOI: 10.12691/ajer-7-1-1
Pub. Date: January 06, 2019
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