Determinants of Biogas Technology Adoption in Rural Households of Aleta Wondo District, Sidama Zone, Southern EthiopiaRead the full article
Journal of Energy publishes research relating to the science and technology of energy generation, distribution, storage, and management. It also covers the environmental, societal and economic impacts of energy use and policy.
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Study of Massive Floating Solar Panels over Lake Nasser
Recently, the technology of floating photovoltaic panels has demonstrated several advantages over land installations, including faster deployment, less maintenance cost, and higher efficiency. Lake Nasser is the second largest man-made freshwater lake in the world with a surface area of almost 5000 square km. Being in one of the hottest areas in the world, evaporation of water causes loss of very precious and scarce resources: freshwater. Fortunately, the lake is also located in a very rich area in solar energy. This paper presents a study to utilize Lake Nasser’s surface for massive production of solar energy, while significantly reducing the loss of water by evaporation from the lake surface. The project has the potential to be one of the largest producers of low-cost clean electric energy in the world for Europe and the Middle East and North Africa (MENA) region, especially with the ongoing efforts to connect the North African countries with the European super power grid. The study shows that the first phase of the project is expected to deliver about 16% of European need of electricity and save about 3 billion m3 of freshwater. The subsequent phases will provide low-cost green energy to replace the combustible fuels in Europe by 2045, while saving up to 10-12 billion m3 of freshwater lost by evaporation from Lake Nasser.
In Situ Transesterification of Spirulina Microalgae to Produce Biodiesel Using Microwave Irradiation
The present technology of transesterification of vegetable oils to produce biodiesel, which is suited to replace petrodiesel, has economic challenges, and therefore, alternative sources are being explored. Microalgae, a renewable, third-generation biofuel resource, have the potential to become a viable feedstock due to their high oil content and environmentally friendly nature. The present study investigates the effect of microwave irradiation on the simultaneous extraction and transesterification of algae lipids to produce fatty acid methyl ester (FAME), in a batch reaction system using sulphuric acid catalyst. In situ transesterification combines the two steps of lipid extraction and transesterification into a single step. The microwave synthesis unit comprised of a 3-neck round bottom flask inside a 1300-Watt microwave oven, fitted with a quick-fit condenser and having an external stirrer. Response surface methodology (RSM) was used to analyse the influence of process variables, dry algae to methanol ratio algae biomass to catalyst ratio and reaction time at rpm stirring rate for in situ reaction. FAME was analysed using gas chromatography (GC). The total lipid content of Arthrospira Spirulina platensis microalgae biomass was found to be by weight. The algae biomass also contained proteins at, moisture content at , and ash content by weight. RSM gave the optimum process conditions as dry algae biomass feed to methanol ratio of 1 : 9, catalyst concentration of and reaction time offor a maximum FAME yield of The major fatty acid composition of FAME was palmitic , linoleic, and linolenic . FAME properties obtained according to European Standards (EN 14214) and American Society for Testing and Materials (ASTM D 6751) standards were as follows: flash point calorific value acid value viscosity , and specific gravity. The study showed that Arthrospira Spirulina platensis microalgae lipid FAME met the biodiesel standards (EN 14214 and ASTM D 6751) and has the potential to replace petrodiesel. Microwave irradiation increased the reaction rate resulting in a reduced reaction time of 7 minutes (as compared to 8 hours for conventional heating) and therefore was found to be a superior heating mode as compared to conventional heating.
Analysis of Resistance Characteristics of a 37 Rod Fuel Bundle under Low Reynolds Number
During the working period of decay heat removal system, the flow rate of liquid sodium in wire-wrapped fuel assembly is very low, generally . In the present study, both experimental methods and numerical simulation methods are applied. First, water experiment of 37-pin wire-wrapped rod bundle was carried out. Then, the numerical simulation study was carried out, the experimental data and the numerical simulation results were compared and analyzed, and a suitable turbulence model was selected to simulate the liquid sodium medium. Finally, numerical simulations under different boundary conditions were performed. Results indicate that except for the low Reynolds number - turbulence model, other turbulence models have little difference with the experimental results. The results of realizable - turbulence model are the most close to the experimental results. Compared with the friction factor obtained by using water medium and liquid sodium medium, the calculation results of water medium and sodium medium under the same condition are basically consistent, with the deviation within 1%. The reason is that the velocity of water is higher than sodium medium at the same Reynolds number, and the transverse disturbance caused by helical wire is larger.
Drivers for Nuclear Energy Inclusion in Ghana’s Energy Mix
Energy has become the driving force for national infrastructure development, including the socioeconomic development of every society. Ghana, like many other African countries, formulated developmental policies to attain middle-income status in the medium term. Socioeconomic growth comes with an upsurge in electricity consumption. Ghana seeks to use industrialization to achieve its middle-income target. To achieve this target, there is a need to develop a reliable, sustainable and affordable energy supply in a benign environment. The entry point for Ghana to become a middle-income economy is a cost-effective and reliable electricity supply. Ghana is endowed with fossil fuel, hydro and renewable resources to drive its industrial ambitions, but the indigenous gas fields feeding some thermal plants for electricity production are decreasing and could run out by early 2030 unless new fields are discovered and may also be affected by price volatility. The untapped hydro resources are also small and unreliable if the country seeks to become a middle-income country. Despite the abundant renewable resources, they are intermittent and do not present a baseload option. In safeguarding Ghana’s energy security, the country seeks to include nuclear energy into her energy mix. This research paper discusses the major drivers for nuclear energy inclusion.
Evaluating the Potential of Domestic Animal Manure for Biogas Production in Ethiopia
Energy is one of the most important needy resources that found in the form of renewable and nonrenewable sources. The world demand for energy grows rapidly, and therefore, it is a time to look alternative and renewable energy resources to replace the rapidly depleting supply of fossil fuels. This study is aimed at analyzing the effects of temperature (°C), retention time (days), and potential of animal waste on the biogas production and its %CH4 compositions as responses to the factors of the study. The materials used in this study were cow dung, sheep, and pig manures. Anaerobic batch digesters (plastic water bottle) with a total volume of 2000 ml were used as digester (bioreactor) in this experiment. The glucose drip (tube) was fitted to the lids of each digester. Average temperature of digester was increased starting from the 6th to 10th day in cow dung and sheep manure. In this experiment, optimum time for best biogas yield was recorded. Analysis of the gas component shows the significant volume of methane component recorded in cow dung (66.9%) followed by sheep manure (62.1%). Cow dung was one of the best in producing biogas, while the sheep manure was medium, and pig manures are fewer producers as compared to others.
Numerical Analysis of Heat Exchanger for Spray-Assisted Low-Temperature Desalination System
A numerical study for heat exchanger for spray-assisted low-temperature desalination system is presented for an existing low-temperature desalination unit at Arusha Technical College. This is aimed at recognizing the effect of mass flow and physical parameters like tube layout (diameter and length) on the overall heat transferred and the pressure drop in the shell-and-tube heat exchanger (STHX), as well as the impact of these parameters on the heat transfer coefficient and the overdesign of the STHX. Also, the study provides a suitable mathematical model for the replacement of the current condensation unit which tends to reduce energy consumption by reducing some of the electrical components in the system. A Math CAD model was developed using the Delaware method to obtain the mentioned parameters. The results show that at 0.8 kg/s flow rate a maximum heat transfer coefficient of 23212 W/m2K is achieved in a minimum diameter of 10 mm within a maximum tube length of 1000 mm heat exchanger and the pressure drop seems to be very low in a range of 0.328-0.957 Pa from all configurations. The configuration with 1000 mm tube length and 10 mm diameter performed well on the mass flow of 0.3 kg/s-0.8 kg/s by providing a suitable overall heat transfer coefficient of 2306-2539 W/m2K, while 12.8 is a maximum overdesign coefficient achieved on 0.8 kg/s mass flow. The study results show the possibility of using STHX instead of the current condensation unit in implementing a proposed system layout with the minimum effect of energy consumption.