Center for Energy Technology

Permanent URI for this college

http://etd.aau.edu.et/handle/123456789/44

Browse

Now showing 1 - 20 of 59

Adopting Building Integrated Photovoltaics (BIPV) for Harnessing Green Economy in Ethiopia: A Study on the Design, Modeling and Economic Analysis of Grid-Tied BIPV
(Addis Ababa University, 2015-01) Berhanu, Tsion; Assefa, Abebayehu (PhD)
Contrary to add-on Photovoltaics (PV), Building-integrated PV (BIPV) refers to the application of PV arrays where they are integral parts of the building envelope having the function of producing electricity as well. Ethiopia, as a country having average daily solar radiation of 5.2kWh/m2, can make use of this technology as a means of achieving the country’s goal of expanding electric power generation and green growth strategy. In addition, by producing power close to the point of use, the technology shall contribute to the reduction of the current 23% transmission and distribution losses encountered in the power system of the country. To this end, the opportunities of meeting some of the country’s electricity demand by introducing grid-tied BIPV in commercial and residential buildings of urban Ethiopia were investigated by taking the new Zemen Bank Headquarter 30-storey Building as a case study. A detailed design, simulation and economic analysis of a grid-tied BIPV system were conducted for four different scenarios of the building using PVsyst software. The results of the simulation showed that with an optimal design a significant amount of energy, 897,000kWh/year, which covers 69.54% of the estimated demand of the building can be generated. This can save up to 26,910USD per year based on the current electricity tariff of Ethiopia. The simulations of the four scenarios revealed that best results can be achieved by considering the system starting from the initial architectural design of the building rather than retrofitting an existing one. On the other hand, the economic evaluation resulted in an energy cost of US$0.11/kWh for the optimal design which is much higher than the prevailing electricity retail price of Ethiopia, US$0.03/kWh. From this it was concluded that grid-parity shall be achieved in the long run since the costs of PV modules is dropping while their efficiency is rising.
Analysis & Development of Solid Waste Management System of Addis Ababa
(Addis Ababa University, 2002-01) Belete, Zerayakob; Kitaw, Daniel(phd)
Solid waste, which is a consequence of day-to-day activity of human kind, needs to be managed properly. Addis Ababa like other cities in developing countries, faces problems associated with poorly managed waste collection operation. This thesis deals with the city’s current solid waste management problems, collection and disposal. The city’s refuse collection operation is modeled using queuing/simulation model. Spreadsheet Monte Carlo simulation technique is used to simulate the collection activities of the vehicles. In a similar manner, the average waite time of the customer( unit volume of waste) is also simulated. The result obtained shows that the collection operation is affected by the relative location of zonal centroid with reference Repi landfill site. Based on the simulation result, vehicle performance in collection operation is also evaluated. The number of vehicles that are required to carry out the operation has been calculated. In regard to solid waste disposal, alternative models are evaluated to meet the city’s disposal need. Land filling with other disposal options is found to be better alternative. The four proposed landfill sites are modeled using linear programming technique for optimized collection/disposal operation. Energy recovery potentials of various disposal options like landfill, incineration and anaerobic digestion have been assessed. Material recovery potential of the city’s refuse is also evaluated for reprocessing. Better solid waste management option is also proposed.
Analysis and Performance Simulation of Solar Powered Water Pumping System: A Case Study in Jigjiga
(Addis Ababa University, 2019-06) Sofiya, Hussein; Yilma, Tadesse (PhD)
In most regions of Ethiopia groundwater is the major source of freshwater for drinking and agriculture, almost all groundwater is obtained from shallow to moderately deep wells. Whether we use diesel generators to generate power or electricity from the grid, the energy consumption is high and also using diesel energy which is one of the major causes of air pollution. The possible solution to minimize this problem is using renewable energy system. In this research the performance analysis of photovoltaic powered water pumping (PVPWP) system with maximum power point tracking (MPPT) controller was carried out under climate condition of Jigjiga. In this research a detailed electrical characteristics of 1800Watt non-tracking PV array (with 6Sx4P configuration) was determined on current vs. voltage as well as power vs. voltage plane by taking manufacturer’s data sheet of the PV module as input. A polynomial performance equation (which relates output flow rate of the pump with the input power and system head) was obtained with curve fitting technique, after performance points of the pump had been taken from the performance curve. Hence the hourly performance variation of the PVPWP system was predicted from the electrical characteristics of the PV array and the performance equation for (50, 60, 70, 80, and 90 meters of pumping heads). The modeled system gives a flow rate of 20-30 m /day for sunny days for the total dynamic head of 80m and solar irradiation of 5000-7000 Wh/m 3 2 /day
Application of Solar-Wind Hybrid for Water Lifting (in Borena Zone, Oromia Region)
(Addis Ababa University, 2012-02) Melkamu, Ibsa; Edessa, Dribssa (PhD)
Water is the primary source of life for mankind and one of the most basic necessities for rural development. The rural demand for water for crop irrigation and domestic water supplies is increasing. At the same time, rainfall is decreasing in many arid countries, so surface water is becoming scarce. Groundwater seems to be the only alternative to this dilemma, but the groundwater table is also decreasing, which makes traditional hand pumping and bucketing difficult. As these trends continue, mechanized water pumping will become the only reliable alternative for lifting water from the ground. Diesel, gasoline, and kerosene pumps have traditionally been used to pump water. However, the non-renewable energy is on the way of depleting from the world and due to this cost of the oils are increasing from time to time, in addition to these the exhausting gases from them is polluting the environment. So due to the cost of the oils, the developing country such as Ethiopia may not able to buy to generate water from the ground for the people and livestock. Since our country is reach in renewable energy, it is the must to replace for generation of power to the renewable one such as solar energy, wind energy, and others. Currently, hybrids of PV and wind with or without backup generators are more promising for supplying uninterrupted power because they work independently of each other. Such systems do not require each component to be oversized. For the Semento kebele, Liban woreda, which has the problem of drinking water for the people and livestock the solar-wind hybrid system with the specification 270kw PV, 11BWC Excel-s, 110kw inverter, Total net present cost (NPC) $1,305,958, levelized cost of energy (COE) $0.458/kwh, and operating cost $47,179/yr is selected after optimizing by using the HOMER software. The demand of water for the site is 2200m3/d and this is easily fulfilled by installing two systems for the kebele. From the installed hybrid system there is excess electrical power which is used for the lighting purpose by using battery and there is also excess water which we use it for the irrigation purpose. So even if our aim is to solve the problem of drinking water there is also problems that are solved with the system.
Assessing Energy Potential and Generation of Electricity from Erta Ale Lava Lake in Ethiopia
(Addis Ababa University, 2018-12) Mekonnen, Ayane; Wondwossen, Bogale (PhD); Gezahegn, Yirgu (Prof.) Co-Advisor
Ethiopia is a developing country, where majority of the population lives in rural areas. In 2016, only 26.56 % of Ethiopian inhabitants have an access to electricity, as reported by World Bank, which could be considered as one of the lowest rates of access to modern energy services, in which biomass primarily shares 92.4% of total energy supply. This project Focus on Assessing Energy Potential and Generation of Electricity from Erta Ale Lava Lake in Ethiopia. The main objective of this project is to design, analysis and optimization of a special type power plant by changing shape, orientation and principle of operation of the steam generator using Lava Lake as a source of energy. Estimation of three dimensional temperature distributions using linear interpolation and energy potential of Erta Ale Lava Lake using shell discretization method as well as estimation of maximum possible extracted power using optimization method has been calculated. Many impossibilities were made possible by developing new mechanisms. After this, a brick coated steam boiler which safely operates at a high temperature up to 1200 oC have been designed, analyzed, optimized. Average temperature of the lava lake estimated to 1200 oC and the lava lake would be estimated to continuously join with mantle and core of the Earth through Magma tube and Magma reservoir. An internal heat content of our Planet was estimated to be 1031 Joules (3x1015 TWH), which is approximately 100 billion times current (2016) total annual energy consumption of the world. An ideal power potential of this lava lake estimated to 408 MW and maximum extractable power estimated to be 200 MW which could be estimated to 1.7 billion birr per annum. Maximum possible length of boiler pipes, number of boiler pipes, space between them and diameter of the pipe has been estimated to be 1500 m, 93 m and 600 mm respectively. This special type power plant mainly consists of brick coated steam generator, cooling tower, pump, reheater, regenerator and other accessories. In general, this extra ordinary energy extraction from Lava Lake is environmentally friendly and easy to control.
Assessing the Effectiveness, Adoption Rate and Technological Gaps of Household Biogas Technologies in Southern Ethiopia: The Case of Hadero Tunto and Boloso Sore Woredas
(Addis Ababa University, 2019-01) Tarekegn, Bekele; Solomon, Kiros (PhD)
The implementation of household biogas technology programme at national level is a recent experience in Ethiopia. Consequently, there are limited empirical evidences concerning to among its effectiveness, adoption rate and technological gap. Thus, this study was done with the objective of assessing the effectiveness, adoption rate and Technological gaps of household biogas technologies in Southern Ethiopia. It employed a mixed triangulation approach involving a total of 80 sample biogas user and non-user households. Both qualitative and quantitative data analysis techniques were utilized. The study results showed that the effectiveness influenced by: About 45% insufficient feeding quantity, 55% poor installation quality, 35% health problem of adopters, feeding quality less than 50% of the biogas plants C/N ratio was recorded optimum level between 20 and 35wich is medium toxic to methanogenic bacteria. More over the digesters effluent pH value was recorded between slightly acidic and alkaline (6.26 – 8.47) media hence, the digesters were not affected by accumulation of acid. Similarly from ambient temperature 25 – 310C one can say that the area has operated in mesophilic range (10-45oC). The adoption rate was affected by: 45% lack financial source, 25% lack of feeding, 20% lack of interest level of the community, 40% non- functionality biogas plants negative promotion and 15% availability of alternative energy source. Technological gaps of stockholders such as 45% limitation of time and effort to control, 65% gaps of operation and maintenance of adopters and 85% gaps of sharing experience to fill technological gaps in study area. Accordingly, the following recommendation were forwarded to improve the effectiveness of biogas plant, in study area maximize volume of dung, installation quality should be by giving training for stockholders on operation and maintenance, hiring skilled person, in order to foster adoption rate of biogas technology and fill technological gaps, energy office should support Stockholders by supplying financial source to share experience and awareness creation training program, to shape attitude of some people in respective community training regularly adopters and non-adopters is better, disseminators skill also need to be developed through training, the interest level of the community should be shaped by improving the effectiveness of biogas plant.
Assessment of Stand-Alone Solar Photovoltaic Power Systems Performance and Reliability for Rural Electrification in Ethiopia
(Addis Ababa University, 2017-05) Woldeyes, Sebsibie; Gebeyehu, Desta (Professor)
The purpose of this study was focused on assessment of stand-alone solar photovoltaic power systems performance and reliability for rural electrification in Ethiopia. It was conducted to assess and evaluate the data collections which were administered on samples randomly selected sites installed in the Benshangul Gumuz, Tigray, Oromia and Amhara regions of Ethiopia. About ten sample sites were identified for each regions and data gathering were made using solar photovoltaic systems investigation check list (see appendices I -VI ) for almost two months. The solar and wind master plan of Ethiopia (used as indicated on the solar radiations data) has a huge solar energy potential for rural electrification through the off-grid system in the samples of randomly selected sites of solar home systems (SHS) and institutional systems (like health post and rural primary schools) in the four regions. The data collected were analyzed using descriptive survey; theoretical, mathematical formulation experimental models, emission reduction analysis and PVsyst software analysis. The analysis and interpretation of data have been made according to the objectives. As can be seen from the investigation of SHS oc V was decreased by 1.54V (7%), sc I whereas decreased by 7.961A (97.3%). Thereby, the output power out oc sc P V  I was reduced by 4.37W (21.85%) after installation. Similar situations have been observed for institutional systems too. Based on the findings of this study, the performance and the reliability of stand-alone PV power systems were affected by variety of factors, such as failure of the components, system configuration, maximum power point tracking, system orientation, tracking solar panels and the ambient conditions. Moreover, loss of PV systems have been observed everywhere in the sample sites due to an accumulation of dust, failure of system design, high temperature and shading. Some of these factors may not be the cause for a total failure, but still have a de-rating impact on the output power of a PV system. In fact, any parameter that impacts the output power of a PV system causes a de-rating in its nominal generation, and can potentially degrade its capability to supply the load, and that leads to a reliability issue. So, it is critical to adapt standard design practices of mathematical formulations, experimentally and PVsyst methods by numerical simulation to identify the ways to improve performance and reliability of stand-alone PV power systems for further practicality in the country. Keywords: Stand-alone, Solar photovoltaic system, Maximum power point tracking, System orientation, Tracking solar panels, Performance, Reliability
Biogas System Planning for Rural Households Based on Energy Demand (The Case of Holeta District)
(Addis Ababa University, 2017) Mesfin, Debebe; Abubeker, Yimam (PhD)
This research is conducted to study the energy consumption trend and to make easy of planning the biogas system design which can helps to meet the energy demand of the rural households found in Holeta district. The energy demand of the households is assessed based on the questionnaire paper. The information of the assessed households is collected randomly from different family sizes that live in “Geda Jogo” and “Ada odo” Villages. Households are using electricity mostly for lighting purpose. Fire wood, Charcoal and dung cake are the main sources of energy to meet the cooking Energy demand. The average amount of annual fertilizer consumption by the peasant households is 220 kg. Spreadsheet modeling tool is prepared and it is used to estimate Households biogas demand, gas production potential of the households and Digester volume including the expected Loading rate. It is also used to forecast the basics of Economical aspects which should be known before the plant is designed. To crosscheck the proper functionality of the spreadsheet modeling tool Manual calculations has been performed for the average and peak values observed in the surveyed households and compared with the values found from the spreadsheet model. For the average values, the Biogas demand, the gas generating potential of the Households and digester volume observed in the spreadsheet calculation tool are 6.001m 3 /day, 6.8 m 3 / day and 20.3949 m 3 respectively. The values gained using manual calculations are 6.114m 3 /day, 6.8m 3 /day and 20.4 m i 3 . For the peak values calculation in spreadsheet modeling tool, the Biogas demand, the gas generating potential of the Households and the digester volume needed are 9.19m 3 /day, 8.8 m 3 / day and 26.3934 m 3 respectively. Where as in the manual calculation the values are 9.16 m 3 /day, and the digester volume is . Priority rank on the households energy demand has been performed, so that it will help on the biogas system design. The economical aspect of the biogas system is also included and how the households could be benefited using this technology. The estimated cost to construct the plant for the average values are ETB 29,840 with a payback period of 3 years. The cost spent to buy chemical fertilizer could be saved. Finally the benefit cost ratio is calculated to be 1.44 which is greater than 1.
Characterization and Experimental Analysis of Biodiesel Extracted from Sclerocarya Birrea (Marula) Fruit Using Catalyst
(Addis Ababa University, 2021-01) Bikila, Gebeyehu; Solomon, Kiros (Ass. Prof.)
The investigation of indigenous resources as alternative energy is the reasonable solution for the diminishing of naturally existing materials for production of fuel from crude oil, environmental concern. Many researchers have been involved in producing a low-price fuel from naturally existing raw materials. Thus, in this specific work biodiesel production was examined from Marula seed. The seeds were collected from Arba Minch Nech Sar National Park and the seeds Proximate analysis has been conducted to determine moisture content, ash content, crude fiber content and fat contents. The result found was 5.90%, 4.27%, 11.84% and 47.66% respectively. The extraction of the oil was performed by solvent method using n-hexane as solvent through Soxhlet apparatus and fixing the extraction time. This study aimed to extract a biodiesel from sclerocarya birrea by examining the physio-chemical properties, and the biodiesel production was optimized for pre-determined parameters such as Catalyst Concentration (CC), Reaction Temperature (RT) and Methanol to Oil Ratio (MOR) by implementing Design Expert Software (DES). The optimum conversion efficiency of marula oil to Fatty Acid Methyl Ether (FAME) was 93.45% at optimal condition of 9:1 methanol to oil ratio for 1.75%of catalyst loading at 60oC of reaction temperature. The properties of sclerocaryabirrea which were determined exist in the recommended standards. The oil content of the seed was found 41.57%. The values of the physiochemical properties of the oil were viscosity 92.8mpas, specific density 0.923, acid value 7.51, Saponification value 229miligrams and free fatty acid 3.8% and the biodiesel were characterized as of its calorific value (CV) which was 42.56 MJ/Kg, viscosity of 11.3mpas, iodine value of 115 I2/gm, and flash point of 235oC. In this thesis work, it was concluded that Sclerocaryabirrea can be a possible input for biodiesel production which in turn minimize the dependency on fossil fuels.
Characterization and Optimization of Biodiesel Production From Mexican Poppy (Argemone Mexicana)
(Addis Ababa University, 2012) Tsega, Metshet; Kiros, Snolomon (PhD)
Biodiesel production has generated heated debate on energy security for food crisis. This debate has changed the direction of biodiesel research into the use of non-edible oil sources referred to as second generation biodiesel feedstock. Ethiopia despite having high potential of various non-edible oily plant species, only very few non edible sources of biodiesel are known compared to the number of non-edible oily plant species identified. Thus, exploration of cheap and non-edible sources of biodiesel such as Argemone Mexicana can help to increase the production and use of biodiesel. This plant has invaded many ecosystems and communities in Ethiopia. However, due to lack of research and skill, there was a gap to find optimum conditions and properties of newly identified non-edible oil plant of oil methyl ester. Therefore, the objectives of the present study was to find a way of converting this invasive plant to useable form for the society which was affected by A. Mexicana by converting the seed oil to biodiesel production, characterization of the oil and fatty acid methyl ester (FAME). After the seed samples were collected and purified, the physicochemical and instrumental parameters were determined. The biodiesel was produced by heterogeneous CaO catalyst from A. mexicana oil through transesterification method. Experimental design using design expert 7.0.0 software were implemented to identify the oil yield, the effects of different process parameters for FAME production and to find the optimum conditions to maximize the yield of FAME. A total of 40 % yield of oil was extracted and converted into methyl ester by the process of transesterification. The physicochemical studies and the comparisons revealed that transesterification improved the important fuel properties. The best performance result was obtained at a catalyst concentration of 1.0%, molar ratio 9:1 and reaction time of 1 hr, while the reaction temperature and agitation speed was set at 600C and 600 rpm. The FAME yield obtained from transesterification process ranged from 56.3 to 91.2% while the optimum result was found 93% from the design expert software. The results showed that transesterification improved the important fuel properties testes which were relatively closer value with the ASTM and EN standards. Key words: Biodiesel production, Argemone Mexican , transesterification, FAME
Characterization and Process Optimization of Biodiesel Production from Croton Macrostachyus ‘besana’ Seed using KOH Catalyst
(Addis Ababa University, 2018-07) Wondwosen, Shiferaw; Solomon, Kiros (PhD)
Energy security, socioeconomic aspect, and environmental concern are the major arising factor to be considered while selecting the source of energy in today's word including Ethiopia. The rising cost of petroleum fuels, depletion of reserves and strict world protocols on exhaust emissions have also necessitated the need for replacement of petroleum fuels with less polluting, readily available and renewable sources of fuels for automobile and industrial engines. This enforces the worlds to look over the biofuel as a major substitute for mineral fuel sources. Production of biodiesel from non-edible feedstocks is attracting more attention than in the past, for the purpose of manufacturing alternative fuels without interfering with the food chain. Among those non-edible feedstocks, croton macrostachyus seed is another option and which is newly identified feedstock which is indigenous in Ethiopia. The seed was collected from the southeastern part of the country and solvent oil extraction method was selected to extract oil from croton seed. The study aimed at optimizing the biodiesel production process experimentally by varying catalyst concentration, reaction temperature and the molar ratio of methanol to oil. These process parameters were optimized by using design expert software. The optimum conversion efficiency of croton oil to fatty acid methyl ether (FAME) obtained was 96% at the optimal condition of 6:1 methanol to oil ratio, 1% catalyst loading, and 50 XI o C reaction temperature. The properties of croton methyl-ether which were determined fell within the recommended standards. Oil content of the seed was found 53.34% which is beyond estimated value before this study. The main physicochemical properties of biodiesel production from croton oil were characterized and evaluated according to the minimum requirement of international standard (ASTM and EN). It was found that croton biodiesel viscosity 4.613mm 2 /s, density 0.854g/cm 3 , calorific value 39.889MJ/kg, flash point 220 o c, iodine value 107.084mgI/gm and FFA 0.435 mg KOH/gm. The results indicated that the properties of fatty acid methyl ether obtained from Croton macrostachyus seed were agreed with the standard specification of the ASTM and EN. In addition, the oil content of croton seed was observed that 53.34% which is beyond estimated value before. Finally from this study croton seed was discovered as new biodiesel feedstock and extend the choice of feedstock.
Comparative Analysis of Briquetting Most Viable Biomass Waste to Substitute Charcoal in Ethiopia
(Addis Ababa University, 2014-04) Belay, Anteneh; Alemu, Demiss(PhD)
Agricultural residues seem to be the most promising energy resources for developing countries. However, the majority of them have low energy density. One of the favorable technologies for enhancing that property is charcoal Briquetting. A large amount of agricultural and solid wastes are left in the field after harvest. The primary objective of the study was to investigate the comparative analysis of resource availability, physico-chemical properties and performance of biomass charcoal produce from the most promising wastes. Specific objective were to develop and characterizing composite charcoal briquettes, investigate factors affecting densification of composite charcoal briquettes and compare resources availability, physic-chemical property and performance of charcoal briquettes with wood charcoal. The composite charcoal briquettes were produced using ASTM standard by a combination of process factors. The three process factors were dwell time, clay binder ratio and pressure. Design expert software, Box-Henken model were employed to investigate the effect of process factors. The Density was found in the range of 783.00-1,187.00 kg/m^3. The coefficient of multiple determinations for prediction of the proposed density model was about 95.7%. The effect of the three variables against density was investigated. When every two combinations of the above variables were increased, density of briquettes was also found to increase. Optimum point of dwell time, pressure and clay binder concentration was found at 3.6 minute, 45 bars and 18.27% respectively. The optimal point was validated. The Production of 1300 tones/yr briquettes plant was evaluated. The total investment cost was found to be 1.9137milloion birr. The net present value and the internal rate of return of the project were 2,753,976 Birr and 19% respectively it implies the project was feasible. Base on the resource estimation using production to residue ratio, the quantity of available agricultural residue, cotton stalk, coffee husk, bamboo residue and jatropha press cake in Ethiopia was approximately 4,655.887, 219.933, 109.757, 109.757,1,000 and 0.228Ktones/yr respectively. When the fixed carbon of charcoal made from bamboo, cotton stalk, coffee residue and composite with that of Acacia charcoal, 60.85, 58.4, 63.9, 68.25 and 69.74w/w % were found respectively. The above value all had relatively similar which makes it possible to substitute wood charcoal. Regarding heating values of briquettes produced from bamboo, cotton Comparative Analysis of Briquetting Most Viable Biomass Waste to Substitute Charcoal in Ethiopia AAU, AAiT, M.Sc. Thesis by Anteneh B. xiv stalk, coffee residue, composite and Acacia spp. charcoal were 29135.94KJ/Kg, 19209.03KJ/Kg, 11710.48KJ/Kg , 23446.08KJ/Kg and 32573.304 KJ/Kg respectively. But all the heat values of briquettes were lower than that of charcoal. If the country substitutes wood charcoal by charcoal briquettes, it will reduce 47.06 CH4 / year and 1530.383 Co2/year for every production of 1300 tons per year. The study showed that charcoal from bamboo; cotton stalk, coffee residue and agricultural residue could be used as substitutes for Acacia charcoal as they had comparable potential energy. But jatropha press cake currently had a low possibility to be use in our scenario. Generally, this research concludes that the biomass charcoal had positive value of production method, fixed carbon and performance, but one negative value was obtained from calorific value. With ¾ positive values, these biomass wastes can substitute wood charcoal in Ethiopia.
Comparative Experimental Investigation Between Parabolic Dish and Flat Plate Collector Based Solar Dryer for Saw Dust Briquette Production
(Addis Ababa University, 2019-06) Hosaena, Alemayehu; Solomon, Teklemariam (PhD); Tewodros, Walle (Mr.) Co-Advisor
From different types of briquette drying technology, the open sun drying system is the most widely used, which is found in many developing countries including Ethiopia. For this type of convectional drying process, the time required to remove moisture from the product is too long. In average it requires 3 to 4 days with available sufficient solar radiation. Beside that the recent improved type solar driers (flat plate-based driers) have still inefficiency regarding to the drying time. This happened due to the low drying air temperature effect that limits the drying time and efficiency. The main objective of this project was to design, construct and test more efficient solar drier compare to the recent developed dryer type. To prove the new type of drier performance, the experiment has been done by comparing the performance of the parabolic dish based drier (PDSCD) with the Flat plate based drier (FPSCD). The comparative assessment has been done with scientific experiment using different measuring methods and tools discussed in this paper. The experiment was conducted in the Addis Ababa Institutes of Technology compound free field area for both solar driers. The drying air temperature has been increased using concentrator collectors. The PDSCD and FPSCD absorber surface temperature, drying air temperature, air speed at the outlet of the drying chamber, moisture content variation, the relative humidity at ambient and inside the drying chamber were measured with unloaded and loaded setup using direct and indirect measuring methods. The amount of moisture removed from the drying chamber of PDSCD and FPSCD is 0.039 kg and 0.022 Kg respectively. The measured result indicates that performance PDSCD has a better moisture removing capacity rate than FPSCD. After analysis of the measured result, the thermal efficiency parabolic dish collector and Flat plate collector is determined 31.55% and 8.95 % respectively. And the overall drying system efficiency of the PDSCD and FPSCD is 31.55 % and 8.95 % respectively where the PDSCD has better performance than FPSCD.
Design and Analysis of Solar Thermal System for Hot Water Supply to Minilk II Hospital New Building
(Addis Ababa University, 2016-06) Kebede, Dagim; Tadesse, Yilma (PhD)
Solar energy technology has led to the development of a number of solar appliances used for lighting, electricity, cooking and solar thermal systems. The most hopeful among them is the solar thermal system, to achieve the energy necessity for different applications at domestic as well as at the industry level. In this research work an attempt has been made to design and analyses solar thermal system for hot water supply to Minilik II Hospital new building. The selected solar collector and the heat storage are also designed based on: the amount of hot water supplied to the hospital throughout the day and the energy needed to heat the demanded hot water. Mechanical system of hot water distribution in the hospital, building structure, array of solar collector and thermal storage system of the project will be investigated. Transient performance of the system is computed using a numerical heat transfer model of a single glass cover flat plate collector solar water heater with riser and header type active system. The various design parameters are gathered from the inside country solar water heater manufacturers and dealer companies and also from the world experience. The meteorological data for simulation was prepared by taking the average of six years starting from 2010 - 2015. From the annual contribution of solar energy to the heating load and solar fraction the estimated values of investment cost, the unit solar energy cost and the pay-back period of the system was calculated. It was found that for Minilik II hospital of total daily hot water consumption of 30.475 m3, a total of 108 collectors with two storage tanks of each capacity 18.3 m3 are needed with initial capital cost of 1,006,865 Birr per project, which will cost a total of 1,864,054 Birr per project through-out its life time and the life cycle cost saving will be Birr per project. The unit price of solar thermal energy is 0.033 Birr per KWh and the payback period of the project is 2.2 year. Since the unit cost of solar energy (0.033 Birr/KWh) is less than the unit cost of electricity (0.46 Birr/KWh) in Ethiopia, therefore water heating by solar energy is a viable alternative to heating by electricity and fossil fuel (furnace oil).
Design and Development of low Power Output Solar Chimney Power Plant
(Addis Ababa University, 2018-07) Ashenafi, Tesfaye; Solomon, Teklemariam (PhD); Tewodros, Walle
In order to convert solar energy resource into useful power source different technology has been used so far. SCPP is proposed to be a cost-effective sector for the production of electrical energy in a large scale for the future. In SCPP system solar air collector, chimney tower and turbine are the three essential main components. In this study a detail design and modeling of SCPP is investigated for maximum power output of 30 ��. The optimization of geometry for each component is modeled using MATLAB software, Moreover MATLAB is used to predict the performance of large scale electricity generation from the plant. ENERGY 2D software is used to study flow characteristics of air temperature inside the collector. As a result for 30 kW power output the selected optimized dimensions: chimney height, collector diameter, chimney diameter and collector height (distance between the edges of collector and the ground) are estimated to be 15m, 15m, 0.2m and 0.2m respectively. For a fixed chimney diameter and collector height, an increase in the height of the chimney rises the power output upto a certain optimum height, an increases in chimney height beyond the optimum point results an energy loss due to pressure drop along the chimney will start to dominate the energy rise due to the stack effect. The model developed is scaled down to a chimney height of 3 �� and collector diameter of 2 �� with maxmum power output of 32 W. In the experiment under investigation the characteristics of the temperature inside the collector throughout the day was studied by varying height of the collector above the ground from 0.17 m upto 0.4 m. The temperature of the fluid is minimum when the collector height is 0.4 m and maximum at 0.17 m. The result obtained for a temperature difference between collector exit and collector inlet from the comparison of experimental and simulated modeled are in a good agreement under a certain condition. So, the implementation of solar chimney power plant as a rural electrification is feasible with the potential to provide electrical energy throughout the day for a desired potential.
Design and Development of Three Small Generators Operated Micro Wind Turbine
(Addis Ababa University, 2021-02) Tekalegn, Amanuel; Abdulkadir, Aman (PhD)
World is struggling to mitigate climate change due to uses of fossil fuel for energy gen- eration and also searching substitution for fossil fuel in energy sector. Wind energy is one of the lowest environmental impact forms of clean energy available today. In order to convert wind in to energy many technologies are used up to know from small o grid to large wind farm wind turbine. However, it's di cult to nd cost e ective and durable Micro wind turbine for o grid use to generate electricity in rural part of Ethiopia which is in dark for a long period of time. This study aims to Design And develop Three Small Generators operated Micro Wind Turbine with production capacity of 2:4KW, to o -grid use for rural part of Ethiopia with durability and low cost relatively to current Micro wind turbine. Polyvinyl chloride (PVC) is used to manufacture the small wind turbine blade and Three small generator are driven by direct coupled external ring gear with turbine axle. PVC blade is manufactured with best twist angle through the radius of blade for better direct wind contact to get better energy extraction from low wind speed. This Three Small Generators operated Micro Wind Turbine development costs took up to 28,885 ETB. At the end of this research is done and commercialized the electricity demand can de- crease in o grid users, the electricity coverage can cover rural (remote) area of Ethiopia around 30 Percent of the rural population which is in need of electricity.
Design and Experimental Analysis of Charcoal Production from Maize Waste (Corncob)
(Addis Ababa University, 2020-10) Geda, Feyera; Wondwossen, Bogale (PhD)
Maize is the second dominant crop that is used as a food next to Teff in Ethiopia. However, there is much left-over corncob after harvest and during processing. Some peoples need the waste of this corn for cooking purposes and baking Injera. Pyrolysis is the process at which charcoal is produced within low oxygen environmental conditions. Developing an innovative pyrolysis system for the production of charcoal from corncob that is economical, efficient, and environmentally friendly is very important. The main objective of this research work to design and experimental analysis of charcoal production from corncob by slow pyrolysis. The continuous pyrolysis system has been designed, manufactured, and tested. Data collection, characterization of corncob, and charcoal analysis were done. The physical characterizations of the corncobs have also been done by estimating the proximate analysis. Bomb calorimeter was used to measure the energy content of the corncobs and the produced charcoal. As the quality properties and chemical composition of plant material are one of the most important indicators of how much waste can be used in charcoal production the characterizes of moisture content, Volatile matter content, fixed carbon content, and an ash content of the corncob were found as 9.11%, 65.84%, 15.76%, 9.28% respectively. Based on the experimental result the corncobs charcoal was 1.55% of moisture, 13.65% of Volatile matter, 65.64% of fixed carbon and 18.26% of ash contents were observed. Based on the result, 2.1 kg of biochar is produced from 3kg of corncobs at rpm of 12.5 and 24℃/min of residence time at the temperature of 600℃. This implies a product yield of 70 % has been found. The parameters like temperature, rotation of the motor, and moisture contents of the waste have effects on the production of the charcoal from corncobs using this machine. Based on the experimental result, the lower heating values of the corncobs and its charcoal were found to be 16.97 MJ/kg and 27.43 MJ/kg respectively. Thus, by using this machine
Design and Simulation of Grid-Tied Photovoltaic, Thermal and Biogas Energy Generating Systems to Power Universities in Ethiopia :A Case of Addis Ababa University , Collage of Natural and Computational Science.
(Addis Ababa University, 2015-12) Abiti, Gezahegn; Assefa, Abebayehu (PhD)
This paper confers with a study and unfold to systematic know how on how to furnish Ethiopian universities with power using their own abundantly available renewable energy resources and to establish a project for the same purpose. In pursuance of that, it was conducted by collecting and analyzing relevant and required data like electrical energy consumption, weather and site of the targeted universities while also rendering comprehensive attention to other design standards as well as specifications of machineries. The worst case design is thoroughly regarded herein the design section for it is more convincing with respect factor of safety in the event solar radiation falls below the annual average and when there is a minimum amount of biogas resource. The simulation, optimization and sensitivity analysis of the project is dealt by renewable energy tools of HOMER software. Foundation of the hybrid energy generating system is surfaced and actualized by making estimation of solar and biogas resource at a given site. The source data for AAUCNCSc revealed that a mean incident solar radiation of 3.66 kWh/m2/day and a potential of about 24 tons of biogas resource per a day can be collected considering safety factor for the variation as per day to day and month to month basis. The data collected for this study further showed that the electrical energy demand of the site was 104,870 kWh in the design year (July 2012) in which a combination of the two systems are going to offset the necessity. The assessment conducted revealed that out of the total of 104,870 kWh energy needed close to 81% is furnished by and fulfilled with biogas energy generating system while the remaining 19% of it is contributed by PV/T system and yet 0.00492kWh/yr (0.00%) is found to be excess which ought to be sold to the national grid . Pursuant to the financial analysis of HOMER, given to designed HPV/TBS and within an optimum cost of electricity (COE) of 0.263 $/kWh, renewable fraction (RF) of 1 can be obtained. Generally, if and when the total cost of PV/T modules, the Biogas generators and the converter are US$ 535,750.00, US$ 50,000.00 and US$ 8,000.00 respectively. The software further showed that in the emission analysis 4,172,041kg/yr of CO2, 18,099 kg/yr SO2 and 7,935 NO can be removed if this renewable design of the hybrid system is to be implanted instead of non renewable equivalent.
Design of Coolant Heater For An Emergency ELECTRIC Generator Drive Diesel Engine By Solar Energy For A Cement Industry
(Addis Ababa University, 2016-12) Meleta, Tadesse; Alemu, Demiss(PhD)
coolant and lubricant to attain the optimum operating temperature without delay in an industry using diesel engine to drive emergency electric generator in attaining its rated power capacity for one of the diesel engine driven emergency electric generator installed for Mugher Cement Factory. The result will serve for avoiding the cement production equipment of the rotary kiln and related drive systems from thermal gradient deformation immediately after unexpected main grid failure. In order to improve the circulating coolant temperature and the pre-heating time requirement, electric heater has been installed. To measure the improvement of engine efficiency during starting up period after main grid failure, temperature data are collected from the generator set controller and measuring instruments both before and after installation of electric heater. These data have been collected when this experiment was made on site in Mugher Cement Factory. The data contain readings of temperatures [°C] obtained from measuring instruments and installed controller. The analysis of the system has been done by using controller performance display readings and performance measuring instruments. Besides, temperature reading data has been analyzed by using some statistical methods, particularly to investigate the improvements achieved or the severity of the existing problem. From the performance improvements, the results computed from observed data as well as from test instruments, the generator set shows that its performance has been clearly improved by using heater to heat the coolant. Besides these, it can be deduced, even if not tested, that coupling of the solar thermal technology can further improve its performance. Based on these preliminary results, a solar water heater of 100 litre capacity, with provision of auxiliary electrical heater in addition to solar heater, in comparison with the cases of electrical heater, is designed in detail to be locally fabricated and installed for the case of Mugher Cement Factory. Generally, selecting and adopting proper solar water heating technology for the circulating coolant of emergency electric generator drive diesel engine has improved preheating time in attaining engines thermostat opening temperature in a lesser time to avoid the rotary kiln and related drive-driven systems thermal gradient deformation immediately after the main grid failure of a cement industry. This is an indication of the applicability of the result of this thesis. xvii The output of the research shall contribute reliability for industry’s production processing equipment, especially the key equipment that operate at high process temperature, by avoiding rapid cooling that causes the thermal gradient deformation and leads to complete equipment damage and consequently loss of production, revenue and employee lay off due to inefficiency of the engine. The finding of this research can be used as the potential of making the diesel engine driven electric generator that enable to attain its full load immediately by adopting similar technologies for institutions that require immediate back up. Furthermore, it creates an opportunity in looking at heating water by harnessing energy from the sun for industrial and commercial firms in order to overcome the rising of oil prices as well as utilization of environmental-friendly alternative sources of energy, specifically renewable energy technologies and promoting green energy technology. Key words: Engine coolant, heating time, delay time, heater, emergency generator, kiln, cooler, solar radiation, solar collector.
Design of Solar Photovoltaic System to Power Air Conditioning Unit for A Light City Train (Case Study on Addis Ababa Light Rail)
(Addis Ababa University, 2020-10) Rukia, Hassen; Solomon, Tesfamariam (PhD); Fitsum, Sahilu (Mr.)
Energy is the basic utility required to drive trains. Trains use either fossil fuel or electricity to energize the system. The Addis Ababa city light rail has two routes namely: the North-south Line (MENILIK II Square to KALITI Route) and the East-west Line. The train gets electricity from the grid. Electrical energy coming from the grid enters the control unit from where to be supplied to different units. One of the energy-intensive units is the air-conditioning system. This research work focused on designing a rooftop solar photovoltaic system to provide the energy required for the air conditioning units of the 17.1 kilometers from Ayat to Torhailoch Route. The data collected from the Ethiopian Methodology Agency, NASA, and PVGIS showed the sun can be provided at minimum solar insolation of 4.8 kWh/m²/day to the route line. The air conditioning system of the train is a DLD25 type air conditioning unit. The cooling capacity is 6 kW and power of 2.25 kW for each AC, the air supply volume is 1300m3/h, and the total electrical power is 9 kW for 4 air conditioner. The train travels at an average speed of 70 km/h without significantly changing its direction from East to West and vice versa. In a coach, 36 photovoltaic modules (having a 66.35 m2 aperture area) can be installed in an effective rooftop area of 71.6 m2. The battery size is 150Ah, 12V controller size of 80 A, 220V, and 30 KW of inverter size. The PVSYST and MATLAB software simulation results projected within different months electrical energy varying between 11.48 kW and 14.45 kW can be generated. The train in general requires 260 kW of electricity. Of this 9 kW or 3.5 % amount of energy is consumed by the air conditioner. Hence, by supplementing the locomotive with solar PV modules 1034775 Birr can be substitute per annum. As compared to other researches, this thesis work is to simplify the mounting of the solar PV modules by considered the solar insolation variation within the route to know the performance of the system. Hence it is recommended to Addis Ababa Light Rail Train to apply this solar-powered air conditioning system.

Browse

Browsing Center for Energy Technology by Title

Results Per Page

Sort Options