RP-Department of Energy Engineering
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Item Performance of Maximum Power Point Tracking Charge Controller under Moderate- to High-Temperature Field Conditions(Journal of Sustainable Development of Energy, Water and Environment Systems, 2024) Hassan, Adamu; Njoka, Francis; Kidegho, GideonOwing to the effect of temperature on the maximum power point of photovoltaic modules, the anticipated benefits of maximum power point tracking charge controller are also greatly affected under high-temperature environments. This paper presents experimental study results based on the investigations of the effect of high cell temperatues on the performance of maximum power point tracking charge controllers. The study was carried out over three months at Kenyatta University in Nairobi, Kenya under moderate and high temperature conditions. The experiments are carried out using two market-ready maximum power point tracking charge controllers and a normal pulse-width modulation charge controller as the reference. The study establishes that below 50 °C, the maximum power point tracking charge controller exhibits significant advantages over its counterpart with about 24% - 29%, additional energy gain. However, at high cell temperatures, the maximum power point tracking charge controller loses its added advantage over the pulse-width modulation charge controller and its performance benefits drop from an average of 28% to 0.2%. This demonstrates that an ordinary pulse-width modulation charge controller would achieve the same yields under high-temperature conditions and at an even lower premium.Item Characterization, Performance Evaluation and Optimization of Wheat Straw – Bagasse Blended Fuel Pellets(CBIORE, 2024-02) Matasyoh, Isabel Musula; Osodo, Booker; Kombe, Emmanuel; Muguthu, JosephThis study was carried out to assess the fuel pellets produced from wheat straw and sugarcane bagasse. The wheat straw and bagasse were blended into four ratios including; 10:90, 30:70, 70:30 and 90:10 (wheat straw: bagasse) and developed into fuel pellets. The fuel pellets were characterized to determine the moisture content, volatile matter, fixed carbon, ash content, calorific value, bulk density and mechanical durability. The ignition time, burning rate and specific fuel consumption of the wheat straw – bagasse blended fuel pellets were studied at varying blend ratios (10:90, 30:70, 70:30 and 90:10), moisture contents (9.1%, 10.6%, 12.6% and 14.7%) and raw material particle sizes (2 mm, 4 mm, 6 mm and 10 mm). Results indicated that the wheat straw: bagasse blend ratios containing more proportion of bagasse (30:70 and 10:90) recorded a shorter ignition time, higher burning rate and lower specific fuel consumption. Larger raw material particle sizes exhibited shorter ignition time, higher burning rate and specific fuel consumption. Moreso, the fuel pellets with low moisture contents also recorded shorter ignition time, higher burning rate and lower specific fuel consumption. It was concluded that fuel pellets with high quantity of bagasse, large particle sizes and low moisture content demonstrated favorable combustion characteristics. Response surface methodology was used in the optimization so as to determine the optimum combination of blending ratio, moisture content and raw material particle size that would result in the lowest ignition time, highest burning rate and lowest specific fuel consumption. Results indicated that an optimum combination of a wheat straw: bagasse blend ratio of 10:90, moisture content of 14.70% and a particle size of 10.00 mm resulted in the lowest ignition time, highest burning rate and lowest specific fuel consumption.Item The Impact of Roof Material Profile and Pigmentation on the Performance of Photovoltaic Modules(MDPI, 2023-11) Aigbedion, Nosakhare; Njoka, Francis; Munji, MathewThis study combines simulations and experiments to study the heat interactions between various types of roofs and the photovoltaic (PV) modules installed on them. Specifically, the performance of PV modules on a clay roof was compared with their performance on two types of metal roofs, a Box-profile metal roof and an Orientile metal roof, which differ in shape and geometry. Additionally, this study examined the cooling potential of three common metal roof pigments, iron (iii) oxide (Fe2O3 ), titanium dioxide (TiO2 ) and basalt, on roof-installed PV modules. An unpigmented roof was also studied for comparison purposes. Model development and simulation were implemented in COMSOL Multiphysics, and the simulation results were validated and compared with field experiments. The maximum open-circuit voltages of the PV installations were found to be 21.096 V for the clay roof, 20.945 V for the Box-profile metal roof and 20.718 V for the Orientile metal roof. This study revealed that the unpigmented roof had higher solar cell temperatures compared to the pigmented models, with temperature gains ranging from 2.2 ◦C to 2.71 ◦C. Moreover, the unpigmented model displayed significantly higher surface radiosity than the pigmented models. The performance output of the modules also varied depending on the metal roof sheet shape and geometry, with the Box-profile metal roof yielding better results than the Orientile metal roof sheet. These results indicate that a specific roof pigmentation may have a small impact on a single PV module, but it can become significant in a large array of modules, especially if cooling through natural convection is hindered.Item Modeling, Simulation and Performance Evaluation of a PVT System for the Kenyan Manufacturing Sector(Cell Press, 2023) Ngunzi, Veronica; Njoka, Francis; Kinyua, RobertManufacturing is an end-use sector that uses the most delivered energy, accounting for around 50% of all transported fuel globally and 40% of carbon dioxide emissions worldwide. Solar photovoltaic-thermal (PVT) energy can substitute the transported energy to meet thermal and electrical energy requirements, mitigating high energy costs and climatic problems. This research aimed to develop, simulate, and evaluate the capabilities of a solar photovoltaic-thermal system for potential use in Kenya’s manufacturing sector. A multistage cluster sampling technique was used in the study to characterize the manufacturing industry. Additionally, a PVT system was simulated using MATLAB Simulink to ascertain the relationship of temperature and the PV electrical efficiency. The impact of incorporating a thermal collector into the PV system on electrical, thermal, and overall system efficiency, and also the system’s potential for use in thermal processes in manufacturing, were assessed. From the characterization results, the agroprocessing sector dominates with 35% representation, and the small-scale thermal energy category dominates at 80%. The simulation findings show that a small temperature increase leads to a small increment in short circuit current but a significant decline in open circuit voltage. As a consequence, the maximum power (Pmax) of the PV decreases, lowering its electrical efficiency. However, the integration of PV with thermal collector improved the electrical, thermal, and the entire system efficiencies by, 16.01%, 20%, and 36.13%, respectively. More than 75% of the electrical and thermal energy processes fall in the small energy category. Hence, the PVT system is suitable for small-scale low-to-medium heat thermal energy categories or as a substitute system for higher temperature processes to raise feed water temperatures and reduction of thermal energy cost. This study gives a new approach of the application of PVT system for thermal industrial applications.Item Validation of Calculated Pressure Drop Using Experimental Data with Standard Methods of an Existing Software(World Journal of Research and Review, 2020) Joel, Ogbonna F; Ikiensikimama, Sunday S; Oyoo, Daniel OThe aim of this research was to determine the pressure drop along a 450 km long multiproduct pipeline. Empirical formulae and quantitative methods were applied in order to establish pressure drop as an operating parameter. Flow rates used were obtained from the daily operation records of two consecutive years and were in the range of 629 – 765 m3/hr. Using four methods, observed pressure drop results when pumping products through the pipeline were as follows: Shell-MIT was 954.5 – 1411.9 bar (gasoline), 1257.6 – 1860.3 bar (kerosene) and 1535.0 – 2270.5 bar (diesel); Benjamin Miller was 0.509 – 0.728 bar/km (gasoline), 0.693 – 0.988 bar/km (kerosene), 0.773 – 1.101 bar/km (diesel); T. R. Aude was 0.590 – 0.841 bar/km (gasoline), 0.814 – 1.161 bar/km (kerosene), 0.907 – 1.294 (diesel); Darcy was 0.578 – 0.857 bar/km (gasoline), 0.703 – 1.042 bar/km (kerosene), 0.858 – 1.272 bar/km (diesel). Simulations using pipe-flow wizard were carried out in order to authenticate the calculated parameters. Results confirmed that Shell-MIT method is only applicable to crude oil pipelines. From comparison of calculated pressure drop, Benjamin Miller’s method was most preferred as it observed the least value within the same flow rate range. Simulation results validated the calculated pressure drop and therefore, calculated Benjamin Miller’s and T. R. Aude’s values are recommended for use in further review study of the said pipeline.Item Enforcement of Access to Effective Technical Support Services in the Kenyan Solar Energy System(JENRR, 2019) Mugo, Jackbed Gakii; Muguthu, Joseph N.Energy is the prime mover of development cutting across industrialisation, manufacturing and residential consumption. Recently, Kenya, being ranked high among the most developed countries in Africa, has mapped way for embracement of renewable energy technology with increasing debate on sustainable development and environmental issues associated with fossil fuels, as the prime energy sources. Generally, Kenya is making efforts to Scale - Up renewable energy programs via construction of stand-alone solutions as well as various types of mini - grids. However, a common problem cutting across all these consumers is quick failure of such projects with very little access to technical solutions or none at all. Substantial developments in solar energy in Kenya, as one of the renewable energy sources, has been mainly challenged by lack of effective capacity building and poor technical support. This cuts across both domestic systems as well as the most rising aspect of small and medium sized minigrids. This paper aims at investigating the leading role of access to viable technical support services in mitigating solar energy adoption challenges. The paper focuses on challenges faced by small and medium sized consumers in search for technical advice and support prior to purchase, during installation and after purchase and installation stages. The research conducted survey via questionnaries, analyzed data obtained, identified technical support factors in order of priority and gives adaptable recommendation for the state in ensuring that solar projects are sustainable and that customers find value for their money.Item Characterization and Ranking of Various Mix Ratios of Cow, Pig and Sheep Manure(Journal of Energy Research and Reviews, 2021-04) Matwek, Sheila Chepkirui; Nyaanga, Daudi M.; Osodo, B. O.This work determined the characteristics of various mix ratios of the cow to pig to sheep manures and ranked them with help of principal component analysis (PCA). Ten mix ratios (by mass) namely 1:1:1, 3:1:1, 1:3:1,1:1:2, 2:1:1, 1:2:1, 1:1:2, 1:3:3, 3:3:1, 3:1:3 of cow, pig and sheep manures respectively were selected. Laboratory analysis was done to determine the total solid (TS) content, carbon to nitrogen ratio, pH, and volatile solid (VS) content using standard procedures. The results obtained (except that of pure feedstocks) were subjected to principal component analysis to determine the principal component scores for the mix ratios to enable ranking. The total solids content of pure cow, pig, and sheep manure were found to be 19.18%, 23.50%, and 30.35% respectively. Corresponding carbon to nitrogen ratios values were 23.68, 13.27 and 29.00, pH values were 6.50, 7.90 and 7.00 and volatile content were 88.37%, 84.57% and 80.00%. Upon mixing the three manures at various mix ratios total solid content varies from 22.28% to 26.75%. Total solids content, carbon to nitrogen ratio, pH and volatile solids content varies from 22.28% to 26.75%, 18.76 to 25.05, 7.13 to 7.56 and 85.94% to 82.59% respectively. Using the first principal component scores mix ratio 1:1:3 of cow dung, pig, and sheep manure was the top-ranked followed by 3:1:3 and the third one was 1:1:2 with scores of 2.540, 1.638, and 1.580 respectively. The 4th ranked mix ratio was 1:3:3, 5th ranked was1:1:1, 6th ranked was 2:1:1, the 7th one was 3:1:1, 8th one was 1:1:2, then 3:1:1 and lastly 1:3:1 with the scores of 0.191, -0.006, -0.147, -0.259, -1.440, -1.810 and -2.287 respectively. Higher positive scores were associated with a possibility of producing higher biogas yield possibly due to the right combination of the several parameters in the mixture while a lower score might indicate a lower gas yield due to an improper combination of parameters. It was then concluded that principal component analysis is a suitable method for selecting few mix ratios to use in anaerobic digestion among the many. It saves on time and resources due to the reduced number of experiments.Item Performance of an Integrated Solar-Greenhouse Photovoltaic Ventilated Dryer with Clay-CaCl2 Energy Storage Desiccants for Tomato Drying(science publishing group, 2021-04) Mbacho, Susan Andrew; Thoruwa, Thomas; Lang’at, Nickson Kipngetich; Ako, EliasThe use of solar energy in drying of perishable crops such as tomatoes is a good alternative to the problem of post-harvest processing in tropical eastern African countries. A review of the literature revealed that most of the solar crop drying systems developed during the last five decades have small loading capacity and cannot operate during the night. Therefore, an integrated solar greenhouse dryer system [SGDS] with Clay-CaCl2 desiccant energy storage system was designed and tested. Such SGDS have the advantage over other solar systems of high loading capacity and structural simplicity. In addition, they have relatively good thermal crop drying performance compared to most solar dryers. However, their main limitation, like most solar dryers, is their inability to dry at night. Therefore, to enhance night-time drying capacity, a prototype SGDS integrated with a low-cost Clay-CaCl2 desiccant energy storage system was designed, fabricated, and tested. The drying performance of this prototype was evaluated using loads of fresh tomatoes during October – December 2019 at Nairobi, Kenya. The dryer was able to dry fresh tomatoes from 93.9% (mcwb) to 8.3% (mcwb) within 27hours with solar greenhouse drying efficiency of 23% during daytime and desiccant drying efficiency of 19.9% during nighttime. The drying rate for the two-day light drying was 0.985kg/h and 0.875kg/h respectively and that in night drying using desiccants was 0.34kg/h. Based on these results, it was concluded that prototype solar greenhouse dryer with Clay-CaCl₂ energy storage has great potential for drying perishable produce such as tomatoes in tropical countries.Item Climate Change Mitigation and Adaptation through Anaerobic Digestion of Urban Waste in Malawi: A Review(ResearchGate, 2020-05) Chamdimba, Hope Baxter Nqcube; Mugagga, Reuben Gad; Ako, Elias OnyangoImproper waste management and disposal in major cities of Malawi transpires to be one of the major environmental setbacks as waste remains uncollected and usually disposed in open dump sites. Such waste emits greenhouse gases (GHGs) into the atmosphere that contribute to global warming and climate change in addition to pollution of water sources. The effects of climate change to Malawi have been far reaching to the extent of experiencing floods and droughts. This in retrospect has also had lasting impacts on Shire River where more than 95% of the country’s electricity is generated. Consequently, the rate of power generation is greatly hindered which has thus left only 11% of the population with access to electricity partly due to droughts. This paper therefore focusses on the capturing of methane from municipal solid waste as a solution to climate change and energy challenges through the utilization of methane, a combustible gas which is beneficial in regard to cooking, heating and electricity generation. This is amplified with particular review of the challenges, opportunities, policy framework in place and the pertinent role of anaerobic digestion as the game changer in climate change mitigation and adaptation in Malawi.Item Prospects and Constraints to Attaining Universal Access to Modern Energy in Malawi: A Review(science publishing group, 2021) Chamdimba, Hope Baxter; Mugagga, Gad Reuben; Ako, EliasThe Malawi Government regards energy as a life blood of the economy and as such a number of national policy documents have emphasized energy as one of the national priority areas that demand urgent intervention by the government and stakeholders. There is also a consensus that ensuring universal access to modern energy in an energy deficit country will also help improve living standards of people in line with national and global goals. Through a 2018 National Energy Policy, Malawi effectively domesticated the Sustainable Development Goal Seven and the Sustainable Energy for All objectives which among others seek to ensure universal access to modern energy by the year 2030. However, now in the last decade of the 2030 agenda, the country is not yet on the path to achieving the universal access to energy goal despite of having numerous opportunities for reversing the energy poverty trends. Doing a post-mortem is of essence in order to determine prospects and constraints to achievement of the national energy goals and objectives regarding universal access to modern energy. Therefore, this paper seeks to discuss the status of energy access to modern energy in the country, the prospects and constraints in relation to energy policy, regulatory environment, institutional capacity, energy resource, capital investment, technology and human resource.Item Selection and Verification of a Drying Model for Maize (Zea mays L.) in Forced Convection Solar Grain Dryer(science and education publishing, 2017) Osodo, Booker; Nyaanga, Daudi; Muguthu, JosephVarious researchers have fitted experimental drying curves for various products to existing drying models. In this study, an experimental forced convection solar grain dryer was used to select the best fitting drying model for shelled maize. 0.04 m thick grain layer of shelled maize was dried an air velocity of 0.408 m/s and a 40°C drying air temperature. Using Root Mean Square Error (RMSE), Coefficient of Determination (R2) and Chi Square (𝜒𝜒2) the selected drying model was the one by Midilli et al. (2002), with R2, 𝜒𝜒2 and RMSE values of 0.9487, 0.4278 and 0.1723 respectively. The model coefficients were determined for drying air temperatures of 40, 45, 50 and 55°C. It was found that the predicted and experimental data agreed satisfactorily with R2 and RMSE values of 0.9225-0.9786 and 0.0325-0.0750 respectively. A computer simulation model was developed to predict moisture ratio at a given drying time.Item Quality Failure Analysis and Quality Improvement Methods in Small and Medium Manufacturing Companies (A Case Study of Shamco Industries Limited)(IJSTR, 2018-04) Ngugi, Joseph Chege; Muchiri, Peter; Muguthu, Joseph; Nkundineza, CelestinThis paper elucidates the analysis of quality failure in small and medium manufacturing companies and established methodological approaches that mitigate these problems in order to improve on the quality of products manufactured. The study was carried out at shamco industries limited a steel furniture manufacturing company in Nairobi County in Kenya. The company’s records for the year 2014-2016 provided the secondary data regarding the customer complaints that led to the poor quality of steel furniture. The study adopted a case study methodology and brainstorming was the main method that was used to collect primary data. The defects were ranked in the order of severity, occurrence and detect-ability using Failure Mode and Effect Analysis (FMEA). The most common defect was dripping paint which appeared in almost all products. The most critical defect on the other hand was breaking of welded joints. After brainstorming with the experts in the company, root causes of these defects were determined. It was found that causes due to the Workers were 35%, due to the processes were 30%, due to materials were 24% and due to the machines were 11% respectively. The research provided the knowledge of quality failure analysis and established practical solutions to the detected defects. The paper concludes that similar analysis on quality is required to be done in other manufacturing companies so that quality of the products manufactured can be improved and become competitive in the global market.Item Optimum Air Velocity, Air Temperature and Maize Layer Thickness for Highest Moisture Removal Rate and Drying Efficiency in a Forced Convection Grain Dryer(sciepub, 2018-11) Osodo, Booker; Nyaanga, Daudi; Kiplagat, Jeremiah; Muguthu, JosephThe performance of a forced convection grain dryer may be evaluated based on different criteria, such as drying rate, moisture removal rate and efficiency. This performance is dependent upon various drying parameters, such drying air velocity and temperature as well as grain layer thickness. It is necessary to apply an optimal combination of levels of the various parameters in order to achieve improved performance of such a dryer. This study developed an experimental grain dryer and investigated its performance under different drying conditions. The Taguchi approach was used to determine the optimal combination of drying air velocity, temperature and grain layer thickness that could be used to ensure greatest drying efficiency and moisture removal rate (MRR). ANOVA and LSD tests were used to determine whether change of air velocity and grain layer thicknesses significantly affected drying efficiency as well as MRR.The experimental grain dryer developed was of dimensions 0.5 m x 0.5 m x 1.0 m and was equipped with a 0.7 kW centrifugal fan. It was found that the optimal combination of grain layer thickness and air velocity were 0.04 m and 0.34 m/s respectively for solar drying, if drying efficiency was the determining criterion. When drying was done under laboratory conditions, a combination of 0.41 m/s air velocity, 45°C air temperature and 0.02m layer thickness resulted in greatest MRR and drying efficiency. These findings are useful because use of combination enable the design and use of such a dryer in a manner that ensures minimal energy wastage. Appropriate time management is also facilitated as drying can be undertaken at the shortest possible time.Item Investigation on Optimal Cutting Parameters in Turning AISI 8660 Steel Using Silicon (Sic) Whisker Reinforced Ceramic Tool(ResearchGate, 2017-07) Wathigo1, J.M; Keraita2, J.N; Byiringiro3, J.B; Muguthu4, J.NThis research was to investigate the effects of process parameter that is cutting speed, feed rate, depth of cut and machining time on the response variables in turning AISI 8660 material using whisker reinforced ceramic cutting tool. Cutting tools are weak and there is continuous effort to improving their performance and wear characteristics so that different grades of materials with varied degree of hardness are machined at minimal cost and economies of production can be realized during machining. This study investigated the rate tool wear and the cutting forces involved during the machining process. High speed machine lathe (Type: MORESEKI) was used on which a three force component dynamometer was mounted on the tool post to measure the cutting forces involved during the machining process. A Toolmakers microscope (model no: 80091) was used to measure the tool flank wear (VB) and the maximum tool wear recorded was 0.27mm and occurred at approximately 3.0 minutes during the machining process. Design of Experiment based on Taguchi technique was developed to obtain the experimental data. Response Surface Methodology (RSM) was used to analyze the data by developing 3D surface plots, contour plots and Main effects plots for Signal to Noise Ratio. The residuals plots analysis for cutting force revealed a normal probability plot for the data used indicating a close fit to the best of line. The histogram indicated 80% and 10% as the highest and lowest frequency for the cutting force. The optimal cutting conditions for toolwear were obtained at v = 158.28 mm/min, f = 1.116mm/rev, d = 1.38mm, and t = 2min with the process having a high composite desirability at 0.8557. The high composite desirability means that the process variable satisfies the target goals which are minimizing cutting forces and toolwear and that SiC whisker reinforced cutting is the recommended tool when machining this material.Item The Impact of Air Mass on the Performance of a Monocrystalline Silicon Solar Module in Kakamega(Physical Science International Journal, 2019-03) Musanga, Ligavo Margdaline; Maxwell, Mageto; Barasa, Wafula Henry; Kombe, Emmanuel YeriThis paper investigates the outdoor performance of a 20 W monocrystalline silicon solar module in relation to air mass (AM) in Kakamega. Direct measurement of air mass and module output parameters from experimental setup was done in Kakamega at a location 0.28270 N and 34.7519 E. Experimental results showed a decrease in ISC and VOC with increasing AM. The maximum output power produced by the module reduced with an increase in AM. Maximum power was therefore seen to be produced at noon in this region. VOC increased from 19.47 to 20.04 then decreased to 19.49 V while ISC increased from 0.36 to 1.19 then decreased to 0.48A. It was observed that both the FF and of a monocrystalline solar module increase with increase in air mass. The module performed better during the afternoon than morning and evening hours with the peak performance observed close to AM 1.Item Effect of Furnace Temperature on the Distribution of Tar during Gasification of Miscanthus(Journal of Energy Research and Reviews, 2018-12) Kombe, Emmanuel YeriBiomass has been extensively recognised as a clean and sustainable energy source with the highest probability to substitute fossil fuel in the energy market. Its utilisation for energy generation is of particular interest to the world at large because of its potential to reduce global carbon dioxide emission. Concerning these considerations, gasification technology comes to the forefront of biomass conversion to various forms of energy for some reasons. Primarily, gasification offers a high flexibility in utilising different kinds of biomass feedstock to produce a combustible gas, making it more active process than pyrolysis and direct combustion. However, the major challenge associated with thermal gasification of biomass is tars and particulates formation. These compounds compromise the state of syngas, potentially harming end use systems especially those delicate to the quality of gas. In this research, tar sampling and analysis was performed based on a modified standard tar protocol followed by gas chromatography-flame ionisation detector (GC-FID) so as to quantify tar concentration in syngas produced from gasification of Miscanthus. Experiments was carried out at various furnace temperature in the range 350-650℃, with temperature enhancement, the abundance of phenolic compounds increases.Item Geothermal Energy Development in East Africa: Barriers and Strategies(Journal of Energy Research and Reviews, 2018-12) Kombe, Emmanuel Yeri; Muguthu, JosephThe East African Rift is among the most crucial regions of the world endowed with a remarkable geothermal potential. Using current technologies, East African countries have a geothermal power potential of more than 15,000 MWe. Nevertheless, the zone is still at an early stage of geothermal development with few plants producing a few hundred MWe. Among East African countries that have carried out research on geothermal resources, Kenya is leading in utilising geothermal energy resources for electricity generation. Eritrea, Uganda, Tanzania and Djibouti are at exploration stage while Malawi and Rwanda have so far not gone past geothermal resource potential record work. This study sought to address the challenges and barriers to the adoption of geothermal energy as well as the strategies to implement geothermal energy plans in East AfricaItem Wind Energy Potential Assessment of Great Cumbrae Island Using Weibull Distribution Function(Journal of Energy Research and Reviews, 2019-01) Kombe, Emmanuel Yeri; Muguthu, JosephWind energy is among the fastest growing energy generation technology which is highly preferred alternative to conventional sources of energy. The major Scottish Government target is to deliver 30% of her energy demand by 2020 from renewable sources of energy as well as meeting the emission targets as set under the Scotland Climate Change Act 2009. In this paper, wind energy potential assessment of Great Cumbrae Island was investigated. For this, a ten year mean monthly wind speed at height 50 m obtained from the National Aeronautic Space Administration (NASA) were analysed using the Weibull probability distributions to assess the wind energy potential of Great Cumbrae Island as a clean, sustainable energy resource. Results from the wind-speed model showed that Great Cumbrae Island as high wind-speed site with a mean wind speed of 7.598 m/s and having power density 483.50 W/m. The annual energy captured by four selected horizontal wind turbine models was determined. The result shows that GE 2.0 platform can capture 4.5 GWh energy in a year which is an acceptable quantity for wind energy.Item Characterization and Ranking of Various Mix Ratios of Cow, Pig and Sheep Manure(Journal of Energy Research and Reviews, 2021-04) Matwek, Sheila Chepkirui; Nyaanga, Daudi M.; Osodo, B. O.This work determined the characteristics of various mix ratios of the cow to pig to sheep manures and ranked them with help of principal component analysis (PCA). Ten mix ratios (by mass) namely 1:1:1, 3:1:1, 1:3:1,1:1:2, 2:1:1, 1:2:1, 1:1:2, 1:3:3, 3:3:1, 3:1:3 of cow, pig and sheep manures respectively were selected. Laboratory analysis was done to determine the total solid (TS) content, carbon to nitrogen ratio, pH, and volatile solid (VS) content using standard procedures. The results obtained (except that of pure feedstocks) were subjected to principal component analysis to determine the principal component scores for the mix ratios to enable ranking. The total solids content of pure cow, pig, and sheep manure were found to be 19.18%, 23.50%, and 30.35% respectively. Corresponding carbon to nitrogen ratios values were 23.68, 13.27 and 29.00, pH values were 6.50, 7.90 and 7.00 and volatile content were 88.37%, 84.57% and 80.00%. Upon mixing the three manures at various mix ratios total solid content varies from 22.28% to 26.75%. Total solids content, carbon to nitrogen ratio, pH and volatile solids content varies from 22.28% to 26.75%, 18.76 to 25.05, 7.13 to 7.56 and 85.94% to 82.59% respectively. Using the first principal component scores mix ratio 1:1:3 of cow dung, pig, and sheep manure was the top-ranked followed by 3:1:3 and the third one was 1:1:2 with scores of 2.540, 1.638, and 1.580 respectively. The 4th ranked mix ratio was 1:3:3, 5th ranked was1:1:1, 6th ranked was 2:1:1, the 7th one was 3:1:1, 8th one was 1:1:2, then 3:1:1 and lastly 1:3:1 with the scores of 0.191, -0.006, -0.147, -0.259, -1.440, -1.810 and -2.287 respectively. Higher positive scores were associated with a possibility of producing higher biogas yield possibly due to the right combination of the several parameters in the mixture while a lower score might indicate a lower gas yield due to an improper combination of parameters. It was then concluded that principal component analysis is a suitable method for selecting few mix ratios to use in anaerobic digestion among the many. It saves on time and resources due to the reduced number of experiments.Item A Comprehensive Review on Status of Solar PV Growth in Uganda(Journal of Energy Research and Reviews, 2019) Mugagga, Reuben Gad; Chamdimba, Hope Baxter NqcubeUganda is faced with a challenge of huge energy deficit just like many other developing countries in Africa. Currently, only 26.7% of the total population has access to electricity. Energy being the life – blood of any growing economy, subsequent endeavors and strategies need to be put in place in order to expand the use of renewable energies for socio-economic development and environmental sustainability. Uganda being endowed with plenty of solar energy resource, its role in achieving national ambitions of Sustainable Energy for All (SE4All) cannot be underestimated. This paper therefore reviews the growth of Solar Photovoltaics (PV) in Uganda that was birthed in the 1980’s and continues to mature steadily today contributing 4.24%(50MW) to the national grid with several un documented off – grid systems. This progress has been realized under different market segments inclusive of the pico and macro solar home systems, Institutional PV, mini-grids, telecommunications and street lighting. Notwithstanding the prevalent challenges, there are numerous existing opportunities for solar PV development consisting of the financial, environmental, Institutional and the socio-economic factors. With more government and different stakeholder engagement however, this growth in the country could be accelerated further as the costs of the technology continue to plummet.