Browsing by Author "Omosa,Isaiah"
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Item Design and Performance of a Gravity Water Fed In-DuctCrossflow Turbine for Hydropower Generation(John Wiley & Sons Ltd., 2025-08) Kitetu,Job; Thoruwa,Thomas F. N.; Omosa,IsaiahIn Kenya, 70% of households are connected to the grid; however, the consumption of electricity, among households, has reduced by 30%. To address power accessibility inadequacy, especially in rural areas, and develop an appropriate in-duct hydropower (HP) generation system, several horizontal crossflow turbine prototypes were designed based on the field survey data collected from existing pressurized water supply ducts. An assessment carried on water supply schemes in Makueni County led to gathering and mapping required data that included; pipelines of diameters ranging from 50 to 200 mm, water pipe slopes of lengths ranging from 40 to 800 m, slope elevation heads between 14 and 183 m, and 33 potential HP sites with HP production capacity between 0.59 and 23.63 kilowatts. Various horizontal crossflow turbines were designed, fabricated, and tested for HP generation performance. The designed horizontal crossflow turbine has specifications that include a 0.99 mm diameter (Do) impeller that rotates clockwise, 12.5 mm blade radius of curvature, 0.7033 turbine efficiency, turbine inner diameter of 30 mm (D30), 10 blades (B10), 100 mm diameter pipe, turbine speed of 2210 revolutions per minute (RPM) and production of 5.92 V at a head of 6 m hence making a turbine designed and designated as D30B10. It provides savings on power cost to the extent that in 7.5 years’ time, an institution would have saved enough funds to install a new station. On the basis of these findings, it was concluded that in-duct power generation technology is a promising energy harvesting system for rural communities. HP from ducts provides a paradigm shift to the rural communities’ source of energy and its use, hence reducing the use of firewood for cooking, which is at 89% and effectively reducing deforestation. More studies are recommended to prototype a full-scale product of the D30B10 turbine to improve technologies for harnessing HP from existing gravity water ducts.Item Determination of the Physiochemical Characteristics of Hotel Food Waste and Its Biogas Fuel Potential(CIGR, 2025) Chamdimba,Hope B.; Omosa,Isaiah; Wandera, Simon M.Hotels are the source of large quantities of food waste, which can potentially be used for the generation of biogas for different applications, including agriculture. Thus, the purpose of this study was to investigate the physiochemical characteristics and biogas potential of the food waste generated by hotels in Nairobi City County, Kenya. To achieve this, a composition and physiochemical analysis of the feedstock were undertaken, which involved collecting and analysing a food waste sample of 130 kg, which gives an accuracy the same as that of a 1000 kg sample, according to the literature. In addition, the theoretical biomethane potential of food waste was determined using the Buswell and Carbon Balance equations, and the theoretical results were validated using anaerobic digestion experiments. The analysis showed that the fractions of different FW groups were fruits and vegetables (46%), roots and tubers (17%), meat and fish (14%), grains and cereals (9%), others (8%), bakery (4%), and tea and coffee (2%). The hotel food waste total solids, volatile solids, pH, COD, carbohydrates, and protein contents were determined to be 9.6%, 8.81%, 4.65, 142.3 g L-1, 70%, and 13%, respectively. The C, H, O, N, and S compositions of the FW were 48.46%, 9.8%, 30.48%, and 2.2%, respectively. The test results showed that, based on these physiochemical characteristics, the hotel food waste had a theoretical methane yield of 643.07 mL gVS-1 and an experimental methane yield of 518.53 ± 9.69 mL gVS-1. The experimental yield was almost equal to an average biomethane potential of food waste (i.e., 525.65 CH4 ml gVS-1) based on the results of the other similar studies. Therefore, the hotel food waste can be used as an alternative feedstock for biogas generation if it is properly secured by, among other things, promoting onsite segregation of the hotel food waste.Item Energy Needs within the Rural Community in Makueni County, Kenya(Society of Chemical Industry and John Wiley & Sons Ltd., 2024) Kitetu,Job; Thoruwa,Thomas; Omosa,IsaiahLiterature shows that only 56% of Kenyan households had access to electricity,with rural areas having the lowest access rate at percent. The high cost ofextending the power grid to remote areas and power losses on distribution aresignificant challenges facing rural electrification. In addressing power accessibil-ity problems, especially in rural areas, there is a need for tapping hydropowergeneration through the invention and implementation of in‐duct turbines tomaximize the utilization of already existing pressurized water ducts that supplywater in various parts of Kenya for hydropower generation. Makueni County isendowed with gravity‐fed water ducts with high potential for hydropower whichcan innovatively be produced by application of in‐duct turbines. This paperfocuses on the assessment of energy needs and applications in rural areas. Theresearch design was exploratory and experimental in nature. It was exploratorybecause, through an assessment, it sought to explore and identify the potentialareas within the water supply lines for the production of hydropower to supplyhydropower in Makueni County. It was experimental because the researcherdeveloped (designed and fabricated) a hydro turbine for use in the production ofhydropower from gravity water ducts of a diameter raging 100 mm. The researchrevealed that 62% (98) used solar power for lighting their homes, while 17% (28),12% (20), and 8% (12) used lanterns, electricity, and kerosene lamps, respectively.Among the fuels assessed was firewood which was identified as the most usedfuel at 89% (140). This was followed at a distance far by paraffin at 6% (9) ofrespondents. The households at 100% (158) identified electricity as a potentialsource of lighting for their household. The study recommends harnessinghydropower to enhance reach to 100% of the rural communities. The energyavailability will provide opportunities for communities and institutions in ruralareas to open their minds to business development and engage in income‐generating activities like the rearing of poultry and the development of lightindustries like the gridding of maize and other cereals