Masters Degrees (DPCMS)

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Browsing Masters Degrees (DPCMS) by Advisor "Chiguvare, Zivayi"

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    Hydrogen purity assessment using laser absorption Spectroscopy
    (University of Namibia, 2025) Shilongo, Rosamunde P.; Chiguvare, Zivayi
    Hydrogen purity assessment is a critical concern in energy applications, especially in fields involving hydrogen injection into natural gas pipelines and fuel cell research. This study addresses the limitations of current hydrogen measurement techniques by developing a novel hydrogen spectrometer (𝐻2-Spectrometer) based on direct Tunable Diode Laser Absorption Spectroscopy (d-TDLAS). The goal is to establish a traceable and accurate methodology for hydrogen purity and concentration measurement without relying on calibration gases. The main objective of this research is to develop and evaluate the performance of the 𝐻2-Spectrometer, specifically investigating its suitability for measuring hydrogen purity and hydrogen concentration in methane hydrogen mixtures. The study also aims to support hydrogen injection into natural gas pipelines by providing precise hydrogen concentration measurements. An experimental design was employed, utilizing the 𝐻2-Spectrometer to measure hydrogen line intensity and concentration. The measurements were taken for 99.999% pure hydrogen and hydrogen-methane gas mixtures to test the spectrometer’s accuracy and reliability. The obtained data were compared against reference values from the HITRAN database and the certificate from the reference gas mix to evaluate performance. The findings revealed that the 𝐻2-Spectrometer demonstrated a significantly lower uncertainty of 1.6% in hydrogen line intensity measurements, compared to the 10% uncertainty reported in the HITRAN database. The measured line intensity obtained was 3.22 × 10−26 cm/molecule, which is slightly higher than the HITRAN value of 3.189 × 10−26 cm/molecule. In terms of hydrogen concentration, the spectrometer achieved an average mole fraction of 0.858 with a 1% uncertainty, closely aligning with the expected value of 0.900 as per the certificate from the reference gas mix with a 2% uncertainty. The 𝐻2 Spectrometer proved to be highly accurate and reliable, with potential applications in hydrogen quality control from electrolysis, fuel cell research, process control, and environmental monitoring. Its ability to provide traceable and precise measurements makes it a valuable tool for hydrogen-related research, optimizing system performance and ensuring compliance with regulatory standards
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    Viability of substitution of electricity with biogas for thermal uses at Neudamm campus of the University of Namibia
    (University of Namibia, 2025) Tomas, Pineas Panduleni; Chiguvare, Zivayi
    The growing demand for sustainable and affordable energy solutions in rural areas has led to increased interest in biogas technology, particularly in developing regions. This thesis presents the design and evaluation of a low-cost biogas digester for the Neudamm Campus of the University of Namibia. The study adresses the campus's energy cost and the underutilisation of livestock manure as a renewable energy resource. A 100 L digester, constructed from locally available materials, was fed with a cow manure-water slurry and operated over a 60-day period. Key operational parameters included an estimated 30-day hydraulic retention time, with pressure monitored three times daily in the first week, twice daily from Days 8–21, and once daily thereafter.. The digester achieved an average daily biogas yield of 0.95 L, equivalent to 7.61 MJ (2.11 kWh). Based on manure availability at Neudamm (22.2 tonnes/day), the system could theoretically produce 318.76 L/day of biogas. This represents a payback period of 2.5 years and an estimated 594% return on investment over a 10-year lifespan. The gas produced was sufficient to substitute part of the campus’s electricity demand for cooking and water heating, demonstrating both economic and environmental benefits, including reduced greenhouse gas emissions and nutrient-rich slurry for fertilizer. The study acknowledges limitations such as short monitoring duration, reliance on pressure as the sole gas measurement, and minor leakage issues. ii Despite these constraints, the study demonstrates the feasibility of low-cost, small scale digesters in Namibia and provides a replicable model for rural settings. The findings contribute to renewable energy knowledge in Southern Africa and highlight practical opportunities for integrating biogas into campus and farm operations