Browsing by Author "Opoku, Richard"

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    Machine learning of redundant energy of a solar PV Mini-grid system for cooking applications
    (Solar Energy, 2023) Opoku, Richard; Adjei, Eunice A.Mensah, Gidphil; Adjei, Eunice A.; Dramani, John Bosco; Kornyo, Oliver; Nijjhar, Rajvant; Addai, Michael; Marfo, Daniel; Davis, Francis; Obeng, George Yaw; 0000-0001-8766-3402; 0000-0003-2702-6465; 0000-0002-7945-8676; 0000-0002-3640-2664; 0000-0001-8886-7853
    Solar PV mini-grids are increasingly being deployed in off-grid and island communities especially in sub-Saharan Africa (SSA) countries to meet household energy demand. However, one challenge of solar PV mini-grids for community energy supply is the mismatch between the PV energy generation and household energy demand. PV mini-grid energy generation is highest in the afternoon whilst household energy demand is highest in the mornings and evenings, but lowest in the afternoons. This mismatch creates redundant energy generation during peak sunshine hours when battery energy storage is full, leading to low profitability for mini-grid systems. In this study, four machine learning models have been applied on an installed 30.6 kW mini-grid system in Ghana to ascertain the level of the redundant energy. The study has revealed that redundant energy exists on the mini-grid, in the range of 56.98 – 119.86 kWh/day. Further analysis has shown that the redundant energy can support household cooking energy demand through sustainable thermal batteries. With the four machine learning (ML) models applied in predicting the redundant energy, the most accurate ML model, K-nearest Neighbour Regressor, had a root mean square error (RMSE) of 0.148 and a coefficient of determination (R2 ) value of 0.998.
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    Rubber seed oil: Potential feedstock for aviation biofuel production
    (Scientific African, Elsevier, 2022-10-04) Baidoo, Martina Francisca; Adjei, Eunice Akyereko; Opoku, Richard; Aidam, God’sable Sitsofe Koku
    The aviation industry is responsible for 12% of transport-related GHG emissions and 2–3% of the global GHG emissions, thus raising concerns for sustainable alternatives such as aviation biofuels. This study sought to analyze the potential of producing aviation fuel from rubber seed oil. Rubber seed oil (RSO) was extracted and the physicochemical properties investigated as well as the fatty acid composition. This result was simulated in ASPEN plus to determine the potential aviation biofuel produced using the UOP HEFA process. The study shows that the golden yellowish oil derived from rubber seed possessed a density 0.9 g/cm3 and pH of 6, refractive index of 1.48, heating value of 23.75 MJ/kg and composed of 75% area of FFA with Oleic and Linoleic acid been the most dominant. The HEFA process on ASPEN Plus showed 81% of feedstock was converted to hydrocarbons with aviation biofuel yield of 46%. It was estimated that the installation of the plant for aviation biofuel production has a total capital cost of $ 8,650,480 and a total operation cost of $ 328,728. The economic analysis shows that at a cost of USD 4/kg (USD 3.01/liter) of aviation biofuel has an Internal rate of return of 18.62% profitability of 1.18 and payback period of 14.9 years of the plant operating. This study established that rubber seed oil shows suitability and potential for sustainable aviation biofuel production.
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    The transition of Ghana’s cooling appliance sector to a circular economy via a small wins governance framework
    (Sustainable Production and Consumption, 2024-02-18) Kuhn, Sascha; Opoku, Richard; Diaba, Desmond Delali; Agyarko, Kofi A.; Never, Babette
    Air conditioning poses environmental, socioeconomic, and political challenges, especially in sub-Saharan countries such as Ghana, where almost all devices are imported. Thus far, socio-economically feasible pathways for a cooling transition to a circular economy are unclear. Drawing on qualitative interviews, field observations and survey data, this study analyses the potential of small wins governance as a pathway to sweeping system change along Ghana’s air-conditioners’ lifecycle. The research analyses the status quo and identifies potential small wins that could lead to transformative shifts in the cooling sector. Through a mixed-methods approach encompassing interviews, surveys, and field assessments, the study uncovers small wins at four stages of the air conditioner lifecycle, from (1) import, (2) retail & purchase, (3) usage & service, and (4) end-of- life management practices. For policymakers and practitioners, our results imply that they should (a) systematically encourage and reap small wins in public-private spaces in the short-term, e.g. changing the incentive structure for staff controlling imports of air conditioners, (b) adjust supporting policies as learning dynamics unfold over time (e.g., energy and refrigerant standards and labels, tax system), but (c) also keep pushing for big wins in the mid-term (e.g., constructions of a recycling plant for refrigerants in West Africa). The findings emphasize the need for a behavioural, consumer-oriented perspective for the pragmatic potential of small wins towards a circular economy. Overall, the study addresses significant gaps in the literature and suggests that bottom-up approaches may offer more success than attempting broad top-down system changes. The paper contributes to the wider discourse on social-ecological transitions and offers valuable insights for policymakers, industry stakeholders, and researchers aiming to foster sustainable practices in the cooling sector.