Photovoltaic Systems
Williams S. Ebhota; Pavel Tabakov
Abstract
This research provides concise insights into fossil fuel consumption challenges, and the factors contributing to global warming, and evaluates the significance of photovoltaic (PV) materials in achieving net-zero-CO2 emissions. The article categorizes constraints in the development of PV cells into four ...
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This research provides concise insights into fossil fuel consumption challenges, and the factors contributing to global warming, and evaluates the significance of photovoltaic (PV) materials in achieving net-zero-CO2 emissions. The article categorizes constraints in the development of PV cells into four main areas: technical factors, leadership impact, political instability, and financial aspects. Primarily, the study delves into technical factors, focusing on the power conversion efficiency (PCE) and power density of PV cells. Theoretically, approximately 67% of solar energy is dissipated in various forms - 47% as heat, 18% as photons, and 2% in local combination loss. Commercially available mono-crystalline silicon (c-Si) and poly-crystalline silicon (poly-c-Si) PV cells typically demonstrate a range of PCEs between 15% to 22% and 13% to 18%, respectively, presenting an efficiency considerably lower than the potential maximum of 100%. The study highlights organic photovoltaic cells (OPVs) as promising third-generation PV modules due to their relatively high power conversion efficiency (HPCE) and eco-friendly attributes. However, their commercial feasibility is under scrutiny owing to constraints such as a limited lifespan, high production costs, and challenges in mass production. Ongoing research and development (R&D) in PV cell technologies aim to enhance PCE and power density, establish cost-effective production methods, and create more reliable and sustainable supply chains. Additionally, the study explores the role of nanotechnology in developing high-power conversion efficiency cells, identifies research gaps and priorities in engineered organic material PV cells, and discusses the potential of OPVs in the R&D of high-efficiency, cost-effective, and environmentally friendly PV cells.
Tide, Wave and Hydro Power
Masood Ebrahimi; Omid Rasooli; Arash Babamiri
Abstract
In the present research, a hydrokinetic turbine is designed, and evaluated technically, economically and environmentally to produce power from low velocity currents. Firstly, the hydraulic characteristics of three existing canals is investigated and the blade profile for the turbine rotor is determined ...
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In the present research, a hydrokinetic turbine is designed, and evaluated technically, economically and environmentally to produce power from low velocity currents. Firstly, the hydraulic characteristics of three existing canals is investigated and the blade profile for the turbine rotor is determined by using the Schmitz's theory and XFOIL software. The geometrical model is then created in the SolidWorks and simulated in the ANSYS Fluent to estimate the power generation capacity. According to the results, a correlation is proposed to estimate the power generation by the turbine in different water velocities. The results are validated with the manufacturers data. The results show that the efficiency of the proposed turbine is almost 90%, the investment payback period is only 3.1 years, with a positive net present value. Environmentally, it shows that for a 1 meter in diameter turbine and water velocity of 1.5 m/s, carbon dioxide will reduce by 0.57 tons per year. The economic and environmental benefits improve greatly at higher water velocities. The results show that the proposed hydrokinetic turbine even by working in low velocity stream can supply electricity demand of rural area near the canals for the long lifespan of the turbine which is more than 25 years.
Geothermal Energy Systems
Hiba Mudhafar Hashim; Firas ABED
Abstract
Geothermal energy is one of the important sources of renewable energy, so researchers are greatly interested in this type of energy. One of the advantages of this type of energy is its use to heat or cool buildings because the ground temperature is fairly constant throughout the year. The research focuses ...
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Geothermal energy is one of the important sources of renewable energy, so researchers are greatly interested in this type of energy. One of the advantages of this type of energy is its use to heat or cool buildings because the ground temperature is fairly constant throughout the year. The research focuses on understanding how soil depth affects the temperature difference, the rate of heat transfer, and the overall performance of the system in Baghdad, Iraq, throughout the year by conducting a mathematical test for the ground heat exchanger and determining the number of appropriate requirements during the study to reach an equation that simulates the distribution of temperatures at depth and time. The software package (CFD ANSYS FLUENT) version 17 was used for numerical analysis. The results showed that the heat transfer rate from air to soil for cooling purposes reached its highest value of -1375 watts during July at a depth of 6 m. As for heating purposes, the maximum value during January reached 579 watts at a depth of 10 m and 499 watts at a depth of 6m. Earth air heat exchanger effectiveness was highest possible at depths of 4 and 5 m, ranging from 0.9 to 0.92 over the year. The highest value of 0.98 for the exchanger effectiveness appeared during March. The results showed good agreement between the mathematical and numerical analysis and comparison with other studies, as the percentage of deviation ranged from 1.7% to 3.6% for depths from 1 m to 10 m.
Photovoltaic Systems
Niti Agrawal
Abstract
Partial shading condition (PSC) has a detrimental effect on the output performance of a photovoltaic (PV) system. The output performance of a partially shaded PV array depends not only on the pattern, intensity and location of the shadow but also on its configuration. In this paper, the output performance ...
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Partial shading condition (PSC) has a detrimental effect on the output performance of a photovoltaic (PV) system. The output performance of a partially shaded PV array depends not only on the pattern, intensity and location of the shadow but also on its configuration. In this paper, the output performance of two configurations namely- series-parallel (SP), a commonly used configuration, and total-cross-tied (TCT), have been compared under diverse PSCs. A Lambert W-function-based technique has been developed to model, simulate and estimate the performance of both the configurations of the PV array. The developed program can evaluate the current, voltage and power for the arrays of different sizes under uniform and different PSCs. A detailed investigation has been carried out for the output performance of both configurations under nine diverse shading patterns and different sizes of arrays. Comparative analysis for the configurations is presented based on parameters such as maximum power obtained, partial shading power loss percentage, efficiency and fill factor. It has been found from the obtained results that the output performance of a PV array under PSC is enhanced by using TCT configuration compared to SP configuration.
Photovoltaic Systems
Christopher T Warburg; Tatiana Pogrebnaya; Thomas Kivevele
Abstract
This study delves into the ongoing discourse surrounding the optimal tilt angles for solar panels to maximize solar PV power generation. Focused on seven equatorial regions in Tanzania; Dodoma, Dar es Salaam, Kilimanjaro, Kigoma, Iringa, Mtwara, and Mwanza. Multiple mathematical models are employed to ...
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This study delves into the ongoing discourse surrounding the optimal tilt angles for solar panels to maximize solar PV power generation. Focused on seven equatorial regions in Tanzania; Dodoma, Dar es Salaam, Kilimanjaro, Kigoma, Iringa, Mtwara, and Mwanza. Multiple mathematical models are employed to ascertain the most efficient panel tilts. Leveraging solar radiation data spanning from 2000 to 2017, we developed an algorithm specifically tailored for computing suitable tilt angles in the southern hemisphere. Our investigation reveals compelling insights into the variation of optimal panel tilts throughout the year. Notably, the monthly optimal tilt angles fluctuate significantly across the regions. June emerges as the month with the highest recorded monthly optimal tilt angle, ranging from 45 degrees in Mtwara to 31 degrees in Kilimanjaro. Conversely, December showcases the lowest tilt angles, spanning from -30 degrees in Mwanza to -26 degrees in both Kigoma and Iringa. Quarterly angles exhibit peaks during the second quarter of the year, reaching 39 degrees in Mtwara and 27 degrees in Kilimanjaro, while experiencing declines in the fourth quarter, plunging to levels between -19 and -24 degrees. Additionally, our study calculates annual optimal tilt angles, revealing a range from 2 degrees in Kilimanjaro to 11 degrees in Mtwara. Crucially, the deployment of monthly optimally tilted solar PV panels demonstrates a noteworthy enhancement, yielding a 6-11% gain in solar radiation compared to horizontally mounted panels. Our study advocates for the adoption of dynamic tilt adjustment strategies of periodic angle alterations to maximize solar PV power generation.