Advanced Energy Technologies
Iessa Sabbe Moosa; Hussein A Kazem; Laila Masoud Rashid Al-Iessi
Abstract
Studies on renewable energy are essential topics that help find new energy sources to replace fossil sources and promote environment friendliness. Hydrogen is the most practical alternative energy carrier source that meets the mentioned purposes. The mass of hydrogen element in the Earth's water was ...
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Studies on renewable energy are essential topics that help find new energy sources to replace fossil sources and promote environment friendliness. Hydrogen is the most practical alternative energy carrier source that meets the mentioned purposes. The mass of hydrogen element in the Earth's water was calculated and found to be about 2.1×1020 kg, which is greater than the mass of the world oil reserves by about 9×105 times. In addition, essential details of water molecular arrangement were investigated in order to better understand the electrolysis of water. Also, the energy of covalent and hydrogen bonds per molecule of water was theoretically calculated and found to be about 8.17×10-19 J/molecule and 3.87×10-20 J/molecule, respectively. In the electrolysis process, two stages should be undertaken: the first stage was to break hydrogen bonds between water molecules, in which all water eclectic dipoles would align in the direction of the Applied Electric Field across the electrolysis unit. The second stage was to break water covalent bonds to generate H2 and O2 gases. Moreover, the lowest cost to generate one kg of hydrogen (0.4 $/kg) by electrolysis method using solar energy was about 0.4 $, which has already been proven, while this value was about 2.8 $/kg upon considering the average price of electricity of Oman in comparison.
Hossein Ghadamian; Hassan Ali Ozgoli; Mojtaba Baghban Yousefkhani; Foad Farhani
Abstract
Regenerative Fuel Cell (RFC) systems are used for the enhancement of sustainable energy aspect in conventional fuel cells. In this study, a photovoltaic-electrolyzer-fuel cell integrated cycle has been presented. The proposed system has been designed as a novel approach for alleviating the ...
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Regenerative Fuel Cell (RFC) systems are used for the enhancement of sustainable energy aspect in conventional fuel cells. In this study, a photovoltaic-electrolyzer-fuel cell integrated cycle has been presented. The proposed system has been designed as a novel approach for alleviating the restrictions on energy streams in the RFC systems. Modeling of the system has been performed from the mass and energy point of view, based on both theoretical and practical procedures. To generate electricity from hydrogen, a proton exchange membrane fuel cell, integrated with an electrolyzer system which works by solar energy, has been used. Optimized results of required photovoltaic area have shown significantdifferences between theoretical and practical approaches. Moreover, all efficiencies of two scenarios including total efficiency have been indicated and analyzed. The main advantage of this system in comparison with single solar systems, is generation of internal energy of about 2.3 kW for producing 1 kW electricity by the fuel cell.
Mehdi Jamali Ghahderijani; Fathollah Ommi
Abstract
In this paper, a solar based hydrogen production in the city of Tehran, the capital of Iran is simulated and the cost of produced hydrogen is evaluated. Local solar power profile is obtained using TRNSYS software for a typical parking station in Tehran. The generated electricity is used to supply power ...
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In this paper, a solar based hydrogen production in the city of Tehran, the capital of Iran is simulated and the cost of produced hydrogen is evaluated. Local solar power profile is obtained using TRNSYS software for a typical parking station in Tehran. The generated electricity is used to supply power to a Proton Exchange Membrane (PEM) electrolyzer for hydrogen production. Dynamic nature of solar power and necessity of reasonable accuracy for estimating of amount of hydrogen production leads to propose a new 1D dynamic fluid flow model for PEM electrolyzer cell simulation. The hydrogen price in this system is estimated using Equivalent Annual Worth (EAW) analysis. Although it is convenient to select a yearly useful lifetime for electrolyzer as well as solar cells in this paper an hourly lifetime is considered which allows finding the hydrogen cost based on electrolyzer operating time. Also, electrolyzer sizing is done by selecting various number of cells for each stack and alternatives are compared from performance and economic point of view. In this regards 4 cases consist of 2, 3, 4 and 5 electrolyzer cell are compared. Hydrogen price at each case is evaluated and sensitivity analysis is performed. The results represent that the system with higher efficiency is not always an economical choice. As an alternative, the electrolyzer turning off at some conditions is also investigated for possibility of extending lifetime and reducing the hydrogen price. It is found that turning off the electrolyzer under specified minimum current density (2000 A/m2) in all cases reduce the final produced hydrogen price however this price and electrolyzer size is still strongly dependent to the electrolyzer capital cost.
