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Hydrogen and Fuel Cells
Published in Muhammad Asif, Handbook of Energy Transitions, 2023
Saeed-ur-Rehman, Hafiz Ahmad Ishfaq, Zubair Masaud, Muhammad Haseeb Hassan, Hafiz Ali Muhammad, Muhammad Zubair Khan
Compressed gas is the most common method of hydrogen storage. In this mode of storage, challenges are faced due to the low density of hydrogen gas. For laboratory and industrial applications, the hydrogen gas is compressed to a maximum of 20 MPa; however, the hydrogen tanks for mobile applications can store gas from 35 to 70 MPa. Compressed gas is an efficient way of storing hydrogen because the volumetric density of hydrogen can be increased by increasing the pressure of the gas. Most commonly, metallic containers are used for industrial applications with pressure from 20 to 30 MPa but these containers can contain only up to 1 wt. % of hydrogen (Type 1). For producing lightweight cylinders, part of the cylinder is replaced with fiber resin composite (Type 2). Metallic part is further reduced by using carbon fiber embedded polymer matrix with a thin metallic liner (Type 3). Complete polymer cylinders are also suggested for lightweight applications (Type 4). As there is always a risk of gas leakage when stored at such high pressures, for compressed hydrogen storage, the cylinder material must have a high tensile strength, low density, and it should not be permeable to hydrogen.
Fuels and other energy sources
Published in Allan Bonnick, Automotive Powertrain Science and Technology, 2020
Compressed hydrogen may be stored on a vehicle and used in an internal combustion engine. Among the advantages claimed for it are no carbon dioxide emissions and products of combustion that are primarily water. The main future use of hydrogen as a propellant for vehicles is thought to be as a source of energy in fuel cells. The electricity produced in the fuel cell is used as a power source for the electric motor that replaces the internal combustion engine of the vehicle. A simple fuel cell is shown in Figure 9.2. The fuel cell consists of two electrodes, an anode and a cathode, that are separated by an electrolyte. Hydrogen passes over hydrogen acts on the anode and oxygen from the atmosphere acts on the cathode. The catalytic action of the anode causes the hydrogen atom to form a proton and an electron. The proton passes through the polymer electrolyte to the cathode, and the electron passes through an external circuit to the cathode. This action provides an electric current in external circuit. In the process the hydrogen and oxygen combine to make water which is the principal emission.
Fuels and combustion & emissions
Published in Allan Bonnick, Automotive Science and Mathematics, 2008
Compressed hydrogen may be stored on a vehicle and used in an internal combustion engine. Among the advantages claimed for it are that there are no carbon dioxide emissions and that the products of combustion are primarily water. The main future use of hydrogen as a propellant for vehicles is thought to be as a source of energy in fuel cells. The electricity produced in these cells is used as a power source for an electric motor replacing the internal combustion engine of the vehicle. A simple fuel cell is shown in Figure 16.8. It consists of two electrodes, an anode and a cathode, that are separated by an electrolyte. Hydrogen acts on the anode and oxygen from the atmosphere acts on the cathode. The catalytic action of the anode causes the hydrogen atom to form a proton and an electron; the proton passes through the polymer electrolyte to the cathode and the electron passes through an external circuit to the cathode. This action provides an electric current in external circuit. In the process the hydrogen and oxygen combine to produce water, which is the principal emission.
Reviews of fuel cells and energy storage systems for unmanned undersea vehicles
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2020
Jun Lu, Tian Tang, Chao Bai, Huizhong Gao, Junguang Wang, Cheng Li, Yuke Gao, Zhaoyuan Guo, Xiao Zong
Compressed hydrogen is the simplest and least expensive solution to hydrogen storage (Baumert and Epp 2002). Due to its low density, high pressures are usually applied (up to 70 MPa) so as to maximize hydrogen content. At 70 MPa and 20°C, the theoretical energy density of compressed hydrogen is 1.26 kWh/L. In order to reduce the weights, state-of-the-art hydrogen tank is usually made of composite fiber. For instance, Figure 9 shows the high-pressure hydrogen tank developed by Toyota, which has been successfully applied in MIRAI fuel cell automobiles (Yamashita et al. 2015). The high-pressure hydrogen tank is made up of a plastic liner, the carbon fiber reinforced plastic (CFRP) layer and glass fiber reinforced plastic (GFRP) from the inner to the outer layer, and bosses at the two ends. The plastic liner encapsulates hydrogen gas, and the CFRP inner layer bears the high pressure of 70 MPa. This is surrounded by the GFRP layer with high impact resistance, and drop protectors. The weight of the tank is reduced by improving the CFRP layer and reducing the amount of material used. As a result, the tank achieves a weight effectiveness of 5.7 wt%.
An overview of development and challenges in hydrogen powered vehicles
Published in International Journal of Green Energy, 2020
Seyed Ehsan Hosseini, Brayden Butler
The most favorable method of hydrogen storage is physical containment, specifically compressed tanks, because they are readily available (Jorgensen 2011). The fill time of these tanks is competitive with fossil fuels when the hydrogen is pre-cooled (Maus et al. 2008). Cost is the main setback for the wide scale use of compressed hydrogen (CH2) tanks because the material and assembly are expensive. Another potential setback is the public’s concern of using such high pressure (70 MPa) storage tanks in vehicles. An alternative to traditional CH2 tanks that is still being researched is a tank with an internal skeleton, which is a complex design of struts in tension within the tank to resist the forces of the compressed hydrogen (Aceves et al. 2006). Liquid hydrogen (LH2) storage has improved significantly, achieving the best specific mass (15%) of other onboard hydrogen storage systems (Fieseler and Allidiers 2006). Energy efficiency is decreased when liquid hydrogen is used. To widely develop LH2 systems, the boil off property should be improved. A promising alternative design is a cryo-compressed tank in which hydrogen is highly compressed at cryogenic temperatures. More studies must be done on this method to determine long-term durability and public acceptance of the system. Hydride storage systems require substantial research and progress to meet the requirements for large-scale use. The most well studied hydride is NaAlH4, but it does not have the capacity necessary for application. Based on the results of the few studies, it is indicated that tanks with no internal heat transfer elements could be constructed based on the moderate heat of absorption of hydrogen on surfaces (Paggiaro et al. 2010).