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Battery Energy Storage
Published in Iqbal Husain, Electric and Hybrid Vehicles, 2021
Energy content of various raw fuels or materials refers to the energy that can be extracted from it for useful work. The parameter for energy content evaluation is specific energy or energy density. Specific energy is the energy per unit mass of the energy source, and its unit is Wh/kg. For fossil fuels, the energy content refers to the calorific or thermal energy that can be extracted from it by burning. Energy content for other materials is similarly evaluated in terms of specific energy for a level comparison. Specific energies of several energy sources are given in Table 5.1. The specific energies are shown without taking containment into consideration. Specific energy of hydrogen and natural gas would be significantly lower than that of gasoline when containment is considered.
The New Energy Reality
Published in Anco S. Blazev, Energy Security for The 21st Century, 2021
Different substances have different amounts and intensities of energy stored in them. This difference is the specific energy contained in each substance, where specific energy is actually the energy density (quantity) per unit mass or volume.
Batteries
Published in S. Bobby Rauf, Electrical Engineering for Non-Electrical Engineers, 2021
Specific Energy is energy expressed on per unit mass basis. Therefore, the units for assessment of specific energy of batteries would be a conventional unit of energy per unit mass. Common unit for quantification of electrical energy is watt-hours, or Wh, often expanded to kilowatt-hours, or kWh, Megawatt-hours, or MWh, etc. Common unit for specification of battery specific energy is Wh/kg. Specific energy is also referred to as the “gravemetric energy density,” not to be confused with “energy density”—which is measured in Wh/L, as discussed later.
Development of a test method to determine the effectiveness of UVC systems on commercial cooking effluent (RP-1614)
Published in Science and Technology for the Built Environment, 2020
Meng Kong, J. Zhang, K. Han, B. Guo, Z. Liu
Concerning flammability, the overall specific energy of stack emissions and relative amounts measured will be used to assess the fuel potential energy in UVC-treated samples and un-treated ones. The specific energy is energy per unit mass (for example, J/mg), used to quantify stored heat or other thermodynamic properties and well tabulated for common species of concern in the literature. For select cooking cases, some of the UVC-treated grease samples and un-treated ones collected from the coupons can be processed with the bomb calorimeter, measuring released heat from the samples and comparing the fuel potential of the two types of samples (UVC-treated and un-treated, ASTM, 2013b, 2013a).
An overview of development and challenges in hydrogen powered vehicles
Published in International Journal of Green Energy, 2020
Seyed Ehsan Hosseini, Brayden Butler
There are countless benefits to using hydrogen instead of fossil fuels. The most notable benefits are that it is considered as an environmentally friendly fuel because it emits only H2O when used in a fuel cell (Zeng and Zhang 2010). Hydrogen, the most plentiful element, has the highest specific energy content compared to the fossil fuels (Balat and Balat 2009). Hydrogen possesses an energy yield of 122 kJ/g, which is 2.75 times larger than numerous hydrocarbon fuels (Kapdan and Kargi 2006). Energy per unit mass stored in hydrogen is about 2.6 times more than gasoline; however, hydrogen is disadvantageous because it requires approximately four times more volume for storage than gasoline when stored as a liquid, and approximately 19 times more volume when stored as a gas (Petkov, Veziroǧlu, and Of n.d.). Utilizing hydrogen as a fuel in an internal combustion engine (ICE) or fuel cell (FC) propelled vehicles is a promising direction for the future of the transportation sector. Hydrogen-fueled ICEs (H2ICEs) have low achievable efficiency of 20–25%, which is a cause for problems when considering the current hydrogen storage capabilities in both gas and liquid states. Lacking the ability to achieve driving ranges comparable to those of fossil-fueled ICE vehicles makes H2ICEs less appealing to consumers. The poor efficiency of H2ICEs and low storage capabilities combined with the lack of hydrogen refueling infrastructure makes the engine type not feasible for consumers at this time. Studies have investigated methods of improving the efficiency of hydrogen ICEs to make the application of hydrogen in ICE vehicles feasible for light- and heavy-duty vehicles. To supplement the low storage capabilities of hydrogen, some studies have investigated the use of dual-fuel fossil fuel-hydrogen ICEs. On the other hand, hydrogen FC vehicles offer more potential with the current efficiency of up to 60%; however, the use of rare-earth metals in different types of FCs increases the cost and creates a limiting factor on the manufacturability (US Department of Energy 2017a). Certain types of membranes used in fuel cells are subject to damage from using less-than-pure quality hydrogen, which shortens the lifespan of the fuel cell stack. Studies have been conducted on improving the operation and increasing the efficiency in order to improve the durability and lifespan of FCs. A hydrogen-based transportation system would drastically alter the fuel production industry and introduces several new economic challenges and opportunities (Chen et al. 2019).