Battery electrical vehicle (BEV) ownership has increased in recent years. There is a general concern over the life cycle of the batteries used in such vehicles. This study provides a comprehensive overview of electric vehicles, encompassing their technical evolution, autonomy, and ownership. The analysis delved into the various types of batteries utilized in these vehicles, examining the composition of their constituent materials and the mechanisms underlying their operation. Additionally, it assessed their performance in terms of energy density storage, recharge capabilities, autonomy, and prospects. A critical evaluation of electric vehicles and their internal combustion engine vehicle (ICEV) counterparts, considering the Life Cycle Assessment (LCA) criterion, was conducted. The LCA criterion encompasses emissions during the entire lifecycle, from the “cradle” to the “tank” (WTT) and the “tank” until the end of its cycle (TTW). The findings of this study indicate that BEVs consistently outperformed ICEVs in terms of greenhouse gas (GHG) emissions in all the sizes of vehicles studied.

Hydrogen storage in high-pressure tanks can be performed with different filling strategies. Many studies have been carried out on supplies with increasing pressure rates. The present work aims to carry out CFD numerical simulations, using Ansys Fluent^®, in a type 3 tank of 70 MPa normal working pressure (NWP) using a constant flow rate, to analyze the influence of inlet key parameters such as initial temperature, mass flow rate, and material properties on the evolution of temperature, pressure, and velocity. From the analysis of the results, it was possible to discover linear relationships between the increase in the total equilibrium temperature and the final hydrogen temperature, as well as a linear increasing relationship between inlet and final temperatures when the equilibrium temperature was fixed. Considering fully adiabatic walls resulted in a significant increase in temperature with no predictable pattern. The difference between total and static temperatures found in the inlet tube decreased with the decrease in mass flow rate and subsequently the Mach number. The choice of a polymer for the tank lining led to higher temperatures when compared to an aluminum lining.

The present work addresses the production of nitrogen oxides in ICEs burning hydrogen mixed with methane. A mathematical model that allows the calculation of nitrogen oxide emissions from such combustion was built; this model uses the extended chemical kinetic mechanism of Zeldovich. Numerical simulations were carried out on the production of NO, varying the following variables: proportion of H₂ to CH₄, the equivalence ratio of the reactant mixture, the compression ratio, and the engine speed. The essential purpose was to assess how NO production is affected by the mentioned variables. The main assumptions were (i) Otto cycle; (ii) instantaneous combustion; (iii) chemical equilibrium reached just at the end of combustion; (iv) the formation of NO only during the expansion stroke of pistons. Results were obtained for various proportions of hydrogen and methane, various equivalence ratios, speeds of rotation, and compression ratios of an engine. In short, the results obtained in the current work show that the lowering of the equivalence ratio leads to a lower concentration of NO; that increasing the compression ratio also lowers the concentration of NO; that NO production occurs until shortly after the beginning of the expansion stroke; and finally, that the NO concentration in the engine exhaust is not very sensitive to the H₂/CH₄ ratio in the fuel mixture.

The use of hydrogen as an alternative to fossil fuels for vehicle propulsion is already a reality. However, due to its physical characteristics, storage is still a challenge. There is an innovative way, presented in this study, to store hydrogen in conventional vehicles propelled by spark-ignition reciprocating engines and fuel cells, using hydrogen as fuel; the storage of hydrogen will be at high pressure within small spheres randomly packed in a tank, like the conventional tank of fuel used nowadays in current vehicles. Therefore, the main purpose of the present study is to assess the performance of this storage system and compare it to others already applied by car manufacturers in their cars. In order to evaluate the performance of this storage system, some parameters were taken into account: The energy stored by volume and stored by weight, hydrogen leakage, and compliance with current standards. This system is safer than conventional storage systems since hydrogen is stored inside small spheres containing small amounts of hydrogen. Besides, its gravimetric energy density (GED) is threefold and the volumetric energy density (VED) is about half when compared with homologous values for conventional systems, and both exceed the targets set by the U.S. Department of Energy. Regarding the leakage of hydrogen, it complies with the European Standards, provided a suitable choice of materials and dimensions is made.

Water is an important resource for human beings, yet there are inhabited places tormented by the scarcity of it. The present study is concerned with places where, seemingly, the best way to get water is through solar distillers. These places should have, typically, high values of solar irradiation and a lack of human and economic resources to build and operate complex equipment. A set of sites scattered around the world was chosen, and then the presumed productivity and thermal efficiency that solar distillers would have if they were installed at these places was calculated. The mathematical model used with this purpose assumes steady state operation; the values of mass of water distilled and distiller efficiency were calculated for every hour, but the results presented are annual averages. Then, an economic study was made based on local costs of construction materials for the distillers, the work force, and the prices of water to predict the payback time of solar distillers. Finally, a study on environmental impact, particularly in terms of greenhouse gas (GHG) emissions, was made to compare reverse osmosis (RO) with solar distillation. For the sites studied, typical values of annual water output are in the range of 414 dm³/m², for Évora, up to 696 dm³/m², for Faya Largeau; the minimum efficiency was found for Évora, as 11.5%, and the maximum efficiency was found for Tessalit, as 15.2%. Payback times are very high, regardless of the areas of the globe where solar distillers are implanted. Regarding the GHG emissions, solar distillation is preferable to RO.