Within the Flexnode Plus project the long-term degradation characteristics of a proton exchange membrane (PEM) electrolyzer (5.5 kW, AC, 1 Nm3/h H2) and fuel cell (1.0 kW, DC, 0.9 Nm3/h) was experimentally tested. The electrolyzer unit was operated at various loads and pressures for approximately 750 hours in total, while the fuel cell was operated at a constant load of 1 Ω resistance for approximately 1120 hours in total. The efficiency of the hydrogen production in the electrolyzer and the electricity production in the fuel cell was expressed using the hourly average system efficiency and average cell efficiency. Inorder to predict the state of health and remaining lifetime of the electrolyzer cell and fuel cell, the decay of the cell voltage over time was monitored and the direct mapping from aging data method was used.The electrolyzer cell showed a stable cell voltage and cell efficiency in the studied time period, with an average cell voltage decay rate of 0.5 μV/h. The average cell voltage of the fuel cell dropped with a rate of 2 μV/h during the studied time period.
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Problems of energy security, diversification of energy sources, and improvement of technologies (including alternatives) for obtaining motor fuels have become a priority of science and practice today. Many scientists devote their scientific research to the problems of obtaining effective brands of alternative (reformulated) motor fuels. Our scientific school also deals with the problems of the rational use of traditional and alternative motor fuels.This article focused on advances in motor fuel synthesis using natural, associated, or biogas. Different raw materials are used for GTL technology: biomass, natural and associated petroleum gases. Modern approaches to feed gas purification, development of Gas-to-Liquid-technology based on Fischer–Tropsch synthesis, and liquid hydrocarbon mixture reforming are considered.Biological gas is produced in the process of decomposition of waste (manure, straw, grain, sawdust waste), sludge, and organic household waste by cellulosic anaerobic organisms with the participation of methane fermentation bacteria. When 1 tonne of organic matter decomposes, 250 to 500–600 cubic meters of biogas is produced. Experts of the Bioenergy Association of Ukraine estimate the volume of its production at 7.8 billion cubic meters per year. This is 25% of the total consumption of natural gas in Ukraine. This is a significant raw material potential for obtaining liquid hydrocarbons for components of motor fuels.We believe that the potential for gas-to-liquid synthetic motor fuels is associated with shale and coalfield gases (e.g. mine methane), methane hydrate, and biogas from biomass and household waste gases.
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For long flights, the cruise is the longest phase and where the largest amount of fuel is consumed. An in-cruise optimization method has been implemented to calculate the optimal trajectory that reduces the flight cost. A three-dimensional grid has been created, coupling lateral navigation and vertical navigation profiles. With a dynamic analysis of the wind, the aircraft can perform a horizontal deviation or change altitudes via step climbs to reduce fuel consumption. As the number of waypoints and possible step climbs is increased, the number of flight trajectories increases exponentially; thus, a genetic algorithm has been implemented to reduce the total number of calculated trajectories compared to an exhaustive search. The aircraft’s model has been obtained from a performance database, which is currently used in the commercial flight management system studied in this paper. A 5% average flight cost reduction has been obtained.
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Electronic book. Book of Abstracts of the 26th International Public Relations Research Symposium BledCom on the theme Trust and Reputation. Trust is a foundation of social (and organizational) order and also serves as the underpinning of healthy relationships, exchanges and transactions. There is a growing concern globally that social and organizational trust is eroding, and that it has become harder for organizations to build and protect relationships with stakeholders many of whom themselves seem to be in conflict. Digitalization and globalization have contributed significantly to changing the world order, leaving many people confused, disoriented and perhaps even scared.
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Densely populated areas are major sources of air, soil and water pollution. Agriculture, manufacturing, consumer households and road traffic all have their share. This is particularly true for the country featured in this paper: the Netherlands. Continuous pollution of the air and soil manifests itself as acification, decalcification and eutrofication. Biodiversity becomes lower and lower in nature areas. Biological farms are also under threat. In case of mobility, local air pollution may have a huge health impact. Effective policy is called for, after high courts blocked construction projects, because of foreseen building- and transport-related NOx emissions. EU law makers are after Dutch governments, because these favoured economics and politics over environmental and liveability concerns. But, people in the Netherlands are strongly divided. The latest provincial elections were dominated by environmental concerns, next to many socio-economic issues. NOx and CO2 emissions by passenger cars are in focus. Technical means and increasing fuel economy norms strongly reduced NOx emissions to a still too high level. A larger number of cars neutralized a technological reduction of CO2 emissions. The question is: What would be the impact of a drastic mandatory reduction in CO2, NOx, and PM10 emissions on car ownership and use in the Netherlands? The authors used literature, scenario analysis and simulation modelling to answer this question. Electric mobility could remove these emissions. Its full impact will only be achieved if the grid-mix, which is still dominated by fossil fuels, becomes green(er), which is a gradual, long-term, process. EVs compete with other consumers of electricity, as many other activities, such as heating, are also electrifying. With the current grid-mix, it is inevitable that the number of km per vehicle per year is reduced to reach the scenario targets (−25% resp. −50% CO2 emissions by cars). This calls for an individual mobility budget per car user.
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Ending subsidies for fossil fuel heating systems from 2025, and phasing out gas boilers and other fossil fuel heaters by 2040. These are just two of the outcomes of a political agreement between the EU Council and the European Parliament, which was reached on December 7, 2023. Which measures were agreed upon, and what will the implications be for the heating sector?
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In this study, aviation, energy, exergy, environmental, exergoeconomic, and exergoenvironmental analyses are performed on a CFM56-3 series high by-pass turbofan engine fueled with Jet-A1 fuel. Specific fuel consumption and specific thrust of the engine are found to be 0.01098 kg/kN.s and 0.3178 kN/kg/s, respectively. Engine's energy efficiency is calculated as 35.37%, while waste energy ratio is obtained as 64.63%. Exergy efficiency, waste exergy rate, and fuel exergy waste ratio are forecasted as 33.32%, 33175.03 kW, and 66.68%, respectively. Environmental effect factor and ecological effect factor are computed as 2.001 and 3.001, while ecological objective function and its index are taken into account of −16597.22 kW and −1.001, respectively. Exergetic sustainability index and sustainable efficiency factor are determined as 0.5 and 1.5 for the CFM56-3 engine, respectively. Environmental damage cost rate is determined as 519.753 $/h, while the environmental damage cost index is accounted as 0.0314 $/kWh. Specific exergy cost of the engine production is found as 40.898 $/GJ from exergoeconomic analysis, while specific product exergy cost is expressed as 49.607 $/GJ from exergoenvironmental analysis. From exergoenvironmental economic analysis, specific exergy cost of fuel is computed as 10.103 $/GJ when specific exergy cost of production is determined as 40.898 $/GJ.
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