With the advancement of data-acquisition systems, information technology, and network technologies, the energy and power system has entered the deep integration of the cyber and physical sides as known as cyber-physical energy and power system (CPEPS) leading to more attention from researchers and practitioners in industry. The feedback loops in which physical processes affect cyber parts and vice versa, therefore, can gain greater efficiency, resilience, and intelligence through the data exchange process between two layers. The concept of CPEPS has been existed for a long time and its applications are gradually increasing in the real world, however, there has been still many potential risks and challenges in the research and development process. Simulation method is a common and simple approach for the purpose of analyzing, evaluating, and considering solutions before actual implementation. For this purpose, this paper provides first the framework of CPEPS, and current applications an... [more]

The design of AC filters must meet the criteria of harmonic distortion mitigation and reactive power support in various operating modes. The stringent reactive power-sharing requirements currently lead to sophisticated filter schemes with high component ratings. In this regard, triple-tuned filters (TTFs) have good potential in harmonic mitigation of a broad range of harmonics. In the literature, the TTF design has been presented using a parametric method, assuming that the TTF is equivalent to a three-arm single-tuned filter (TASTF). However, no direct methods of designing it or finding its optimal parameters have been provided. This paper presents novel mathematical designs of TTFs. Three different design methods are considered—the direct triple-tuned filter (DTTF) design method, as a TASTF, and a method based on the equivalence between the two design methods called the equivalence hypothesis method to design the triple-tuned filter (EHF). The parameters of the three proposed design... [more]

Liquid hydrogen has been studied for use in vehicles. However, during the charging process, liquid hydrogen is lost as gas. Therefore, it is necessary to estimate and reduce this loss and simulate the charging process. In this study, the initial charging process of a vehicle liquid hydrogen tank under room temperature and atmospheric pressure conditions was numerically investigated. A transient thermal-fluid simulation with a phase-change model was performed to analyze variations in the volume, pressure, mass flow rate, and temperature. The results showed that the process could be divided into three stages. In the first stage, liquid hydrogen was actively vaporized at the inner wall surface of the storage tank. The pressure increased rapidly, and liquid droplets were discharged into the vent pipe during the second stage. In the third stage, the mass flow rates of liquid and hydrogen gas at the outlet showed significant fluctuations, owing to complex momentum generated by the evaporatio... [more]

The worldwide population growth and the technological advancements reported in the past few years have led to an increase in the production and consumption of energy. This has increased greenhouse gas (GHG) emissions, the primary driver of climate change. As a result, great attention has been paid to sustainable and green energy sources that can replace or reduce reliance on non-sustainable energy sources. Among the different types of renewable energy sources currently available, bioenergy has been reported as an attractive resource mainly due to its low cost and great availability. Bioenergy can be produced from different biomass sources and converted into biofuels or value-added products through thermochemical, biochemical, and chemical processes. Gasification is a thermochemical process commonly used for bioenergy production, and it is particularly attractive mainly due to its high efficiency. However, its performance is influenced by parameters such as type of feedstock, size of bi... [more]

Polyvinylidene fluoride and its copolymers can be used as active materials for energy harvesting and environmental sensing. Energy harvesting is one of the most recent research techniques for producing stable electrical energy from mechanical sources. Polyvinylidene fluoride−trifluoroethylene (PVDF-TrFE) is applicable for sensors and self-powered devices such as medical implants and wearable electronic devices. The preparation of electrospun P(VDF-TrFE) nanofibers is of great interest for the fabrication of sensors and self-powered devices, nanogenerators, and sensors. In this regard, it is necessary to investigate the effects of various parameters on the morphology and piezoelectric output voltage of such nanofibers. In this study, we have examined the effect of concentration and feed rate on the nanofiber diameter. It has been found that by increasing the concentration and feed rate of the polymer solution, the diameter of the nanofibers increases. The experimental results and the fi... [more]

Combining biomass-fired power generation with CO2 capture and storage leads to so-called negative CO2 emissions. Negative CO2 emissions can already be obtained when coal is co-fired with biomass in a power plant with CCS technology. The need for bioenergy with CO2 capture and storage has been identified as one of the key technologies to keep global warming below 2 °C, as this is one of the large-scale technologies that can remove CO2 from the atmosphere. According to the definition of bioenergy with CO2 capture and storage, capturing and storing the CO2 originating from biomass, along with the biomass binding with carbon from the atmosphere as it grows, will result in net removal of CO2 from the atmosphere. Another technology option for CO2 removal from the atmosphere is direct air capture. The idea of a net carbon balance for different systems (including bioenergy with CO2 capture and storage, and direct air capture) has been presented in the literature. This paper gives a background... [more]

For gas reservoirs that contain water, investigating characteristics of water−gas seepage is crucial to the formulation of gas field development plans and predicting the production capacity and water breakthrough of gas wells. For the purposes of such an investigation, the process of water invasion into a water-containing gas reservoir was studied based on four sandstone samples whose physical properties differed quite vastly (permeability: 0.112−192.251 mD; porosity: 8.33−20.60%). Gas−water relative permeability experiments were conducted on the gas-driven water in the reservoir conditions (temperature: 135 °C; pressure: 75 MPa). Starting with the sandstone samples’ microstructural characteristics, particular attention was paid to the impacts of throat radius and clay content on the water−gas seepage characteristics. It was found that the basic physical properties, microscopic characteristics, and mineral composition of the sandstone samples all affected the water−gas seepage characte... [more]

The Late Paleozoic is an important epoch of coal-bed accumulation in the North China, particularly in its western segment, where a world-class coal field has been found and exploited for three decades. Coal-bearing layers recorded rapid Late Carboniferous to Early Permian sea-level rise that led to the evolution of the shallow marine tidal flat basin, followed by regression that resulted in the formation of deltaic facies. However, little attention has been paid to the tectonic factors that assisted in the coal accumulation processes, which have been demonstrated worldwide to be pivotal. In this study, we evaluate the significant influence of southward subduction of the middle segment of the Paleo-Asian Ocean (PAO) during Carboniferous to Early Permian deposition of coal-bearing neritic to deltaic successions in the western North China Block (NCB). We pinpoint a direct link between basin-filling evolution of the northwestern Ordos Basin and the progressive uplift of the Inner Mongolia... [more]

The number of international collaborations in research and development (R&D) has been increasing in the energy sector to solve global environmental problems—such as climate change and the energy crisis—and to reduce the time, cost, and risk of failure. Successful international project planning requires the analysis of research fields and the technology expertise of cooperative partner institutions or countries, but this takes time and resources. In this study, we developed a method to analyze the information on research organizations and topics, taking advantage of data analysis as well as deep learning natural language processing (NLP) models. A method to evaluate the relative superiority of efficient international collaboration was suggested, assuming international collaboration of the National Renewable Energy Laboratory (NREL) and the Korea Institute of Energy Research (KIER). Additionally, a workflow of an automated executive summary and a translation of tens of web-posted article... [more]

Poland has a large potential for biogas production from agricultural sources and food waste. This potential is still poorly used. There are many reasons for this state of affairs. We can indicate both the policy of the state towards renewable energy sources (RES) with a small amount of energy from biogas contracted at auctions, investment risk, and especially low return on investment in the absence of investment support. An important reason is also the limited state budget. The purpose of this work was to determine the endogenous factors that determine ROE, the direction of the impact of these factors, as well as the strategy of biogas plants in shaping the ROE level. The DuPont model was used in the analysis of ROE changes. We used the deviation method to determine the impact of the various factors on ROE. Against the background of the energy sector in Poland, the value of ROE in the examined biogas plants should be considered satisfactory, and in 2020 it was, on average, 13.9%. The d... [more]

The lubricating oil industry is widespread in the world, but getting rid of the used oils has become an environmental concern. Lubricating oils are used in industries and cars but potentially contaminate groundwater after use. This research uses montmorillonite clay to refine old oil treated with acetic acid. Compared to more conventional procedures, the suggested strategy for treating waste oil is more cost-effective due to the relatively inexpensive cost of the acid and the modest process conditions. Water content, sediment content, density, flash and fire points, viscosity, viscosity index, total acid and base number, pour points, and refractive index were among the physicochemical parameters of the treated oil that were examined as a result of this treatment. We analyzed the oils using Fourier transform infrared spectroscopy (FTIR) and atomic absorption spectrometry (AAS). New oil (10w 40), old oil, oil treated with acetic acid, and montmorillonite clay were all put through their p... [more]

The Galapagos Islands have been declared a World Heritage site due to their unique biodiversity, which makes them a living museum and a natural laboratory for humankind. However, to fulfill the energy needs of its habitants and foreign visitors, the islands have depended on fossil fuel energies that have produced levels of lead and chemical agents that are affecting the islands’ air quality, flora, and fauna. Therefore, zero-carbon initiatives have been created to protect the islands, wherein solar and wind power plants have been studied as reliable alternatives. In this way, Geographical Information Systems based on Multicriteria Decision Methods constitute a methodology that minimizes the destruction and disturbance of nature in order to assess the best location for the implementation of these alternative energy sources. Therefore, by exploring the geographical information along with the Analytical Hierarchical Processes and the Ordered Weighted Average methods, it was possible to id... [more]

In South Korea, Renewable Energy Sources (RES) have been increasing with the application of energy policies, such as Feed in Tariff (FIT) and the Renewable Portfolio Standard (RPS). However, a rapid increase in RES supply leads to an uncertain power supply due to the intermittent output of RES. A representative example is the curtailment of Wind Turbines (WT), which frequently occurs in Jeju Island, South Korea. The proportion of RES power on Jeju Island is 67%, and there are cases where WT is curtailed among the operable sections to maintain the balance of power supply and demand. This paper applies Power-to-Gas (P2G) technology to hydrogenate, store, and utilize unused power to solve this problem. In this paper, Aewol-eup in Jeju Island is selected as a target site for case study. An Integrated Energy System (IES) for various energy operations is designed to control RES output. This paper proposes the optimal facility configuration and finally drives the optimal design and operation... [more]

Nitrogen reduction reaction (NRR) and nitrate reduction reaction (NO3−RR) provide a potential sustainable route by which to produce ammonia, a next-generation energy carrier. Many studies have been conducted over the years, mainly emphasizing material design and strategies to improve catalytic performance. Despite significant achievements in material design and corresponding fundamental knowledge, the produced ammonia is still very limited, which makes it prone to bias. The presence of interferants (e.g., cations and sacrificial reagents), the pH of the solution, and improper analytical procedure can lead to the over or underestimation of ammonia quantification. Therefore, the selection of the appropriate ammonia quantification method, which meets the sample solution condition, along with the proper analytical procedures, is of great importance. In this review, the state-of-the-art ammonia quantification method is summarized, emphasizing the advantages, limitations, and practicality fo... [more]

The testing of roller rotational resistance is essential in improving and searching for new design solutions to reduce the energy consumption of belt transport. The publication presents three methods of testing idler rotational resistance using various laboratory test stands designed and built by the authors. According to the first method, the test consists of applying torque to the roller axis and measuring the resistance force to rotate the roller axis. According to the second method, the test consisted of speeding up the idler, measuring the free stopping time and determining the moment of resistance to rotating the idler. The third stand enables the simulation of loads recommended by the PN-M-46606: 2010 and DIN 22112 standards, as well as operational loads, while measuring the dynamic rotational resistance. The comparative tests used two rollers different in terms of bearing type, hub type and quality of craft. The research object was ø133 × 465 rollers, most commonly used in the... [more]

Currently, thermal power plants operating on hydrocarbon fuels (gas, fuel oil, peat, shale, etc.) are one of the main sources of electricity. An effective and promising method for suppressing harmful emissions (NOx, carbon oxides, soot) from the combustion of fossil fuels is the injection of steam into the combustion chamber. The influence of various mathematical submodels was studied on the accuracy of the numerical simulation of the process of n-heptane combustion in a laboratory burner with steam additive to the reaction zone as a promising chemical engineering method for the disposal of substandard liquid fuels and combustible waste with the production of thermal energy. The problem was solved in a three-dimensional stationary formulation. Systematic verification of these submodels, and a comparison of the results of the calculation with the experimental data obtained were carried out. The comparison with the experimental data was carried out for gas components and temperature dist... [more]

Massive growth in global electrical energy demand has necessitated a genuine exploration and integration of solar and wind energy into the electrical power mix. This incorporation goes a long way in improving the cumulative generated power capacity of the power system. However, wind and solar photovoltaic (PV) are intermittent in nature, making the provisioning of a good maximum power tracking (MPPT) scheme necessary. Furthermore, the integration is characterized by synchronization challenges and introduces various modes of power system oscillations as it is converter-driven. This greatly affects the overall stability of the integrated power mix. Consequently, various technological models have been designed to address these challenges ranging from MPPT schemes, phase-lock loop (PLL), virtual synchronous generator (VSG), power system stabilizers (PSS), flexible AC transmission system (FACTS), coordinated control and artificial intelligence (AI). In this work, a multi-machine power syste... [more]

Real-time battery SOX estimation including the state of charge (SOC), state of energy (SOE), and state of health (SOH) is the crucial evaluation indicator to assess the performance of automotive battery management systems (BMSs). Recently, intelligent models in terms of deep learning (DL) have received massive attention in electric vehicle (EV) BMS applications due to their improved generalization performance and strong computation capability to work under different conditions. However, estimation of accurate and robust SOC, SOH, and SOE in real-time is challenging since they are internal battery parameters and depend on the battery’s materials, chemical reactions, and aging as well as environmental temperature settings. Therefore, the goal of this review is to present a comprehensive explanation of various DL approaches for battery SOX estimation, highlighting features, configurations, datasets, battery chemistries, targets, results, and contributions. Various DL methods are criticall... [more]

Energy efficiency is a key concern in achieving sustainability in modern society [...]

The large volumes of meat and bone meal (MBM) being produced are leading to an increased demand for research into innovative methods of utilizing MBM and obtaining further benefits. The object of this study is to analyze the efficiency of bioethanol and biodiesel production obtained from corn grain fertilized with meat and bone meal produced from animal waste. For the realization of this study, a four-year field experiment was carried out with grain corn fertilized with different doses of meat and bone meal in comparison to fertilization with mineral fertilizers and no fertilization. Fertilization with meat and bone meal should be considered not only for its direct effect but also for the after-effect. The effect of meat and bone meals on obtaining a grain yield higher than that obtained on objects without fertilization and those fertilized with mineral fertilizers was noticeable after applying higher doses from the third year of the study. Fertilization with meat and bone meals did no... [more]

One of the promising ways to increase fuel and modern gas turbine energy efficiency is using cyclic air intercooling between the stages of high- and low-pressure compressors. For intercooling, it is possible to use cooling in the surface heat exchanger and the contact method when water is injected into the compressor air path. In the presented research on the cooling contact method, it is proposed to use a thermopressor that implements the thermo-gas-dynamic compression process, i.e., increasing the airflow pressure by evaporation of the injected liquid in the flow, which moves at near-sonic speed. The thermopressor is a multifunctional contact heat exchanger when using this air-cooling method. This provides efficient high-dispersion liquid spraying after isotherming in the high-pressure compressor, increasing the pressure and decreasing the air temperature in front of the high-pressure compressor, reducing the work on compression. Drops of water injected into the air stream in the the... [more]

The green economy is a form of economic progress. It promotes environmentally sustainable, low-carbon, and inclusive development. It ensures environmental sustainability and preserves the conditions for social progress. The current model of resource management is not sustainable and puts pressure on the environment. The proposed steps toward a green economy are intended to benefit both the environment, the economy, and society. The aim of the study was to assess the spatial differentiation of the relationship between the green economy and the zero waste concept of Eastern Poland’s municipalities. The assessment was performed using a synthetic measure. The choice of variables was determined by the availability of data in the Bank of Local Data of the Central Statistical Office (BDL GUS) for the years 2010−2020 in spatial terms (709) municipalities of Eastern Poland. The synthetic measure of green economy ranged from 0.28 to 0.56 in 2010 and from 0.28 to 0.59 in 2020; and for the waste m... [more]

The recycling of sodium borohydride poses a huge challenge to the drive towards a hydrogen economy. Currently, mechano-chemical, thermo-chemical and electrochemical are the only reported methods of recycling sodium metaborate into sodium borohydride. Much attention has been devoted to the mechano-chemical and thermo-chemical methods of reduction, but little focus has been devoted to electrochemical methods. This review describes the electrochemical behaviour of borohydride (BH4−) and metaborate (BO2−) anions in alkaline solutions. The BH4− is stabilized in highly concentrated alkaline solutions, while the electro-oxidation of BH4− is dependent on the type of electrode material. The attempts to electro-reduce the BO2− into BH4− is reviewed and the challenges, suggestions and future outlook of electro-reduction for the recycling of BO2− into BH4− is highlighted.

Due to cutting-edge innovations in industry and academia, research is more centered around multilevel inverters (MLIs), which play a significant role in different high/medium voltage and high-power applications when contrasted with traditional inverters. Relative analysis of the reduced DC source count and switch inverter topologies highlight its significant benefits, which include control complexity, switch count, source count, reliability, efficiency, cost, voltage stress, total harmonic distortion (THD), and power quality. When switched-capacitor technology is deployed, it is seen that with the assistance of 14 switches, a 53 level result is accomplished, and the THD is just around 1.41%, which is kept up with as per the IEEE 519-2014 norms. Whenever cascaded MLI topology is employed, the inversion efficiency is more prominent, and is about 99.06%. Hence, this review focuses on a few of the late-evolved MLIs utilized, and the benefits and drawbacks for different topologies are exami... [more]

This paper presents an analysis of the possibility of determining the geometric deviations of large crankshafts of engines using both conventional and alternative fuels. Experimental tests were carried out on a test stand adapted to measure crankshafts seated with their main journals on a set of fixed supports with the possibility of height positioning and using a reference measuring system. A comparative assessment of the results was made for a selected crankshaft using the intercorrelation factor ρ, whose value ranged from 0.8982 to 0.9751. It was concluded that the proposed procedures can be useful in assessing of the geometric condition of the crankshafts with axial position deviations and with limited possibilities of their detection resulting from the adopted support conditions with a set of supports positioned at different heights. Experimental tests were supplemented with FE-analyses of the crankshaft supported at multiple locations and loaded with deviations in the position of... [more]