The importance of biomass for energy production is included in the government program “Energy Policy of Poland until 2040”. Biomass is one of the most stable renewable energy sources (RES), and its resources are the largest of all alternative energy sources. The paper presents and discusses the most important conditions that are related to the possible usage of the biomass that is obtained from agriculture for heating purposes. The aim of the study is to assess the energy potential of a selected agro-biomass and to indicate its effective use for the production of district heat. The research uses: in-depth statistical data analysis (data were obtained from the Central Statistical Office and the Agency for Restructuring and Modernization of Agriculture), inference methods, short- and long-term forecasting, the minimum spanning tree (MST) algorithm, and methods of single- and multi-criteria optimization for the selection of the most advantageous variant. The research covers three differen... [more]

The purpose of this study was to develop a process to convert input signals from one facility into another by reflecting geometric and environmental settings. The Dynamic Energy Transport and Integration Laboratory (DETAIL) is one facility in development that aims to emulate the daily interactions among power production industry systems and be capable of receiving real-time data from those systems as inputs. To convert signals and ensure that the temporal sequences and magnitudes reflect the laboratory settings, the ability to scale and project data is essential. To demonstrate this ability, Dynamical System Scaling (a methodology that enables systems to scale and project or extrapolate datasets to desired environments while conserving the observed transient behavior based on first principles) was applied to DETAIL’s thermocline thermal storage system in the Thermal Energy Distribution System. The thermocline system was successfully scaled and a test case was conducted to generate a do... [more]

Boiling conjugate heat transfer is an active field of research encountered in several industries, including metallurgy, power generation and electronics. This paper presents a computational fluid dynamics approach capable of accurately modelling the heat transfer and flow phenomena during immersion quenching: a process in which a hot solid is immersed into a liquid, leading to sudden boiling at the solid−liquid interface. The adopted methodology allows us to couple solid and fluid regions with very different physics, using partitioned coupling. The energy equation describes the solid, while the Eulerian two-fluid modelling approach governs the fluid’s behaviour. We focus on a film boiling heat transfer regime, yet also consider natural convection, nucleate and transition boiling. A detailed overview of the methodology is given, including an analytical description of the conjugate heat transfer between all three phases. The latter leads to the derivation of a fluid temperature and Biot... [more]

The energy consumption estimation of a locomotive for a particular route is important for the selection of a locomotive technology, the improvement of the energy management system, the evaluation of the locomotive’s potential energy generation, among others. The methodologies reported in the literature usually assume that the information of the railway track is available; however, in some cases, the track information is incomplete, not available, or the route is still in a planning stage. Therefore, this paper proposes a methodology to estimate the energy consumption and the potential energy generation of a locomotive when the railway track information is not available or incomplete. The methodology begins by extracting the main technical information of the locomotive to be analyzed. Then, the route is traced on Google Earth with steps of 100 m and the obtained information is processed to generate the longitude, latitude, elevation, and distance of the points along the route. From such... [more]

The controls of most power electronic inverters connected to an electrical power system (EPS) rely on the precise determination of the voltage magnitude, frequency, and phase angle at the point of common coupling. One of the most widely used approaches for measuring these quantities is the phase-locked loop (PLL); however, the precision of this measurement is affected during transients in the EPS and is a function of the type of event and the architecture of the PLL. PLLs based on the second-order generalized integrator (SOGI) are widely used in power converter synchronization, offering an adaptive or fixed-parameter prefilter with low-pass and band-pass characteristics. This article proposes a variant of the SOGI-PLL that offers improved stability and a faster response time. This is accomplished by decoupling the effect of the SOGI’s gains and adding feedback. The modification is carried out in the state space model of the SOGI. Manipulating the attenuation moves the poles of the SOGI... [more]

As a widely-used method of digging roadways in China, gob-side entry driving features specific advantages, such as a high recovery rate and good isolation effects. However, under the condition of hard overburden, the excessive bearing pressure of small coal pillars will easily cause serious internal damage in the coal and the run-through of the plastic zone, leading to harmful gas leakage in the goaf. Therefore, based on the engineering background of small coal pillars in the 18506 working face of Xiqu Coal Mine, this paper comprehensively adopts theoretical analysis, numerical simulation, industrial tests, and other methods, analyzes the evolution mechanism of isolated bearing and plastic fracture areas of small coal pillar under hard overburden, studies the influence law of hard overburden cutting parameters on the isolation and stability of small coal pillars, and puts forward the technology of actively cutting the top to weaken the stress concentration of coal pillars under hard ov... [more]

As the battery provides the entire propulsion power in electric vehicles (EVs), the utmost importance should be ascribed to the battery management system (BMS) which controls all the activities associated with the battery. This review article seeks to provide readers with an overview of prominent BMS subsystems and their influence on vehicle performance, along with their architectures. Moreover, it collates many recent research activities and critically reviews various control strategies and execution topologies implied in different aspects of BMSs, including battery modeling, states estimation, cell-balancing, and thermal management. The internal architecture of a BMS, along with the architectures of the control modules, is examined to demonstrate the working of an entire BMS control module. Moreover, a critical review of different battery models, control approaches for state estimation, cell-balancing, and thermal management is presented in terms of their salient features and merits... [more]

While price responsiveness of residential demand for natural gas has important implications on resource planning and energy modelling, its estimates from prior studies are very diverse. Applying panel data analysis and five parametric specifications to monthly data for the lower 48 states in 1990−2019, we estimate own-price elasticities of residential demand for natural gas in the United States (US). Using results from cross-section dependence (CD) test, panel unit root tests, panel time-series estimators, and rolling-window analysis, we document: (1) the statistically significant (p-value ≤ 0.05) static own-price elasticity estimates are −0.271 to −0.486, short-run −0.238 to −0.555 and long-run −0.323 to −0.796; (2) these estimates vary by elasticity type, sample period, parametric specification, treatment of CD and assumption of partial adjustment; (3) erroneously ignoring the highly significant (p-value < 0.01) CD shrinks the size of these estimates that vary seasonally, regional... [more]

The performance of photovoltaic (PV) solar panels is dependent on certain factors, such as dust effects. Even though Palestine’s energy issues are well-known, no research has been undertaken on the soiling effect on solar energy generation in Palestine’s climatic circumstances. The study’s findings can aid Palestine’s efforts to achieve long-term energy sustainability and solar energy use. Outdoor research was conducted in Tulkarm, Palestine, to explore the impact of dust on PV systems. The current study examined the impact of dust accumulation based on the Mediterranean climate. To accomplish this, a one-year experiment was conducted from 1 January to 31 December 2021. An 85-kW PV power plant at Tulkarm was utilized in the study. Knowing the efficiency reduction over time will aid in minimizing cleaning expenses by selecting the most appropriate cleaning interval. The results concluded that in January, February, November, and December, there will be a two-month cleaning period, monthl... [more]

When a commercial vehicle diesel engine works for an extended period of time at the torque spot, it can easily cause a mechanical failure due to the high temperature of the piston. In this paper, the temperature plug method was used to measure the temperature of the piston at the maximum torque spot. In order to reduce the failure caused by high temperature, the finite element analysis software Ansys was used in this paper to study the effects of different thicknesses of ceramic coatings on the piston surface of a diesel engine on the maximum temperature of the piston substrate. The bonding layer of the ceramic coating was NiCoCrAlY with a thickness of 0.1 mm, and the insulating layer was a La2Zr2O7 coating with respective thicknesses of 0.2 mm, 0.3 mm, 0.5 mm, 0.7 mm, and 0.9 mm. When the thickness of the ceramic coating was increased from 0.3 mm to 1.0 mm, the maximum temperature of the piston base decreased from 347.9 °C to 267.46 °C. This showed that the use of a thermal-barrier co... [more]

By constructing the permeability model to distinguish the fracture zone, plastic zone, and elastic zone around the hydraulic fracturing borehole, we study the influence of some important parameters on the stress distribution around the borehole and the permeability of the coal rock. The research results show that the greater the ground stress, the greater the radial stress in the fracture zone and plastic zone, and the smaller the radial stress in the elastic zone, while the trend of the stress variation in permeability is the opposite to the radial stress. The greater the gas pressure, the greater the permeability of the coal rock in each stress area. The larger the borehole radius, the smaller the radial stress at the same distance from the borehole center, and the greater the permeability of the coal rock. The greater the fracturing pressure, the greater the radial stress on the coal rock at the same distance from the borehole center, and the smaller the permeability of the coal roc... [more]

This article presents the results of analyses of energy efficiency and environmental outcomes of putting into operation high-speed trains—first of that kind in Poland—in 2014 on upgraded 3 kV DC lines. Comparative analyses of these trains in Poland have not been carried out so far and provide a new approach to assessing the feasibility of their adoption and, in a broader context, the advisability of replacing conventional with high-speed rail transport. The analysis supports the advantages of high-speed railway (HSR) and the need to develop a network of high-speed connections using energy-efficient trains in Poland. Putting these trains into service reduced CO2 emissions, which is significant in Poland as a country relying heavily on power generated in coal power plants and complies with the assumptions of the sustainable development policies and EU Green Deal. The outcomes of our analysis can be used for transportation planning to mitigate climate change and the presented approach pro... [more]

The New Energy and Industry Technology Development Organization (NEDO) road map (Japan, 2017) has proposed that a polymer electrolyte fuel cell (PEFC) system, which operates at a temperature of 90 °C and 100 °C, be applied for stationary and mobility usage, respectively. This study suggests using a thin polymer electrolyte membrane (PEM) and a thin gas diffusion layer (GDL), at the same time, to achieve better power-generation performance, at a higher temperature than usual. The focus of this paper is to clarify the effect of separator thickness on the distribution of temperature at the reaction surface (Treact), with the relative humidity (RH) of the supply gasses and initial operation temperature (Tini), quantitatively. In this study, separator thickness is investigated in a system using a thin PEM and a thin GDL. Moreover, this study investigates the difference between the maximum temperature and the minimum temperature obtained from the distribution of Treact as well as the relatio... [more]

Poland, as a member of the European Union (EU), has to fulfill the obligations resulting from its membership in it. It is necessary to comply with numerous directives and other legal provisions adopted by the European Commission in the field of the energy market and production. Meeting the demands of the European Green Deal, as well as the solutions presented in the Fit for 55 package, is very difficult. In Poland, coal is still used in over 67% of electricity production. This article presents an attempt to join the multi-threaded discussion on renewable energy sources (RES) and the possibility of increasing their share in Poland’s energy mix. This article defines the RES support mechanisms in Poland, presents the support systems and instruments functioning within them, and also provides a statistical prediction of trends in energy production from RES for upcoming years. Research utilized the Brown, Holt, and Winters models and the cause-and-effect model. The research conducted in this... [more]

The successful design of a liquid rocket engine is strictly linked to the development of efficient cooling systems, able to dissipate huge thermal loads coming from the combustion in the thrust chamber. Generally, cooling architectures are based on regenerative strategies, adopting fuels as coolants; and on cooling jackets, including several narrow axial channels allocated around the thrust chambers. Moreover, since cryogenic fuels are used, as in the case of oxygen/methane-based liquid rocket engines, the refrigerant is injected in liquid phase at supercritical pressure conditions and heated by the thermal load coming from the combustion chamber, which tends to experience transcritical conditions until behaving as a supercritical vapor before exiting the cooling jacket. The comprehension of fluid behavior inside the cooling jackets of liquid-oxygen/methane rocket engines as a function of different operative conditions represents not only a current topic but a critical issue for the de... [more]

A centralized multiple back-up protection scheme with sharing data between adjacent substations based on IEC 61850 is suggested in this paper to overcome the inherent defects of a conventional back-up protection scheme such as uncertainty of a remote end condition, especially for a distance relay, long operating time delay, and IED/CT fails. A current differential protection element, a distance-based directional protection element, local back-up, and remote back-up protection elements are applied for the multiple back-up protection scheme suggested in this paper. The phasor voltage/current data of the IMU are transferred to a CPCU. In this paper, the IMU has two functions, which are local protection IED and merging unit, as well. The CPCU performs the back-up protection functions by using the phasor voltage/current data collected from other CPCUs located at the adjacent substations. IMU/CT fails are also considered. To verify the back-up protection scheme proposed, a testbed was compos... [more]

The power management strategy (PMS) is intimately linked to the fuel economy in the hybrid electric vehicle (HEV). In this paper, a hybrid power management scheme is proposed; it consists of an adaptive neuro-fuzzy inference method (ANFIS) and the equivalent consumption minimization technique (ECMS). Artificial intelligence (AI) is a key development for managing power among various energy sources. The hybrid power supply is an eco-acceptable system that includes a proton exchange membrane fuel cell (PEMFC) as a primary source and a battery bank and ultracapacitor as electric storage systems. The Haar wavelet transform method is used to calculate the stress σ on each energy source. The proposed model is developed in MATLAB/Simulink software. The simulation results show that the proposed scheme meets the power demand of a typical driving cycle, i.e., Highway Fuel Economy Test Cycle (HWFET) and Worldwide Harmonized Light Vehicles Test Procedures (WLTP—Class 3), for testing the vehicle per... [more]

A comprehensive electric vehicle model is developed to characterize the behavior of the Smart e.d. (2013) while driving, charging and providing vehicle-to-grid services. To facilitate vehicle-to-grid strategy development, the EV model is completed with the measurement of the on-board charger efficiency and the charging control behavior upon external set-point request via IEC 61851-1. The battery model is an electro-thermal model with a dual polarization equivalent circuit electrical model coupled with a lumped thermal model with active liquid cooling. The aging trend of the EV’s 50 Ah large format pouch cell with NMC chemistry is evaluated via accelerated aging tests in the laboratory. Performance of the model is validated using laboratory pack tests, charging and driving field data. The RMSE of the cell voltage was between 18.49 mV and 67.17 mV per cell for the validation profiles. Cells stored at 100% SOC and 40 °C reached end-of-life (80% of initial capacity) after 431−589... [more]

Transportation, like other spheres of human activity, is constantly changing due to economic development [...]

By adding water to fuels, several objectives are pursued, with the main ones being to stabilize combustion, minimize the anthropogenic gaseous emissions, homogenize and stabilize the fuel, as well as improve its fire and explosion safety. Water can be injected into the furnace as droplets or vapor and introduced as part of fuel samples. Water often serves as a coupling or carrier medium for the delivery of the main fuel components. In this paper, we compare the combustion behaviors of high-potential slurry fuels and gas hydrates. We also analyze the contribution of in slurries and gas hydrates to the combustion process. The values of relative combustion efficiency indicators are determined for gas hydrates and slurry fuels. The conditions are identified in which these fuels can be burned effectively in power plants. The research findings can be used to rationalize the alternative ways of using water resources, i.e., gas hydrate powder and promising composite fuel droplets. The results... [more]

Extended-Range Electric Vehicles (EREVs) are intended to improve the range of battery electric vehicles and thus eliminate drivers’ concerns about running out of energy before reaching the desired destination. This paper gives an insight into EREV’s performance operating according to the proposed control strategy over various driving cycles, including the Worldwide Harmonized Light-duty Test Cycle Class 3b (WLTC 3b), Federal Test Procedure (FTP-75), and China Light-Duty Vehicle Test Cycle (CLTC-P). Simulation runs were performed in Matlab-Simulink® for different cases of drive range, electricity mix, and vehicle mass. The control strategy goal was to aim at a specified value of battery state of charge at the targeted range value. The obtained test results included: pure electric drive range, acceleration times, EREV range tests, control strategy range errors, Range Extender (REX) utilization metric and distribution of its engagement instances, fuel consumption, total equivalent CO2 emi... [more]

Lithium titanium oxide (Li4Ti5O12, LTO) is an attractive negative electrode for the development of safe—next-generation—lithium-ion batteries (LIBs). LTO can find specific applications complementary to existing alternatives for LIBs thanks to its good rate capability at high C-rates, fast lithium intercalation, and high cycling stability. Furthermore, LIBs featuring LTO electrodes are inherently safer owing to the LTO’s operating potential of 1.55 V vs. Li+/Li where the commonly used organic-based electrolytes are thermodynamically stable. Herein, we report the combined use of water-soluble sodium alginate (SA) binder and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)-tetraglyme (1m-T) electrolyte and we demonstrate the improvement of the electrochemical performance of LTO-based electrodes with respect to those operating in conventional electrolyte 1M LiPF6-ethylene carbonate: dimethyl carbonate (LP30). We also tackle the analysis of the impact of combining the binder/electrolyte... [more]

Vanadium nitride (VN) with a wide working window has been identified as a promising electrode material candidate for batteries due to the high specific capacitance and the excellent electrical conductivity. Here, we have successfully prepared VCN nanobelts, which display mesoporous structure with high specific surface area (54.4 m2 g−1) and the total pore volume was 0.266 cm3 g−1. Furthermore, the prepared flexible Zn-ion battery (FZIB) with VCN-5 not only exhibited high specific capacitance (81 μAh cm−2), excellent rate capability, and long cyclic durability (77% after 1000 cycles at 0.6 mA cm−2) but also had the characteristics of flexibility. This FZIB is important to reduce the difficulty in thermal management and can be used in a series of applications, including wearable electric devices.

As renewable energy sources, such as solar systems, are becoming more popular, the focus is moving into more effective utilization of these energy sources and harvesting more energy for intermittency reduction in this renewable source. This is opening up a market for methods of energy storage and increasing interest in batteries, as they are, as it stands, the foremost energy storage device available to suit a wide range of requirements. This interest has brought to light the downfalls of batteries and resultantly made room for the investigation of ultra-capacitors as a solution to these downfalls. One of these downfalls is related to the decrease in capacity, and temperamentality thereof, of a battery when not used precisely as stated by the supplier. The usable capacity is reliant on the complete discharge/charge cycles the battery can undergo before a 20% degradation in its specified capacity is observed. This article aims to investigate what causes this degradation, what aggravates... [more]

The objective of this research project is to study the economic development model of the Angolan economy in order to analyze the adoption of an alternative strategy capable of leveraging the economy, based essentially on alternative energies, and therefore, to demonstrate and prove the need to diversify Angola’s economic model, highlighting the benefits of a diversified versus a non-diversified economy with respect to sustainability. The first stage of the design of this empirical study involved establishing a focus group in order to construct and adjust a data collection instrument in the form of a questionnaire to be applied to a broader set of managers and informed professionals with a critical view of the country’s future and the models and alternatives to economic development and diversification of the economy on a sustainable basis. Energy plays a fundamental role in Angola’s economic and social development. Excessive dependency on the oil sector and inefficient production due to... [more]