Improving the efficiency of transport of coal water slurries (CWSs) and determining pipe wear both necessitate accurate predictions of flow characteristics in pipelines with complex geometries. At the bends of the channels, the flow is significantly influenced by the bend curvature, flow rate, and the rheological properties of the slurries that are viscoplastic. Herein, we numerically simulated the flow of CWS in curved channels with different curvature ratios, at different flow rates, and using different rheological models, respectively. The results showed that, due to the yield stress on the cross-stream slices, the velocity profiles showed an unyielded plug. The plug deflects outwards in most circumstances, except at the bend core in the highly curved channel, and, at the same time, at the lower conveying rate, which is due to the fact that the larger inner-wall-pointed pressure gradient has to be balanced by large velocities at the inner bend and, hence, the centrifugal effects are... [more]

Wind charge is produced naturally in space. Knowing the nature of space charge is important for various purposes. If the charge is received for the whole year long by an antenna, then, in this process, the charge can be used as electric power. In the present work, the nature of wind charge in space in the cities of Dhaka and Narayanganj was observed. A net-type antenna was used to receive the wind charge. The results show that the power decreased with the antenna gaps. The output power increased with the antenna’s gross area and the speed of air. The overall output power was increased with humidity. It was shown that wind with a higher distance from the ground carries more electric charge. This research reveals that electric charge is inhomogeneous in wind, and it is collectable as electric power. The nature of the results is similar in both cities, but the output power is larger in Dhaka than in Narayanganj. This alternative power source is environmentally friendly, and it reduces thu... [more]

In recent years, prices for photovoltaics have fallen steadily and the demand for sustainable energy has increased. Consequentially, the assessment of roof surfaces in terms of their suitability for PV (Photovoltaic) installations has continuously gained in importance. Several types of assessment approaches have been established, ranging from sampling to complete census or aerial image analysis methodologies. Assessments of rooftop photovoltaic potential are multi-stage processes. The sub-task of examining the photovoltaic potential of individual rooftops is crucial for exact case study results. However, this step is often time-consuming and requires lots of computational effort especially when some form of intelligent classification algorithm needs to be trained. This often leads to the use of sampled rooftop utilization factors when investigating large-scale areas of interest, as data-driven approaches usually are not well-scalable. In this paper, a novel neighbourhood-based filterin... [more]

Lithium-Sulfur is a promising technology for the next generation of batteries and research efforts for early-stage prototype implementation increased in recent years. For the development of a suitable Battery Management System, a state estimator is required; however, lithium-sulfur behavior presents a large non-observable region that may difficult the convergence of the state estimation algorithm leading to large errors or even instability. A dual Extended Kalman Filter is proposed to circumvent the non-observability region. This objective is achieved by combining a parameter estimation algorithm with a cell model that includes non-linear behavior such as self-discharge and cell degradation. The resulting dual Kalman filter is applied to lithium−sulfur batteries to estimate their State-of-Charge incorporating the effects of degradation, temperature, and self-discharge deviations.

Film-cooling technology is used in high-temperature components of gas turbines to extend their service lives. Hot-gas path components are susceptible to damage or failure in the absence of film cooling. Much of the optimization research efforts have been focused on film hole shapes, heat/mass transfer measurement techniques, and film cooling performance under various mainstream and coolant side operating conditions. Due to recent rapid advancements in the areas of measurement techniques (e.g., pressure-sensitive paints and fast high-resolution imaging) and metal additive manufacturing (AM), film cooling technology has undergone significant changes and shows potential new development. In this review, a historical perspective is discussed covering over five decades of innovation: the geometrical effects from injection angle and hole shapes; flow effects from density ratio, momentum-flux ratio, blowing ratio, advective capacity ratio, and freestream conditions; and more items related to A... [more]

The concept of automatic generation control has an immense role in providing quality power in an interconnected system. To obtain quality power by controlling the oscillations of frequency and tie-line power, a proper controller design is necessary. So, an innovative endeavor has been undertaken to enforce a two-stage controller with the amalgamation of a proportional-derivative with filter (PDN) (integer-order) and a fractional order integral-derivative (FOID), i.e., PDN(FOID). In an effort to acquire the controller’s gains and parameters, a bio-inspired meta-heuristic spotted hyena optimizer is applied. Various examinations manifest the excellence of PDN(FOID) over other controllers such as integral, proportional−integral, proportional−integral-derivative filter, and fractional order PID from perspectives concerning the diminished amount of peak anomaly oscillations, and the instant of settling for a three-area system. The system includes thermal−bio-diesel in area-1; a thermal−geoth... [more]

Electric vehicles (EVs) and photovoltaics (PVs) are new technologies that will play an important role in the transportation industry over the next decade. Using solar panels on the roofs of cars is one of the simplest ways to reduce fuel costs and increase the mobility of electric vehicles. Solar electric cars can be charged anywhere under the Sun without additional infrastructure, but the problem is the size of the solar panel is limited on the roof and the electricity conversion efficiency of the panel is only 15% to 20%. This means they will not provide significant electricity to EVs. An effective way to increase efficiency is to utilize multi-junction solar cells with concentrator photovoltaic (CPV) technology. The challenge is that the moving sun-tracking mechanism will reduce the stability of the vehicle structure. To solve this issue, in this research, we present a static concentrator photovoltaic system for electric vehicles. This structure is more stable and simpler than CPV s... [more]

This study presents the arrangement design of the cooling hole and the application of a fan-shaped hole to improve the cooling performance of the high-pressure turbine. To this end, the first stage nozzle vane of the energy efficient engine (E3) was selected as the base model, and for efficient design, the source term method, called the injection region, was applied for producing the effect of the cooling flow when the RANS analysis was performed. At this time, because the cooling flow rate also changed when the location of the cooling hole changed, a neural network model was constructed to predict the cooling flow rate for the location of the cooling hole. Design optimization was performed to improve the film cooling effectiveness and the temperature uniformity on the vane surface using the streamwise location of the cooling hole as a design variable, and then the cooling performance was investigated by applying several fan-shaped holes instead of cylinder holes on the pressure side.... [more]

Considering the specific heat characteristics of working fluid and existence of various losses in a porous medium (PM) cycle, this paper applies finite time thermodynamic theory to study its efficient power performance with nonlinear variable specific heat model. Range of the cycle pre-expansion ratio is obtained by solving the equation, and PM cycle is converted to Otto cycle by choosing appropriate pre-expansion ratio. Influences of pre-expansion ratio, specific heat characteristics, temperature ratio, and various losses on cycle performances are investigated. Thermal efficiencies are compared at operating points of the maximum power output and efficient power. The results show that PM cycle has better performance than Otto cycle. Under certain conditions of parameters, thermal efficiencies at the maximum efficient power and maximum power output operating points are 50.45% and 47.05%, respectively, and the former is 7.22% higher than the latter. The engine designed with the maximum e... [more]

This paper discusses fuel cell electric vehicles and, more specifically, the challenges and development of hydrogen-fueled buses for people accessing this transportation in cities and urban environments. The study reveals the main innovations and challenges in the field of hydrogen bus deployment, and identifies the most common approaches and errors in this area by extracting and critically appraising data from sources important to the energy perspective. Three aspects of the development and horizons of fuel cell electric buses are reviewed, namely energy consumption, energy efficiency, and energy production. The first is associated with the need to ensure a useful and sustainable climate-neutral public transport. Herewith, the properties of the hydrogen supply of electric buses and their benefits over gasoline, gas, and battery vehicles are discussed. The efficiency issue is related to the ratio of consumed and produced fuel in view of energy losses. Four types of engines−gasoline, di... [more]

Renewable energy has received a lot of attention. In recent years, offshore wind power has received particular attention among renewable energies. Fixed-type offshore wind turbines are now the most popular. However, because of the deep seas surrounding Japan, floating types are more preferable. The floating system is one of the factors that raises the cost of floating wind turbines. Vertical axis wind turbines (VAWT) have a low center of gravity and can tilt their rotors. As a result, a smaller floating body and a lower cost are expected. A mechanism called a floating axis wind turbine (FAWT) is expected to further reduce the cost. FAWT actively employs the features of VAWT in order to specialize itself in the area of offshore floating-type wind turbines. The lifting line theory simulation was used in this study to discuss the performance of the FAWT under the tilted conditions and its wake field. The results show that a tilted VAWT recovers faster than an upright VAWT. This suggests t... [more]

Previously published studies on Australia’s energy security did not examine the country’s domestic energy security situation in tandem with its international energy statecraft. This paper fills this research gap. In order to provide a robust analysis of a country’s strategic options in the energy sector, it is paramount to balance domestic and international dimensions, along with internal and external factors. The paper utilizes the strengths, weaknesses, opportunities, and threats (SWOT) method to review Australia’s strategic options by balancing the inward-looking, domestic risk minimization dimension (energy security), with the outward-looking, international power projection dimension (energy statecraft). The paper also applies the 4A framework (availability, accessibility, affordability, and acceptance) to assess Australia’s energy security performance. On the one hand, the results demonstrate that Australia has many strengths and opportunities as a reliable and stable energy suppl... [more]

In recent years, China has proposed the goal of peaking carbon dioxide emissions by 2030 and achieving carbon neutrality by 2060, which will significantly alter its existing coal-based energy mix. Since coal is China’s primary source of energy and the largest contributor to carbon emissions, coal reduction is an important measure toward carbon neutrality. In order to guarantee the stable development of economy and society in the process of coal reduction, the path and cost of coal reduction need to be studied in depth. Based on coal use in China, this paper examines and measures the stages and costs of coal reduction. It also gives a definition for coal reduction costs for the first time, including economic cost, environment and ecology cost, and health cost, as well as proposes a framework for analyzing the “full cost, full process, and full scenario”. We measure the cost in combination with the KAYA formula, and take into account the time value of the cost. Based on the above measure... [more]

An underappreciated source of renewable energy is wastewater, both municipal and industrial, with global production exceeding 900 km3 a year. Wastewater is currently perceived as a waste that needs to be treated via energy-consuming processes. However, in the current environmental nexus, traditional wastewater treatment uses 1700−5100 TWh of energy on a global scale. The application of modern and innovative treatment techniques, such as microbial fuel cells (MFC), would allow the conversion of wastewater’s chemical energy into electricity without external energy input. It has been demonstrated that the chemically bound energy in globally produced wastewater exceeds 2.5 × 104 TWh, which is sufficient to meet Europe’s annual energy demand. The aim of this paper is to answer the following questions. How much energy is bound in municipal and industrial wastewaters? How much of that energy can be extracted? What benefits will result from alternative techniques of waste treatment? The main f... [more]

This paper describes the implementation of a hydrogen-based system for an autonomous surface vehicle in an effort to reduce environmental impact and increase driving range. In a suitable computational environment, the dynamic electrical model of the entire hybrid powertrain, consisting of a proton exchange membrane fuel cell, a hydrogen metal hydride storage system, a lithium battery, two brushless DC motors, and two control subsystems, is implemented. The developed calculation tool is used to perform the dynamic analysis of the hybrid propulsion system during four different operating journeys, investigating the performance achieved to examine the obtained performance, determine the feasibility of the work runs and highlight the critical points. During the trips, the engine shows fluctuating performance trends while the energy consumption reaches 1087 Wh for the fuel cell (corresponding to 71 g of hydrogen) and 370 Wh for the battery, consuming almost all the energy stored on board.

As the transportation industry develops new forms of energy and electrification, expressway dynamic wireless charging has become an attractive technology that has the potential to completely solve a range of anxieties associated with electric vehicles. The main objective of this paper was to analyze the economic feasibility of dynamic wireless charging projects on highways. First, the roadside cost of dynamic wireless charging was estimated in terms of equipment, construction, and maintenance costs. Then, various indicators of the national economy of expressway dynamic wireless charging were analyzed. Finally, using the GM (1,1) model, a prediction model for evaluating the associated economic benefits is proposed in this study. As a case study, a national economic evaluation of retrofitting a dynamic wireless charging infrastructure on the Guiyang to Xinzhai Expressway was calculated with the following results: the economic internal rate of return (EIRR) is 11.27% to 29.11%, the econom... [more]

In Poland, electricity production is based on nonrenewable energy sources. The energy market is dominated by corporations. Rising electricity prices and threats of power shortages have become, among others, prerequisites for the development of distributed sources based on renewable sources, primarily using photovoltaic panels. The development of the renewable energy market is slow due to the lack of legal solutions and insufficient state support. Polish farmers, especially fruit growers, whose electricity consumption costs are a significant item in production costs, may become part of the energy sector by building a local energy system. In 2022, Poland introduced two new legal regulations, which currently provide three options for obtaining electricity using renewable micro-installations. The conducted study aimed at indicating which of the legally permitted option is the most advantageous for fruit farms in Poland. Growers can produce energy by being a prosumer who settles accounts in... [more]

The article presents the global characteristics of the Polish manufacturing industry and the structure of its energy consumption and carbon dioxide emissions related to direct emission as a result of fuel combustion and indirect emission as a result of electricity consumption. The share of individual sectors in energy consumption and emission levels was determined, and the changes in this share over the last 20 years were determined. A method for determining the carbon productivity index for the emissions of individual industries with the use of global macroeconomic indicators was proposed. The index allows for the comparison of the productivity of individual industries, regardless of the nature of production. The change in carbon productivity in Polish industry over time was presented. On this basis, it was assessed which industries are particularly promising in terms of decarbonising the Polish industry.

The efficient use of energy resources is profoundly changing power grid regulation and policy. New forms of power generation coupled with storage and the presence of new, increasingly flexible loads such as electric vehicles enable the development of multi-agent planning systems based on new forms of interaction. For instance, consumers can take advantage of flexibility by interacting directly with the grid or through aggregators that bridge the gap between these end-users and traditional centralised markets. This paper aims to provide insight into the benefits for aggregators and end-users from a financial perspective by proposing a methodology that can be applied to different scenarios. End-users may provide flexibility services related to private vehicle charging stations or battery storage systems. The paper will analyse different remuneration levels for end-users by highlighting the most beneficial scenarios for aggregators and end-users and providing evidence on potential conflic... [more]

While world energy demand has certainly decreased with the beginning of the COVID-19 pandemic in 2020, the need has been significantly on the rise since 2021, all as the world’s fossil fuel resources are depleting; it is widely accepted that these resources emit greenhouse gases (GHG), which are the leading cause for the climate crisis. The main contributors to global warming are manufacturing, energy, and agriculture. The agricultural sector is composed of diversified and potential mobilizable sources of waste which can become an attractive alternative to fossil fuels for energy production, and thus sequester and use carbon. Therefore, a paradigm shift towards more sustainable energy alternatives, efficient waste management, and new technologies is necessary. One good solution is the energetic valorization of lignocellulosic biomass (LCB) which can also originate from agricultural wastes. The biomass consists of cellulose, hemicellulose, and lignin, which are sources of fermentable su... [more]

The Smarter Together project implemented in the three lighthouse cities (LHCs) of Lyon, Munich, and Vienna a set of co-created and integrated smart solutions for a better life in urban districts. The implemented solutions have been monitored using a novel integrated monitoring methodology (IMM) following a co-creation process involving key stakeholders of the LHCs. With focus on holistic building refurbishment and the integration of onsite renewable energy supply (RES), the three LHCs refurbished around 117,497 m2 of floor area and constructed 12,446 m2 of new floor area. They implemented around 833 kWp of PV, 35 kW of solar thermal and 13,122 kW of geothermal heating systems. Altogether, the realized solutions for low-energy districts in the three LHCs will annually save around 4000 MWh/a, generate 1145 MWh/a of RES and reduce around 1496 tCO2/a of CO2 emissions, corresponding to specific values of 37.6 kWh/m2.a and 11.9 kg-CO2/m2.a for final energy saving and CO2 emission reductions,... [more]

In this study, two types of fermentation methods: SSF and consolidation SHF/SSF were used for production of acetone-butanol-ethanol (ABE) from corn straw as a feedstock. Clostridium acetobutylicum DSM1731 was used as the fermenting organism. Corn straw was thermochemically pretreated and then hydrolyzed using three types of enzymes. The impact has been investigated on the effect of mineral compounds supplementation ((NH4)2SO4, MgSO4, (NH4)3PO4) on ABE productivity and butanol content. From the SSF, where mineral salts were supplemented into the fermentation medium, it was found that the maximum ABE and butanol concentrations were 28.35 g/L and 24.03 g/L, respectively, corresponding to a productivities of 0.295 g/L/h (ABE) and 0.250 g/L/h (butanol). In the consolidation SHF/SSF method with mineral compounds supplementation, the maximum ABE and butanol concentrations were 31.35 g/L and 28.64 g/L, respectively, corresponding to productivities of 0.327 g/L/h (ABE) and 0.298 g/L/h (butanol)... [more]

This article reviews the state of the knowledge and technology in the field of friction-loss measurements in internal combustion piston engines. The dependencies that describe the loss of energy in combustion engines and injection apparatus are presented. Currently, very little can be found in the literature on the study of frictional forces in injection apparatus, but mainly in the piston−cylinder group, so this work significantly fills that gap. The aim of this article is to construct a device and to develop a method for assessing the technical state of injector nozzles to minimize friction losses in internal combustion engines at the stages of evaluation, design, production and operation. This article presents a stand for determining the maximum friction forces due to gravity loading by water-jet control. This article also presents test results on the maximum friction force between a needle and a body of injector nozzles in piston combustion engines on a designed and purpose-built s... [more]

This article studies the stator windings asymmetry fault in direct-drive permanent magnet synchronous generator(PMSG)-based wind turbines (WTs), having passive converters at the generator side, through developing a power-hardware-in-the-loop (P-H-i-L) system. It is based on a digital real-time simulation (DRTS) of turbine blades, a wind generator in the abc reference frame, and a three-phase diode rectifier mathematical models. The DC voltage, provided by the model of the three-phase diode rectifier, is linked to a one-level hardware boost converter by using a programmable DC power supply. Furthermore, the maximum power point tracking technique, based on the optimal torque, is evaluated when the one-level boost converter supplies a resistive load. Stator windings asymmetry fault in the PMSG is identified by analyzing the rectifier output voltage, the rotor speed, and the electrical signatures of the boost converter. It shows that this kind of fault clearly gives rise to the amplitudes... [more]

In recent years, global warming and climate change associated with emissions of CO2 from fossil fuel-fired power systems are a big worry for authorities in many countries worldwide. The utilization of biomass as an alternative, carbon-neutral fuel can reduce emissions of CO2 and other greenhouse gases. Furthermore, the coupling of oxy-combustion of biomass with CO2 capture is an option for carbon-negative power generation technology. In this study, emissions of NOx, SO2, and CO from the air- and oxy-combustion of three energy crops (Miscanthus giganteus, Sida hermaphrodita, and Salix viminalis) are presented and compared with emissions from other biomass fuels and reference coal. Combustion tests in air and O2/CO2 mixtures were conducted in a 12-kW bench-scale CFB combustor at 850 °C. Measurements of flue gas compositions were taken using an FTIR spectrometer. In all tested atmospheres, emissions of SO2, N2O, and CO for biomass were lower than those for the reference coal. The oxidatio... [more]