The accident-tolerant fuel concept involves replacing the conventional cladding system (zirconium) with a new material or coating that has specific thermomechanical properties. The aim of this study is to evaluate the neutronics performance of a chromium coating concept and design solutions. A Zircaloy−uranium fuel system (Zr−U) is currently used as a standard fuel system in pressurized water reactors around the world. This investigation presents the benefits of utilizing an alternative cladding material such as chromium coating and the effects on the thermal neutron parameters of the way in which the chromium coating is introduced in the reactor fuel. Among these significant benefits is an increase in the reactor fuel’s thermal conductivity, which improves reactor safety. Two types of fuel-cladding systems were investigated: Zircaloy−uranium (Zr−U) and Zircaloy−chromium (Zr−Cr−U) coating fuel systems. Neutronics analysis evaluations were performed for the selected fuel assemblies and... [more]

Waste heat present in exhaust gas produced from various industrial processes or internal combustion engines in transport are a reservoir of untapped energy [...]

Overhead line ice-shedding causes line breakage and results in electrical faults occurring between transmission lines, which seriously affects the safe operation of the power grid. In this paper, a risk assessment method for ice-shedding on 500 kV compact overhead lines is proposed. Two ratios were used to assess the discharge risk and mechanical failure risk of a line. A 500 kV compact overhead line in southern China was taken as an example, the proposed risk assessment method was used to carry out a risk assessment of the ice-shedding line with an ice thickness of 15 mm, and the suppression effects of different spacer arrangement schemes on the ice-shedding line were analyzed. The results showed that the impact coefficient of the conductor reached 1.88, the maximum jump height of the lower phase conductor reached 22.596 m, and the interphase clearance of the conductor decreased sharply when the lower phase conductor of 500 kV case line underwent full-span ice-shedding synchronously.... [more]

In order to accommodate more intermittent renewable energy in coal-dominated power systems, conventional thermal power plants need to improve their operational flexibility to balance the energy system at all times. However, flexible operation of coal-fired power plants could reduce energy efficiency and increase CO2 and pollutant emission, so it is important to consider environmental implications and optimize the dispatch of wind and coal power units in the system. In this paper, based on the output profile of wind power, a wind power peak (T, H) simulation model based on Gaussian distribution was established. Using a high-proportion wind power wind−coal combined base load power generation system as an example, the economical and environmentally friendly unit operation based on different wind power penetration was studied by simulation, and the decision strategy was established. Wind energy curtailment boundary was determined with power generation cost, energy consumption, CO2 and poll... [more]

Enhancing the accuracy of the battery state of charge (SOC) estimation is essential in developing more effective, dependable, and convenient electric vehicles. In this paper, a hybrid CNN and gated recurrent unit-long short-term memory (CNN-GRU-LSTM) approach, which is a recurrent neural network (RNN) based model with an explainable artificial intelligence (EAI) was used for the battery SOC estimation, where the cell parameters were explicitly synchronized to the SOC. The complexed link between the monitoring signals related to current, voltage, and temperature, and the battery SOC, was established using the deep learning (DL) technique. A LG 18650HG2 li-ion battery dataset was used for training the model so that the battery was subjected to a dynamic process. Moreover, the data recorded at ambient temperatures of −10 °C, 0 °C, 10 °C, and 25 °C are fed into the method during training. The trained model was subsequently used to estimate the SOC instantaneously on the testing datasets. A... [more]

The rapid growth in renewable energies has given rise to their integration into the grid system. These renewable and clean energy sources are dependent on external conditions such as wind speed, solar irradiation, and temperature. For a stable connection between these sources and power grid systems, a controller is necessary to regulate the system’s closed-loop dynamic behavior. A sliding mode control (SMC) using a new reaching law is proposed for the integration of a Modified Capacitor-Assisted Extended Boost (MCAEB) quasi-Z Source 7 level 18 switch inverter with the grid. An SMC-based controller was implemented to regulate the current flow between the inverter and the grid. SMC has the advantages of ease of implementation, robustness, and invariance to disturbance. The simulation results of SMC and the proportional integral (PI) controller are compared in terms of settling time, steady-state error, and total harmonic distortion (THD) during transient response, steady-state response a... [more]

This article presents selected methods of limiting the bearing voltages of synchronous machines with permanent magnets supplied from power electronic converters. The authors analyzed methods based on the use of various shielding windings placed in slot wedges and mounted in the stator end-winding region. The values of the parasitic capacitances of the machine, on which the levels of bearing voltages depend, were determined using the finite element method. Three-dimensional simulation models were used for the calculations. The analysis of the influence of the shielding windings on the bearing voltage waveforms was conducted on the basis of circuit models with two- and three-level converters. The obtained calculation results indicate a high potential in limiting bearing voltages.

The government of Karnataka has resolved to promote and employ an increasing number of alternative fuels, particularly, wind energy. Selecting a windmill supplier is a key decision when developing a wind energy project, and investors must evaluate various qualitative and quantitative variables that interact symmetrically to discover the best source. As a result, a multi-criteria decision-making procedure is applied to choose a wind turbine provider for wind power projects. A variety of approaches have been used to address this judgment process, some of which were predicated on the use of multi-criteria judgment techniques alone or in conjunction with some different multiple-criteria decision approaches. In this study, the researchers advocated selecting windmill producers for geothermal power generation using a judgment method based on a spherical fuzzy system. After the analyses of the last stage of this research, turbine manufacturers for installations could be suggested. The purpose... [more]

Mixed obstacles have a great influence on the deflagration process of liquefied petroleum gas (LPG)-air premixed combustible gas with concentration gradient. The arrangement of mixed obstacles may further stimulate overpressure and flame propagation. In this work, based on experimental and numerical simulations, this paper analyzes the flame and overpressure, and mainly studies the coupling relationship among the explosion overpressure characteristics, the structure of flame and the speed of flame propagation. The result shows that when the rectangular obstacle is 100 mm away from the ignition source, not only the speed of flame is the fastest, but also the time required to reach the maximum over-pressure is the shortest. In this configuration, an elongated flame is formed between a rectangular obstacle and a flat obstacle, and an obvious backflow structure appears. In addition, the average growth rate of overpressure has a minimum value, reaching at −35 MPa/s. The existence of rectang... [more]

Magnesium borohydride (Mg(BH4)2) is an attractive compound for solid-state hydrogen storage due to its lucratively high hydrogen densities and theoretically low operational temperature. Hydrogen release from Mg(BH4)2 occurs through several steps. The reaction intermediates formed at these steps have been extensively studied for a decade. In this work, we apply spectroscopic methods that have rarely been used in such studies to provide alternative insights into the nature of the reaction intermediates. The commercially obtained sample was decomposed in argon flow during thermogravimetric analysis combined with differential scanning calorimetry (TGA-DSC) to differentiate between the H2-desorption reaction steps. The reaction products were analyzed by powder X-ray diffraction (PXRD), near edge soft X-ray absorption spectroscopy at boron K-edge (NEXAFS), and synchrotron infrared (IR) spectroscopy in mid- and far-IR ranges (SR-FTIR). Up to 12 wt% of H2 desorption was observed in the gravime... [more]

Hydrogen is acknowledged as a potential and appealing energy carrier for decarbonizing the sectors that contribute to global warming, such as power generation, industries, and transportation. Many people are interested in employing low-carbon sources of energy to produce hydrogen by using water electrolysis. Additionally, the intermittency of renewable energy supplies, such as wind and solar, makes electricity generation less predictable, potentially leading to power network incompatibilities. Hence, hydrogen generation and storage can offer a solution by enhancing system flexibility. Hydrogen saved as compressed gas could be turned back into energy or utilized as a feedstock for manufacturing, building heating, and automobile fuel. This work identified many hydrogen production strategies, storage methods, and energy management strategies in the hybrid microgrid (HMG). This paper discusses a case study of a HMG system that uses hydrogen as one of the main energy sources together with a... [more]

The need for a verification method for aggregation techniques for passive electrical systems is necessary as power systems increase in complexity. Model reduction is crucial to increase the number of simulations necessary to ensure a stable and reliable design of power systems. This paper presents a novel modal domain-based technique to identify the best aggregation technique for a given system and to indicate the validity of the aggregation. This is done by benchmarking different aggregation techniques and using the dominant contribution factor ratio as a validity parameter. The different aggregation techniques are compared via time-domain simulations against the full detailed model. It is found that (1) the power loss aggregation technique is the most precise when it weighs the equivalent impedances of the parallel feeders, (2) unequal current generation does not impact the aggregation accuracy, (3) individual string aggregation provides the best results for dynamic simulations, and... [more]

Lithium, a silver-white alkali metal, with significantly high energy density, has been exploited for making rechargeable lithium-ion batteries (LiBs). They have become one of the main energy storage solutions in modern electric cars (EVs). Cobalt, nickel, and manganese are three other key components of LiBs that power electric vehicles (EVs). Neodymium and dysprosium, two rare earth metals, are used in the permanent magnet-based motors of EVs. The operation of EVs also requires a high amount of electricity for recharging their LiBs. Thus, the CO2 emission is reduced during the operation of an EV if the recharged electricity is generated from non-carbon sources such as hydroelectricity, solar energy, and nuclear energy. LiBs in EVs have been pushed to the limit because of their limited storage capacity and charge/discharge cycles. Batteries account for a substantial portion of the size and weight of an EV and occupy the entire chassis. Thus, future LiBs must be smaller and more powerful... [more]

Heat enhancement has been addressed by studying flow in channels with different shapes. The present paper investigates a particular channel shape with divergent and convergent forms. Two configurations are addressed: wall channels and pin-fin walls forming divergent/convergent shapes. The flow is assumed to be in a laminar and steady-state condition. The numerical model investigated the heat enhancement for different flow rates represented by Reynolds numbers. The average Nusselt number and the performance evaluation criterion revealed that wall channels outperformed the pin-fin shape. The performance evaluation criterion is higher than 1 for the wall channels. The main reason for this is that the flow passes through and above the wall creating mixing. This flow configuration happened since the wall height is shorter than the test cavity height. It is important to emphasize that pin-fins forming convergent channels did not improve heat enhancement when compared to convergent channels.... [more]

Recently, the concept of the microgrid (MG) has been developed to assist the penetration of large numbers of distributed energy resources (DERs) into distribution networks. However, the integration of DERs in the form of MGs disturbs the operating codes of traditional distribution networks. Consequently, traditional protection strategies cannot be applied to MG against short-circuit faults. This paper presents a novel intelligent protection strategy (NIPS) for MGs based on empirical wavelet transform (EWT) and long short-term memory (LSTM) networks. In the proposed NIPS, firstly, the three-phase current signals measured by protective relays are decomposed into empirical modes (EMs). Then, various statistical features are extracted from the obtained EMs. Afterwards, the extracted features along with the three-phase current measurement are input to three different LSTM network to obtain exact fault type, phase, and location information. Finally, a trip signal based on the obtained fault... [more]

The design of heat exchangers may change dramatically through the use of additive manufacturing (AM). Additive manufacturing, colloquially known as 3D printing, enables the production of monolithic metal bodies, devoid of contact resistance. The small volume of the exchanger, its lightness of weight, and the reduction of its production costs, compared to conventional methods, make the production of heat exchangers by AM methods conventional technologies. The review study presents a new look at the TPMS as a promising type of developed surface that can be used in the area of heat transfer. (Thus far, the only attractive option. The most important feature of additive manufacturing is the ability to print the geometry of theoretically any topography. Such a topography can be a minimal surface or its extended version—triply periodic minimal surface (TPMS). It was practically impossible to manufacture a TPMS-based heat exchanger with the method of producing a TPMS.) The issues related to th... [more]

Synchronized converters are being studied as a viable alternative to address the transition from synchronous generation to power-electronics-based generation systems. One of the important features that make the synchronous generator an unrivaled alternative for power generation is its stability properties and inherent inertial response. This work presents a stability analysis of a synchronverter-based system conducted through the bifurcation theory to expose its stability regions in a grid-connected configuration with an aggregate load model conformed by a ZIP model and an induction motor model. One and two-parameter bifurcation diagrams on the gain, load, and Thévenin equivalent plane are computed and analyzed. All the results confirm the strong stability properties of the syncronverter. Some relevant findings are that the reduction in a droop gain or time constant results in Hopf bifurcations and inertia reduction, but the increase in the time constant leads to decoupling between the... [more]

Alternating current (AC) copper losses in motors increase with carrier frequency of the pulse width modulation (PWM) and are further increased by leakage flux of the permanent magnet. Therefore, AC copper losses increase with motor speed. Conventional techniques for reducing AC copper losses tend to increase other losses. In this paper, AC copper loss was reduced by wrapping a magnetic tape made of a magnetic composite material around the winding. This method controlled the flux path through the winding. Magnetic composite materials are mixtures of magnetic powders and liquid resins whose magnetic properties can be manipulated by changing the combination and other factors. When Fe−Si−Al magnetic tape was wrapped around the winding, the AC copper loss was reduced by 40%. The loss was further reduced by optimizing the magnetic properties of the magnetic composite material. The AC copper loss was maximally reduced when the specific permeability was 100 and the saturation flux density was... [more]

To meet the target of reducing greenhouse gas emissions, hydrogen as a carbon-free fuel is expected to play a major role in future energy supplies. A challenge with hydrogen is its low density and volumetric energy value, meaning that large tanks are needed to store and transport it. By injecting hydrogen into the natural gas network, the transportation issue could be solved if the hydrogen−natural gas mixture satisfies the grid gas quality requirements set by legislation and standards. The end consumers usually have stricter limitations on the gas quality than the grid, where Euromot, the European association of internal combustion engine manufacturers, has specific requirements on the parameters: the methane number and Wobbe index. This paper analyses how much hydrogen can be added into the natural gas grid to fulfil Euromot’s requirements. An average gas composition was calculated based on the most common ones in Europe in 2021, and the results show that 13.4% hydrogen can be mixed... [more]

With the coming of the 2022 Beijing Winter Olympic Games, China’s artificial ice rink construction will be in rapid development. A parametric evaluation of the cooling pipe in a direct evaporation rink was performed by numerical simulation. The results showed that the influence of the temperature of the antifreeze pipe on the ice surface temperature can be ignored. The evaporation temperature of the working medium in the cooling pipe is between −32 °C and −22.4 °C to ensure the ice surface temperature is between −5 °C and −3 °C. With the increase in the cooling pipe spacing, the required evaporation temperature of the working medium in the cooling pipe and the uniformity of the ice surface temperature decreased. The required evaporation temperature of the working medium in the cooling pipe decreases by 1.2−1.5 °C for every 10 mm increment of spacing. With the increase in the cooling pipe diameter, the required evaporation temperature of the working medium in the cooling pipe and the un... [more]

The authors compare the energy consumption and CO2 emissions from vehicles using internal combustion engines (ICE), battery electric vehicles (BEV), fuel cell electric vehicles (FCEV), and two types of hybrid vehicles, BEV-ICE hybrid and BEV-FCEV hybrid. This paper considers several scenarios for four countries’ electricity production from primary energy sources to estimate total CO2 release. Energy consumption of the vehicle per 100 km, emissions during manufacturing, battery production, and lifecycle of the vehicle are considered in the total amount evaluation of CO2 released. The results show that with current technologies for battery manufacturing, and a significant proportion of national grid electricity delivered by fossil fuels, BEV is the best choice to reduce carbon emissions for shorter driving ranges. In the case of electricity generation mainly by low-carbon sources, FCEV and BEV-FCEV hybrid vehicles end up with lower carbon dioxide emissions. In contrast, with electricity... [more]

The main source of mercury (Hg) anthropogenic emissions is the combustion of hard and lignite coal in power plants. Reduction of Hg emissions from coal-based power production systems involves Hg removal from the fuel before combustion/gasification by thermal treatment (i.e., low-temperature pyrolysis). Herein, we present the results of laboratory and bench-scale studies on Hg removal from coal via thermal fuel treatment. The influence of the process temperature and coal residence time in the reaction zone on Hg removal efficiency and fuel parameters is studied. The properties of the process products are analyzed as follows: proximate and ultimate analysis for solids as well as H2, N2, CO, CO2, CH4, organic compounds C2−C5, density, and HHV for gaseous. The results show a substantial reduction of Hg in the fuel using a low-temperature pyrolysis process. At moderate pyrolysis temperature provided Hg removal efficiencies of up to 50% for hard coal and over 90% for lignite, with a moderate... [more]

Scarcity has made fresh water too economically and socially too valuable to be used by the processing industry without restriction. Wet evaporative cooling cycles offer competitive advantages in terms of CoP compared to other cooling cycles with relatively low cost but requiring extensive quantities of water. Dry cooling, on the other hand, requires large heat-transfer areas, in addition to high power requirements. In this study, a hybrid cycle is proposed for high-end cooling loads of 215 MW. The proposed cycle combines the benefits of phase change to make dry cycles competitive. Furthermore, the proposed cycle also diminishes the extensive use of various chemicals used in wet cooling cycles. The applicable dry bulb temperature range is 25−50 °C. Variations in cooling fluid cold temperature due to ambient conditions are curtailed to a maximum of 2 °C by the proposed cycle. A technoeconomic comparison of the proposed solution to wet evaporative cooling is presented, and the effects are... [more]

In this study, the effect of shape variables on the film cooling effectiveness of the compound angled asymmetric laidback fan shaped hole was experimentally investigated, and the optimum values of select design variables were presented. Among the shape variables of the compound angled asymmetric laidback fan shaped hole, the windward and leeward lateral expansion angles and the compound angle were selected as design variables. Test points were chosen using the central composite design method, and the selected design variables were optimized using the Kriging model. The film cooling effectiveness was measured using the PSP technique, and the experiment was conducted under the two density ratios of 1.5 and 2.0 and four blowing ratios of 1.0, 1.5, 2.0, and 2.5. Experimental results showed that the film cooling performance was improved for higher density ratios than lower density ratios. The main effects analysis indicated that larger windward and leeward lateral expansion angles induced h... [more]

Catalytic reactions in producing biofuels often face issues such as low product yield, low selectivity to preferred products and serious environmental issues which leads to the exploration of green technologies. Microwave technology is one of the green technologies that is widely applied in the field such as medical, food, signal processing or navigation, and has been reviewed for its potential in the catalytic reactions for biofuel production. With the application of microwave technology, its unique heating mechanism consists of magnetic field energy and electric field energy that enables the selective heating of materials, allowing rapid reaction and enhancement of catalytic performance of catalysts. In general, this review has discussed on the fundamentals and mechanisms of microwave technology with an in-depth discussion on the application of microwave-absorbing catalysts for biofuel production, especially in ammonia synthesis, bio-oil and 5-HMF production as well as methanation. L... [more]