In this paper, we propose a concise but general two-dimensional model based on the penetration model in order to simulate the heat and mass transfer and drying kinetics of sludge in the paddle dryer. The sludge control equations were developed to simulate the heat and mass transfer of sludge and the penetration model was introduced to describe the mixing of sludge. Compared to the experimental results in the existing literature, the drying kinetics simulated simulated by the present model were in good agreement with the experimental data under various operation conditions. The effects of four key parameters on drying kinetics in the paddle dryer were studied. The results showed that the water content increased with the increase of sludge flowrate and the decrease of wall temperature and sludge density. Furthermore, the stirring velocity had little effect on the drying kinetics of the sludge. The present study contributes to the better understanding of the sludge drying kinetics and pro... [more]

In high voltage insulation systems, dielectric materials may be exposed to partial discharges (PD), which can lead to equipment failures and safety hazards. Therefore, it is crucial to detect and characterize PD activity on the surface of insulation systems. Techniques such as radio frequency signal analysis and ultraviolet radiation emission detection are commonly used for this purpose. In this research study, an analysis was conducted on the signals emitted by surface PD in the radio frequency and ultraviolet radiation emission ranges. The goal was to indicate possible directions for further basic research aimed at building a knowledge base and improving measurement methods. The analysis confirmed that radio frequency and ultraviolet signal analysis can provide important information about the activity and location of PD on the surface, including the intensity and nature of PD. The experimental investigation presented in this paper provides valuable insights into the potential for usi... [more]

The installed wind power capacity is growing worldwide. Remote condition monitoring of wind turbines is employed to achieve higher up-times and lower maintenance costs. Machine learning approaches can be used for detecting developing faults in wind turbines in their earlier occurrence. However, training fault detection models may require large amounts of past and present data. These data are often not available or not representative of the current operation behaviour. These data can be acquired with supervisory control and data acquisition systems. Note also that newly commissioned wind farms lack data from previous operation, whilst older installations may also lack representative working condition data as a result of control software updates or component replacements. After such events, a turbine’s operation behaviour can change significantly so its data are no longer representative of its current behaviour. Therefore, this paper shows that cross−turbine transfer learning can improve... [more]

Perovskite Solar Cells (PSCs) have attracted attention due to their low cost, easy solution processability, high efficiency, and scalability. However, the benchmark expensive hole transport material (HTM) 2,2′,7,7′-tetrakis[N, N-di(4-methoxyphenyl)amino]-9,9′-spirobifluorene (Spiro-MeOTAD), which is traditionally solution-processed with toxic solvents such as chlorobenzene (CB), dichlorobenzene (DCB), or toluene, is a bottleneck. To address this issue, this work investigates the implementation of Zn(II), Cu(II), or Co(II) tetra-tert-butylphthalocyanines (TBU4-Cu, TBU4-Zn, TBU4-Co), established macrocyclic derivatives whose synthesis and processing inside the devices have been redesigned to be more environmentally sustainable and cost-effective by substituting conventional solvents with greener alternatives such as anisole, propane-1,2-diol, and their mixture, as dopant-free HTMs in planar n-i-p PSCs. The anisole-processed HTMs provided power conversion efficiencies (PCE) up to 12.27% f... [more]

As a result of the dissemination of the sustainability concept, social disclosures have become an important area of non-financial reporting, and the energy sector is no exception. The purpose of our article is a multi-faceted evaluation of sustainability reports published by companies operating in the Polish energy sector, from the perspective of social disclosures. The study involved the Polish listed companies that made up the WIG-Energia index. The time scope of the study covers the 2017−2021 period. In total, 54 non-financial reports were analyzed. In the first place, a comparative analysis was carried out to assess the social disclosures made by the WIG-Energia companies against the background of the biggest and the most liquid (blue chip) WIG20 companies. All the applied tools: ESG rating, NFR_S index, and multidimensional data visualization, have confirmed that the energy companies year by year have been presenting larger and larger extents of social disclosures. At the same tim... [more]

Penetration of wind power plants (WPPs) in the electric power system will complicate the system load flow analysis. Consequently, the traditional load flow algorithm can no longer be used to find the solution to the load flow problem of such a system. This paper proposes a doubly fed induction generator (DFIG)-based WPP model for a load flow analysis of the electric power system. The proposed model is derived based on the power formulations of the WPP—namely, DFIG power, DFIG power loss, and WPP power output formulas. The model can be applied to various DFIG power factor operating modes. In the present paper, applications of the proposed methods in two representative electric power systems (i.e., IEEE 14-bus and 30-bus systems) have been investigated. The investigation results verify the proposed method’s capability to solve the load flow problem of the system embedded with DFIG-based variable-speed WPPs.

The expansion of end-to-end Industry 4.0 technologies in various industries has caused a technological shock in the mineral resource sector, wherein itsdigital maturity is lower than in the manufacturing sector. As a result of the shock, the productivity and profitability of raw materials extraction has begun to lag behind the industries of its deep processing, which, in the conditions of volatile raw materials markets, can provoke sectoral crises. The diffusion of Industry 4.0 technologies in the mining sector (Mining 4.0) can prevent a technological shock if they are implemented in all segments, including quarrying (Surface Mining 4.0). The Surface Mining 4.0 technological platform would connect the advanced achievements of the Fourth Industrial Revolution (end-to-end digital artificial intelligence technologies, cyber-physical systems and unmanned production with traditional geotechnology) without canceling them, but instead bringing them to a new level of productivity, resource con... [more]

In recent years, renewable energy (RE) has shown promise as a sustainable solution to the rising energy demand worldwide. Photovoltaic (PV) technology has emerged as a highly viable RE alternative. The majority of PV schemes use specific PV models with specified parameters. This study proposes a PV model with generic specifications, a PV array, a DC/DC converter, a DC/AC inverter, maximum power point tracking (MPPT), and grid synchronization using a feedback control system under the MATLAB/Simulink environment. Various MPPT techniques have been adapted to track the PV’s maximum power point (MPP); however, there are various uncertainties. To address these challenges, this paper presented a perturb and observe (P&O) strategy to track the MPP of PV systems reliably. The MPP of a PV system varies according to meteorological order, such as solar radiation and cell temperature. The MPPT primarily gathers the maximum current and voltage of the PV array and provides them to the load using a bo... [more]

The in-vessel Loss-of-Coolant Accident (LOCA) is one of the design basis accidents in the design of the EU DEMO tokamak fusion reactor. System-level codes are typically employed to analyse the evolution of these transients. However, being based on a lumped approach, they are unable to quantify localised quantities of interest, such as local pressure peaks on the vacuum vessel walls, to which the failure criteria are linked. To calculate local quantities, the 3D nature of the phenomenon needs to be considered. In this work, a 3D transient model of the in-vessel LOCA from a water-cooled blanket is developed. The model is implemented in the commercial CFD software STAR-CCM+. It simulates the propagation of the water jet in the vessel from the beginning of the accident, thus accounting for the phase change of the water, i.e., from the pressurised liquid phase to the vapour phase inside the vessel, being the latter at a much lower pressure than in the blanket coolant pipes. Due to the large... [more]

In order to accurately calculate the geometric characteristics of the twin-screw compressor and obtain the optimal profile parameters, a calculation method for the geometric characteristics of twin-screw compressors was proposed to simplify the profile parameter design in this paper. In this method, the database of geometric characteristics is established by back-propagation (BP) neural network, and the genetic algorithm is used to find the optimal profile design parameters. The effects of training methods and hidden layers on the calculation accuracy of neural network are discussed. The effects of profile parameters, including inner radius of the male rotor, protection angle, radius of the elliptic arc, outer radius of the female rotor on the comprehensive evaluation value composed of length of the contact line, blow hole area and area utilization rate, are analyzed. The results show that the time consumed for the database established by BP neural network is 92.8% shorter than that of... [more]

Recent research has shown an increasing interest in wireless power transfer (WPT) technology for drone batteries. The inconvenience of wired charging, especially for drones, is a huge obstacle. In this research project, a WPT platform was proposed by applying four transmitting coils and a single receiving coil. To meet the industrial standards required for transmitter Tx and receiver Rx, a calculation of the parameters was implemented. An H-bridge MOSFET was used as a DC−AC inverter, a bridge diode was used as an AC−DC rectifier, and a Pi low pass filter was added to the receiver circuit design to filter the high-frequency noise. Experimental investigations were conducted to study the maximum power and power efficiency of the coil’s alignment. The focus of this article was to design and fabricate workable multiple-transmitter coils and a single-receiver coil for a wireless power transfer system, in order to charge a 3S LiPo drone’s battery. It not only covers an overview of wireless po... [more]

This study explored underground biomethanation as a means to achieve carbon neutrality and promote carbon circular utilization by methanating CO2 and hydrogen-rich industrial waste gas in depleted natural gas reservoirs (MECHIG). This approach not only aids the development of carbon capture, utilization, and storage (CCUS) technologies, but also effectively processes industrial waste gas, thereby reducing pollutant emissions. In order to verify the feasibility of the MECHIG concept, this study builds upon the analysis of the MECHIG process overview and employs the net present value (NPV) analysis method to investigate its economic viability. Additionally, the study conducts a sensitivity analysis on six factors, namely methanation efficiency, facility site investment, hydrogen content in waste gas, natural gas prices, operation and maintenance (O&M) investment, and CO2 capture and injection prices. The results indicate the following: (1) Under the baseline scenario, the NPV of the MECH... [more]

The need for and interest in very-short-term load forecasting (VSTLF) is increasing and important for goals such as energy pricing markets. There is greater challenge in predicting load consumption for residential-load-type data, which is highly variable in nature and does not form visible patterns present in aggregated nodal-type load data. Previous works have used methods such as LSTM and CNN for VSTLF; however, the use of DNN has yet to be investigated. Furthermore, DNNs have been effectively used in STLF but have not been applied to very-short-term time frames. In this work, a deep network architecture is proposed and applied to very-short-term forecasting of residential load patterns that exhibit high variability and abrupt changes. The method extends previous work by including delayed load demand as an input, as well as working for 1 min data resolution. The deep model is trained on the load demand data of selected days—one, two, and a week—prior to the targeted day. Test results... [more]

In this paper, an asymmetric rotor interior permanent magnet (ARIPM) motor with high demagnetization prevention capability and robust torque performance is proposed. The key contribution of this paper lies in two aspects. On the one hand, a novel asymmetric rotor with a shifted magnet axis is proposed to improve the demagnetization prevention capability and torque density. In order to obtain a proper asymmetric rotor topology of the ARIPM motor, the multi-physical performances, especially the PM demagnetization characteristics of five types of PM arrangements, are analyzed. Furthermore, an asymmetric rotor with V- and VV-type PM arrangement is preliminarily designed, considering the multi-physical performance balance and the potentially high anti-demagnetization ability. On the other hand, it is found that the asymmetric rotor structure can not only improve the nominal value of motor performance but also can enhance the resistance to the influence of manufacturing uncertainties. Theref... [more]

The energy stored in fossil fuels is released through combustion and is a fundamental process in the production of cement. The negative aspect of this combustion is the emission of greenhouse gases and dust. This paper presents the results of a study conducted within a cement plant in Ożarów (south-eastern Poland). The chemical properties (selected elements) in the needles of Scots pine (Pinus sylvestris L.) were determined. The needle surface was scanned using a scanning electron microscope (SEM) and was characterised in terms of chemical composition through energy dispersive spectroscopy (EDS). The concentrations of selected analytes in the biennial needles formed the following descending sequence: Fe > Al > Mn > Zn > Cu > Pb > Cr > Ni. SEM/EDS microphotographs showed the presence of particles of varying shape, size and chemical composition indicative of anthropogenic origin.

This paper proposes correlation equations of heat transfer and pressure drop for the design and operation of tunnel kilns loaded with lattice brick settings of different geometrical parameters in the form of Nusselt number and friction factor. The developed correlation equations considered parameters that were not investigated in previous studies, such as the relative roughness of the bricks and the stack channels, and they also extended the Reynolds numbers to a practical range that was not covered before in a simple, practical form. The correlation equations are valid for Reynolds number between 125 and 10,200, Prandtl number between 0.68 and 0.73, brick’s relative roughness between 0.23 and 0.93, voidage fraction between 0.48 and 0.653, and the geometrical parameters of the tested lattice brick settings. The achieved correlations of the Nusselt number and the friction factor are well compared with the available correlations in the literature in their valid range of parameters. It is... [more]

In this research sustainable refrigerants are tested as filler gases in Transparent Thermal Insulation (TTI) for the first time. These are compared with pig fat, a readily available material with good thermal inertia that is proposed as an organic phase change material (PCM). The aim of this paper is to compare the thermal behaviour of a Hybrid Air Conditioning System (HACS) with TTI filled with R134a, R1233zd and a pig-fat-based PCM. Numerical simulations using the OPAQUE 3 program and two online platforms are used to evaluate the possible application of TTI and PCM as passive systems. Additionally, three TTI models are used to simulate the heat transfer processes of TTI, PCM and R134a. The velocity of the flow in the air gap is also analysed numerically in both laminar and turbulent states. For the assessment, infrared thermographic imagery is used to measure the temperatures in the HACS, giving values of 46.17 °C by day and 38.05 °C at night. The results show that the heat loss and... [more]

The solid oxide fuel cell (SOFC) system is complicated because the characteristics of gas, heat, and electricity are intricately coupled. During the operation of the system, problems such as frequent failures and a decrease in the stack’s performance have caused the SOFC system to work less well and greatly shortened the SOFC’s practical life. As such, it is essential to accurately forecast its remaining useful life (RUL) to make the system last longer and cut down on economic losses. In this study, both model-based and data-driven prediction methods are used to make predictions about the RUL of SOFC. First, the linear degradation model of the SOFC system is established by introducing degradation resistance as the index of health status. Using the Kalman filtering (KF) method, the health status of SOFC is evaluated online. The results of the health state estimation indicated that the KF algorithm is accurate enough to provide a good basis for the model-based RUL prediction. Then, a lon... [more]

The main objective of this paper is to propose two innovative monitoring methods for electrical disturbances in low-voltage networks. The two approaches present a focus on the classification of voltage signals in the frequency domain using machine learning techniques. The first technique proposed here uses the Fourier transform (FT) of the voltage waveform and classifies the corresponding complex coefficients through a multilayered neural network with multivalued neurons (MLMVN). In this case, the classifier structure has three layers and a small number of neurons in the hidden layer. This allows complex-valued inputs to be processed without the need for pre-coding, thus reducing computational cost and keeping training time short. The second technique involves the use of the short-time Fourier transform (STFT) and a convolutional neural network (CNN) with 2D convolutions in each layer for feature extraction and dimensionality reduction. The voltage waveform perturbations taken into con... [more]

A large number of application cases show that air filter media are easy to fail under extreme conditions of high humidity, haze, rain and snow, thus seriously affecting the energy efficiency of gas turbines. To study the impact of humidity on the dust-holding performance of filter media, three typical filter media applied for gas turbines with a similar efficiency are selected, and their dust-holding performance is investigated at a humidity of 30%, 60% and 75%, respectively. The results showed that the dust-holding pressure drop curves of three filter media were divided into two phases. With the increase of humidity, the increasing pressure drop rate of three filter media decreased. The pressure drop synthetic fiber, glass fiber composite filter media and the synthetic fiber composite filter media with a sandwich structure were more significantly affected by humidity during the filter cake filtration phase. Under the same conditions, filter media with a sandwich structure had the high... [more]

This research aims to compare, from a technical and financial perspective, the application of biological (methane-capture) and thermal (incineration) treatments of waste in Mexico City in order to generate clean energy. For each alternative, pessimist (50%), realistic (80%), and optimistic (100%) scenarios were considered in terms of the efficiency collection rates of methane and the efficiency of the capacity conversion factor for incineration. For the methane project, the LandGEM model was used to evaluate the potential generation of methane. In order to calculate the electricity output that could be generated through incineration, we relied on two key factors: the total amount of heat that could be generated by burning the waste and the average level of moisture in the waste material. The evaluation resulted in an annual energy generation of 206.09 GWh for methane and 4183.39 GWh for incineration, both in the realistic scenario. Both projects reported positive financial indicators w... [more]

Laminated shales are widely developed in the Dongying Sag and have attracted much attention as an oil reservoir. Macroscopically, these shales generally have multi-scale cyclicity, which is closely related to the development of laminae. Therefore, analyzing the origin of their cyclicity is helpful to understanding the formation mechanism of laminated shales and the vertical heterogeneity of shale reservoirs, which are of great significance for continental shale oil exploration and development. In this study, a gamma ray (GR) logging series, high-resolution elemental geochemical data, high-resolution core scanning photos and grayscale data, and mineralogical data were used to characterize the cyclicity of shale at different scales, and their relationship with different astronomical cycles was discussed. The results show that the Es3L and Es4U shale in the Dongying Sag has cyclicity from the meter-scale to the ten-meter scale and then to the hundred-meter scale, which is mainly manifeste... [more]

Global warming might be mitigated if emissions were interrupted through carbon capture technologies, as there is a significant amount of comprehensive studies on them. An outline of the main gaps and trends of a technology is critical for further development. In this context, this study provides an overview of calcium looping carbon capture processes that have proven their potential and commercial viability. A bibliometric analysis is conducted on both Scopus and Web of Science database by seeking the keywords “calcium looping”, “co2 capture”, and “fluidized bed” in titles, abstracts, and keywords. Word selection was based on a list of relevant papers on the topic. These items of data have been processed and analyzed based on the number of publications and citations by emphasizing recent publication evolution, journal influence, the use of specific keywords, and co-citation. Results reveal that the European Union (EU) leads the rankings on the topic, followed by Canada. Keyword choice... [more]

Recently, the development of integrated inverters for photovoltaic systems has been widely performed to reduce overall system size, costs, and losses. Thus, integrated inverters have emerged as a prominent solution for replacing two-stage power conversion composed of a step-up converter and a voltage source inverter. Thereby, this paper proposes an integrated inverter topology for single-phase grid-tied photovoltaic systems. The proposed power converter, called a Single-Phase Integrated Zeta Inverter (SP-IZI), can boost the input voltage and inject a sinusoidal and regulated current into the mains with low harmonic distortion. The SP-IZI is based on integrating modified DC-DC Zeta converters, designed and controlled to operate in a discontinuous conduction mode, and presents similarities with the Modified Zeta Inverter (MZI). In this way, this paper compares the main parameters of both topologies and provides a complete study of the SP-IZI, involving both quantitative and qualitative s... [more]

The commercialization of perovskite solar cells is hindered by the poor thermal stability of organic−inorganic hybrid perovskite materials. Herein, we demonstrate that crystalline thermoplastic polymer additives, such as a mixture of polyethylene oxide (PEO, 100,000 MW) and polyethylene glycol (PEG, 12,000 MW), can improve the thermal stability of CH3NH3PbI3 (MAPbI3) perovskites and thereby enhance device stability. High-quality less-defect perovskite films were obtained by establishing a strong reaction between hydroxy groups in the PEO + PEG mixture and the uncoordinated Pb2+ in MAPbI3 perovskites, leading to a high power conversion efficiency of over 18% despite the presence of insulating thermoplastic polymers in the MAPbI3 film. More importantly, as compared with pristine MAPbI3 perovskite solar cells, the PEO + PEG-modified counterparts showed significantly improved stability under thermal treatment at 85 °C in ambient air with a relative humidity of 50−60%, remaining at nearly 7... [more]