This work aimed to improve how the equipment of a grid-tied solar-wind system used the installed power of the storage battery while reducing the cost of electricity consumed by a local object from the grid. A method for calculating the parameters for a given load schedule is proposed, along with the value of the reduction in electricity consumption. Values for the power generation of a wind generator and photovoltaic battery are based on archival data. The possible power ratio of the wind generator and the photovoltaic battery is 1:8.33. The formation of the state of charge of the battery involves: a calculation of its value for the morning peak according to the forecast for the next day; adjustable discharge in the evening with full or partial compensation for the load consumption according to the forecast for the next day; a night charge with a given current value. At a one-tariff plan, one battery discharge cycle per day is used. A night charge from the grid is not used. With a two-... [more]

This paper presents the development and implementation of a reinforcement learning agent as the mode selector for a multi-chamber actuator in a load-sensing architecture. The agent selects the mode of the actuator to minimise system energy losses. The agent was trained in a simulated environment and afterwards deployed to the real system. Simulation results indicated the capability of the agent to reduce energy consumption, while maintaining the actuation performance. Experimental results showed the capability of the agent to learn via simulation and to control the real system.

More than 78 million tons of photovoltaic modules (PVMs) will reach their end of life (EOL) by 2050. If they are not responsibly managed, they can (a) pollute our terrestrial ecosystem, (b) indirectly encourage continuous mining and extraction of Earth’s finite resources, and (c) diminish the net environmental benefit of harvesting solar energy. Conversely, successfully recovering them could reduce resource extraction and waste and generate sufficient economic return and value to finance the production of another 2 billion PVMs by 2050. Therefore, EOL PVMs must participate in the circular economy, and business and political leaders are actively devising strategies to enable their participation. This article aims to facilitate and expedite their efforts by comprehensively reviewing and presenting the latest progress and developments in EOL PVM recovery methods and processes. It also identifies and thoroughly discusses several interrelated observations that impede or accelerate their eff... [more]

In this study, pyrolysis of municipal sewage sludge samples from different sources including cattle and chicken manure as well as brook mud, was investigated using a thermogravimetric analysis coupled with a Fourier transform infrared spectrometer (TG-FTIR) at different heating rates (25, 50 and 100 °C/min). In order to determine the kinetic parameters, Arrhenius, model-free Kissinger−Akira−Sunose (KAS), as well as Friedman and Flynn−Wall−Ozawa (FWO) methods were compared. The thermogravimetric results revealed that pyrolysis involved different stages, and that the main decomposition reactions took place in the range of 200−600 °C. In this range, decomposition of biodegradable components (e.g., lipids and polysaccharides), proteins and carbohydrates occurred; meanwhile, there were samples (e.g., cattle manure, brook mud) in which the decomposition step could be observed even at temperatures above 700 °C. According to the Arrhenius method, the activation energies of the first decomposit... [more]

Because of its benefits in terms of high speed, non-destructiveness, and three-dimensionality, as well as ease of integration with computer simulation, computed tomography (CT) technology is widely applied in reservoir geology research. However, rock imaging is restricted by the device used as there is not a win−win for both the image receptive field and corresponding resolution. Convolutional neural network-based super-resolution reconstruction has become a hot topic in improving the performance of CT images. With the help of a convolution kernel, it can effectively extract characteristics and ignore disturbance information. The dismal truth is that convolutional neural networks still have numerous issues, particularly unclear texture details. To address these challenges, a generative adversarial network (RDCA-SRGAN) was designed to improve rock CT image resolution using the combination of residual learning and a dual-channel attention mechanism. Specifically, our generator employs re... [more]

A concern for ensuring energy security is particularly important in the 2020s, a decade significantly marked by economic and political uncertainty: the coronavirus pandemic, the Russian-Ukrainian war, and inflation turning into stagflation in many markets. Additionally, the national and international climate policy promoting the acquisition of energy from non-renewable sources is only a part of the problem that forces a revision of the direction and degree of diversification of energy sources. States, bearing in mind the inevitability of change, in order to maintain energy security, should not only accurately read these phenomena but also effectively prevent them. One of the available solutions is to build a multi-energy concern to ensure energy independence through diversified production and distribution of electricity and non-renewable fuels. To this end, a large international entity centred around the PKN Orlen group has existed in Poland for several years. The construction of this... [more]

Simulation models of transport systems are a key tool for solving many problems in the field of management of these systems. The methodologies for creating such models use datasets on both transport infrastructure and demand for the delivery of goods or passenger transport, however, many factors are considered based on assumptions due to the complexity. This article describes the approach to modeling the cargo transportation system for road transport in Poland based on data obtained by the Central Statistical Office from the TD-E survey. This approach avoids many assumptions about demand as the demand parameters are estimated based on a sample representing the general population—a set of all economic entities generating freight traffic. Basic procedures in the developed approach have been implemented as Python scripts. As a result of the use of the proposed methodology, a country-wide road transport model was obtained based on the TD-E survey from 2018. The adequacy of the developed mo... [more]

The Ordos Basin contains abundant coal resources in the Upper Paleozoic strata. They are shallowly buried or exposed in the periphery of the basin, forming recoverable coal mines and coalbed methane resources. For the deeply buried coal seams of the basin, however, due to complex changes and difficult mining, less attention was paid before. In recent years, with the exploitation of tight gas related to coal source rocks, a large amount of drilling and seismic data has been accumulated in the southeastern Ordos Basin, which makes it possible to study the distribution change and factors controlling Upper Paleozoic coal seams. Delineation of deep coal development and distribution is an important basis for coal, coalbed methane and related tight gas resources in the Upper Paleozoic. We use core, logging and seismic data to analyze the coal geophysics, thickness variation, paleotopography and sedimentary facies in the southeastern Ordos Basin. The lower part of the Shanxi Formation (Fm.) an... [more]

The horizontal drop film evaporator is a key component of the mechanical vapor recompression crystallization system, which can be used to evaporate effluent and recycle secondary vapor energy. However, the properties of heat transfer and flow of the salty effluent sprayed external of the horizontal drop film evaporation tube are obviously different from that of ordinary water. We established a 3D model for a horizontal drop film evaporator in the system, and water and sodium sulfate mixture were manufactured to reproduce the real salty effluent. By applying the VOF (volume of fluid) model, the liquid-gas interface of a salty effluent spray drop film formed on a horizontal tube in the evaporator was traced. The impacts of various heat flux, sodium sulfate content, spray density, and temperature on the local Nusselt number were studied, and a dimensionless correlation was established. The results showed that the effect of surface tension cannot be negligible; as the sodium sulfate conten... [more]

Aerosol pollutant particles indoors significantly affect public health. The conventional wisdom is that natural ventilation will alleviate the dispersion of airborne or aerosol particles. However, we show that the problem is far more complex and that natural ventilation should be applied under specific conditions to be effective. We performed several simulations of a simplified (and easily reproducible) room with a window opening and aerosol particles stratified layers. Opening a window can scatter particles present in stratified layers indoors and potentially contribute to the degradation of indoor air quality for a significant period of time. Moreover, we show that thermal instabilities arising from the temperature gradients due to temperature differences between the indoor and outdoor environment spread the particles randomly indoors, adversely affecting air quality and architectural design. Recommendations for more efficient natural ventilation minimizing aerosol pollutant particle... [more]

This paper introduces a new geometry for the study of dry band formation. Firstly, a thermoelectric simulation of a 69 kV uniformly polluted composite insulator was performed. The results obtained show that thermal stress is greater at the rod surface where current density is maximum. In order to experimentally reproduce the constriction of current density lines on the insulator rod surface, which is the cause of dry band formation, the development of a new simple geometric setup, which was then tested experimentally, was proposed. For this purpose, an ESDD value corresponding to a high level of pollution was used for each polluted sample, and the samples were placed in a climate chamber at constant 90% relative humidity and a constant ambient temperature of 20 °C. Low-voltage tests permitted the determination of the wetting duration, which corresponds to the maximum surface conductance of the polluted layer. The values obtained agree with the 10−40 min duration recommended in IEC 6050... [more]

Solar photovoltaic PV plants worldwide are continuously monitored and carefully protected to ensure safe and reliable operation through detecting and isolating faults. Faults are very common in modern solar PV systems which interrupt normal system operation adversely affecting the performance of the PV systems. When undetected, faults not only cause significant reduction in the efficiency and life span of the PV system, but also result in damage and fire hazards compromising their reliability. Therefore, early fault detection and diagnosis of photovoltaic plants is a necessity for safe and reliable operation required for growing solar PV systems. Unfortunately, several recent fire incidents have been reported recently caused by undetected faults in solar PV systems. Motivated by this challenge, this paper, utilizing a proposed fuzzy logic algorithm, presents a novel technique for detecting and classifying faults in solar PV systems. Furthermore, the proposed method introduces fault ind... [more]

By 2025, biogas is estimated to become a larger part of Indonesia’s energy mix. Biogas is a renewable energy source that also has economic and environmental advantages. Domestic biogas generation has been embraced in Indonesia as a response to the country’s energy security concerns in rural areas. Since the 1970s, 48,038 biogas plants have been built in the region. To fully develop this technology, Indonesia must discontinue relying on fossil fuels and substitute current fossil-fuel-based energy. This article provides an overview of renewable technology in Indonesia, as well as addressing domestic energy demands and referring to existing literature on the socio-technical and socio-economic barriers to biogas adoption in Indonesia. Based on a rigorous review of 71 publications published in Web of Science (WoS) between 2010 and 2021, this study explores existing barriers for biogas adoption by summarizing the current literature from technical, economic, social and environmental perspecti... [more]

Failure detection methods are of significant interest for photovoltaic (PV) site operators to help reduce gaps between expected and observed energy generation. Current approaches for field-based fault detection, however, rely on multiple data inputs and can suffer from interpretability issues. In contrast, this work offers an unsupervised statistical approach that leverages hidden Markov models (HMM) to identify failures occurring at PV sites. Using performance index data from 104 sites across the United States, individual PV-HMM models are trained and evaluated for failure detection and transition probabilities. This analysis indicates that the trained PV-HMM models have the highest probability of remaining in their current state (87.1% to 93.5%), whereas the transition probability from normal to failure (6.5%) is lower than the transition from failure to normal (12.9%) states. A comparison of these patterns using both threshold levels and operations and maintenance (O&M) tickets indi... [more]

In power system planning, the growth of renewable energy generation leads to several challenges including system reliability due to its intermittency and uncertainty. To quantify the relatively reliable capacity of this generation, capacity credit is usually adopted for long-term power system planning. This paper proposes an evaluation of the capacity credit of renewable energy generation using stochastic models for resource availability. Six renewable energy generation types including wind, solar PV, small hydro, biomass, biogas, and waste were considered. The proposed models are based on the stochastic process using the Wiener process and other probability distribution functions to explain the randomness of the intermittency. Moreover, for solar PV—the generation of which depends on two key random variables, namely irradiance and temperature—a copula function is used to model their joint probabilistic behavior. These proposed models are used to simulate power outputs of renewable ene... [more]

This article presents a new approach for the efficient calculation of sensitivities in radiation dose estimates, subject to imprecisely known nuclear material cross-section data. The method is a combined application of adjoint-based models to perform, simultaneously, both the sensitivity calculation together with optimal adaptive mesh refinement. Adjoint-based sensitivity methods are known for their efficiency since they enable sensitivities of all parameters to be formed through only two solutions to the problem. However, the efficient solutions can also be obtained by their computation on optimal meshes, here guided by goal-based adjoint approaches. It is shown that both mesh adaptivity and sensitivity can be computed by the same adjoint solution, meaning both can be performed without additional costs. A simple demonstration is presented based on the Maynard fixed-source problem where uncertainties, with respect to material cross-sections, of doses received in local regions are exami... [more]

The purpose of the article is to define the risk factors in rail transport and to show that the lack of sufficient identification of risks in individual phases affects the implementation of this type of transport. A literature study has been conducted to identify key risk factors and their impact on rail transport in Poland. For this purpose, a list of railway accidents in 2010−2020 in which people were injured, or there were significant losses in terms of the environment was presented. The realization of the objective focused on research proceedings covering the theoretical and cognitive sphere. This study included an analysis of the existing theoretical heritage in the area of risk management processes in rail transport, as well as a survey of the empirical research, which concentrated on the identification and assessment of key factors that influence the realization of rail transport in Poland. The work is of a utilitarian nature, as the need for conscious risk management has been d... [more]

Stress shadowing affects the simultaneous propagation of fractures from multiple perforation clusters. Employing uniform perforation parameters for all clusters cause the unbalanced growth of fractures, which arouses the demand of optimizing non-uniform perforation parameters. An optimization workflow combining a fracture propagation model and the particle swarm optimization method (PSO) is proposed for multi-cluster fracturing in this study. The fracture model considers the coupling of rock deformation and fluid flow along the wellbore and fractures, and it is solved by using the Newton iteration method. The optimization is performed by taking the variance of multiple fracture lengths as fitness value function in the frame of the PSO method. Numerical results show that using the same spacings and perforation parameters for all clusters is detrimental to the balanced growth of multiple fractures. The variance of fracture lengths drops greatly through optimization of cluster spacings an... [more]

Energy consumption in the building sector is a major concern, particularly in this time of worldwide population and energy demand increases. To reduce energy consumption due to HVAC systems in the building sector, different models based on measured data have been developed to estimate the cooling load. The purpose of this work is to develop a linear regression model for cooling load of a research room based on the radiant time series (RTS) components of the cooling load that consider the building material and the environment. Using the forward step method, linear regression models were developed for both all-seasons and seasonal data from three years of cooling load data obtained from the RTS method for a research room at Mangosuthu University of Technology (MUT), South Africa. The male and female occupants, window cooling load, and roof cooling load were found to be the most influential predictors for the cooling load model. The obtained relative errors between the best all-seasons mo... [more]

The operation of many nuclear pressurized water reactors is being extended beyond their design lifetime limit. From the perspective of possible further lifetime extension, safety requirements are a priority. Therefore, the quantification of the neutron irradiation embrittlement of the reactor pressure vessel (RPV) is an important issue, as this is a guiding parameter that influences the reactor lifetime. In this context, the Institut de Radioprotection et de Sûreté Nucléaire developed a calculation scheme for the analysis of RPV aging under neutron irradiation, named VACS (vessel aging calculation scheme). VACS couples a deterministic approach (CASMO5 and SIMULATE5) to evaluate the full-core fission neutron source term and a Monte Carlo modeling (MCNP6) approach to model the neutron attenuation from the core to sites of interest (RPV, surveillance capsules, etc.). To ensure the reliability of aging predictions, this paper describes a detailed analysis of the neutron H.B. Robinson-2 rea... [more]

The electronic wedge brake system (EWB) used in the automotive industry is a new structure designed for brake-by-wire systems. This paper proposes a novel EWB system which is mainly composed of a screw-driven wedged inner brake pad, a fixed outer brake pad, a fixed caliper-flexible brake rotor and a hybrid stepper motor. The proposed EWB system does not have a planetary gear set or a ball screw mechanism, it simplified the existing EWB systems. The proposed EWB system is designed to take advantage of the self-interlocking ability of the screw mechanism to hold the brakes with zero-overhauling and the self-energizing ability of the wedge brake pad to reduce the braking effort. In the braking phase, the screw driven wedge inner brake pad forces the flexible rotor against a fixed flat brake pad. The rotor is elastically deformed to make the contact against the fixed pad. Except for the applied force, the friction force between the brake rotor and the wedge pad exerts additional force as t... [more]

Combining iron and copper ores can generate an oxygen carrier that has a synergic effect of high temperature resistance and high reactivity. In this work, typical cements available in the market were studied as binders to bind magnetite and chalcopyrite to develop a suitable oxygen carrier for chemical-looping combustion (CLC). A first selection step suggested that an aluminate cement, namely CA70, could favor the generation of oxygen carrier particles having good crushing strength, good particle yield, and high reactivity. The CA70-bonded oxygen carrier was then subjected to cyclic tests with CH4, CO, and H2 in reduction and in air oxidation at temperatures of 850, 900, and 950 °C with gas concentrations of 5, 10, 15, and 20% in a batch-fluidized bed reactor. The increase in temperature promoted the fuel conversion. At 950 °C, the conversions of CH4 and CO reached up to 80.4% and 99.2%, respectively. During more than 30 cycles, the oxygen carrier kept a similar reactivity to the fresh... [more]

In this work, a discontinuous airfoil fin printed circuit heat exchanger (PCHE) was used as a recuperator in a micro gas turbine system. The effects of the airfoil fin geometry parameters (arc height, maximum arc height position, and airfoil thickness) and the airfoil fin arrangements (horizontal and vertical spacings) on the PCHE channel’s thermo-hydraulic performance were extensively examined by a numerical parametric study. The flow features, local heat transfer coefficient, and wall shear stress were examined in detail to obtain an enhanced heat transfer mechanism for a better PCHE design. The results show that the heat transfer and flow resistance were mainly increased at the airfoil leading edge owing to a flow jet, whereas the airfoil trailing edge had little effect on the thermo-hydraulic performance. The airfoil thickness was the most significant while the arc height and the vertical spacing were moderately significant to the performance. Moreover, only the airfoil thickness h... [more]

Water content and water−coal interface wettability are always the difficult issues of coalbed methane adsorption/desorption. In order to study the effects of the pore structure and wettability of different macro coal components on methane adsorption and desorption, we compared and analyzed the wettability difference between vitrain and durain, and revealed the influence of wettability on methane adsorption and desorption through a pore structure analysis, wettability measurements, an adsorption−desorption experiment and adsorption heat calculations under different conditions, taking the No. 4 coal in Dafosi Coal Mine of the Huanglong coalfield as the research object. The results show that both vitrain and durain are relatively hydrophilic substances. However, vitrain has a low ash content, high volatility, and less oxygen, and the pores are mainly semi-closed pores compared with dark coal. Vitrain also has poor connectivity, poor sorting, a small pore diameter, and a coarser surface, r... [more]

The article discusses alternatives to the development of the common electricity market of the Eurasian Economic Union countries. In the study, the authors identified three tasks: to analyze the process of forming a unified energy market for the EAEU countries; to assess the achievability of indicators of “greening” the economy of the EAEU countries according to the adopted Millennium Goals by 2025 and 2030; and to consider the impact of various factors on the development of the common electricity market of the Eurasian Economic Union countries in the conditions of the current economic crisis. The research hypothesis suggests that the energy unification of the countries will not lead to the abandonment of the use of traditional energy resources, but the need to increase the efficiency and environmental friendliness of their use will come into focus, and the active inclusion of the electric power industry in modern global “green” trends based on the development of renewable energy genera... [more]