The article investigated the possibility of reusing heat resistant glass cullet to improve the mechanical properties of high-temperature composites. This is an excellent recycled aggregate that may be used as a substitute for alumina cement, and for fine natural aggregate in the production of concrete based on hydraulic binder. The experimental programme comprised of strength testing conducted on 40 × 40 × 160 mm cuboidal samples. The model mixture was modified by filler that comprised glass recyclate, amounting to 5%, 10%, and 15% of the mass of gravel and cement. Given the degree of glass grounding, use was made of two fractions, 0/4 and 0/0.125 mm. Six modified mixtures were produced. Tests were then carried out on their selected physical and mechanical properties as well as the impact of temperature, topography, and chemical composition exerted on the composite. Next, the progress and development of compressive strength and flexural strength after 14 and 28 days of curing were stud... [more]

Signs of wetness in housing are a significant obstacle to the renovation and energy rehabilitation of old and energy-intensive heritage buildings, especially in cold climates. Thus, in order to avoid the numerous possibilities of degradation caused by the moisture transfer phenomena in the building envelope, the a disruptive aeraulic process, which focuses on the ventilation of an air gap between the thermal insulation and the wet wall, has been designed and its assessed. This system avoids the presence of liquid water at the wall surface by maintaining the hygrothermal balance within the wet wall. This enables the mechanical durability of the supporting structure, the absence of biological activity and/or frost and, hence, the durability of the thermal insulation. These issues are investigated through a case study based on a real site. Over a year of measurements, the wet wall was constantly maintained in hygroscopic balance, around 90% RH, guaranteeing the preservation of its mechani... [more]

Fast-growing methods of automatic data acquisition allow for collecting various types of data from the production process. This entails developing methods that are able to process vast amounts of data, providing generalised knowledge about the analysed process. Appropriate use of this knowledge can be the basis for decision-making, leading to more effective use of the company’s resources. This article presents the approach for data analysis aimed at determining the operating states of a wheel loader and the place where it operates based on the recorded data. For this purpose, we have used several methods, e.g., for clustering and classification, namely: DBSCAN, CART, C5.0. Our approach has allowed for the creation of decision rules that recognise the operating states of the machine. In this study, we have taken into account the GPS signal readings, and thanks to this, we have indicated the differences in machine operation within the designated states in the open pit and at the mine bas... [more]

Scientific and timely sustainability evaluation of the photovoltaic industry along the Belt and Road is of great significance. In this paper, a novel hybrid evaluation model is proposed for accurate and real-time assessment that integrates modified set pair analysis with least squares support vector machine that combines improved cuckoo search algorithm. First, the indicator system is set from five principles, namely economy, politics, society, ecological environment and resources. Then, the traditional approach is established through modifying set pair analysis on the basis of variable fuzzy set coupling evaluation theory. A modern intelligent assessment model is designed that integrates improved cuckoo search algorithm and least squares support vector machine where the concept of random weight is introduced in improved cuckoo search algorithm. In the case analysis, the relative errors calculated by the proposed model all fluctuate in the range of [−3%, 3%], indicating that it has the... [more]

Combustion processes continue to be essential for the energy supply sector. A reliable energetic evaluation of these processes is crucial, particularly since the pollutants resulting from combustion have a significant impact on global warming. This work evaluates a combustion using the exergetic evaluation and the Physical Optimum (PhO) as it is described in VDI-Guideline 4663. Differences between PhO and exergy are investigated, allowing a distinct differentiation and examining the PhO’s added value in combustion analysis. Based on the evaluation of a simulated methane combustion, this paper shows that the PhO-Factor may be used to evaluate combustion processes. However, it shows that the PhO of a combustion process is a simplification of this fuels exergy and does not provide advantages to the exergy evaluation. Nevertheless, an adaption of the PhO is not carried out in the context of this work since the minimal deviation of the simulated energy indicators currently cannot justify an... [more]

This article analyses the business community in Poland and their views on climate change and the objectives of the European Green Deal (EGD). The authors focus on the analysis of the attitude of entrepreneurs towards the cultural and ideological stereotypes promoted by climate denialists. This article shows that the ideological factor may play a certain role in shaping the attitudes of entrepreneurs towards energy transition. The research was carried out on a sample of 400 entrepreneurs. The research results indicate that the ideological factor is of particular importance among entrepreneurs who are concerned about the costs of energy transition and the expenditure related to the implementation of the EGD for economic reasons. According to the authors, the stereotypes promoted by climate sceptics may find fertile ground, particularly when accompanied by fears of additional financial costs. Attitudes towards the goals of energy transition among entrepreneurs usually differ depending on... [more]

Since the outbreak of COVID-19 and the American decoupling policy, the global value chains (GVCs) have been switched to regional GVCs, and, in the worst case, are subject to a potential alteration of reversing the GVCs, ultimately entailing a severe impact on international trade and the global energy market. This paper applies a quantitative approach using a computational general equilibrium (CGE) model to estimate the effects of the reverse GVC factors on the global economy, trade, and energy market. These reverse GVC factors will decrease the global GDP, and such effect will bring a greater influence on both China as well as the United States, which is pursuing decoupling. The increased trade costs due to these factors will reduce the GVC indices, mostly in ASEAN by 0.2~1.15%, followed by Korea, Japan and China. Surprisingly, the GVC index in the United States is expected to be strengthened due to the enhanced GVC with its allies such as Canada and Mexico. In China, the use of oil, g... [more]

This paper develops simplifying entropic models of irreversible closed cycles. The entropic models involve the irreversible connections between external and internal main operational parameters with finite physical dimensions. The external parameters are the mean temperatures of external heat reservoirs, the heat transfers thermal conductance, and the heat transfer mean log temperatures differences. The internal involved parameters are the reference entropy of the cycle and the internal irreversibility number. The cycle’s design might use four possible operational constraints in order to find out the reference entropy. The internal irreversibility number allows the evaluation of the reversible heat output function of the reversible heat input. Thus the cycle entropy balance equation to design the trigeneration cycles only through external operational parameters might be involved. In designing trigeneration systems, they must know the requirements of all consumers of the useful energies... [more]

The rapid economic growth observed in Central European countries in the last thirty years has been the result of profound political changes and economic liberalization. This growth is partly connected with reducing carbon dioxide (CO2) emissions. However, the problem of CO2 emissions seems to remain unresolved. The aim of this paper is to test whether the Environmental Kuznets Curve (EKC) hypothesis holds true for Central European countries in an annual sample data that covers 1995−2016 in most countries. We examine cointegration by applying the Autoregressive Distributed Lag bound testing. This is the first study examining the relationship between CO2 emissions and economic growth in individual Central European countries from a long-run perspective, which allows the results to be compared. We confirmed the cointegration, but our estimates confirmed the EKC hypothesis only in Poland. It should also be noted that in all nine countries, energy consumption leads to increased CO2 emissions... [more]

Electromagnetic interference (EMI) from renewable power systems to the grid attracts more attention especially in the low-frequency range, due to the low switching frequency of high-power inverters. It is significantly important to derive EMI models of power inverters as well as to develop strategies to suppress the related conducted emissions. In this work, black-box modelling is applied to a three-phase inverter system, by implementing an alternative procedure to identify the parameters describing the active part of the model. Besides, two limitations of black-box modelling are investigated. The first regards the need for the system to satisfy the linear and time-invariant (LTI) assumption. The influence of this assumption on prediction accuracy is analysed with reference to the zero, positive and negative sequence decomposition. It is showing that predictions for the positive/negative sequence are highly influenced by this assumption, unlike those for the zero sequence. The second l... [more]

Power generation using dielectric elastomer (DE) artificial muscle is attracting attention because of its light weight, low cost, and high-efficiency. Since this method is a system that produces electricity without emitting carbon dioxide nor using rare earths, it would contribute to the goal of environmental sustainability. In this paper, the background of DEs, the associated high efficiency wave energy generation (WEG) systems that we developed using DEs, as well as the latest development of its material are summarized. By covering both the challenges and achievements, this paper discusses the opportunities to build the foundation of an energy recycling society through the usage of these WEGs. To make these possibilities commercially successful, the advantages of DEs need to be integrated with traditional technologies. To achieve this, the method of using DEs alone and a system used in combination with an oscillating water column were also considered. Finally, the current status and... [more]

Semi-transparent Building Integrated Photovoltaics provide a fresh approach to the renewable energy sector, combining the potential of energy generation with aesthetically pleasing, multi-functional building components. Employing a range of technologies, they can be integrated into the envelope of the building in different ways, for instance, as a key element of the roofing or façade in urban areas. Energy performance, measured by their ability to produce electrical power, at the same time as delivering thermal and optical efficiencies, is not only impacted by the system properties, but also by a variety of climatic and environmental factors. The analytical framework laid out in this paper can be employed to critically analyse the most efficient solution for a specific location; however, it is not always possible to mitigate energy losses, using commercially available materials. For this reason, a brief overview of new concept devices is provided, outlining the way in which they mitiga... [more]

Wastewater and sewage sludge contain organic matter that can be valorized through conversion into energy and/or green chemicals. Moreover, resource recovery from these wastes has become the new focus of wastewater management, to develop more sustainable processes in a circular economy approach. The aim of this review was to analyze current sewage sludge management systems in Scandinavia with respect to resource recovery, in combination with other organic wastes. As anaerobic digestion (AD) was found to be the common sludge treatment approach in Scandinavia, different available organic municipal and industrial wastes were identified and compared, to evaluate the potential for expanding the resource recovery by anaerobic co-digestion. Additionally, a full-scale case study of co-digestion, as strategy for optimization of the anaerobic digestion treatment, was presented for each country, together with advanced biorefinery approaches to wastewater treatment and resource recovery.

The article discusses the use of pivot bearing friction liners, made of selected materials, in railway freight wagons’ spherical centre bowls. Comparative studies on the effect of suspension dynamics on the equivalent stresses in the liner material were carried out using the finite element method and multibody simulation. The results show the magnitude and location of the highest stresses in the liner with varying input loads, friction coefficients and interacting materials. The analysis is a basis for a simulation method for predicting the fatigue life of the suspension friction liner placed in the centre bowl between the bogie frame and the vehicle body.

A large number of modular multilevel converters (MMC) are connected to HVDC transmission systems nowadays. This paper aims at the short-circuit fault in the DC line of the HVDC transmission system and the problem of capacitor voltage imbalance in MMC, proposing a new type of MMC sub-module, which has both the DC fault self-clearing ability and the capacitor voltage self-balancing ability. This sub-module combines the topology of half bridge and full bridge. It uses the reverse capacitor voltage to forcibly turn off the conducting diode to block the fault current loop. At the same time, the two capacitances charge and discharge states are consistent by utilizing the operating mode of the sub-module. It is possible to directly achieve a self-balancing capacitor voltage without complex balancing voltage control. The MATLAB/Simulink simulation verifies the effectiveness of the DC fault blocking capability and capacitor voltage balance capability of the proposed sub-module.

Energy communities, mostly microgrid based, are a key stakeholder of modern electrical power grids. Operating a microgrid based energy community is a challenging topic due to the involved uncertainties, complexities and often conflicting objectives. The aim of this paper is to present a novel methodology demonstrating that energy community flexibility can contribute to each community member’s wellbeing when a grid fault occurs. A three-house energy community will be modelled considering as consumption sources non-controllable and controllable devices in each house. As power supply sources, PV systems installed in a community’s houses are considered, as well as the power obtained from main grid. Each house’s flexibility inside the community will be studied to improve the management of loads during a fault occurrence. Moreover, three different scenarios will be considered with different available power in the community. With these simulations, it was possible to understand that houses’ e... [more]

Internal combustion engine emissions are a serious worldwide problem. To combat this, emission regulations have become stricter with the goal of reducing the proportion of transportation emissions in global air pollution. In addition, the European Commission passed the real driving emissions−light-duty vehicles (RDE-LDV) regulation that evaluates vehicle emissions by driving on real roads. The RDE test is significantly dependent on driving conditions such as traffic or drivers. Thus, the RDE regulation has the means to evaluate driving dynamics such as the vehicle speed per acceleration (v·apos) and the relative positive acceleration (RPA) to determine whether the driving during these tests is normal or abnormal. However, this is not an appropriate way to assess the driving dynamics because the v⋅apos and the RPA do not represent engine load, which is directly related to exhaust emissions. Therefore, in the present study, new driving dynamic variables are proposed. These variables use... [more]

The purpose of this study was to determine the degree of influence of alternative options for generating electricity by households on the level of energy independence of countries. The research methodology was based on the use of correlation−regression analysis, as well as adapted non-linear optimization by choosing one of three scenarios for electricity generation by households for 20 countries. Regression analysis showed the dependence of a country’s energy security on households’ energy independence. It is determined that an increase in households’ energy production helps to reduce the level of energy dependence in developed countries. However, for developing countries, there is no such interrelation. The solution of the formulated problem of nonlinear optimization for the studied countries has demonstrated that the criterion of energy dependence is superior to the criterion of a country’s energy security. In the long term, this study can be deepened in the direction of assessing th... [more]

In the interests of the environment, many countries set limits on the use of non-renewable energy sources and promote renewable energy sources through policy and legislation. Consequently, the demand for components for renewable energy systems exhibits an upward trend. For this reason, managers, investors, and banks are interested in knowing whether investing in a business associated with the semiconductor and related device manufacturing sector, especially the photovoltaic (PV) systems manufacturers, is worthy of a penny. Using a sample for the period of 2015−2018, we apply a new approach to panel data, extending existing research using Classification Trees with the k-Nearest Neighbor and Altman model. Our aim is to analyze the financial conditions of enterprises to identify key indicators that distinguish companies producing PV system components (labeled “green, G”) from companies that do not manufacture PV components (“red, R”). Our results show that green companies can be distingui... [more]

Commonly based on the liquid diffusion theory, drying theoretical studies in porous materials has been directed to plate, cylinder, and sphere, and few works are applied to non-conventional geometries. In this sense, this work aims to study, theoretically, the drying of solids with oblate spheroidal geometry based on the thermodynamics of irreversible processes. Mathematical modeling is proposed to describe, simultaneously, the heat and mass transfer (liquid and vapor) during the drying process, considering the variability of the transport coefficients and the convective boundary conditions on the solid surface, with particular reference to convective drying of lentil grains at low temperature and moderate air relative humidity. All the governing equations were written in the oblate spheroidal coordinates system and solved numerically using the finite-volume technique and the iterative Gauss−Seidel method. Numerical results of moisture content, temperature, liquid, vapor, and heat flux... [more]

The purpose of the article is to determine how personality traits (extraversion, neuroticism, conscientiousness, agreeableness and openness to experience) affect organizational citizenship behaviors for the environment (OCBE), especially in the context of energy saving. The purpose is also to verify the hypothesis that this impact is significantly moderated by individuals’ demographic characteristic (sex, age, length of service, work type and economic sector of employment). To achieve the purposes, a survey was conducted in 2020 on 454 working people from Poland. The analysis was based on structural equation modeling (SEM). The research model assumed that particular types of personality affect direct and indirect OCBEs, including energy-saving patterns. The model also included the aforementioned demographic characteristics of respondents. I proved that personality traits have a significant impact on direct and indirect organizational citizenship behaviors for the environment. In the ca... [more]

Gas turbine power plants are widely employed with constrained efficiency in the industrial field, where they often work under variable load conditions caused by variations in demand, leading to fluctuating exhaust gas temperatures. Suitable energy harvesting solutions can be identified in bottoming cycles, such as the conventional Organic Rankine Cycles (ORC) or the innovative supercritical CO2 (s-CO2) systems. This paper presents a detailed comparison of the potential of ORC and s-CO2 as bottomers of industrial gas turbines in a Combined Heat and Power (CHP) configuration. Different gas turbine models, covering the typical industrial size range, are taken into account and both full- and part-load operations are considered. Performance, component dimensions, and operating costs are investigated, considering ORC and s-CO2 systems specifics in line with the current state-of-the-art products, experience, and technological limits. Results of the study show that the s-CO2 could be more appr... [more]

Coke is an integral component of the blast furnace charge; therefore, it plays an important role in the integrated steelmaking process. Achieving the required coke quality parameters by producers requires the use of a high proportion of the highest quality coking coals (hard coking coals) in the coking blends, which significantly increases the unit production costs. Approximately 75% of these costs are constituted by the cost of the coal blend’s preparation. There is a deficit in the best quality coking coals on the world market and their supply are characterized by large fluctuations in quality parameters. Therefore, from the point of view of the economics of coke production, it is advantageous to produce high-quality coke from a coke blend with the highest possible content of cheaper coals. The paper presents the results of the influence of coal charge bulk density and semi-soft coking coal content in the coking blend on the textural and structural parameters of coke, which determine... [more]

Bidirectional coupling systems for electricity and natural gas composed of gas units and power-to-gas (P2G) facilities improve the interactions between different energy systems. In this paper, a combined optimization planning method for an electricity-natural gas coupling system with P2G was studied. Firstly, the characteristics of the component model of the electricity-natural gas coupling system were analyzed. The optimization planning model for the electricity-natural gas coupling system was established with the goal of minimizing the sum of the annual investment costs and the annual operation costs. Based on the established model, the construction statuses for different types of units, power lines, and pipelines and the output distribution values for gas units and P2G stations were optimized. Then, the immune algorithm was proposed to solve the optimization planning model. Finally, an electricity-natural gas coupling system composed of a seven-node natural gas system and a nine-nod... [more]

The underlying objective of the paper is to identify and evaluate in the research process vital factors that impact the development of design and construction enterprises of photovoltaic farms on the energy markets, in particular narrowed down to renewable energy sources (RES) markets, including energy coming from photovoltaic sources. The first part of the paper, the epistemological one, introduces a scientific discourse pertaining to conditionings and restrictions related to RES markets in the dimensions of sustainable development. This has been done with the use of literature query, legislative and administrative acts, and reports drawn up for the European Commission. In this reference, we summarized the EU’s essential measures aimed at promoting the idea of sustainability. The second part of the paper, the empirical one, presents a summary of the results obtained within the research pertaining to “opportunities and threats in managing projects of photovoltaic farms in production en... [more]