In this study, biochar was prepared via hybrid doping of N, O, and S by applying one-pot pyrolysis of poplar wood and S-containing urea formaldehyde at 900 °C. Different doping ratios were adopted, and the contents of O, N, and S were in the ranges of 2.78−5.56%, 2.16−4.92%, and 1.42−4.98%, respectively. This hybrid doping significantly enhanced the efficiency of the removal of tetracycline (40 mg/L) from wastewater to 71.84% in comparison with that attained by using normal poplar biochar (29.45%). The adsorption kinetics and isotherms indicated that the adsorption process was favorable and was dominated by chemisorption instead of physisorption; the dominant adsorption process may be justified by the existence of abundant functional groups. The adsorption capacity was barely related to the surface area (R2 = 0.478), while it was closely related to the concentration of graphitic N (R2 = 0.985) because graphitic N enhanced the π−π interactions. The adsorption capacity was also highly re... [more]

The study of heat transfer deals with the determination of the rate of heat energy transfer from one system to another driven by a temperature gradient. It can be observed in many natural phenomena and is often the fundamental principle behind several engineering systems. Heat transfer analysis is necessary while designing any product. The most common numerical method used to analyze heat transfer is the finite element method. This paper uses the finite element method to demonstrate steady and transient heat conduction in a three-dimensional bracket. The goal here was to determine the temperature distribution and rate of heat flow in the solid. This is crucial in designing machine elements as they are subjected to various thermal loads during operation and also due to fluctuations in the surrounding environmental conditions. The temperature significantly affects stress, displacements, and volumetric strains. Thus, to analyze thermal stresses induced in a machine element, it is necessar... [more]

Solar photovoltaic (PV) deployment is rapidly expanding around the world. However, the soiling factor has an impact on its performance. Saudi Arabia has high solar irradiation and plans to diversify its energy mix for electricity generation by deploying more solar PV across the country. However, it is located in an arid and desert environment, making it a challenging project due to dust accumulation on solar modules. The soiling and PV performance in Saudi Arabia are examined in this paper. Furthermore, it highlights several mitigation techniques that can be used to maintain PV performance through preventive and restorative measures. Furthermore, this study looks into the size and characterization of dust in Saudi Arabia, as well as the entire life cycle of dust accumulation on PV modules. In this review study, the performance of solar PV systems is evaluated under soiling in different regions of Saudi Arabia. Depending on the local environment and other factors, the PV performance has... [more]

The Xishan coalfield is an important coking coal-producing area in China. The No. 8 and No. 9 coals of the Taiyuan formation were sampled and tested from nine mines in the center and north of the Xishan coalfield, and the coal’s quality characteristics, element occurrence characteristics, enrichment characteristics, and sedimentary environment characteristics were analyzed to provide a foundation for clean and efficient coal utilization and identification of associated coal resources. The results obtained from the experiment show that Li in No. 8 coal is the enrichment element. The enrichment coefficient of the U element of ML8 is 13.78, which is close to the industrial index of recycling. The enrichment hazardous elements are Cu, Mo, Cd of ML8, Mo of DQ8, and Th of ZCD8. Along with K value and Sr/Ba ratio, seawater has a greater influence on the south of No. 8 coal than on the north and on the east of No. 9 coal than on the west. No. 8 coal (except ML8) was formed under an oxidation e... [more]

Imaging concentrators like the parabolic trough solar concentrators have been widely employed for energy production in solar power plants. The conventional imaging solar concentrators form a non-uniform Gaussian distribution on receiving absorbers yielding the highest temperatures. The traditional CSP system normally truncated a peripheral region of heat flux to better use the central part. CPV/T systems using the waste heat recovery method can largely improve the total efficiency. However, for the CPV module, the coolant temperature was usually below 80 °C, which limited the applications of the thermal cycle such as the ORC system. In this article, a novel trough-type free-form secondary solar concentrator (TFSC) for PV/Thermal hybrid application has been proposed. Different from other CPV/T concepts using a combined PV panel and cooling tunnel/tube, the current concept separates the receiver in two parts. The secondary free-form reflector is generated by the geometric construction me... [more]

Concrete, an integral part of a nuclear power plant (NPP), experiences degradation during their operational lifetime of the plant. In this review, the major causes of concrete degradation are extensively discussed including mechanisms that are specific to NPPs. The damage mechanism could be chemical or physical. The major causes of chemical degradation include alkali−aggregate reactions, leaching, sulfate attack, bases and acids attack, and carbonation. Physical degradation is a consequence of both environmental and mechanical factors combined. These factors are mainly elevated temperature, radiation, abrasion and erosion, salt crystallization, freeze−thaw distortions, fatigue and vibration. Additionally, steel reinforcements, prestressing steels, liner plates, and structural steel also experience degradation. The prospective areas in the structural components of the NPP where the degradation could occur are mentioned and the effective solutions to the causes of degradation are highlig... [more]

The power attenuation of internal combustion engines in high-altitude environments restricts the performance of unmanned aerial vehicles. Herein, a single-zone model of a hydrogen-doped high-efficiency hybrid cycle rotary engine that considers high-altitude environments was proposed. The indicated values for power, thermal efficiency, and specific fuel cost were used to evaluate the power performance, energy conversion efficiency, and economic performance of the engine, respectively. Then, the effects of adjusting the hydrogen fraction, ignition angle, and rotational speed on high-altitude performance were analyzed. The results showed that high-altitude environments prolonged combustion duration and reduced in-cylinder pressure, thereby causing power attenuation; however, increasing the hydrogen fraction can increase the indicated power. At an altitude of 6 km, the indicated power with a hydrogen fraction of 0.3 was approximately 20.7% higher than that obtained with pure gasoline. The... [more]

A novel combined power and refrigeration system is proposed based on organic Rankine and jet refrigeration cycles. The system has a wider application range and can be adjusted to different cooling and evaporation temperatures. To meet the needs of diverse populations, the cooling and evaporation temperature can be as low as −60 degrees Celsius. The genetic algorithm is used to optimize the system, and the proposed system’s energy, exergy, economy, and environment are analyzed under optimal conditions. The results desmonstrate that the exergy damage, environmental impact rate, and exergy economic coefficient of steam turbine are the largest. The system’s exergy damage and the turbine’s investment cost are reduced, and the system’s performance is improved. The condenser has the greatest potential for improvement and should be considered a priority component for system improvement. In addition, the system parameters are analyzed. Higher low-pressure steam generation temperature, dryness o... [more]

As one of the effective solutions to recover waste heat, absorption refrigeration systems are used in various industrial or refrigeration places. Flat-plate falling-film absorption is one of the newer types, and the lattice Boltzmann method (LBM) has certain advantages compared with the traditional numerical simulation method. In this work, an LBM is used to analyze flat-plate falling-film absorption. Using the additional calculation of the pressure by the pseudo-force model, a lithium bromide−water working fluid−heat and mass transfer model driven by steam partial pressure is realized. The results show that the turbulence generated in the surface wave has a favorable effect on the absorption process; the degree of turbulence gradually decreases with the increase in the Reynolds number, which weakens the increasing effect of the surface wave on the absorption. When the Reynolds number is moderate, the solitary wave flows forward relative to the front thin liquid film, which promotes co... [more]

The Paris Climate Agreement and the 2030 Agenda for Sustainable Development Goals declared by the United Nations set high expectations for the countries of the world to reduce their greenhouse gas (GHG) emissions and to be sustainable. In order to judge the effectiveness of strategies, the evolution of carbon dioxide, methane, and nitrous oxide emissions in countries around the world has been explored based on statistical analysis of time-series data between 1990 and 2018. The empirical distributions of the variables were determined by the Kaplan−Meier method, and improvement-related utility functions have been defined based on the European Green Deal target for 2030 that aims to decrease at least 55% of GHG emissions compared to the 1990 levels. This study aims to analyze the energy transition trends at the country and sectoral levels and underline them with literature-based evidence. The transition trajectories of the countries are studied based on the percentile-based time-series an... [more]

The automotive domain is a very good candidate for energy management, particularly due to the huge amounts of energy lost by heat through exhaust and water-cooling systems. This makes the optimization of vehicle cooling modules directly related to energy consumption and carbon dioxide emission. In this context, contemporary designs that employ diffusers between the forward-facing of an automobile and its heat exchanger subjected to airflow are presented in this work. The ultimate aim is to reduce the fuel consumption and carbon dioxide emissions of vehicles. Based on the aforementioned design, the intensity of the air velocity would be decreased but distributed over a larger exchanger surface. Consequently, the velocity non-uniformity of the airflow upstream would decrease and therefore, the thermal performance would increase. The above-mentioned conclusion is a result of parametric numerical analysis and its associated numerical results that disclosed the enhancement of water-air heat... [more]

With stricter IMO regulations on CO2 taking effect in 2023 and ambitious goals to reduce carbon intensity by 2030, the maritime industry is scrambling to clean up its act. Conventional methods and equipment are now being reevaluated, upgraded or completely replaced. The difference between a short-term fix and a long-term sustainable option is how flexible vessels will be to use new energy sources or technology as they become viable. The review discusses the recent literature on renewable energy sources, technical and operational strategies for new and existing ships, technology maturity, and alternative fuels. It is found that the IMO’s targets can be met by combining two or three technologies, or via a radical technology shift which can provide innovative, high-efficiency solutions from an environmental and economic standpoint. It has also been noted that policies and enforcement are essential management instruments for mitigating the unfavourable environmental effects of marine trans... [more]

Mergers and acquisitions (M&A) may serve as a catalyst in energy transition by accelerating this trend and “greenwashing” the deals. M&A are often used by large energy companies as a tool to explore potential synergy benefits. Recently, M&A strategies in the energy industry have been pursued to transform traditional business models into more “sustainable” models. On the one hand, it may be observed that companies are taking a proactive rather than reactive approach towards environmental-, social-, and governance (ESG)-related M&A deals. On the other hand, sustainable M&A deals do not interest activist shareholders and regulatory authorities only anymore. Inclusion of a sustainability framework and managing ESG-related risks have become part of the overall strategy of most companies within the energy industry. This research addresses the problem of how energy M&A are contributing to sustainable development on the one hand and reflecting sustainable developments on the other hand. The cu... [more]

The aim of this study was to identify environmentally and socially sustainable behaviors and explore the role of mobile applications in encouraging them among young residents of Poland. The study involved a literature review and a survey carried out on a sample of 772 representatives of Generation Z (through the use of CAWI method). The collected material was subjected to quantitative and qualitative analyses involving factor analysis and statistical tests. The analysis of the obtained dataset shows that there is a significant difference between pro-environmental behaviors assigned to the following areas: (I) purchasing activity enhanced by visual identification, (II) sustainable consumption, (III) behavior stimulated by legal regulations and economic factors. The research revealed a statistically significant difference between the sustainable behaviors of men and women, and a slight difference between the behaviors of people from different places of residence and with different levels... [more]

Heat pump technology offers a path towards reducing the use of fossil fuels to heat space, providing energy bill savings and reducing air pollution and GHG emissions. The choice of heating method is based on costs; hence, this study examines the gains from operating heat pump systems in public buildings as well as alternative systems using electricity, LPG, and heating oil. The study focuses on the Ruda-Huta municipality in Poland that, as is common in rural areas, lacks access to a district heating system or piped gas. The empirical analysis includes heat pump installations in eight municipal buildings. The study found that the use of ground source heat pumps proved competitive with existing heating systems in terms of payback time. Calculations for three heating energy source scenarios, i.e., electricity, LPG, and heating oil, used the Simple Pay Back Time (SPBT) and the Levelized Cost of Heat (LCOH) methods and the average prices of the three energy types for the period 2012−2021. T... [more]

Low salinity water injection (LSWI) is considered to be more cost-effective and has less environmental impacts over conventional chemical Enhanced Oil Recovery (EOR) methods. CO2 Water-Alternating-Gas (WAG) injection is also a leading EOR flooding process. The hybrid EOR method, CO2 low salinity (LS) WAG injection, which incorporates low salinity water into CO2 WAG injection, is potentially beneficial in terms of optimizing oil recovery and decreasing operational costs. Experimental and simulation studies reveal that CO2 LSWAG injection is influenced by CO2 solubility in brine, brine salinity and composition, rock composition, WAG parameters, and wettability. However, the mechanism for increased recovery using this hybrid method is still debatable and the conditions under which CO2 LSWAG injection is effective are still uncertain. Hence, a comprehensive review of the existing literature investigating LSWI and CO2 WAG injection, and laboratory and simulation studies of CO2 LSWAG injecti... [more]

This paper presents the high contact resistance (HCR) and rotor bar faults by an extraction method for an induction motor using Discrete Wavelet Transform (DWT) and Artificial Neural Network (ANN). The root mean square (RMS) and mean features are obtained using DWT, and ANN is used for classification using activation functions. Activation provides output by assigning the specific input with respect to the transfer function according to the nature and type of the activation function. Method: The faulty conditions are induced using MATLAB by adopting the motor current signature analysis (MCSA) method to achieve current signature signals of the healthy and faulty motors. Results: The DWT technique has been applied to obtain fault-specific features of the average continuously varying signal (RMS) and an average of the data points (mean) at levels 5, 7, 8, and 9, followed by ANN to classify the faults for condition monitoring. Utility: The utility of the results is to reduce unscheduled dow... [more]

An e-bike sharing system (e-BSS) solves many of the shortcomings of BSS but requires high financial investments compared to BSS. This article proposes a sustainable and targeted extension of the existing BSS with e-bikes and charging piles. The existing BSS in the selected city area is divided into sub-areas using the Voronoi diagram and reference points (landmarks). Then, the integrated approach of the Analytic Hierarchy Process (AHP) and Data Envelopment Analysis (DEA) is used to assess the adequacy of the existing bike-sharing stations for updating with e-bikes and charging piles. The joint approach allows decision-makers to look at the whole process and highlight the link between the criteria assessment and user preferences in the context of the chosen reference point. This can encourage future users to use e-BSSs. Based on a thorough literature review, the defined system of criteria takes into account all dimensions of sustainability: the requirements of most stakeholders and the... [more]

Environmental protection is currently one of the key priority areas of the European Union (EU). The search for effective solutions for the supply and use of energy in cities is currently a key topic. The reduction in gas emissions and the use of renewable energy sources are goals that result from environmental aspects. The purpose of this publication is to conduct a literature review in the area of municipal energy management. Municipal energy management systems integrate many areas, from energy supply systems and the modernization of public transport to the energy demand reduction of residential and commercial facilities. The results of the literature review research have allowed for the classification of articles based on the following criteria: research methodology, research purpose, research data collection method, use of research results article type, and research subject area.

The current production of water energy in Poland is much lower than the theoretical and technical potential. The aim of the article is to analyse the current state of hydropower in Poland as well as the prospects and conditions for development. Poland's total technical hydropower potential is estimated at 12,000−14,000 GWh/year, but currently, approx. 20% of this potential is used. The considerations undertaken in the study concern, for example, pumped-storage power plants and the development of small hydropower plants. Hydropower plants are not only important from the point of view of electricity production and storage, but also fulfill many other functions, including the general social, which is an essential element of the implementation of the concept of sustainable development. The analyses show that the hydropower sector in Poland may be an important element of low-carbon energy and an important element of energy security. Increasing the volume of electricity production from hydro... [more]

Due to industrialization, urbanization, and rapid population increases, the worldwide energy demand is increasing daily. The need for energy meets limitations, and searching for new energy sources is crucial, particularly for European countries. Energy crises occur temporarily due to different circumstances and cause oil price fluctuations. The present study aims to identify circular economy (CE) determinants that conditionally increase/decrease energy use to remain sustainable. It focuses on the linkage between energy consumption and circular economy in the European Union (EU) member states. In the econometric panel model specifications, two alternative endogenous variables are considered, i.e., total energy consumption and energy consumption from renewable sources. The results demonstrate that the selected CE indicators decreased the former and increased the latter. The data covered the period from 2010−2019. The significance of this study relies upon identifying the current level of... [more]

The presence of earthworms in soil contaminated with petroleum products (PPs) increase the rate of decomposition. The use of more than one animal species simultaneously in soil remediation could accelerate the process. However, the effects may be different when long-term aging soil contamination exists during which toxic by-products can be formed. This study evaluated the effect of soil contamination with PPs (petrol, diesel fuel, and used engine oil) carried out 12 and 24 months earlier on the life parameters of Lumbricus terrestris L. during single- and dual-species breeding with Porcellio scaber Latr. The changes in the content of total petroleum hydrocarbons (TPH) in the soil were also measured, as were the levels of polycyclic aromatic hydrocarbon (PAH) accumulation in the bodies of the test animals. Survival of earthworms cultivated separately (single-species experiment) in soil contaminated with diesel fuel 12 months earlier significantly decreased, while body mass gain was not... [more]

The improvement of the overall utilization rate of compressed natural gas (CNG) engine fuel is the basis of efficient energy utilization. On the foundation of heat balance theory of internal combustion engines, this study fully considers the operation characteristics of CNG engines and systematically analyzes the distribution characteristics of different waste heat under variable working conditions. The nonlinear relationship between speed and intercooler heat source becomes evident with the increasing of intake mass flow rate. In accordance with the structural characteristics, the thermodynamic model, heat transfer model and environmental model of dual-loop organic Rankine cycle (DORC) are constructed. The system potential in full working environments is systematically evaluated. Compared with the speed, airmass flow has a significant effect on comprehensive performance of loop. The maximum power, heat transfer area and power output of per unit heat transfer area (POPA) of DORC are 36... [more]

In the context of increased energy demands and finding solutions for energetic autonomy, the use of waste base materials has increased in recent years in all areas of research. In this context, waste waters, sludge or slurry, biodegradable materials, second generation effluents, and their byproducts are some of the key substrates of interest to obtain biogas through AD (anaerobe digestion). The goal is to utilize these materials as a base for the generation of renewable energy and thereby make it the main source of energy for households or industries. This paper aims to characterize, from a physical and chemical point of view, wastewater from Timis county as a base substrate material in the co-fermentation process with cereal residual biomass. We aimed to determine the energetic potential of the wastewater and perform preliminary testing at a small and pilot-sized experimental installation for biogas production with Timis wastewater as the main energy carrier. The novelty of the paper... [more]

The shift toward renewable energy resources, and photovoltaic systems specifically, has gained a huge focus in the past two decades. This study aimed to assess several environmental and economic impacts of a photovoltaic system that installed on the rooftop of an industrial facility in Dubai, United Arab Emirates (UAE). The life cycle assessment method was employed to study all the flows and evaluate the environmental impacts, while several economic indicators were calculated to assess the feasibility and profitability of this photovoltaic system. The results showed that the production processes contributed the most to the environmental impacts, where the total primary energy demand was 1152 MWh for the whole photovoltaic system, the total global warming potential was 6.83 × 10−2 kg CO2-eq, the energy payback time was 2.15 years, the carbon dioxide payback time was 1.87 years, the acidification potential was 2.87 × 10−4 kg SO2-eq, eutrophication potential was 2.45 × 10−5 kg PO43-eq, th... [more]