Hot gas conditioning is a remarkable stage for decreasing typical and harsh contaminants of syngas produced in the biomass gasification process. Downstream contaminants containing hydrogen sulphide (H2S) can significantly deteriorate fuel stream conversion reactors and fuel cell systems. Thus, an effective gas cleaning stage is required to remove critical streams that endanger the whole pathway toward the biomass conversion process. In this work, we studied H2S capture from biofuel syngas by using a kinetic deactivation model to analyze the effect of the operating conditions on the adsorption performance. Furthermore, the particle sorbent influence on other reactions, such as methane reforming and water gas shift (WGS), were also evaluated. Breakthrough curves were plotted and fitted following a first-order linearized deactivation model to perform both the H2S adsorption capacity and thermodynamic analysis. Moreover, the influence of the operating conditions was studied through a break... [more]

Conventional economic theory indicates that the free market contributes to allocative efficiency. However, specific energy markets present network industry characteristics which distance them from perfect competition. These markets, therefore, need effective regulation. The liberalizing reforms which took place in the Organization for Economic Cooperation and Development (OECD) and emerging countries from the 1990s onwards have reduced the share of state ownership in the energy sector, but not its functions of regulation, coordination and planning. It is also worth noting the expansion of the government’s agenda due to the energy transition that has unequivocally imposed itself in the 21st century. This article uses the Slacks-Based Measure of the Data Envelopment Analysis (SBM-DEA) methodology to investigate the relationship between market liberalization and sustainability in a low-carbon energy transition context. Taking the cases of the natural gas and electricity markets, we verify... [more]

Multiple anodes can significantly enhance the treatment potential of constructed wetlands coupled with a microbial fuel cell (CW-MFC) system, which has not yet been explored. Thus, the present study evaluates the potential of multi-anodes and single cathode-based CW-MFC at significantly higher organic loading rates for treatment performance and bioelectricity generation. For this purpose, two identical but different materials, i.e., graphite granules (GG) and granular activated charcoal (GAC), were used to set up multiple anodes and single cathode-based CW-MFCs. The graphite granules (GG)-based system is named CW-MFC (GG), and the granular activated charcoal (GAC) based system is named as CW-MFC (GAC). These systems were evaluated for chemical oxygen demand (COD), NH4+-N removal efficiency, and electrical output at relatively higher organic loading rates of 890.11 g COD/m3-d and 1781.32 g COD/m3-d. At an OLR of 890.11 g COD/m3-d, the treatment efficiency was found to be 24.8% more in C... [more]

The article presents the effect of using a tillage tool with skimmers, second stage skimmers, and bodies (double-deck plow) on the reduction of traction resistance and energy consumption by at least 1.1 kN, i.e., 3.3%. In addition, the statistical characteristics of the plowing depth and the width of the longitudinal profile of the field are stabilized. The use of agricultural machinery with skimmers, secondary skimmers, or bodies ensures even distribution of plowing depth fluctuations. The use of a plow without skimmers mounted on it leads to a regular and significant increase in the spread of fluctuations in the working depth and cross-section of the field. The normalized correlation function of this process is characterized by the presence of a noticeably marked periodic component. When the plow is used without skimmers mounted on it, the working period of the unit practically corresponds to the working width of the tillage tool. The use of skimmers with a grinding angle of 25° caus... [more]

Solid oxide fuel cell (SOFC) performance degradation analysis and optimization studies are important prerequisites for its commercialization. Reviewing and summarizing SOFC performance degradation studies can help researchers identify research gaps and increase investment in weak areas. In this study, to help researchers purposely improve system performance, degradation mechanism analysis, degradation performance prediction, and degradation performance optimization studies are sorted out. In the review, it is found that the degradation mechanism analysis studies can help to improve the system structure. Degradation mechanism analysis studies can be performed at the stack level and system level, respectively. Degradation performance prediction can help to take measures to mitigate degradation in advance. The main tools of prediction study can be divided into model-based, data-based, electrochemical impedance spectroscopy-based, and image-based approaches. Degradation performance optimiz... [more]

Most of current prosumer-energy-management approaches are focused on economic optimization by self-consumption maximization. Nevertheless, a lack of energy management strategies (EMS) that tackle different interaction possibilities among community-clustered solar plus battery prosumers has been detected. Furthermore, such active prosumer EMS may include participation in ancillary service markets such as automatic frequency restoration reserves (aFRR) through an optimized battery-energy storage-system (BESS) operation, as well as incorporating community-level energy management. In this study, an optimal EMS that includes aggregated aFRR-market participation of five solar plus battery prosumers participating in an energy community (EC), with the aim of reducing total costs of ownership for each individual prosumer is proposed. For its validation, different scenarios have been analyzed. The results show that the proposed EMS allows a levelized cost of energy (LCOE) reduction for all commu... [more]

This paper proposes a novel maximum power point tracking algorithm applied to photovoltaic systems. The proposed method uses the derivative of power versus voltage to define the tracking path and has the advantage of requiring only a voltage sensor to be implemented. The absence of the current sensor and the auxiliary circuitry employed for conditioning the current signal imply cost reduction, configuring the main contribution of the proposed method, whose performance is kept close to the classical incremental conductance method, even with the reduced number of components. A DC-DC zeta converter is introduced in the content of this work as an interface between a photovoltaic array and a resistive load. The paper describes the operating principle and presents the mathematical formulation related to the proposed algorithm. Interesting simulation and experimental results are presented to validate the theory by comparing the proposed method with its traditional version under several scenar... [more]

The publication presents heat and electricity management in the Polish steel industry. The paper is based on actual data on heat and electricity consumption and intensity by processes in the steel industry in Poland in Industry 4.0 conditions. Two steel production processes are used in Poland: EAF Electric Arc Furnace and BOF Basic Oxygen Furnace. The analysis is an analysis of actual data is used to characterise the electricity and heat consumption by processes in the Polish steel industry. The analysis shows that the EAF technology is always more electricity intensive and the BOF technology more heat intensive. On the basis of conducted analysis, it can be concluded that pro-environmental innovations in the steel industry should first aim to reduce the electricity consumption of EAF technology and the heat consumption of BOF. An analysis of data for Poland for the period 2004−2020 shows that both cases occurred. The study shows that the heat consumption of BOF technologies has been s... [more]

Promoting efficiency of liquid−liquid extraction at a high pH is a main challenge for the recovery of volatile fatty acids (VFAs) from organic wastes. In this study, the extraction efficiency of VFAs from artificial solution and acidification fermentation broth of kitchen wastes using ionic liquids (ILs) was assessed at high pH. The effect of ILs addition ratio in diluent, volumetric solvent to feed ratio (S/F) on extraction efficiency were investigated. The solvent consists of [P666,14][Cl] (IL101) and dodecane was found to be the promising solvent for VFA extraction at pH 6.0, especially for butyric acid. The IL-101 ratio in dodecane and S/F was significant factors for the liquid−liquid extraction of VFAs. In general, a higher IL-101 ratio and S/F can promote the extraction efficiency of single VFAs. As a result, the maximum extraction rate of acetic acid (38.4−49.9%) and butyric acid (66.0−92.1%) from different VFA concentration solutions was observed at 10% IL-101 in dodecane and S... [more]

In this work, pure BiFeO3 and samples doped with different concentrations of chromium were synthesized to improve the optical properties and efficiency of solar cells based on BiFeO3. The sol-gel method was used for synthesis due to its ability to produce nanostructured materials with high purity and good homogeneity, as well as the possibility of controlling the size and shape of the resulting particles. The samples were characterized by different analytical techniques. Thermal analysis results indicate that the dopant increases the weight loss of the sample from 61 to 81%, with an increase in the exothermal in the nucleation and crystallization temperature range. The X-ray diffraction patterns and UV-visible spectra show a dependence of the crystallite size and bandgap with respect to the amount of Cr dopant, decreasing from 168 to 73 nm and from 2.14 to 1.92 eV, respectively. Scanning electron microscopy images display a decreasing grain size as a result of an increasing amount of d... [more]

This paper proposes a new control strategy for single-phase voltage source inverters that does not rely on switching based on Pulse Width Modulation. The technique is similar to conventional current hysteresis control, but instead of the output current, the low-pass-filtered inverter output voltage is utilised as the feedback signal. Nevertheless, the switching instants are not determined by a predefined band, but rather by a low-cost Complex Programmable Logic Device (CPLD)-based control logic, which ensures a nearly constant switching frequency. Similar to hysteresis-based control methods, the proposed method ensures a rapid dynamic response. Notable characteristics of the proposed method include a quick dynamic response, a well-defined harmonic spectrum, and an improved total harmonic distortion (THD), particularly during load current and source voltage changes. The proposed method is implemented on a 1 kW, 230 V, 50 Hz prototype. Simulation and experimental results are presented to... [more]

The article presents the experimental results of combining a basic microstructure with partly closed pores and a mesh covering for heat transfer enhancement at the film flow of a refrigerant mixture. To reveal the effect of the combined structure, heat transfer on a microstructured surface without a covering as well as on a smooth surface with a mesh covering only has been studied. All experimental series were carried out using a binary mixture of R114 and R21 refrigerants. The mixture film flowed down the outer surface of a vertical cylinder in the undeveloped turbulence regime, when the film Reynolds number varied from 400 to 1300. It is shown that a microstructured surface with a fin pitch of 200 μm, fin height of 220 μm, and longitudinal knurling pitch of 160 μm, created by deformational cutting, demonstrates significant heat transfer enhancement: up to four times as compared to a smooth surface. However, adding a mesh covering with an aperture of 220 μm and a wire diameter of 100... [more]

As the important technology of renewable energy systems, power electronics technology is directly bound up with the prospect and development of renewable energy technology. As the output end of renewable energy systems, a single-phase H-bridge converter needs to stabilize the output current. When predictive current control (PCC) tracks the reference current, the dynamic response is the fastest, but the control delay and the changes in model parameters will cause the output current steady-state error. The sliding mode predictive current control (SMPCC) algorithm is proposed to control the output current better. The proposed SMPCC scheme uses the combination of traditional PCC and variable structure scheme, and it establishes the mathematical model according to the state equation of the converter. Taking the exponential reaching law as control law, the expression of the variable structure controller is obtained. The MATLAB experimental and simulation results show that SMPCC can not only... [more]

Permeability is a crucial parameter for enhancing shale oil recovery through CO2 injection in oil-bearing shale. After CO2 is injected into the shale reservoir, CO2 corrosion and adsorption-induced strain can change the permeability of the oil shale, affecting the recovery of shale oil. This study aimed to explore the influence of CO2 corrosion and adsorption-induced strain on the permeability of oil shale. The deformation of the internal pore diameter of oil shale induced by CO2 corrosion under different pressures was measured by low-pressure nitrogen gas adsorption in the laboratory, and the corrosion model was fitted using the experimental data. Following the basic definitions of permeability and porosity, a dynamic mathematical model of porosity and permeability was obtained, and a fluid−solid coupling mathematical model of CO2-containing oil shale was established according to the basic theory of fluid−solid coupling. Then the effects of adsorption expansion strain and corrosion co... [more]

One possible step for reducing humans’ use of fossil fuel due to transport tasks is to replace diesel trucks with battery electric ones. This paper introduces the energy distribution diagram, which makes it easy to visualise the trucks’ daily energy consumption over their full service life. The energy distribution is used to investigate which driving patterns are suitable for cost-effective battery electric trucks when compared to commercial diesel trucks. It is shown that the battery capacity that results in the lowest cost per kilowatt-hour propulsion energy depends on the driving pattern, and an algorithm for selecting the most cost-effective capacity is presented. In many instances, it was found that battery electric trucks competed favourably with diesel trucks, especially when the trucks had low variations in daily energy consumption. It is beneficial to determine the circumstances under which they may be cheaper, as this will facilitate the transition to battery electric trucks... [more]

The installation of a corona ring on an insulator string on a transmission line is one of the solutions to reduce the electric field stress surrounding the energised end of the insulator string. However, installing a corona ring with an optimum design to reduce the electric field magnitude on an insulator string is a challenging task. Therefore, in this work, a method to achieve the optimum design of a corona ring for 132 kV composite non-ceramic insulator string was proposed using two optimisation methods: the Imperialist Competitive Algorithm (ICA) and Grey Wolf Optimisation (GWO). A composite non-ceramic insulator string geometry with and without a corona ring was modelled in finite element analysis and used to obtain the electric field distribution in the model geometry. The electric field distribution was evaluated using a variation in the corona ring’s dimensions, i.e., the ring diameter, the ring tube diameter and the vertical position of the ring along the insulator string. Fro... [more]

Phase change material (PCM) water tanks have a major influence on the efficiency improvement of solar energy systems. This article discusses the effects of PCM under various inlets in a tank based on related research. So as to research the performance of the water storage tank, this paper built a set of water tank experimental systems using sodium acetate trihydrate. The thermal characteristics of two different water tanks were analyzed at 2, 6 and 10 L/min when the inlet temperature was 20 °C and the initial high temperature was 80 °C. The test results indicate that adding PCMs helps to provide an extra 1.4% of stored heat, prolong the hot water outlet time, and has a better thermal stratification, compared with ordinary water tanks. However, PCMs do not give off heat quickly at high flow rates. Besides the exergy efficiency (EE) gradually decreasing, the MIX number first decreases and then increases; the fill efficiency (FE) has the opposite trend with the flow increasing. FE has a m... [more]

The Société Nationale des Chemins de fer Français (SNCF) is facing a significant challenge to meet the growth in rail traffic while maintaining continuous service, particularly in densely populated areas such as Paris. To tackle this challenge, the SNCF has implemented several electrification projects. These projects aim to reduce line losses and decrease voltage drops on the railway network. Amongst the possible technological choices, high temperature superconductor (HTS) cables have been evaluated, since they offer greater energy density at lower electrical losses than conventional cables. This feature is advantageous in order to transmit more electrical energy at a lesser footprint than conventional cable, therefore avoiding costly modifications of the existing infrastructures. In the present work, the electromagnetic response of two HTS cables topologies, unipolar and bipolar, was analyzed, and their impact on a direct current (DC) railway network under load was assessed. A commerc... [more]

Electromobility is developing rapidly in all areas of transportation, starting with small personal vehicles and passenger cars through public transportation vehicles and ending with noticeable expansion in the area of urban transportation services. So far, however, there is a lack of research determining how the effect of load weight defines the energy intensity of a vehicle under real conditions, especially in the areas of urban, suburban and highway driving. Therefore, this paper presents an analysis of a representative delivery vehicle and its energy consumption in two transportation scenarios where cargo weight is a variable. A survey was also conducted to determine the actual demand and requirements placed on the electric vehicle by transportation companies.

Fractures are developed in carbonate rock areas, and the fracture water flow significantly influences the heat exchange between buried pipes and the rock mass by induing heat convection, providing the carbonate rock area a strong heat exchange capacity and preferable conditions for shallow geothermal development and utilization. In this paper, the calculation method of heat exchange capacity of buried pipes based on fracture distribution characteristics is proposed and deduced, featuring such advantages as quick speed and low cost. Taking an actual project in carbonate rock area as an example, the heat exchange capacity of buried pipes was obtained by the following two methods: in-situ thermal response test and calculation based on fracture distribution characteristics. In the thermal response test, the initial ground temperatures of the two test holes were 15.18 °C and 12.72 °C. By fitting the linear equation of time and average temperature with a linear thermal source model, the heat... [more]

The growing world population is contributing to the increasing amounts of waste and a significant increase in energy demand. Therefore, coal will increasingly be replaced by refuse-derived fuel (RDF), which is produced from municipal solid waste. The use of such fuel poses many difficulties because of its heterogeneity and high mercury emission. One method to stabilize the properties of RDF and reduce the mercury content is thermal pretreatment. The purpose of this study was to investigate the release of mercury from RDF samples following thermal pretreatment. The study was carried out in the temperature range of 100−350 °C. Statistical analysis was performed on the correlation between the composition of the RDF samples and the release of mercury. The RDF samples showed a very high variation in the mercury content, ranging from 45 to 849 µg Hg/kg (1.7 to 35.3 µg Hg/MJ). Thermal pretreatment removed a significant amount of mercury at 250 °C (94−99%). Paper content positively affected me... [more]

Enterprises operating in the energy and heating (E&H) sector play a particularly important role in the economy of each country. At the same time, the conditions in which they currently operate mean that the managers of these organizations have many decision-making problems that they have to deal with. They can be supported by the introduction of well-functioning controlling. This forces scientists to conduct extended research aimed at determining the current and future directions of development of controlling in E&H sector enterprises. At the moment, this is not a frequent field of research exploration. The area of research concerns issues related to the use of controlling in E&H sector enterprises. The objective of this paper is to present the results of the research obtaining knowledge on to what extent companies in the energy and heating sector use controlling tools helping them to increase efficiency of enterprises and effectiveness of the decisions made by managers. The scientific... [more]

Disposable bamboo chopsticks (DBCs) are rarely recycled, and there are not many options for recycling them. Some treatment processes use high technology and complex processes that are not convenient for production at the local level, resulting in practical difficulties in upcycling DBC waste. DBC is lignocellulosic biomass; therefore, DBC has the potential to be recycled and upcycled. The waste management of wood that transforms it into a sustainable material as a biochar with a pyrolysis process accords well with the circular economy model. This research effort aims to upcycle DBC to convert it into biochar with different pyrolysis temperature ranges set at 400 °C (DBC-400), 450 °C (DBC-450), and 500 °C (DBC-500), with a holding time of 60 min. The morphology and essential physicochemical properties of the biochar were analyzed. The research found that all biochar had physicochemical properties and structures appropriate to the agricultural and environmental purposes. Based on the mol... [more]

In the process of geo-energy drilling, the real-time vibration measurement of drill pipes is of significance for an understanding of the downhole conditions and the properties of rock. However, the vibration sensors used in downhole areas at present require additional power sources, such as batteries, and replacing the batteries would significantly reduce production efficiency and increase costs. In our work, a new vibration measurement method using a triboelectric nanogenerator is proposed which will synchronously achieve axial and lateral vibration, and also simultaneously be self-powered. The triboelectric nanogenerator is mainly made of nanomaterials, such as polyimide film and polytetrafluoroethylene (PTFE), and depends on the pulse signal generated by the contact of the two friction layers to measure the vibration frequency. Axial vibration tests show that the output voltage signal amplitude is approximately 3 V, the measurement range is from 0 to 9 Hz, the measurement error is l... [more]

The rapidly growing global demand for pollutant-free cooking energy has proliferated the research and development of energy efficient and clean cook-stoves. This paper presents a comprehensive review on the gradual improvements in cook-stove designs, focusing on gaseous and liquid fuel-operated cook-stoves around the world. Various literatures concerning the technical aspects such as design and testing, are brought together to provide an insight into the present status of developments in cook-stoves. This review of cook-stove performance covers topics such as stable operating conditions, flame propagation aspects, heat transfer and temperature distribution within the burner, fuel consumption, thermal efficiency, and emissions. Covering both laboratory-scale and field studies, the various cook-stove technologies reported so far are summarized with relevant comments regarding their commercial viabilities. The numerical modeling of combustion in cook-stoves; human health and the environme... [more]