Cement manufacturing is an emission-intensive process. The cement industry is responsible for 8% of the global CO2 emissions, and produces a ton of cement uses up to 102 kWh of electrical energy, leading to a significant amount of indirect emissions depending on the emission intensity of the electricity source. Captive power generation can be potentially utilised as a mitigation approach to reduce emissions and as well as expenditure on electricity tariffs. In this study, a system dynamic simulation model is built to evaluate the impact of captive power generation on a cement plant’s net emissions and expenditure through electricity use, under different scenarios for carbon-tax, grid emission factor, and electricity tariffs. The model is then utilised to simulate a reference plant under realistic scenarios designed based on the conditions in Germany and United Arab Emirates. Furthermore, the model is utilised to calculate the payback period of investments on captive power plants under... [more]

Engine knock determination has been conducted in various ways for spark timing calibration. In the present study, a knock classification model was developed using a machine learning algorithm. Wavelet packet decomposition (WPD) and ensemble empirical mode decomposition (EEMD) were employed for the characterization of the in-cylinder pressure signals from the experimental engine. The WPD was used to calculate 255 features from seven decomposition levels. EEMD provided total 70 features from their intrinsic mode functions (IMF). The experimental engine was operated at advanced spark timings to induce knocking under various engine speeds and load conditions. Three knock intensity metrics were employed to determine that the dataset included 4158 knock cycles out of a total of 66,000 cycles. The classification model trained with 66,000 cycles achieved an accuracy of 99.26% accuracy in the knock cycle detection. The neighborhood component analysis revealed that seven features contributed sig... [more]

Sludge incineration is a sludge resource management and disposal method that can greatly decrease the volume of sludge, reduce the degree of harm and realize the recovery of sludge heat energy. Most of the research on sludge incineration focuses on the combustion process and gas emissions, but there are relatively few studies on the sludge fuel molding and drying process before sludge incineration. Besides, independent incineration of sludge has high energy consumption. This paper proposes a pre-incineration treatment method in which sludge and corn stover are mixed to make fuel pellets and then dried. Specifically, the influence of molding pressure, raw material ratio and raw material particle size on the physical properties of the fuel, and the related mechanism, were studied. The density of fuel particles is mainly affected by the forming pressure, and the impermeability is mainly determined by the proportion of sludge in the raw material. The order of the variables based on their e... [more]

In this study, we assumed that 28 European countries (Decision Making Units (DMUs)) aimed to accomplish higher economic outputs, using fewer resources and producing fewer emissions in the form of environmental degradation. In this context, we studied the drivers of total factor productivity change (TFPCH) in DMUs, associated with either managerial capabilities (efficiency change (EC)) or innovations (technical change (TC)) in resource-saving production methods, before and after the integration of CO2 (carbon dioxide) emissions as an additional variable (undesirable output) in the initial model of one output (gross domestic product (GDP)) and five inputs (labor, capital, energy, domestic material consumption and recycled municipal waste). The primary focus of this study is to identify best practices that policymakers can adopt as they attempt to reduce productivity loss. Our results highlight the weak areas of individual countries and seem to indicate the action that should be taken to... [more]

Hydrogen production is a topical issue in an energy scenario where decarbonization is a priority, especially with reference to the transport sector that has a great weight on global emissions. Starting from this consideration, GIF (Generation-IV International Forum) investigated the possibility to produce hydrogen by nuclear energy. The “classic” strategy is based on the use of nuclear as energy source for the electrolysis; but on the medium-long term, a more sustainable and smart approach could be founded on the use of thermochemical processes (e.g., I-S) that require a direct coupling of a chemical plant to a nuclear reactor. In order to develop this strategy, it is mandatory to design and optimize all the key components involved in this complex plant. In this study, we developed the 3D-CAD and CFD models of the intermediate heat exchanger (IHX) installed in the Japanese HTTR nuclear power plant. This component is extremely important for both the safety of the two plants and the stab... [more]

Widespread interest in environmental issues is growing. Many studies have examined the effect of distributed generation (DG) from renewable energy resources on the electric power grid. For example, various studies efficiently connect growing DG to the current electric power grid. Accordingly, the objective of this study is to present an algorithm that determines DG location and capacity. For this purpose, this study combines particle swarm optimization (PSO) and the Volt/Var control (VVC) of DG while regulating the voltage magnitude within the allowable variation (e.g., ±5%). For practical optimization, the PSO algorithm is enhanced by applying load profile data (e.g., 24-h data). The objective function (OF) in the proposed PSO method considers voltage variations, line losses, and economic aspects of deploying large-capacity DG (e.g., installation costs) to transmission networks. The case studies validate the proposed method (i.e., optimal allocation of DG with the capability of VVC wi... [more]

Conventionally, high-pressure water-based fluids have been injected for hydraulic stimulation of unconventional petroleum resources such as tight gas reservoirs. Apart from improving productivity, water-based frac-fluids have caused environmental and technical issues. As a result, much of the interest has shifted towards alternative frac-fluids. In this regard, n-heptane, as an alternative frac-fluid, is proposed. It necessitates the development of a multi-phase and multi-component (MM) numerical simulator for hydraulic fracturing. Therefore fracture, MM fluid flow, and proppant transport models are implemented in a thermo-hydro-mechanical (THM) coupled FLAC3D-TMVOCMP framework. After verification, the model is applied to a real field case study for optimization of wellbore x in a tight gas reservoir using n-heptane as the frac-fluid. Sensitivity analysis is carried out to investigate the effect of important parameters, such as fluid viscosity, injection rate, reservoir permeability et... [more]

Today, the pace of development of decentralized transactive management systems has increased significantly due to growing renewable energy source technologies and communication infrastructure at the distribution system level. Such bilateral energy transactions have changed the structure of electricity markets and led to the emergence of a local energy market in electricity distribution. While examining this change of attitude, this paper analyzes the effects of local market formation on the performance and performance of distribution companies. Accordingly, the technical requirements in the three areas of operation, network control, and ICT in the new workspace are thoroughly examined. The hardware requirements will be presented in two parts for the end-user and the distribution systems. Then, the proposed local distribution market framework will be introduced, and finally, the conclusion will be presented.

The paper presents the concept of controlling the designed optoelectronic scanning and tracking seeker. The above device is intended for the so-called passive guidance of short-range anti-aircraft missiles to various types of air maneuvering targets. In the presented control method, the modified linear-quadratic regulator (LQR) and the estimation of input signals using the extended Kalman filter (EKF) were used. The LQR regulation utilizes linearization of the mathematical model of the above-mentioned seeker by means of the so-called Jacobians. What is more, in order to improve the stability of the seeker control, vector selection of signals received by the optoelectronic system was used, which also utilized EKF. The results of the research are presented in a graphical form. Numerical simulations were carried out on the basis of the author’s own program developed in the programming language C++.

Monolithic perovskite−silicon tandem solar cells with MoOx hole selective contact silicon bottom solar cells show a power conversion efficiency of 8%. A thin 15 nm-thick MoOx contact to n-type Si was used instead of a standard p+ emitter to collect holes and the SiOx/n+ poly-Si structure was deposited on the other side of the device for direct tunneling of electrons and this silicon bottom cell structure shows ~15% of power conversion efficiency. With this bottom carrier selective silicon cell, tin oxide, and subsequent perovskite structure were deposited to fabricate monolithic tandem solar cells. Monolithic tandem structure without ITO interlayer was also compared to confirm the role of MoOx in tandem cells and this tandem structure shows the power conversion efficiency of 3.3%. This research has confirmed that the MoOx layer simultaneously acts as a passivation layer and a hole collecting layer in this tandem structure.

This paper shows a new concept to generate medium voltage (MV) in wind power application to avoid an additional transformer. Therefore, the generator must be redesigned with additional constraints and a new topology for the power rectifier system by using multiple low voltage (LV) power rectifiers connected in series and parallel to increase the DC output voltage. The combination of parallel and series connection of rectifiers is further introduced as DC-cascade. With the resulting DC-cascade, medium output voltage is achieved with low voltage rectifiers and without a bulky transformer. This approach to form a DC-cascade reduces the effort required to achieve medium DC voltage with a simple rectifier system. In this context, a suitable DC-cascade control was presented and verified with a laboratory test setup. A gearless synchronous generator, which is highly segmented so that each segment can be connected to its own power rectifier, is investigated. Due to the mixed AC and DC voltage... [more]

Currently, hydrogen is mainly generated by steam methane reforming, with significant CO2 emissions, thus exacerbating the greenhouse effect. This environmental concern promotes methane cracking, which represents one of the most promising alternatives for hydrogen production with theoretical zero CO/CO2 emissions. Methane cracking has been intensively investigated using metallic and carbonaceous catalysts. Recently, research has focused on methane pyrolysis in molten metals/salts to prevent both reactor coking and rapid catalyst deactivation frequently encountered in conventional pyrolysis. Another expected advantage is the heat transfer improvement due to the high heat capacity of molten media. Apart from the reaction itself that produces hydrogen and solid carbon, the energy source used in this endothermic process can also contribute to reducing environmental impacts. While most researchers used nonrenewable sources based on fossil fuel combustion or electrical heating, concentrated s... [more]

To improve the proficiency of energy systems in addition to increasing the usage of renewable energies, thermal energy storage (TES) is a strategic path. The present literature review reports an overview of the recent advancements in the utilization of salt hydrates (single or binary mixtures) and composites as sorbents for sorption heat storage. Starting by introducing various heat storage systems, the operating concept of the adsorption TES was clarified and contrasted to other technologies. Consequently, a deep examination and crucial problems related to the different types of salt hydrates and adsorbents were performed. Recent advances in the composite materials used in sorption heat storage were also reviewed and compared. A deep discussion related to safety, price, availability, and hydrothermal stability issues is reported. Salt hydrates display high theoretical energy densities, which are promising materials in TES. However, they show a number of drawbacks for use in the basic... [more]

Given the effects of steep dips and large lateral variations in seismic velocity beneath the Vancouver Island continental shelf, seismic processing and travel time inversion are inadequate to obtain a detailed velocity model of the subsurface. Therefore, seismic full waveform inversion is applied to multichannel seismic reflection data to obtain a high-resolution velocity model beneath the Tofino fore-arc basin under the continental shelf off Vancouver Island margin. Seismic velocities obtained in this study help in understanding the shallow shelf sediment structures, as well as the deeper structures associated with accreted terranes, such as Pacific Rim and Crescent terranes. Shallow high velocities, as large as ∼5 km/s, were modeled in the mid-shelf region at ∼1.5−2.0 km depth. These coincide with an anticlinal structure in the seismic data, and possibly indicate the shallowest occurrence of the volcanic Crescent terrane. In general, seismic velocities increase landward, indicating s... [more]

The environmental footprint (EF) indicator has emerged as a tool to measure human demand for productive land and water and it is used for the evaluation of the impact of products or economic activities on the environment. There are many indicators that are used in the decision making for the investment in the power sector, however, predominant are the economic indicators which underestimate the depreciation of natural capital (environment) and the value added generated by the public services. Many research studies have been carried out in an attempt to demonstrate the versatility of the EF by extending its applicability not only to environmental assessment, but also to use it, among other economic indicators, when assessing sustainable investment. Sustainable investment (SI) combines fundamental analysis and engagement with an evaluation of environmental, social and corporate governance (ESG) factors. The purpose of this article is, upon evaluating the EF, to identify the opportunities... [more]

There are many oil and gas fields around the world where the vast number of wells have been abandoned or suspended, mainly due to the depletion of reserves. Those abandoned oil and gas wells (AOGWs) are often located in areas with a prospective geothermal potential and might be retrofitted to a geothermal system without high-cost drilling. In Poland, there are thousands of wells, either operating, abandoned or negative, that might be used for different geothermal applications. Thus, the aim of this paper is not only to review geothermal and petroleum facts about the Eastern Carpathian Foredeep, but also to find out the areas, geological structures or just AOGWs, which are the most prospective in case of geothermal utilization. Due to the inseparability of geological settings with both oil and gas, as well as geothermal conditionings, firstly, the geological background of the analyzed region was performed, considering mainly the autochthonous Miocene formation. Then, geothermal and petr... [more]

Water content is an important factor in the deformation-destruction process of coal bodies. To analyze the influence of water on the creep acoustic emission (AE) characteristics of coal rock surrounding a borehole, we conducted graded loading creep AE tests of single-hole specimens with different water contents (0%, 4%, 8% and water-saturation) under uniaxial loading. The findings include the following: the water content affects the creep mechanical properties of the coal body around a borehole. The creep transient strain and steady-state strain increased exponentially with rising water content; the saturated specimen showed the highest increase, reaching 44.5% and 28.6%, respectively. The specimen water content affected the cumulative ringing count (CRC) and the axial strain during creep. The axial strain increased with rising water content, the CRC increased linearly with rising axial strain. The higher the water content, the greater the CRC rise. At different stress levels, the CRC... [more]

Air conditioning systems have become essential equipment in many buildings. However, fire safety design and management in buildings rarely consider whether to turn the system off or keep it on in a fire. This study ignites a stack of wood in a room center or corner to explore the influence of air inlet actions of a fan coil unit (FCU) with the door opened or closed. Simulation results using Fire Dynamics Simulator (FDS) demonstrate that the heat release rate (HRR) and room temperature obviously decrease when the room doorway is closed, regardless of whether the air conditioner is turned on. The air supply for combustion is poor. When the door of the room is opened, turning off the air conditioner can effectively reduce the HRR and the room temperature in the early stages of fire growth. However, along with the fire growth, turning on air conditioning can help decrease the heat radiation feedback and the consequent HRR. Therefore, the conclusion that air conditioning always enhances a f... [more]

The paper presents the methods of determination of the actual operation of solid fuel heating boilers in Poland. The analysis was based on an average annual distribution of the actual power outputs of the solid fuel heating boilers operated in four selected locations in Poland. Based on said data, three characteristic percent shares have been estimated of the nominal power outputs, at which the heating boilers in Poland operate throughout the year (divided into four characteristic portions—the seasons of the year). Additionally, for the analysis, the authors took into account the average annual temperature amplitude and the annual air quality information for the discussed locations and analyzed 30 solid fuel heating boilers in terms of their performance in the laboratory certification tests. In the final stage of the investigations, the authors initiated laboratory tests on the application of the combustion quality analyzers and their potential benefits.

Air-cooled battery thermal management system (BTMS) technology is commonly used to control the temperature distribution of the battery pack in an electric vehicle. In this study, parallel plates are introduced to improve the cooling efficiency of the BTMS, which can change the airflow distribution of the battery pack. Firstly, the effect of the number of parallel plates on the cooling performance of the BTMS is investigated; within the acceptable range of power consumption loss, the model with two parallel plates shows the best cooling efficiency, and Tmax and ΔTmax are reduced by 2.42 and 3.46 K, respectively. Then, the influences of the length and height of parallel plates are studied; the optimal values for length and height are 1.5 and 30 mm, respectively. Finally, the conclusions drawn above are used to design three optimization schemes for the model with four parallel plates; the cooling efficiency of the battery pack can be improved efficiently, which illustrates the feasibility... [more]

The purpose of this paper is to highlight that, in order to assess the availability of different HVDC cable transmission systems, a more detailed characterization of the cable management significantly affects the availability estimation since the cable represents one of the most critical elements of such systems. The analyzed case study consists of a multi-terminal direct current system based on both line commutated converter and voltage source converter technologies in different configurations, whose availability is computed for different transmitted power capacities. For these analyses, the matrix-based reliability estimation method is exploited together with the Monte Carlo approach and the Markov state space one. This paper shows how reliability analysis requires a deep knowledge of the real installation conditions. The impact of these conditions on the reliability evaluation and the involved benefits are also presented.

Rotational Piezoelectric Energy Harvesting (RPZTEH) is widely used due to mechanical rotational input power availability in industrial and natural environments. This paper reviews the recent studies and research in RPZTEH based on its excitation elements and design and their influence on performance. It presents different groups for comparison according to their mechanical inputs and applications, such as fluid (air or water) movement, human motion, rotational vehicle tires, and other rotational operational principal including gears. The work emphasises the discussion of different types of excitations elements, such as mass weight, magnetic force, gravity force, centrifugal force, gears teeth, and impact force, to show their effect on enhancing output power. It revealed that a small compact design with the use of magnetic, gravity, and centrifugal forces as excitation elements and a fixed piezoelectric to avoid a slip ring had a good influence on output power optimisation. One of the i... [more]

This article describes the effect of high-power electromagnetic environments (HPEMs) on the operation of all basic elements of electrical power networks. Frequency bands are defined for the HPEM environments. Attention is focused particularly on directed energy weapons (DEWs) and intentional electromagnetic interference (IEMI). A classification of DEW and IEMI generators in terms of E-field level and target distance from the DEW or IEMI generator antenna aperture is also described. The main focus of this article is on the design and testing of a low-tech DEW generator used to determine the electromagnetic immunity of standard electronic circuits. In addition, verification of electromagnetic immunity for a simple electronic circuit without adequate protection against the E-field is also explained. The outcome of this article is the determination of the E-field limits for fault-free operation, for malfunctioning states of the tested circuits and for irreversible destruction of the circui... [more]

This work proposed a base method for automated assessment of Small Hydro-Power (SHP) potential for a run-of-river (RoR) scheme using geographic information systems (GIS). The hydro-power potential (HP) was represented through a comprehensive methodology consisting of a structured raster database. A calibrated and validated hydrological model (Soil and Water Assessment Tool—SWAT) was used to estimate monthly streamflow as the Mesh Sweeping Approach (MSA) driver. The methodology was applied for the upper part of the Huazuntlan River Watershed in Los Tuxtlas Mountains, Mexico. The MSA divided the study area into a rectangular mesh. Then, at every location within the mesh, SHP was obtained. The main components of the MSA as a RoR scheme were the intake, the powerhouse, and the surge tank. The surge tank was located at cells where the hydro-power was calculated and used as a reference to later locate the intake and powerhouse by maximizing the discharge and head. SHP calculation was perform... [more]

The paper presents the methodology for the estimation of the long-term actinides radiotoxicity and isotopic composition of spent nuclear fuel from a fleet of Pressurized Water Reactors (PWR). The methodology was developed using three independent numerical tools: the Spent Fuel Isotopic Composition database, the Nuclear Fuel Cycle Simulation System and the Monte Carlo Continuous Energy Burnup Code. The validation of spent fuel isotopic compositions obtained in the numerical modeling was performed using the available experimental data. A nuclear power embarking country benchmark was implemented for the verification and testing of the methodology. The obtained radiotoxicity reaches the reference levels at about 1.3 × 105 years, which is common for the PWR spent nuclear fuel. The presented methodology may be incorporated into a more versatile numerical tool for the modeling of hybrid energy systems.