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Energies, Volume 15, Issue 18 (September-2 2022) – 366 articles

Cover Story (view full-size image): Battery participation in the service of power system frequency regulation is universally recognized as a viable means for counteracting the dramatic impact of the increasing utilization of renewable energy sources. The regulating power due to power system changes is described as an Ornstein–Uhlenbeck or an exponential shot noise process driven by a homogeneous Poisson process depending on the frequency response features requested of the battery. Because of that, the battery state of charge is modeled as the output of a dynamic filter having this exponential shot noise process as input, and its characterization constitutes the central role for the correct characterization of the battery life. Numerical simulations are carried out for demonstrating the goodness and the applicability of the proposed probabilistic approach. View this paper
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14 pages, 11420 KiB  
Review
The Study for Technical Analysis on the Development Potential of Multi-Zone Oil, Gas in Crossfield, Canada
by Bryan Sangho Moon, Wangdo Lee and Youngsoo Lee
Energies 2022, 15(18), 6860; https://doi.org/10.3390/en15186860 - 19 Sep 2022
Viewed by 1877
Abstract
Crossfield is located in the province of Alberta in Canada and is one of the most well-known reservoirs of hydrocarbons. Since the 1950s, there has been continuous exploitation of more than 10 formations such as Cardium, Viking, Ellerslie, Elkton, Shunda, and Wabamun. Because [...] Read more.
Crossfield is located in the province of Alberta in Canada and is one of the most well-known reservoirs of hydrocarbons. Since the 1950s, there has been continuous exploitation of more than 10 formations such as Cardium, Viking, Ellerslie, Elkton, Shunda, and Wabamun. Because of its location near the Foothills, the southwestern part of the Western Canada Sedimentary Basin, the Crossfield area has a complex geology and relatively deeper reservoirs, therefore requiring an in-depth examination of each formation. In this study, geological, technical, and economic analyses were performed on each formation within the 10 sections of the study lands in the Crossfield area. As the result of the study, there was potential for drilling 48 horizontal wells in the Cardium A zone and the Viking formation. In addition, it turned out to be economically feasible even at the WTI price of 60 dollars per barrel considering Alberta’s Royalty Framework, which is determined by the production rate and the price of oil, and the Horizontal Oil New Well Royalty Rate feature. A further study is required to investigate the exploitation potential of the Cardium B zone, the Ellerslie, and the Elkton formations in this area. Full article
(This article belongs to the Section H1: Petroleum Engineering)
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24 pages, 7686 KiB  
Article
Leakage Analysis and Hazardous Boundary Determination of Buried Gas Pipeline Considering Underground Adjacent Confined Space
by Zhixue Wang, Yongbin Liu, Haibin Liang, Zhe Xu, Fanxi Bu, Jina Zhang, Hua Du, Yan Wang and Shuangqing Chen
Energies 2022, 15(18), 6859; https://doi.org/10.3390/en15186859 - 19 Sep 2022
Cited by 4 | Viewed by 2083
Abstract
Urban underground construction projects are intertwined vertically and horizontally, and adjacent confined spaces such as water supply and drainage pipelines, side ditches and underground canals may exist near buried gas pipelines. Once the buried gas pipeline leaks, the gas will diffuse into the [...] Read more.
Urban underground construction projects are intertwined vertically and horizontally, and adjacent confined spaces such as water supply and drainage pipelines, side ditches and underground canals may exist near buried gas pipelines. Once the buried gas pipeline leaks, the gas will diffuse into the confined space through the soil and even enter the residential room by the confined space, which brings serious potential safety hazards. In this paper, the underground adjacent confined space hazardous boundary (HB) of underground gas pipeline leakage was defined, the distribution properties of gas leakage diffusion flow field were analyzed by numerical simulation and the distribution law of gas entering the confined space was studied. Using the least-squares method and multiple regression theory, the gas concentration prediction model in the adjacent confined space of buried gas pipeline leakage was established, the HB calculation model was further deduced, and the HB drawing board was drawn. The results showed that in the initial stages, the internal and external pressure and velocity distribution of the pipeline near the leakage hole were unstable, reaching a stable state after 60 s, and then the reverse flow occurred in the pipeline downstream of the leak hole. Reducing the minimum construction distance between the buried gas pipeline and the confined space improved the gas distribution concentration in the confined space. When the minimum construction distance increased from 3 m to 9 m, the gas concentration distribution decreased from 90.21% to 0.88%. Meanwhile, increasing the pipeline pressure and leakage diameter enhanced the gas concentration distribution in the confined space. The HB calculation model and HB drawing board realize the rapid determination of the HB between buried gas pipeline and confined space and offer a more reasonable basis for the design of gas pipeline safe distance in urban underground engineering construction. Full article
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17 pages, 5087 KiB  
Article
Optimal Rotary Wind Turbine Blade Modeling with Bond Graph Approach for Specific Local Sites
by Abdulbasit Mohammed, Belete Sirahbizu and Hirpa G. Lemu
Energies 2022, 15(18), 6858; https://doi.org/10.3390/en15186858 - 19 Sep 2022
Cited by 3 | Viewed by 1502
Abstract
The wind turbine blade is an important component for harnessing wind energy. It plays a vital role in wind turbine operation. In this work, a study was conducted to investigate the dynamic behavior of an optimal rotary wind turbine blade with a bond [...] Read more.
The wind turbine blade is an important component for harnessing wind energy. It plays a vital role in wind turbine operation. In this work, a study was conducted to investigate the dynamic behavior of an optimal rotary wind turbine blade with a bond graph approach simulated with MATLAB/Simulink. The model is considered as a twisted Rayleigh beam which is made of several sections of the type SG6043 airfoil. This type of airfoil is suitable for low wind conditions, and each section is subjected to aerodynamic loads that are computed using the blade element momentum theory. The bond graph model was developed based on the law of conservation of mass and energy in the systems, and then the model was converted to the MATLAB/Simulink toolbox; results were validated with SG6043 airfoil data and real wind data collected from selected specific sites of Abomsa, Metehara, and Ziway areas in Ethiopia. Full article
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11 pages, 956 KiB  
Article
The Modeling of Bubble Lift-Off Diameter in Vertical Subcooled Boiling Flow
by Jingyu Du, Chenru Zhao, Hanliang Bo and Xin Ren
Energies 2022, 15(18), 6857; https://doi.org/10.3390/en15186857 - 19 Sep 2022
Cited by 3 | Viewed by 1553
Abstract
Bubble lift-off diameter is characterized as the size of a bubble rising from a wall, which is vital in the boundary condition of heat transfer model and interfacial area transport equation. In this paper, mechanistic force analysis was conducted to explore a predictive [...] Read more.
Bubble lift-off diameter is characterized as the size of a bubble rising from a wall, which is vital in the boundary condition of heat transfer model and interfacial area transport equation. In this paper, mechanistic force analysis was conducted to explore a predictive model for bubble lift-off diameter in a vertical channel of subcooled boiling flow. Specifically, the component of growth force normal to the wall and the shear lift force lead to the lift-off of a bubble on the vertical surface. Through force analysis, we found that bubble lift-off diameter is arranged to be related to wall superheat, latent heat, liquid velocity, fluid properties, bulk liquid subcooling, etc. To account for the contribution of the influencing factors, the dimensionless bubble lift-off diameter was correlated with dimensionless parameters, including the Prandtl number, the Reynolds number, the Jacob number, and dimensionless subcooling. The proposed correlation was assessed according to experimental data and the predictions showed good agreement with the data. Full article
(This article belongs to the Topic Nuclear Energy Systems)
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15 pages, 5489 KiB  
Article
Wireless Power Transmission System for Powering Rotating Parts of Automatic Machineries
by Vladimir Kindl, Tomas Kavalir, Jiri Sika, Jan Hnatik, Michal Krizek and Michal Frivaldsky
Energies 2022, 15(18), 6856; https://doi.org/10.3390/en15186856 - 19 Sep 2022
Cited by 3 | Viewed by 1709
Abstract
This paper deals with the analysis of a suitable compensation topology of a wireless power transmission system for powering the rotating parts of modern automatic machine tools. It summarizes the important properties of the serio-parallel compensation topology suitable for this application and demonstrates [...] Read more.
This paper deals with the analysis of a suitable compensation topology of a wireless power transmission system for powering the rotating parts of modern automatic machine tools. It summarizes the important properties of the serio-parallel compensation topology suitable for this application and demonstrates a detailed mathematical derivation using the first harmonic approximation. The paper details the industrial implementation of the system in a specific automatic machine tool application and demonstrates the strong technical advantages of the proposed design. Important theoretical conclusions and technical assumptions made when considering the system layout are verified by experimental laboratory measurements and the final deployment of the technology in the professional tool DMU 40 eVo linear. Full article
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26 pages, 10474 KiB  
Article
Numerical and Experimental Investigations on the Ignition Behavior of OME
by Frederik Wiesmann, Lukas Strauß, Sebastian Rieß, Julien Manin, Kevin Wan and Thomas Lauer
Energies 2022, 15(18), 6855; https://doi.org/10.3390/en15186855 - 19 Sep 2022
Cited by 10 | Viewed by 1587
Abstract
On the path towards climate-neutral future mobility, the usage of synthetic fuels derived from renewable power sources, so-called e-fuels, will be necessary. Oxygenated e-fuels, which contain oxygen in their chemical structure, not only have the potential to realize a climate-neutral powertrain, but also [...] Read more.
On the path towards climate-neutral future mobility, the usage of synthetic fuels derived from renewable power sources, so-called e-fuels, will be necessary. Oxygenated e-fuels, which contain oxygen in their chemical structure, not only have the potential to realize a climate-neutral powertrain, but also to burn more cleanly in terms of soot formation. Polyoxymethylene dimethyl ethers (PODE or OMEs) are a frequently discussed representative of such combustibles. However, to operate compression ignition engines with these fuels achieving maximum efficiency and minimum emissions, the physical-chemical behavior of OMEs needs to be understood and quantified. Especially the detailed characterization of physical and chemical properties of the spray is of utmost importance for the optimization of the injection and the mixture formation process. The presented work aimed to develop a comprehensive CFD model to specify the differences between OMEs and dodecane, which served as a reference diesel-like fuel, with regards to spray atomization, mixing and auto-ignition for single- and multi-injection patterns. The simulation results were validated against experimental data from a high-temperature and high-pressure combustion vessel. The sprays’ liquid and vapor phase penetration were measured with Mie-scattering and schlieren-imaging as well as diffuse back illumination and Rayleigh-scattering for both fuels. To characterize the ignition process and the flame propagation, measurements of the OH* chemiluminescence of the flame were carried out. Significant differences in the ignition behavior between OMEs and dodecane could be identified in both experiments and CFD simulations. Liquid penetration as well as flame lift-off length are shown to be consistently longer for OMEs. Zones of high reaction activity differ substantially for the two fuels: Along the spray center axis for OMEs and at the shear boundary layers of fuel and ambient air for dodecane. Additionally, the transient behavior of high temperature reactions for OME is predicted to be much faster. Full article
(This article belongs to the Special Issue Combustion Characteristics of Cleaner Fuels 2022)
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24 pages, 2147 KiB  
Review
Biodiesel Emissions: A State-of-the-Art Review on Health and Environmental Impacts
by Abdulelah Aljaafari, I. M. R. Fattah, M. I. Jahirul, Yuantong Gu, T. M. I. Mahlia, Md. Ariful Islam and Mohammad S. Islam
Energies 2022, 15(18), 6854; https://doi.org/10.3390/en15186854 - 19 Sep 2022
Cited by 21 | Viewed by 4335
Abstract
Biodiesel is an alternative source of fuel for various automotive applications. Because of the increasing demand for energy and the scarcity of fossil fuels, researchers have turned their attention to biodiesel production from various sources in recent years. The production of biofuels from [...] Read more.
Biodiesel is an alternative source of fuel for various automotive applications. Because of the increasing demand for energy and the scarcity of fossil fuels, researchers have turned their attention to biodiesel production from various sources in recent years. The production of biofuels from organic materials and waste components allows for the use of these waste resources in transporting resources and people over long distances. As a result, developing sustainable measures for this aspect of life is critical, as knowledge of appropriate fuel sources, corresponding emissions, and health impacts will benefit the environment and public health assessment, which is currently lacking in the literature. This study investigates biodiesel’s composition and production process, in addition to biodiesel emissions and their associated health effects. Based on the existing literature, a detailed analysis of biodiesel production from vegetable oil crops and emissions was undertaken. This study also considered vegetable oil sources, such as food crops, which can have a substantial impact on the environment if suitable growing procedures are not followed. Incorporating biodegradable fuels as renewable and sustainable solutions decreases pollution to the environment. The effects of biodiesel exhaust gas and particulates on human health were also examined. According to epidemiologic studies, those who have been exposed to diesel exhaust have a 1.2–1.5 times higher risk of developing lung cancer than those who have not. In addition, for every 24 parts per billion increase in NO2 concentration, symptom prevalence increases 2.7-fold. Research also suggests that plain biodiesel combustion emissions are more damaging than petroleum diesel fuel combustion emissions. A comprehensive analysis of biodiesel production, emissions, and health implications would advance this field’s understanding. Full article
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16 pages, 3103 KiB  
Article
Life Cycle Assessment of Energy Consumption and CO2 Emission from HEV, PHEV and BEV for China in the Past, Present and Future
by Renjie Wang, Yuanyuan Song, Honglei Xu, Yue Li and Jie Liu
Energies 2022, 15(18), 6853; https://doi.org/10.3390/en15186853 - 19 Sep 2022
Cited by 12 | Viewed by 2959
Abstract
In order to fulfill the commitment of China to achieve carbon peak by 2030 and carbon neutrality by 2060, all industries have been taking their respective carbon reduction actions. The transportation industry accounts for 11% of CO2 emission of the whole society, [...] Read more.
In order to fulfill the commitment of China to achieve carbon peak by 2030 and carbon neutrality by 2060, all industries have been taking their respective carbon reduction actions. The transportation industry accounts for 11% of CO2 emission of the whole society, and its energy conservation and carbon reduction benefit is of great significance to the national carbon reduction process. New energy vehicles are undoubtedly one of the most important means of carbon emission reduction in the transportation sector. However, electric vehicles still have CO2 emissions, as the fossil fuel use comes from upstream power. To systematically and comprehensively evaluate the CO2 emissions of HEV, PHEV and BEV in the whole process, this study introduces the life-cycle method to research on the past and current situations, and predict future scenarios for ICEV and EV light-duty vehicles at the national and regional levels, by deeply analyzing the generation mix and generating efficiency from the WTT stage, and fuel economy from the TTW stage. The study shows that compared with ICEV, HEV and PHEV could reduce around 30% of CO2 emissions. Currently, BEV could reduce 37% of CO2 emission in the region where the proportion of coal-fired power is high, and 90% of CO2 emission in the region where the proportion of hydro power is high. This study discusses the impact of the proportion of renewable energy application on the carbon emissions from electric vehicles, analyzes the environmental benefits of promoting electric vehicles in different regions, and lays a foundation for the promotion strategy of electric vehicles for different regions in the future. Full article
(This article belongs to the Special Issue Modeling and Control of Hybrid Powertrain System)
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17 pages, 2214 KiB  
Article
McCARD Criticality Benchmark Analyses with Various Evaluated Nuclear Data Libraries
by Ho Jin Park, Mohammad Alosaimi, Seong-Ah Yang, Heejeong Jeong and Sung Hoon Choi
Energies 2022, 15(18), 6852; https://doi.org/10.3390/en15186852 - 19 Sep 2022
Cited by 2 | Viewed by 1442
Abstract
International Criticality Safety Benchmark Evaluation Project (ICSBEP) criticality analyses were conducted using the McCARD Monte Carlo code for 85 selected benchmark problems with 7 evaluated nuclear data libraries (ENDLs): ENDF/B-VII.1, ENDF/B-VIII.0, JENDL-4.0, JENDL-5.0, JEFF-3.3, TENDL-2021, and CENDL-3.2. Regarding the analyses, it was confirmed [...] Read more.
International Criticality Safety Benchmark Evaluation Project (ICSBEP) criticality analyses were conducted using the McCARD Monte Carlo code for 85 selected benchmark problems with 7 evaluated nuclear data libraries (ENDLs): ENDF/B-VII.1, ENDF/B-VIII.0, JENDL-4.0, JENDL-5.0, JEFF-3.3, TENDL-2021, and CENDL-3.2. Regarding the analyses, it was confirmed that the keff results are sensitive to the ENDL. It is noted that the new-version ENDLs show better performance in the fast benchmark cases, while on the other hand, there are no significant differences in keff among the different ENDLs in the thermal benchmark cases. The sensitivity of the keff results depending on the ENDL may impact nuclear core design parameters such as the shutdown margin, critical boron concentration, and power defects. This study and keff results will be a good reference in the development of new types of nuclear cores or new design codes. Full article
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22 pages, 11590 KiB  
Article
Propagation of Disturbances Generated by DC Electric Traction
by Zbigniew Olczykowski and Jacek Kozyra
Energies 2022, 15(18), 6851; https://doi.org/10.3390/en15186851 - 19 Sep 2022
Cited by 1 | Viewed by 1460
Abstract
In Poland, rail transport is powered by the electric system with the use of traction substations that supply the electric traction with DC voltage of 3 kV. The necessity to change the alternating voltage to the constant and changing loads of the substation [...] Read more.
In Poland, rail transport is powered by the electric system with the use of traction substations that supply the electric traction with DC voltage of 3 kV. The necessity to change the alternating voltage to the constant and changing loads of the substation cause the electric traction to be a recipient, generating a number of disturbances to the network. These disturbances affect the quality of electricity in the power system from which traction substations are supplied, and the power quality in auxiliary and non-traction lines. This article analyzes the measurements of power quality indicators recorded at selected points of the traction substation system. The parameters characterizing the power quality were recorded, among others, in the main lines supplying traction substations, non-traction lines and auxiliary circuits. The presented article is the first in a series of publications related to the assessment of the impact of DC electric traction on the power system. The recorded data will be the basis for computer simulations defining, inter alia, the impact of power supply conditions for traction substations on the power system and to propose methods of reducing disturbances generated by a dynamically changing substation load. Full article
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20 pages, 13401 KiB  
Article
Numerical Investigation of Inlet Boundary Layer in an Axial Compressor Tandem Cascade
by Zonghao Yang, Bo Liu, Xiaochen Mao, Botao Zhang and Hejian Wang
Energies 2022, 15(18), 6850; https://doi.org/10.3390/en15186850 - 19 Sep 2022
Cited by 1 | Viewed by 1329
Abstract
To explore the inlet boundary layer (IBL) influence on the tandem cascade aerodynamic performance, this paper took the high subsonic compressor NACA65 K48 cascade and its modified tandem cascade as the research object. The effects of the IBL thickness and the skewed IBL [...] Read more.
To explore the inlet boundary layer (IBL) influence on the tandem cascade aerodynamic performance, this paper took the high subsonic compressor NACA65 K48 cascade and its modified tandem cascade as the research object. The effects of the IBL thickness and the skewed IBL on the aerodynamic performance of the original cascade and tandem cascade were analyzed based on the numerical method. The results show that the tandem cascade effective design makes it better than the original cascade in the aerodynamic performance under different IBL conditions. Compared with the collateral IBL, the skewed IBL can effectively improve the aerodynamic performance of the original cascade and tandem cascade by suppressing the endwall cross flow, but an increase in the IBL thickness will suppress this advantage. In addition, the increase of incidence angle or the IBL thickness will make the tandem cascade forward blade corner separation more serious and cause the flow passage to be blocked, which seriously affects the rear blade diffusing capacity. In general, the IBL thickness is positively correlated with the tandem cascade total pressure loss and negatively correlated with the static pressure rise (except for the −6° incidence angle). The skewed IBL can effectively reduce the total pressure loss and increase the static pressure rise within −4°~7° incidence angle, but the law is opposite at a −6° incidence angle. At a 0° or 2° incidence angle, the performance improvement effect of the skewed IBL on the tandem cascade is the best, and this positive effect diminishes as it tends towards a larger positive incidence angle or a smaller negative incidence angle. Full article
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15 pages, 384 KiB  
Article
The Influence of Low Carbon Emission Engine on the Life Cycle of Automotive Products: A Case Study of Three-Cylinder Models in the Chinese Market
by Meixia Pan, Wanming Chen, Shengyuan Wang and Xiaolan Wu
Energies 2022, 15(18), 6849; https://doi.org/10.3390/en15186849 - 19 Sep 2022
Cited by 1 | Viewed by 1556
Abstract
There is a development trend for fuel vehicles to adopt low-carbon emission engines. The sales of cars with low-carbon three-cylinder engines in the Chinese market have declined. Is the life cycle of automotive products with three-cylinder engines entering a recession stage? In order [...] Read more.
There is a development trend for fuel vehicles to adopt low-carbon emission engines. The sales of cars with low-carbon three-cylinder engines in the Chinese market have declined. Is the life cycle of automotive products with three-cylinder engines entering a recession stage? In order to achieve this research objective, which is to investigate whether assembling a three-cylinder engine affects the life cycle of an automotive product, this paper constructs an ecological theory-based approach to measuring the life cycle of automotive products. First, the logistic model is used to measure the intrinsic growth rate, internal inhibition coefficient, and theoretical upper limit of product sales scale before and after the automotive products are equipped with three-cylinder engines. In the second stage, the Lotka–Volterra model is used to calculate the intrinsic growth rate, internal inhibition coefficient, theoretical upper limit, and symbiosis coefficient of the sales scale of the products before and after the three-cylinder engine, taking the Chinese automobile manufacturing enterprises as an example for empirical analysis. The research results show that the selection of three- cylinder engine for automotive products will not lead to the product life cycle entering the recession period ahead of time. Full article
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16 pages, 3853 KiB  
Article
Water Recuperation from Hydrogen Fuel Cell during Aerial Mission
by Lev Zakhvatkin, Alex Schechter and Idit Avrahami
Energies 2022, 15(18), 6848; https://doi.org/10.3390/en15186848 - 19 Sep 2022
Cited by 2 | Viewed by 3211
Abstract
A water recuperation system (WRS) from an open-cathode proton exchange membrane fuel cell (PEMFC) is designed to increase the energy density of hydrogen production by hydrolysis of metal hydrides. WRS may significantly reduce the water weight in the carried fuel. The design is [...] Read more.
A water recuperation system (WRS) from an open-cathode proton exchange membrane fuel cell (PEMFC) is designed to increase the energy density of hydrogen production by hydrolysis of metal hydrides. WRS may significantly reduce the water weight in the carried fuel. The design is based on circulating the humid air through the PEMFC stack in a closed dome. To ensure oxygen supply to the PEMFC, the WRS has a ventilation inlet and an exhaust outlet. The required conditions for ventilation flow are developed theoretically and examined experimentally in a WRS prototype with a commercial PEMFC at 20–100 W. The experimental system includeds a closed dome, an edge cooling system for the PEMFC, a controllable ventilation air inlet, and an exhaust port. The humid exhaust air was cooled down to the ambient temperature to improve vapor condensation. Results show high efficiency (80% recuperated water from prediction), with a potential to achieve gravimetric hydrogen storage capacity (GHSC) of >6 wt% at an ambient temperature of 27 °C. The described principle may be applied for small fixed-wing drones where the cold ambient air may be utilized both for providing oxygen supply and for thermal management of the PEMFC and the humid exhaust, thus allowing higher GHSC. Full article
(This article belongs to the Special Issue Advanced Studies for PEM Fuel Cells in Hydrogen-Fueled Vehicles)
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27 pages, 9067 KiB  
Article
A Study on Bio-Coke Production—The Influence of Bio-Components Addition on Coke-Making Blend Properties
by Michał Rejdak, Małgorzata Wojtaszek-Kalaitzidi, Grzegorz Gałko, Bartosz Mertas, Tomasz Radko, Robert Baron, Michał Książek, Sten Yngve Larsen, Marcin Sajdak and Stavros Kalaitzidis
Energies 2022, 15(18), 6847; https://doi.org/10.3390/en15186847 - 19 Sep 2022
Cited by 7 | Viewed by 4519
Abstract
Due to global warming, technologies reducing CO2 emissions in the metallurgical industry are being sought. One possibility is to use bio-coke as a substitute for classic coke made of 100% fossil coal. Bio-coke can be produced on the basis of coal with [...] Read more.
Due to global warming, technologies reducing CO2 emissions in the metallurgical industry are being sought. One possibility is to use bio-coke as a substitute for classic coke made of 100% fossil coal. Bio-coke can be produced on the basis of coal with the addition of substances of biomass origin. Blends for the production of bio-coke should have appropriate coke-making properties to ensure the appropriate quality of bio-coke. The article presents the results of the research on the influence of the addition (up to 20%) of bio-components of different origins to the coke blend on its coke-making properties, i.e., Gieseler Fluidity, Arnu—Audibert Dilatation and Roga Index. The bio-components used in the research were raw and thermally processed waste biomass of different origins (forestry: beech and alder woodchips; sawmill: pine sawdust; and the food industry: hazelnut shells and olive kernels) and commercial charcoal. Studies have shown that both the amount of additive and the type of additive affect the obtained coking properties. There was a decrease in fluidity, dilatation and Roga Index values, with more favorable results obtained for the addition of carbonized biomass and for additives with a higher apparent density. A regressive mathematical model on the influence of the share of the additive and its properties (oxygen content and apparent density) on the percentage decrease in fluidity was also developed. Full article
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25 pages, 38961 KiB  
Article
Influence of Multi-Period Tectonic Movement and Faults on Shale Gas Enrichment in Luzhou Area of Sichuan Basin, China
by Xuewen Shi, Wei Wu, Yuguang Shi, Zhenxue Jiang, Lianbo Zeng, Shijie Ma, Xindi Shao, Xianglu Tang and Majia Zheng
Energies 2022, 15(18), 6846; https://doi.org/10.3390/en15186846 - 19 Sep 2022
Cited by 2 | Viewed by 1617
Abstract
The Luzhou area in the southern Sichuan Basin has experienced multiple tectonic movements, forming a complex fault system; the activity has an important impact on the enrichment of shale gas in this area. In order to reveal the influence of the fracture system [...] Read more.
The Luzhou area in the southern Sichuan Basin has experienced multiple tectonic movements, forming a complex fault system; the activity has an important impact on the enrichment of shale gas in this area. In order to reveal the influence of the fracture system on the differential enrichment of shale gas, this paper takes the southern Sichuan Basin as the research object. The structural evolution process and fracture development characteristics of the different tectonic units in Luzhou area of southern Sichuan were characterized by conducting a seismic profile analysis, structural recovery using a back-stripping method, and core hand specimen description. We clarified the control effect of the structural deformation and fracture on the differential enrichment of shale gas, and we established a differential enrichment model of shale gas in the Luzhou area. The results show that: (1) The Luzhou area has undergone the transformation of a multi-stage tectonic movement. There are many sets of detachment structures in the longitudinal direction, and the plane structural form is a thin-skin fold-thrust belt composed of wide and narrow anticlines in the north–south direction. (2) The faults in the study area are affected by the Himalayan tectonic movement. The high-angle reverse faults are developed, and the number of large faults is small. The second and third faults are mainly developed. The second faults are only developed at the high position of the structure, which has a significantly destructive effect on shale gas reservoirs, while the third and fourth faults have no significant destructive effect on shale gas reservoirs. (3) In the study area, the types of cracks are categorized into transformational shear cracks, bed-parallel shear cracks, intraformational open cracks, lamellation cracks, shrinkage cracks, and abnormal high-pressure cracks. The thickness of the shale rock mechanical layer, brittle mineral content, and organic matter content jointly control the crack development degree in the shale of the Wufeng–Longmaxi Formation. (4) The uplift erosion, structural deformation, and fracture development caused by the structural evolution have affected the preservation of shale gas, resulting in the differential enrichment of shale gas reservoirs in the region. Based on the enrichment factors of shale gas, we established a differential enrichment model of shale gas in typical structural units and optimized the favorable enrichment areas, which are important contributions for guiding shale gas exploration and development in the Sichuan Basin. Full article
(This article belongs to the Special Issue New Challenges in Unconventional Oil and Gas Reservoirs)
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39 pages, 6751 KiB  
Article
Re-Defining System LCOE: Costs and Values of Power Sources
by Yuhji Matsuo
Energies 2022, 15(18), 6845; https://doi.org/10.3390/en15186845 - 19 Sep 2022
Cited by 6 | Viewed by 3354
Abstract
The mass introduction of variable renewable energies, including wind and solar photovoltaic, leads to additional costs caused by the intermittency. Many recent studies have addressed these “integration costs,” and proposed novel metrics that replace the traditional metric known as the levelized cost of [...] Read more.
The mass introduction of variable renewable energies, including wind and solar photovoltaic, leads to additional costs caused by the intermittency. Many recent studies have addressed these “integration costs,” and proposed novel metrics that replace the traditional metric known as the levelized cost of electricity (LCOE). However, the policy relevance of those metrics remains unclear. In this study, the author investigates and re-defines the concept of system LCOE, referring to prior studies, and proposes concrete methods to estimate them. Average system LCOE allocates the integration cost to each power source, dividing that by the adjusted power output. Marginal system LCOE revises the concept of system LCOE and value-adjusted LCOE proposed by prior studies, to be clearer and more policy-relevant. These metrics are also applied to Japan’s power sector in 2050, suggesting the necessity of aiming for a “well-balanced energy mix” in future power systems with decarbonised power sources. Full article
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27 pages, 9951 KiB  
Article
Assessment of the Impact of Renewable Energy Expansion on the Technological Competitiveness of the Cogeneration Model
by Yonghoon Im
Energies 2022, 15(18), 6844; https://doi.org/10.3390/en15186844 - 19 Sep 2022
Cited by 2 | Viewed by 1475
Abstract
The rapid transition from an efficiency-oriented to a renewable energy-based green environment raises questions about the sustainability of cogeneration models in the coming era of climate change. For securing the technological competitiveness of a cogeneration model in terms of sustainability, it is essential [...] Read more.
The rapid transition from an efficiency-oriented to a renewable energy-based green environment raises questions about the sustainability of cogeneration models in the coming era of climate change. For securing the technological competitiveness of a cogeneration model in terms of sustainability, it is essential to come up with alternatives that can flexibly respond to changes in the market conditions. From the surveyed field operation data of the cogeneration model applied to an apartment complex, it was found that the actual operation performance may differ significantly from the theoretical expectation. Through diagnostic simulation analysis, the main cause of the disappointing performance in the case of the current cogeneration model after installation has been assessed, and the importance of a consistent operation strategy was demonstrated by the event-based correlation analysis based on field operation data. The impact of the rapid expansion and dissemination of the renewable energy market on the relative primary energy savings benefit evaluation of the cogeneration model was analyzed for various operating conditions. Full article
(This article belongs to the Topic Energy Saving and Energy Efficiency Technologies)
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11 pages, 2811 KiB  
Article
Study on Detonation Characteristics of Ammonium Nitrate-Polyhydroxy Alcohol Mixtures
by Józef Paszula, Alan Kępisty, Andrzej Maranda and Bożena Kukfisz
Energies 2022, 15(18), 6843; https://doi.org/10.3390/en15186843 - 19 Sep 2022
Viewed by 1384
Abstract
This paper presents the results of detonation parameters for ammonium nitrate-polyhydroxy alcohol mixtures and ternary explosive compositions modified by flaked aluminium. The detonation velocities, overpressures of blast waves and their specific impulses were determined. It was shown that the viscosity of liquid fuels [...] Read more.
This paper presents the results of detonation parameters for ammonium nitrate-polyhydroxy alcohol mixtures and ternary explosive compositions modified by flaked aluminium. The detonation velocities, overpressures of blast waves and their specific impulses were determined. It was shown that the viscosity of liquid fuels is the leading property that determines the detonation parameters of the tested compositions. Full article
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19 pages, 724 KiB  
Article
The Impact of Economic Factors on the Sustainable Development of Energy Enterprises: The Case of Bulgaria, Czechia, Estonia and Poland
by Anna Misztal, Magdalena Kowalska and Anita Fajczak-Kowalska
Energies 2022, 15(18), 6842; https://doi.org/10.3390/en15186842 - 19 Sep 2022
Cited by 2 | Viewed by 1594
Abstract
The sustainable development of enterprises is based on three pillars: economic, social, and environmental. Sustainable development aims to limit climate change and its negative impact on the natural environment. The main aim of this paper is to assess the impact of selected energy [...] Read more.
The sustainable development of enterprises is based on three pillars: economic, social, and environmental. Sustainable development aims to limit climate change and its negative impact on the natural environment. The main aim of this paper is to assess the impact of selected energy economy factors (government expenditure, environmental taxes, outlays on renewable energy sources, prices of futures contracts for CO2 emissions, outlays on R&D, and the EU Emissions Trading System (ETSEU)) on the sustainable development of the energy sectors in Bulgaria, Czechia, Estonia, and Poland, from 2008 to 2022. We use the correlation coefficients, the Ordinary Least Squares (OLS), Vector Autoregressive (VAR) Models, and the simultaneous equation. The research results indicate a variation in the direction and strength of the influence of individual economic factors in the studied countries (p < 0.05). The results can support operational and strategic decisions sustaining the sustainable development of enterprises in the analyzed countries. The results indicate the need to reform selected economic factors, with an emphasis on the increased importance of environmental taxes and the reform of the EU ETS, which is a key tool for reducing greenhouse gas emissions cost-effectively. Full article
(This article belongs to the Special Issue Economics and Finance of Energy and Climate Change)
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30 pages, 6690 KiB  
Review
An Overview of Microbial Fuel Cells within Constructed Wetland for Simultaneous Nutrient Removal and Power Generation
by N. Evelin Paucar and Chikashi Sato
Energies 2022, 15(18), 6841; https://doi.org/10.3390/en15186841 - 19 Sep 2022
Cited by 12 | Viewed by 3035
Abstract
Water, energy, and food are indispensable for sustainable economic development. Despite nutrients, especially phosphorus and nitrogen, being essential for plant growth and thus food supplies, those present in wastewater are considered an environmental burden. While microbial fuel cells (MFCs) are receiving much interest, [...] Read more.
Water, energy, and food are indispensable for sustainable economic development. Despite nutrients, especially phosphorus and nitrogen, being essential for plant growth and thus food supplies, those present in wastewater are considered an environmental burden. While microbial fuel cells (MFCs) are receiving much interest, combining wastewater treatment with an MFC has emerged as an option for low-cost wastewater treatment. Among others, a constructed wetland (CW) coupled with an MFC (CW-MFC) has the potential to provide a low carbon footprint and low-energy wastewater treatment, as well as nutrient and energy recovery from wastewater. Findings from this review show that the organic and nutrient removal and power generation by the integrated CW-MFC systems are affected by a number of factors including the organic loading rate, hydraulic retention time, system design, plant species, dissolved oxygen, substrate/media type, influent feeding mode, electrode materials and spacing, and external resistance. This review aims to summarize the current state of the CW-MFC and related technologies with particular emphasis on organic and nutrient removal, as well as on the bioenergy recovery from different wastewaters. Despite the benefits that these technologies can offer, the interactive mechanisms between the CW and MFC in the integrated system are still unclear. Further research is needed to fully understand the CW-MFC and related systems. The results of this work provide not only an overview and insight into existing knowledge but also the future direction of the CW-MFC technologies. Full article
(This article belongs to the Special Issue Microbial Fuel Cells II)
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12 pages, 3243 KiB  
Article
Evaluation of the Current Shunt Influence on the Determined Wideband Accuracy of Inductive Current Transformers
by Michal Kaczmarek, Piotr Kaczmarek and Ernest Stano
Energies 2022, 15(18), 6840; https://doi.org/10.3390/en15186840 - 19 Sep 2022
Cited by 4 | Viewed by 1196
Abstract
This manuscript presents performed laboratory studies and the analysis of the impact of current shunt values used in the differential connection on the wideband metrological performance of inductive current transformers. Moreover, a comparison of the accuracy of wideband and 50 Hz-type inductive current [...] Read more.
This manuscript presents performed laboratory studies and the analysis of the impact of current shunt values used in the differential connection on the wideband metrological performance of inductive current transformers. Moreover, a comparison of the accuracy of wideband and 50 Hz-type inductive current transformers in the specified frequency range from 50 Hz to 5 kHz is presented. The main factor which may influence the wideband accuracy of inductive current transformers is the phenomenon of self-generation. This causes rapid changes in the accuracy, and simultaneously causes the most positive and the most negative values of current error and phase displacement. To evaluate the metrological performance in the differential measurement setup for higher harmonics of the distorted current, a digital acquisition board was used. Obtained results show that if proper values of current shunt resistance are chosen, such devices may be used to evaluate the wideband accuracy of inductive current transformers. The results indicate that the typical units designed for the transformation of sinusoidal current with a frequency of 50 Hz can achieve a comparable metrological performance to that of the wideband inductive current transformer. Full article
(This article belongs to the Special Issue Development of Voltage and Current Transformers in Power System)
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15 pages, 4598 KiB  
Article
Structural Parameter Optimization of the Helical Blade of the Variable-Pitch, Downhole, Cyclone Separator Based on the Response Surface Method
by Qi Nie, Meiqiu Li and Sizhu Zhou
Energies 2022, 15(18), 6839; https://doi.org/10.3390/en15186839 - 19 Sep 2022
Cited by 2 | Viewed by 1870
Abstract
Aiming at the problems of pipeline blockage and equipment wear caused by large sand production in shallow gas hydrate mining on the seabed, based on the solid-state fluidization mining method, the idea of in situ separation of natural gas hydrate is proposed, and [...] Read more.
Aiming at the problems of pipeline blockage and equipment wear caused by large sand production in shallow gas hydrate mining on the seabed, based on the solid-state fluidization mining method, the idea of in situ separation of natural gas hydrate is proposed, and the downhole design is based on the physical parameters of hydrate mixed slurry. For the in situ helical separator, the CFD-Fluent commercial software was used to establish an analysis model and optimize the response surface of the model. The effects of the three-stage variable-pitch helix and blades on the performance of the separation device were investigated. The simulation results and response surface optimization were conducted through experiments to verify the accuracy. The results show that the third-stage pitch has the greatest impact on the separation efficiency and pressure drop, while the first-stage pitch has the least impact. The pressure drop and separation efficiency are fully considered. After the response surface optimization, the optimal three-stage pitch is the first-stage pitch x1 = 72.227 mm, the pitch of the second stage x2 = 105 mm, and the pitch of the third stage x3 = 124.817 mm. The separation efficiency of the optimal structure is verified by experiments. Compared with the previously used fixed-pitch downhole cyclone separator, the three-stage variable pitch cyclone, the separator improves the separation efficiency from 88.29% to 97.16% while keeping the pressure drop unchanged. Full article
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15 pages, 1929 KiB  
Article
Assessment of Cytochrome c and Chlorophyll a as Natural Redox Mediators for Enzymatic Biofuel Cells Powered by Glucose
by Urte Samukaite Bubniene, Sarunas Zukauskas, Vilma Ratautaite, Monika Vilkiene, Ieva Mockeviciene, Viktorija Liustrovaite, Maryia Drobysh, Aurimas Lisauskas, Simonas Ramanavicius and Arunas Ramanavicius
Energies 2022, 15(18), 6838; https://doi.org/10.3390/en15186838 - 19 Sep 2022
Cited by 3 | Viewed by 1910
Abstract
The development of new high-power biofuel cells has been limited in the past by slow or indirect charge transfer. In this study, enzymatic biofuel cell (EBFC) systems were explored with different materials used to evaluate their applicability as redox mediators. Redox mediators of [...] Read more.
The development of new high-power biofuel cells has been limited in the past by slow or indirect charge transfer. In this study, enzymatic biofuel cell (EBFC) systems were explored with different materials used to evaluate their applicability as redox mediators. Redox mediators of different natures have been selected for this research. Cytochrome c, Chlorophyll a, and supernatant of ultrasonically disrupted algae Chlorella vulgaris cells were examined as potential redox mediators. The effect of heparin on the EBFC was also evaluated under the same analytical conditions. The measurements of open circuit potential (OCP) and the evaluation of the current response in two modes of measurement were performed (i) during potential cycling in cyclic voltammetry measurements or (ii) at the constant potential value in chronoamperometry, and were applied for the evaluation of EBFC. Cytochrome c, Chlorophyll a, and the supernatant of ultrasonically disrupted algae Chlorella vulgaris cells-based redox mediators were efficient in the glucose oxidase (GOx) based EBFC. Electron transfer from GOx to the electrode was facilitated through the redox mediators adsorbed on the electrode. Electrodes modified with Chlorophyll a- and Cytochrome c-based redox mediators were suitable for the development of glucose biosensors. This was demonstrated by increasing the glucose concentration within 0 mM–100 mM in the system, the current density increased, and the system reached equilibrium rather faster regarding the electrochemical reaction. The power density is an important feature in revealing the action of biofuel cells. The highest power values were generated by the systems based on the application of redox-mediated Chlorophyll a and the supernatant of ultrasonically disrupted Chlorella vulgaris cells. The surface power density was about 2.5–4.0 µW/cm2. Control of a study was performed with a polished graphite electrode and the maximum surface power density was 0.02471 µW/cm2. Full article
(This article belongs to the Section A4: Bio-Energy)
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12 pages, 1203 KiB  
Article
Simultaneous Extraction of Rapeseed Oil and Enzymatic Transesterification with Butanol in the Mineral Diesel Medium
by Egle Sendzikiene, Violeta Makareviciene and Migle Santaraite
Energies 2022, 15(18), 6837; https://doi.org/10.3390/en15186837 - 19 Sep 2022
Cited by 1 | Viewed by 1159
Abstract
Increasing environmental pollution is driving an increase in the production and use of biofuels. The cost price of biodiesel could be reduced by using low-quality oilseeds unfit for human consumption and by applying the simultaneous oil extraction and transesterification process, avoiding the oil [...] Read more.
Increasing environmental pollution is driving an increase in the production and use of biofuels. The cost price of biodiesel could be reduced by using low-quality oilseeds unfit for human consumption and by applying the simultaneous oil extraction and transesterification process, avoiding the oil pressure stage. The purpose of this study was to investigate the enzymatic biofuel production process (in situ) by using rapeseed with high oil acidity for simultaneous oil extraction and transesterification with a mixture of butanol and mineral diesel fuel. The investigation of the in situ process was performed using a mixture of butanol and mineral diesel and the most effective biocatalyst Lipozyme TL IM was selected. The novelty of this paper consists of the fact that mineral diesel was used as the oil extractant, and the amount chosen was such that, at the end, a mixture of fuel with a ratio 9:1 of mineral diesel to biodiesel was be produced. The experiments were carried out using ground rapeseeds under laboratory conditions. The efficiency of oil extraction was investigated by the FTIR spectrometry method, and the efficiency of transesterification was determined by the gas chromatography method. It was found that the optimal reaction duration was 7 h, reaction temperature was 40 °C, and lipase content was 6% (from the oil content in rapeseed). An oil extraction efficiency of 99.92 ± 0.04 (w/w) was observed at these conditions. A transesterification degree of 99.08 ± 0.08% (w/w) met with the requirements of the standards for biodiesel fuel. The physical and chemical properties of the produced fuel mixture met the requirements of the standards for mineral diesel and biodiesel; therefore, it can be used in diesel engines. Full article
(This article belongs to the Section B: Energy and Environment)
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23 pages, 5484 KiB  
Review
Review of Single-Phase Bidirectional Inverter Topologies for Renewable Energy Systems with DC Distribution
by Meshari Alshammari and Maeve Duffy
Energies 2022, 15(18), 6836; https://doi.org/10.3390/en15186836 - 19 Sep 2022
Cited by 3 | Viewed by 3372
Abstract
Recent developments in renewable energy installations in buildings have highlighted the potential improvement in energy efficiency provided by direct current (DC) distribution over traditional alternating current (AC) distribution. This is explained by the increase in DC load types and energy storage systems such [...] Read more.
Recent developments in renewable energy installations in buildings have highlighted the potential improvement in energy efficiency provided by direct current (DC) distribution over traditional alternating current (AC) distribution. This is explained by the increase in DC load types and energy storage systems such as batteries, while renewable energy sources such as photovoltaics (PVs) produce electricity in DC form. In order to connect a DC distribution system to the alternating current grid (e.g., for backup, delivering energy storage to the grid) there is a need for a bidirectional inverter, which needs to operate over a wide range of source and load conditions and is therefore critical to the overall system performance. However, DC distribution in buildings is relatively new, with much of the research focused on the control of the DC bus connection between sources and loads, rather than on the grid connection. Therefore, this review aims to explore recent developments in bidirectional inverter technologies and the associated challenges imposed on grid-connected DC distribution systems. The focus is on small-scale building applications powered by photovoltaic (PV) installations, which may include energy storage in the form of batteries. An evaluation of existing inverter topologies is presented, focusing on semiconductor technologies, control techniques, and efficiency under variable source and load conditions. Challenges are identified, as are optimal solutions based on available technologies. The work provides a basis for future developments to address current shortcomings so that the full benefits of DC distribution can be achieved. Full article
(This article belongs to the Topic Power Converters)
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21 pages, 6258 KiB  
Article
Comparison of the Combustion Process Parameters in a Diesel Engine Powered by Second-Generation Biodiesel Compared to the First-Generation Biodiesel
by Piotr Łagowski, Grzegorz Wcisło and Dariusz Kurczyński
Energies 2022, 15(18), 6835; https://doi.org/10.3390/en15186835 - 19 Sep 2022
Cited by 4 | Viewed by 1595
Abstract
The use of biofuels to power compression–ignition engines makes it possible to reduce emissions of certain harmful components of exhaust gases. The purpose of this study was to determine the influence of second-generation biofuels on the course of indicator graphs and heat release [...] Read more.
The use of biofuels to power compression–ignition engines makes it possible to reduce emissions of certain harmful components of exhaust gases. The purpose of this study was to determine the influence of second-generation biofuels on the course of indicator graphs and heat release characteristics of the Perkins 1104D-44TA compression–ignition engine. For comparative purposes, the same tests were carried out by feeding the engine with first-generation biofuel and diesel fuel. Babassu butyl esters (BBuE) were used as the second-generation biofuel. The second fuel was a first-generation biofuel—rapeseed oil methyl esters (RME). Analysis of the results made it possible to draw conclusions about the effect of using 2nd and 1st generation biofuels on the parameters of the combustion process. When the DF engine was powered, the lowest fuel dose per work cycle was obtained. In the case of RME and BBuE fuels, it depends on the engine load. For low loads, higher consumption is for RME, and for higher loads, fuel consumption for BBuE in-creases most often. This is due to the lower calorific value of the esters. The results of these tests indicate that feeding the engine with BBuE and RME fuel in most loads resulted in higher maximum combustion pressures compared to feeding the engine with DF which may be directly related to the higher cetane number of these fuels compared to DF and the oxygen content of these fuels. Feeding the engine with BBuE and RME esters compared to DF did not result in large differences in the maximum heat release rates HRmax. However, the values of the first and second maximum heat release rates x1max and x2max, in addition to the type of fuel, are strongly influenced by the operating conditions, especially the engine load. Analyzing the combustion angles of 5, 10, 50, and 90% of the fuel dose, it can be seen that feeding the engine with BBuE and RME esters for most measurement points results in faster combustion of the fuel dose compared to DF. Full article
(This article belongs to the Special Issue Thermal and Combustion Applications)
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19 pages, 5129 KiB  
Article
Experimental Investigations and Modeling of Atmospheric Water Generation Using a Desiccant Material
by Ahmed Almasarani, Imtiaz K. Ahmad, Mohamed F. El-Amin and Tayeb Brahimi
Energies 2022, 15(18), 6834; https://doi.org/10.3390/en15186834 - 19 Sep 2022
Cited by 6 | Viewed by 1700
Abstract
Harvesting atmospheric water by solar regenerated desiccants is a promising water source that is energy-efficient, environmentally clean, and viable. However, the generated amounts of water are still insignificant. Therefore, more intensive fundamental research must be undertaken involving experiments and modeling. This paper describes [...] Read more.
Harvesting atmospheric water by solar regenerated desiccants is a promising water source that is energy-efficient, environmentally clean, and viable. However, the generated amounts of water are still insignificant. Therefore, more intensive fundamental research must be undertaken involving experiments and modeling. This paper describes several experiments, which were conducted to predict and improve the behavior of water absorption/desorption by the Calcium Chloride (CaCl2) desiccant, where the uncertainty did not exceed ±3.5%. The absorption effect in a deep container was studied experimentally and then amplified by pumping air into the solution. The latter measured water absorption/desorption by a thin solution layer under variable ambient conditions. Pumping air inside deep liquid desiccant containers increased the water absorption rate to 3.75% per hour, yet when using a thin layer of the solution, it was found to have increased to 6.5% per hour under the same conditions. The maximum amount of absorbed water and water vapor partial pressure relation was investigated, and the mean absolute error between the proposed formula and measured water content was 6.9%. An empirical formula, a one-dimensional mathematical model, was then developed by coupling three differential equations and compared to experimental data. The mean absolute error of the model was found to be 3.13% and 7.32% for absorption and desorption, respectively. Governing mathematical conservation equations were subsequently formulated. The mathematical and empirical models were combined and solved numerically. Findings obtained from the simulation were compared to experimental data. Additionally, several scenarios were modeled and tested for Jeddah, Saudi Arabia, under various conditions. Full article
(This article belongs to the Special Issue Numerical Simulation of Thermofluid Dynamics)
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14 pages, 4787 KiB  
Article
Efficacy of Green Oxide Nanofluids as Potential Dispersants for Asphaltene in Iraqi Crudes, Experimental, Tunning and Statistical Analysis
by Dana Khidhir and Hiwa Sidiq
Energies 2022, 15(18), 6833; https://doi.org/10.3390/en15186833 - 19 Sep 2022
Cited by 2 | Viewed by 1671
Abstract
Asphaltene are large molecular crude constituents and their existence is related to numerous problems. However, nanofluids have proven to be a very stable and effective way of dealing with asphaltene agglomerations. This research addresses the effectiveness of nanofluids as compared to traditional and [...] Read more.
Asphaltene are large molecular crude constituents and their existence is related to numerous problems. However, nanofluids have proven to be a very stable and effective way of dealing with asphaltene agglomerations. This research addresses the effectiveness of nanofluids as compared to traditional and available (FLOW-X) commercial inhibitors. The synthesis and characterization of two green NPs and the preparation of nanofluids were performed successfully in this study. It was found that by tuning the concentration of nanofluid, the efficiency increases by 17%. Crude samples have shown different responses to nano inhibitors. It was found that nanofluids increase asphaltene dissolution by nearly 22% as compared to commercial inhibitors. Full article
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10 pages, 3485 KiB  
Article
A Trolley Wire De-Icing System
by Grzegorz Radomski, Sławomir Karyś and Paweł Stawczyk
Energies 2022, 15(18), 6832; https://doi.org/10.3390/en15186832 - 19 Sep 2022
Viewed by 1750
Abstract
This paper presents a dedicated system for de-icing trolley wires. The proposed issue is appropriately under the protection of intellectual property for solving as described in patent no.B1 230665 PL in the Patent Office of the Republic of Poland. In the solution presented [...] Read more.
This paper presents a dedicated system for de-icing trolley wires. The proposed issue is appropriately under the protection of intellectual property for solving as described in patent no.B1 230665 PL in the Patent Office of the Republic of Poland. In the solution presented herein, de-icing is achieved mainly by electrodynamic force excitation and secondarily as a result of heating. Because ice is removed primarily through vibrations, it avoids a large consumption of electricity associated with the high specific heat of water. More importantly, operation is nearly simultaneously applied to the total distance of the trolley power grid between two substations. For this reason, it requires less electricity consumption and less time to apply than in heating, mechanical, or chemical methods. Full article
(This article belongs to the Special Issue Power Quality Analysis and Control of Railway Power Supply Systems)
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14 pages, 521 KiB  
Article
Economic Conditions for the Development of Energy Cooperatives in Poland
by Daria Kostecka-Jurczyk, Katarzyna Marak and Mirosław Struś
Energies 2022, 15(18), 6831; https://doi.org/10.3390/en15186831 - 19 Sep 2022
Cited by 5 | Viewed by 1877
Abstract
One of the important areas of the energy transformation is the citizens involvement in the energy production process. This is a prerequisite for maintaining the security of supply and price stabilization. In order for all citizens to have equal opportunities to use green [...] Read more.
One of the important areas of the energy transformation is the citizens involvement in the energy production process. This is a prerequisite for maintaining the security of supply and price stabilization. In order for all citizens to have equal opportunities to use green energy, regardless of financial and housing opportunities, energy cooperatives are established in many countries. In Poland, the first renewable energy cooperatives emerged in 2021 but, unfortunately, their role in the energy transformation process will be rather limited in the near future. This is mainly due to the numerous legal, economic and social barriers that hinder their creation. This article adopts the hypothesis that there are too many barriers in Poland that discourage the creation of energy cooperatives or other forms of collective prosumption. The main obstacle is the limitations of installed power, coerced by the poor condition of the network infrastructure. The aim of the article is to answer the question of whether, given the current legal and economic conditions, a large-scale development of energy cooperatives is possible in Poland, or will the existing barriers make this development limited and not contribute to the country’s energy transformation? To answer this question, primary and secondary sources were used. Primary research relied on interviews in all cooperatives operating in Poland. Based on the literature on the subject, reference was made to the experiences of other EU countries. The research shows that there are strong economic, legal and mental barriers to the development of cooperatives in Poland. Overcoming them requires changes in the law, in the energy policy including decentralization of the energy market and increased public confidence in collective forms of prosumption. Full article
(This article belongs to the Special Issue Renewable Energy Systems for Energy Communities)
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