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Energies, Volume 17, Issue 1 (January-1 2024) – 274 articles

Cover Story (view full-size image): The focus of this work is to generate passive transfer function (TF) matrices that model the radiation forces for WEC arrays. The intended use is real-time control design. Presented here is a passivity-based approach to estimate radiation force TFs that accurately replace the convolution operation in the Cummins equation while preserving the physical properties of the radiation function. A two-stage numerical optimization is used: (i) fitting a radiation damping TF matrix to the system’s radiation frequency response, and (ii) by enforcing and increasing the passivity index. This approach ensures a high degree of match with the radiation function without degrading its passivity characteristics. The approach was assessed by (i) the accuracy of the LTI systems in approximating the TF matrix and (ii) the stability of the overall system. View this paper
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19 pages, 1082 KiB  
Article
Exploring the User Adoption Mechanism of Green Transportation Services in the Context of the Electricity–Carbon Market Synergy
by Dong Pan, Bao Wang, Jun Li and Fei Wu
Energies 2024, 17(1), 274; https://doi.org/10.3390/en17010274 - 4 Jan 2024
Cited by 1 | Viewed by 1109
Abstract
Promoting green transportation development in the context of electric–carbon market synergy can help promote sustainable transport and tackle climate change. The sharing economy has given rise to innovative and successful business models in recent years. To occupy current and potential markets, many enterprises [...] Read more.
Promoting green transportation development in the context of electric–carbon market synergy can help promote sustainable transport and tackle climate change. The sharing economy has given rise to innovative and successful business models in recent years. To occupy current and potential markets, many enterprises that participate in sharing economy activities have engaged in a fiercely competitive environment. It is an important way for enterprises to generate profits and improve competitiveness by encouraging consumers’ continuous consumption or stimulating repurchase intentions. This study investigates the effects of consumer satisfaction on consumer repurchase intention (CRI) and how such effects are moderated by the consumer’s risk perception and sustainability awareness in the case of ride-sharing services, which are viewed as a mode of green transportation service. The results of a survey of 358 Chinese consumers who have used ride-sharing services suggest that transaction-based and experience-based satisfaction have positive and significant effects on the CRI of ride-sharing services. Moreover, the results indicate that consumer risk perception negatively moderates the relationships between satisfaction and CRI, while consumer sustainability awareness plays different roles depending on the type of satisfaction (transaction-based versus experience-based). Finally, implications and suggestions for future studies are discussed. Full article
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20 pages, 1594 KiB  
Article
New Power System Planning and Evolution Path with Multi-Flexibility Resource Coordination
by Xuejun Li, Jiaxin Qian, Changhai Yang, Boyang Chen, Xiang Wang and Zongnan Jiang
Energies 2024, 17(1), 273; https://doi.org/10.3390/en17010273 - 4 Jan 2024
Viewed by 821
Abstract
With the continuous development of large-scale wind and photovoltaic power worldwide, the net load fluctuation of systems is increasing, thereby imposing higher demands for power supply assurance and new energy consumption capacity within emerging power systems. It is imperative to establish a quantifiable [...] Read more.
With the continuous development of large-scale wind and photovoltaic power worldwide, the net load fluctuation of systems is increasing, thereby imposing higher demands for power supply assurance and new energy consumption capacity within emerging power systems. It is imperative to establish a quantifiable and efficient model for planning new power systems, to propose an analytical approach for determining optimal evolutionary paths, and to advance research on flexible resource planning across wide areas. In this paper, based on the simplified operating characteristics of multi-type flexible resources, a source-grid-load-storage collaborative planning and evolution analysis framework is established. Secondly, the lowest total cost of the whole life cycle of the system is taken as the optimization goal, the multiple flexible resource investment decisions and production operation constraints of various flexible resources on all sides of the system are considered, and the source-grid-load-storage planning model is established. Then, through the investment decision-making strategy setting of the system in different planning level years, the evolutionary path analysis method of the whole life cycle economy and weighted environmental protection benefit of the system is given. Finally, by taking the sending-end power grid in Gansu Province as an example, a case study is carried out. Calculations of new energy, key channels within the province, energy storage capacity, and load-side response capacity requirements for 2025, 2030, and 2060 are optimized. Based on the above analysis, the optimal evolution path of the power grid is proposed. When considering the weighted benefits of economy and environmental protection, the greater the weight of environmental protection benefits, the greater the possibility of choosing a radical scheme. The model and method proposed in this paper can provide technical reference for the future development planning and evolution analysis of new power systems. Full article
(This article belongs to the Section F1: Electrical Power System)
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18 pages, 4280 KiB  
Article
Improved State-of-Charge Estimation of Lithium-Ion Battery for Electric Vehicles Using Parameter Estimation and Multi-Innovation Adaptive Robust Unscented Kalman Filter
by Cheng Li and Gi-Woo Kim
Energies 2024, 17(1), 272; https://doi.org/10.3390/en17010272 - 4 Jan 2024
Cited by 1 | Viewed by 1054
Abstract
In this study, an improved adaptive robust unscented Kalman Filter (ARUKF) is proposed for an accurate state-of-charge (SOC) estimation of battery management system (BMS) in electric vehicles (EV). The extended Kalman Filter (EKF) algorithm is first used to achieve online identification of the [...] Read more.
In this study, an improved adaptive robust unscented Kalman Filter (ARUKF) is proposed for an accurate state-of-charge (SOC) estimation of battery management system (BMS) in electric vehicles (EV). The extended Kalman Filter (EKF) algorithm is first used to achieve online identification of the model parameters. Subsequently, the identified parameters obtained from the EKF are processed to obtain the SOC of the batteries using a multi-innovation adaptive robust unscented Kalman filter (MIARUKF), developed by the ARUKF based on the principle of multi-innovation. Co-estimation of parameters and SOC is ultimately achieved. The co-estimation algorithm EKF-MIARUKF uses a multi-timescale framework with model parameters estimated on a slow timescale and the SOC estimated on a fast timescale. The EKF-MIARUKF integrates the advantages of multiple Kalman filters and eliminates the disadvantages of a single Kalman filter. The proposed algorithm outperforms other algorithms in terms of accuracy because the average root mean square error (RMSE) and the mean absolute error (MAE) of the SOC estimation were the smallest under three dynamic conditions. Full article
(This article belongs to the Special Issue Advanced Application Technology of Lithium-Ion Batteries)
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13 pages, 2929 KiB  
Article
Experimental Study of Evaporation Characteristics of Acoustically Levitated Fuel Droplets at High Temperatures
by Bin Pang, Guangcan Yang, Xiaoxin Liu, Yu Huang, Wanli Li, Yongqing He, Zhongyuan Shi, Zhaochu Yang and Tao Dong
Energies 2024, 17(1), 271; https://doi.org/10.3390/en17010271 - 4 Jan 2024
Viewed by 857
Abstract
Examining fuel droplet evaporation is crucial for enhancing fuel engine efficiency, conserving energy, and reducing emissions. This study utilizes experimental methods involving ultrasonic standing wave levitation and high-speed cameras to investigate the impact of temperatures and droplet properties, including initial diameter and composition, [...] Read more.
Examining fuel droplet evaporation is crucial for enhancing fuel engine efficiency, conserving energy, and reducing emissions. This study utilizes experimental methods involving ultrasonic standing wave levitation and high-speed cameras to investigate the impact of temperatures and droplet properties, including initial diameter and composition, on the evaporation process. The evaporation behaviors of fuel droplets, like hexadecane and diesel, are documented across a temperature spectrum spanning 150 °C to 550 °C, with an initial droplet equivalent diameter ranging from 0.10 to 0.30 mm. The evaporation rate positively correlates with temperature and may vary by 15% to 71% between hexadecane and diesel droplets. Full article
(This article belongs to the Section I1: Fuel)
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26 pages, 7334 KiB  
Article
An Energy Storage Capacity Configuration Method for a Provincial Power System Considering Flexible Adjustment of the Tie-Line
by Bing Sun, Zheng Zhang, Jing Hu, Zihan Meng, Bibin Huang and Nana Li
Energies 2024, 17(1), 270; https://doi.org/10.3390/en17010270 - 4 Jan 2024
Viewed by 653
Abstract
A high proportion of renewable generators are widely integrated into the power system. Due to the output uncertainty of renewable energy, the demand for flexible resources is greatly increased in order to meet the real-time balance of the system. But the investment cost [...] Read more.
A high proportion of renewable generators are widely integrated into the power system. Due to the output uncertainty of renewable energy, the demand for flexible resources is greatly increased in order to meet the real-time balance of the system. But the investment cost of flexible resources, such as energy storage equipment, is still high. It is necessary to propose a method for determining the capacity of energy storage scientifically. An optimization and planning method of energy storage capacity is proposed. It is characterized by determining the optimal capacity of energy storage by carrying out 8760 hours of time series simulation for a provincial power grid with energy storage. Firstly, the current situation of power supply and demand for provincial power grids is analyzed. The difficulty of realizing a power balance at different time scales is analyzed. Then, the source load balancing solutions at different time scales are proposed. The difficulty of a long-term power balance can be alleviated by flexibly adjusting the power on the tie-line of the provincial power grid. And the difficulty of a short-term power balance can be met through energy storage. In addition, an optimal planning model of an energy storage system is established with the power supply cost as the objective function. The optimal capacity of the energy storage is determined by comparing the objective function of different planning schemes. Finally, a case study is carried out. It is found that flexible adjustment of interprovincial interconnection lines can reduce the maximum demand for electricity from 8.439 billion kWh to 2.299 billion kWh. At the same time, the curtailment ratio of renewable electricity can be decreased from 12.6% to 5.0% by using energy storage. However, the average power supply cost of the system gradually increases from 0.307 CNY/kWh to 0.485 CNY/kWh. It is necessary to fully tap into the various values of energy storage equipment. Full article
(This article belongs to the Section D: Energy Storage and Application)
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19 pages, 1921 KiB  
Article
Economic Feasibility Study of the Production of Biogas, Coke and Biofuels from the Organic Fraction of Municipal Waste Using Pyrolysis
by Benedito Franciano Ferreira Rodrigues, Anderson Rocha Amaral, Fernanda Paula da Costa Assunção, Lucas Pinto Bernar, Marcelo Costa Santos, Neyson Martins Mendonça, José Almir Rodrigues Pereira, Douglas Alberto Rocha de Castro, Sergio Duvoisin, Jr., Pablo Henrique Ataide Oliveira, Luiz Eduardo Pizarro Borges and Nélio Teixeira Machado
Energies 2024, 17(1), 269; https://doi.org/10.3390/en17010269 - 4 Jan 2024
Cited by 2 | Viewed by 1146
Abstract
The objective of this study is to analyze the economic viability of municipal household solid waste (organic matter + paper) for the production of gas, coke and biofuel through the pyrolysis and distillation process. The waste was collected in the city of Belém [...] Read more.
The objective of this study is to analyze the economic viability of municipal household solid waste (organic matter + paper) for the production of gas, coke and biofuel through the pyrolysis and distillation process. The waste was collected in the city of Belém do Pará-Brazil and pretreated at the Federal University of Pará. The analyzed fraction (organic matter + paper) was subjected to the pretreatment of drying, crushing, and sieving and was subsequently subjected to proximate characterization and, finally, pyrolysis of the organic fraction (organic matter + paper) in a fixed bed reactor. Initially, it was necessary to review the literature, and with the yields obtained by pyrolysis of the fraction, economic feasibility analyses were carried out. The economic indicators for evaluating the most viable pyrolysis process were basic payback, discounted payback, net present value, internal rate of return, and profitability index, which are all financial metrics commonly used in investment analysis and decision making. These metrics provide valuable insights into the financial viability and attractiveness of investment projects. They are essential tools for assessing the feasibility and profitability of various ventures, helping decision-makers make informed choices in allocating resources. The analysis of the indicators showed the economic viability considering an analysis horizon of 10 years of materials based on organic material and paper. The breakeven point obtained was USD 0.96/dm3 and the minimum biofuel sales price found in this project was USD 1.30/dm3. The sensitivity research found that material costs (organic matter + paper), bio-oil yield, total project investment and electricity, respectively, are the variables that most affect the minimum biofuel sales price. Full article
(This article belongs to the Special Issue Solid Waste to Energy)
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15 pages, 3020 KiB  
Article
An Energy Management Strategy for an Electrified Railway Smart Microgrid System Based on Integrated Empirical Mode Decomposition
by Jingjing Ye, Minghao Sun and Kejian Song
Energies 2024, 17(1), 268; https://doi.org/10.3390/en17010268 - 4 Jan 2024
Viewed by 710
Abstract
The integration of a renewable energy and hybrid energy storage system (HESS) into electrified railways to build an electric railway smart microgrid system (ERSMS) is beneficial for reducing fossil fuel consumption and minimizing energy waste. However, the fluctuations of renewable energy generation and [...] Read more.
The integration of a renewable energy and hybrid energy storage system (HESS) into electrified railways to build an electric railway smart microgrid system (ERSMS) is beneficial for reducing fossil fuel consumption and minimizing energy waste. However, the fluctuations of renewable energy generation and traction load challenge the effectiveness of the energy management for such a complex system. In this work, an energy management strategy is proposed which firstly decomposes the renewable energy into low-frequency and high-frequency components by an integrated empirical mode decomposition (IEMD). Then, a two-stage energy distribution approach is utilized to appropriately distribute the energy flow in the ERSMS. Finally, the feasibility and effectiveness of the proposed solution are validated through case study. Full article
(This article belongs to the Section A1: Smart Grids and Microgrids)
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13 pages, 3369 KiB  
Article
Decarbonizing Energy of a City: Identifying Barriers and Pathways
by Neil J. Hewitt
Energies 2024, 17(1), 267; https://doi.org/10.3390/en17010267 - 4 Jan 2024
Viewed by 698
Abstract
As researchers and ultimately deployers of energy decarbonisation solutions, we collectively see significant but often siloed efforts that in isolation may appear as an appropriate solution to an aspect of energy decarbonisation. However, when systemwide thinking is applied, a former attractive solution may [...] Read more.
As researchers and ultimately deployers of energy decarbonisation solutions, we collectively see significant but often siloed efforts that in isolation may appear as an appropriate solution to an aspect of energy decarbonisation. However, when systemwide thinking is applied, a former attractive solution may become more challenging and, likewise, a less attractive silo may become more appropriate as part of an energy systemwide approach. Thus, the aim of this paper is to combine proposed energy decarbonisation concepts, e.g., electrification, hydrogen, biogas etc., with the status of the system in which they intend to operate, and then highlight the barriers, opportunities, and alternatives that may come into play when the whole system is taken into account. This is a hypothetical study using the city of Belfast, Northern Ireland, UK as an example and reflects, in part, the city’s desire to decarbonise while enhancing its economic prosperity. The “system” is defined as the region boundaries, i.e., Northern Ireland will supply the energy (all or in part) to the city of Belfast. The methodology deployed here therefore is a framework of energy thinking that is the basis of such energy decarbonisation plans at a city-wide level. Full article
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31 pages, 14797 KiB  
Article
The Effect of Internal Combustion Engine Nozzle Needle Profile on Fuel Atomization Quality
by Oleh Klyus, Marcin Szczepanek, Grzegorz Kidacki, Paweł Krause, Sławomir Olszowski and Leszek Chybowski
Energies 2024, 17(1), 266; https://doi.org/10.3390/en17010266 - 4 Jan 2024
Viewed by 824
Abstract
This article presents the results of research on the impact of changing the cross-section of an atomizer’s flow channel, which is caused by changing the flow geometry of the passive part of the needle on the drop diameter distribution of the fuel spray. [...] Read more.
This article presents the results of research on the impact of changing the cross-section of an atomizer’s flow channel, which is caused by changing the flow geometry of the passive part of the needle on the drop diameter distribution of the fuel spray. A three-hole type H1LMK, 148/1 atomizer with hole diameters, dN, equal to 0.34 mm, is analyzed. A nozzle with a standard (i.e., unmodified) needle and three nozzles using needles with a modified profile in the flow part of the needle, marked by the code signatures 1L, 2L, and 3L, are tested. An increasing level of fuel turbulence characterizes the needles during the flow along their flow part due to the use of one (1L), two (2L), and three (3L) de Laval toroidal nozzles, respectively, obtained by mechanically shaping the outer surface of the flow part of the spray needle. The spray produced is tested using the Malvern Spraytec STP 500 device cooperating with the dedicated Malvern version 4.0. During the tests, measurements and an analysis of the spray droplet size distribution over the entire injection duration, equal to 7 ± 2 ms, are made for each nozzle. The experiment makes it possible to determine the effect of the nozzle needles’ profiles on the time distribution of the actual droplet diameters; the time distribution of the Sauter mean droplet diameters, D[3,2]; the percentile shares of the droplet diameters Dv (10), Dv (50), and Dv (90); the distribution span during the development of the spray stream; and the time distribution of the shares of the droplets with diameters belonging to selected diameter classes D[x1−x2] in the spray. The results of the measurements of the drop diameter distribution indicate that using atomizers with a modification to the flow channel allows for an increase in the share of droplets with smaller diameters compared to the standard atomizer. Full article
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19 pages, 4242 KiB  
Review
Innovation Solution in Photovoltaic Sector
by Filip Czepło and Piotr F. Borowski
Energies 2024, 17(1), 265; https://doi.org/10.3390/en17010265 - 4 Jan 2024
Viewed by 926
Abstract
The modern world is moving towards a zero-emission economy; therefore, various actions are being taken to reduce the share of fossil fuels in energy production. The article examines the potential for the continued expansion of photovoltaic farms, with a special emphasis on farms [...] Read more.
The modern world is moving towards a zero-emission economy; therefore, various actions are being taken to reduce the share of fossil fuels in energy production. The article examines the potential for the continued expansion of photovoltaic farms, with a special emphasis on farms utilising east–west panel orientation. The east–west orientation is an innovative solution with many advantages over the traditional north–south arrangement. The paper also makes a detailed assessment of the photovoltaic farm environment by applying two analyses based on the following factors: Political, Economic, Social, and Technological (PEST) and Demographic, Economic, Environmental, Political, Legal, Informational, Social, and Technological (DEEPLIST) factors. This is followed by an insightful, comprehensive review of the most important factors that contribute to the efficiency of photovoltaic installations, namely site conditions, existing infrastructure, and ability to connect to the electricity grid. The paper also devotes space to an analysis of daily energy price changes that affect the economic efficiency of the installation and discusses the potential for energy storage in the context of photovoltaic farms. The development of photovoltaics also requires investing in energy storage. All discussed issues fall within the scope of photovoltaic farm development and optimal use of energy resources. Full article
(This article belongs to the Special Issue Sustainable/Renewable Energy Systems Analysis and Optimization)
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15 pages, 1518 KiB  
Article
Wind Power Short-Term Time-Series Prediction Using an Ensemble of Neural Networks
by Tomasz Ciechulski and Stanisław Osowski
Energies 2024, 17(1), 264; https://doi.org/10.3390/en17010264 - 4 Jan 2024
Viewed by 804
Abstract
Short-term wind power forecasting has difficult problems due to the very large variety of speeds of the wind, which is a key factor in producing energy. From the point of view of the whole country, an important problem is predicting the total impact [...] Read more.
Short-term wind power forecasting has difficult problems due to the very large variety of speeds of the wind, which is a key factor in producing energy. From the point of view of the whole country, an important problem is predicting the total impact of wind power’s contribution to the country’s energy demands for succeeding days. Accordingly, efficient planning of classical power sources may be made for the next day. This paper will investigate this direction of research. Based on historical data, a few neural network predictors will be combined into an ensemble that is responsible for the next day’s wind power generation. The problem is difficult since wind farms are distributed in large regions of the country, where different wind conditions exist. Moreover, the information on wind speed is not available. This paper proposes and compares different structures of an ensemble combined from three neural networks. The best accuracy has been obtained with the application of an MLP combiner. The results of numerical experiments have shown a significant reduction in prediction errors compared to the naïve approach. The improvement in results with this naïve solution is close to two in the one-day-ahead prediction task. Full article
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22 pages, 12382 KiB  
Article
Assessing Combined High Photovoltaic and Electric Vehicle Charging Penetration in Low-Voltage Distribution Networks: A Case Study in Malta
by Brian Azzopardi and Yesbol Gabdullin
Energies 2024, 17(1), 263; https://doi.org/10.3390/en17010263 - 4 Jan 2024
Viewed by 774
Abstract
High Photovoltaic (PV) and Electric Vehicle (EV) Charging Penetration challenges the grid’s Low-Voltage (LV) Distribution Network’s stability due to voltage variations and the overloading of feeders. This research paper investigates the potential of combined PV and Electric Vehicle (EV) charging integration within LV [...] Read more.
High Photovoltaic (PV) and Electric Vehicle (EV) Charging Penetration challenges the grid’s Low-Voltage (LV) Distribution Network’s stability due to voltage variations and the overloading of feeders. This research paper investigates the potential of combined PV and Electric Vehicle (EV) charging integration within LV DN, using a representative DN in Malta as a case study. The European Union (EU) has set forth objectives and guidelines that suggest a high likelihood of Distributed Networks (DNs) incorporating a significant number of Photovoltaic Systems (PVs), resulting in overvoltage occurrences, as well as a substantial number of Electric Vehicles (EVs), which may charge in an erratic manner, leading to undervoltage and overloading events. A distribution network (DN) may experience unfavorable situations concurrently due to the simultaneous occurrence of photovoltaic (PV) generation and electric vehicle (EV) charging, particularly in residential case studies. Effectively employing either dispersed or centralized storage is a viable approach to tackle these issues. However, this strategy may defer the requirement for expensive DN investments. The study showcases the extent of automated mitigation attained in the urban zones of Malta. The data presented primarily comprises empirical measurements obtained at the onset of the LV feeder. Full article
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20 pages, 8742 KiB  
Article
Compression Ignition Internal Combustion Engine’s Energy Parameter Research Using Variable (HVO) Biodiesel and Biobutanol Fuel Blends
by Gintaras Valeika, Jonas Matijošius, Olga Orynycz, Alfredas Rimkus, Artūras Kilikevičius and Karol Tucki
Energies 2024, 17(1), 262; https://doi.org/10.3390/en17010262 - 4 Jan 2024
Viewed by 1200
Abstract
This study investigates the impact of different biofuels, such as pure hydrogenated vegetable oil, hydrogenated vegetable oil, and biobutanol, as well as their blends, on the non-energetic operational characteristics of a compression ignition internal combustion engine. The research investigations were conducted using a [...] Read more.
This study investigates the impact of different biofuels, such as pure hydrogenated vegetable oil, hydrogenated vegetable oil, and biobutanol, as well as their blends, on the non-energetic operational characteristics of a compression ignition internal combustion engine. The research investigations were conducted using a turbocharged direct injection compression ignition engine that was put within a Skoda Octavia 1.9 TDI automobile. Throughout the investigation, the primary emphasis was placed on analyzing energy characteristics such as power, brake-specific fuel consumption (BSFC), brake thermal efficiency (BTE), and other related factors. The analysis involved the utilization of multiple combinations of bio-based fuels, namely four mixes of HVO with biobutanol (HVO100, HVOB5, HVOB10, and HVOB20), which were subsequently compared to fossil diesel (D100). The findings of the study indicate that the utilization of HVO100 fuel results in notable reductions in power output and mass fraction when compared to D100 gasoline. HVO100 fuel demonstrates superior performance to D100 gasoline, exhibiting a range of 1.7% to 28% improvement in brake-specific fuel consumption. Additionally, at an engine speed of 4500 rpm, the use of HVO100 fuel leads to a decrease in brake thermal efficiency of 4.4%. Full article
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18 pages, 2360 KiB  
Article
Weather Forecast Control for Heating of Multi-Family Buildings in Comparison with Feedback and Feedforward Control
by Daniel Olsson, Peter Filipsson and Anders Trüschel
Energies 2024, 17(1), 261; https://doi.org/10.3390/en17010261 - 4 Jan 2024
Viewed by 743
Abstract
Our joint environmental and energy commitments mean we must reduce the building’s energy use. Improved central heating control can play a role in how this is accomplished. There are three common control strategies: feedforward (traditional), feedback, and model predictive control (MPC). The latter [...] Read more.
Our joint environmental and energy commitments mean we must reduce the building’s energy use. Improved central heating control can play a role in how this is accomplished. There are three common control strategies: feedforward (traditional), feedback, and model predictive control (MPC). The latter two often work in parallel, where feedback uses indoor temperature sensors to adjust the supply water temperature. In contrast, the supply temperature setpoint is continuously calculated in MPC, fed with weather forecasts. The weather forecasts are often highlighted as essential ingredients in MPC, but at the same time, it is emphasized that temperature sensors are used to ensure a pleasant indoor temperature. To an outside observer, it is difficult to determine what is what in such combined control arrangements. Is energy saved because of the room sensors or because of the model? And what role do the weather forecasts play? This study quantifies the impact of the control strategy on energy use and indoor temperature. It concludes that PI-based feedback heating control saves approximately as much energy as MPC, and weather forecasts do not save significantly more energy than real-time weather data but are easier to obtain. The overall results for both control strategies align with the lower end of the result ranges of previous studies. The novelty is that the impact of weather forecasts has been studied separately and that different control strategies are compared against each other based on a model of a typical Swedish multi-family building. Full article
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28 pages, 5878 KiB  
Review
Hydrogen Storage System Attained by HCOOH-CO2 Couple: Recent Developments in Pd-Based Carbon-Supported Heterogeneous Catalysts
by Paula Riquelme-García, Miriam Navlani-García and Diego Cazorla-Amorós
Energies 2024, 17(1), 260; https://doi.org/10.3390/en17010260 - 4 Jan 2024
Viewed by 1282
Abstract
The present review revisits representative studies addressing the development of efficient Pd-based carbon-supported heterogeneous catalysts for two important reactions, namely, the production of hydrogen from formic acid and the hydrogenation of carbon dioxide into formic acid. The HCOOH-CO2 system is considered a [...] Read more.
The present review revisits representative studies addressing the development of efficient Pd-based carbon-supported heterogeneous catalysts for two important reactions, namely, the production of hydrogen from formic acid and the hydrogenation of carbon dioxide into formic acid. The HCOOH-CO2 system is considered a promising couple for a hydrogen storage system involving an ideal carbon-neutral cycle. Significant advancements have been achieved in the catalysts designed to catalyze the dehydrogenation of formic acid under mild reaction conditions, while much effort is still needed to catalyze the challenging CO2 hydrogenation reaction. The design of Pd-based carbon-supported heterogeneous catalysts for these reactions encompasses both the modulation of the properties of the active phase (particle size, composition, and electronic properties) and the modification of the supports by means of the incorporation of nitrogen functional groups. These approaches are herein summarized to provide a compilation of the strategies followed in recent studies and to set the basis for a hydrogen storage system attained using the HCOOH-CO2 couple. Full article
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16 pages, 2799 KiB  
Article
Flue Gas Recirculation System for Biomass Heating Boilers—Research and Technical Applications for Reductions in Nitrogen Oxides (NOx) Emissions
by Bartosz Ciupek, Rafał Urbaniak, Dobrosława Kinalska and Zbigniew Nadolny
Energies 2024, 17(1), 259; https://doi.org/10.3390/en17010259 - 4 Jan 2024
Cited by 1 | Viewed by 871
Abstract
The paper discusses the results of investigations of the change in thermal and emission-related parameters of a heating boiler fueled with biomass after a modification with a proprietary flue gas recirculation system made for this type of equipment. The results provide insight into [...] Read more.
The paper discusses the results of investigations of the change in thermal and emission-related parameters of a heating boiler fueled with biomass after a modification with a proprietary flue gas recirculation system made for this type of equipment. The results provide insight into the combustion process with a multistage flue gas recirculation that materially affected the boiler operation: a reduction in the mass concentration of nitrogen oxides (NOx) by reducing the combustion temperature. The authors also observed a reduction in the emission of particulate matters (PM) and carbon monoxide (CO). For the investigations, the authors used a heating boiler fitted with an automatic fuel feed (timber pellets) and a proprietary patented flue gas recirculation system (Polish patent Pat. 243395) for low power solid fuel heating boilers. Aside from the measurement of the mass concentration of the emitted pollutants, the research focused on the measurements of the temperature inside the combustion chamber, the temperature of the flue gas and the level of oxygen in the flue gas. The aim of the research was to confirm the validity of using the flue gas recirculation technique to reduce emissions of harmful substances from biomass heating boilers, as a technique not previously used for this group of devices. Moreover, the aim of the research was to test an original engineering solution, in the form of a flue gas distribution valve, and investigate its effect on reducing NOx emissions and improving other thermal and emission parameters of the boiler. The obtained research results confirm the validity of the chosen actions and provide a positive premise for the practical use of this technology in solid fuel heating boilers. Full article
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15 pages, 13830 KiB  
Article
Optimizing Formic Acid-Assisted Co-HTL of Digested Sewage Sludge and Lignocellulosic Waste for Enhanced Bio-Crude Yield and Energy Recovery
by Kristoffer Mega Herdlevær and Tanja Barth
Energies 2024, 17(1), 258; https://doi.org/10.3390/en17010258 - 4 Jan 2024
Viewed by 738
Abstract
In recent years, hydrothermal liquefaction (HTL) has gained attention as a means of enhancing and increasing the production of biofuels from biomass. Co-HTL involves the simultaneous processing of two or more feedstocks, with the potential for interactions that can affect the overall yield [...] Read more.
In recent years, hydrothermal liquefaction (HTL) has gained attention as a means of enhancing and increasing the production of biofuels from biomass. Co-HTL involves the simultaneous processing of two or more feedstocks, with the potential for interactions that can affect the overall yield and quality of the resulting biofuels. This study investigates the bio-crude yield, chemical composition, and energy content of bio-crudes obtained through formic acid-assisted hydrothermal liquefaction of combined digested sewage sludge (DSS) and lignocellulose (LC). The bio-crude yields are in the range of 26.8–58.9 wt%, with a higher heating value (HHV) of approximately 32 MJ/kg. The best experiment shows that mixtures with more DSS and high levels of process condition variables (350 °C, formic acid present, and 50 wt% EtOH) give high bio-crude yields with a maximum value of 58.9 wt%. For comparison, pure DSS and LC run at these process conditions resulted in a bio-crude yield of 52.5 wt% and 48.3 wt%, respectively. Partial least squares (PLS) regression reveals a synergistic effect from mixing the feedstocks, as the quadratic term of the regression equation for mixture ratio shows a negative coefficient. GC–MS data show that combining feedstocks results in the formation of new compounds, mostly phenols, that are not present in the bio-crudes from the separate feedstocks. Thus, combining feedstocks will not only increase the resource availability for hydrothermal liquefaction and streamline the process but will also increase the overall production of bio-crude with its synergistic effect. Full article
(This article belongs to the Section A4: Bio-Energy)
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12 pages, 1450 KiB  
Article
Thermal Performance of Lignocellulose’s By-Product Wallboards with Bio-Based Microencapsulated Phase Change Materials
by Inga Zotova, Staņislavs Gendelis, Edgars Kirilovs and Dejan Štefanec
Energies 2024, 17(1), 257; https://doi.org/10.3390/en17010257 - 4 Jan 2024
Cited by 1 | Viewed by 799
Abstract
The growing availability and decreasing cost of microencapsulated phase change materials (PCMs) present an opportunity to develop innovative insulation materials for latent heat energy storage. By integrating PCMs with traditional insulation materials, it is possible to enhance the thermal capacity of a building [...] Read more.
The growing availability and decreasing cost of microencapsulated phase change materials (PCMs) present an opportunity to develop innovative insulation materials for latent heat energy storage. By integrating PCMs with traditional insulation materials, it is possible to enhance the thermal capacity of a building by up to 2.5-times, virtually without increasing the building’s mass. To improve buildings’ indoor structural performance, as well as improving their energy performance, microencapsulated PCMs are integrated into wallboards. The integration of microencapsulated PCMs into the wallboard solves the PCM leakage problem and assures a good bond with the building materials to achieve better structural performance. The novelty of this research is the application of encapsulated phase change material dispersion and technology for its incorporation into the structure of hemp shives and longitudinally milled wood chip-based insulation boards, using cold pressing technology to reduce the energy consumption of board production. As a result, low-density insulation boards for indoor application were produced by varying their structure and the amount of phase change materials in the range of 5% to 15% by board mass. The obtained board prototypes can be used as microclimate and thermoregulation elements of interiors, as well as functional aesthetic elements of interior design. Full article
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19 pages, 1753 KiB  
Article
Exploration of Alternatives to Reduce the Gap in Access to Electricity in Rural Communities—Las Nubes Village Case (Barranquilla, Colombia)
by Alvin Henao and Luceny Guzman
Energies 2024, 17(1), 256; https://doi.org/10.3390/en17010256 - 3 Jan 2024
Viewed by 843
Abstract
The global crisis associated with COVID-19 and the Russia-Ukraine conflict has affected progress towards the Sustainable Development Goals (SDGs). Projections for SDG7 (Ensure access to affordable, reliable, sustainable, and modern energy for all) indicate a slowdown in the pace of electrification. Thus, the [...] Read more.
The global crisis associated with COVID-19 and the Russia-Ukraine conflict has affected progress towards the Sustainable Development Goals (SDGs). Projections for SDG7 (Ensure access to affordable, reliable, sustainable, and modern energy for all) indicate a slowdown in the pace of electrification. Thus, the problem of poverty will persist in many regions as long as access to electricity remains difficult. This work analyzes some solutions to the lack of electricity supply in a rural community using organic waste from its economic activity and the integration of other available renewable sources to make electricity affordable and reliable. A model that minimizes the levelized cost of energy and restricts the proportion of annual energy not supplied to less than 5% of the community’s annual demand optimizes the performance of off-grid and on-grid systems. These systems have in common the production of electricity from biogas produced from swine manure, supplemented with wind and solar generation. Batteries and diesel generators support the operation of off-grid systems. As expected, the grid-connected system presented the best performance; however, the result reaffirms the need for governments to ensure the policy and infrastructure conditions that facilitate the grid connection of vulnerable communities to achieve SDG7. Full article
(This article belongs to the Section F: Electrical Engineering)
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15 pages, 4916 KiB  
Article
Synchronous Fracture Expansion Pattern of Hydraulic Fracturing with Different Perforation Spacing
by Yulong Jiang, Kai Wang, Xiaoqiang Zhang and Tingting Cai
Energies 2024, 17(1), 255; https://doi.org/10.3390/en17010255 - 3 Jan 2024
Viewed by 643
Abstract
Using the self-developed “TCHFSM-I” large-size true triaxial fracturing seepage simulation device and fluid injection flow dynamic monitoring device, we studied the crack initiation and expansion law of multi-fractures under different perforation spacing conditions and revealed the mechanism of multi-fractures expanding from non-equilibrium to [...] Read more.
Using the self-developed “TCHFSM-I” large-size true triaxial fracturing seepage simulation device and fluid injection flow dynamic monitoring device, we studied the crack initiation and expansion law of multi-fractures under different perforation spacing conditions and revealed the mechanism of multi-fractures expanding from non-equilibrium to equilibrium on the basis of the evolution law of the injection pressure and characteristics of the distribution of the injection flow. The results show that when the perforation spacing is small (<60 mm), the central injection fracturing cracks are affected by the extension of the upper and lower injection cracks, and their extension lengths are shorter; on the contrary, the extension lengths of the upper, central and lower injection cracks are basically the same, and the three hydraulically fractured cracks shift from non-equilibrium to equilibrium extension. When the perforation spacing is small, the fracture initiation pressure of the middle perforation is much larger than that of the upper and lower perforations. However, as the perforation spacing increases, the fracture initiation pressure of the middle perforation gradually decreases. Its fracture initiation pressure is basically the same as that of the upper and lower perforations. The expansion of the three hydraulically fractured cracks is independent of each other. In addition, the evolution law of the injection flow rate can better reflect the multi-fracture fracture initiation and expansion pattern, and the evolution pattern of the injection flow rate can better reflect the synchronous fracture initiation and expansion mechanism of multi-fracture fracture. The results of the study can provide technical guidance for efficient coalbed methane extraction. Full article
(This article belongs to the Topic Advanced Engines Technologies)
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19 pages, 1079 KiB  
Article
Energy Management Scheme for Optimizing Multiple Smart Homes Equipped with Electric Vehicles
by Puthisovathat Prum, Prasertsak Charoen, Mohammed Ali Khan, Navid Bayati and Chalie Charoenlarpnopparut
Energies 2024, 17(1), 254; https://doi.org/10.3390/en17010254 - 3 Jan 2024
Viewed by 1426
Abstract
The rapid advancement in technology and rise in energy consumption have motivated research addressing Demand-Side Management (DSM). In this research, a novel design for Home Energy Management (HEM) is proposed that seamlessly integrates Battery Energy Storage Systems (BESSs), Photovoltaic (PV) installations, and Electric [...] Read more.
The rapid advancement in technology and rise in energy consumption have motivated research addressing Demand-Side Management (DSM). In this research, a novel design for Home Energy Management (HEM) is proposed that seamlessly integrates Battery Energy Storage Systems (BESSs), Photovoltaic (PV) installations, and Electric Vehicles (EVs). Leveraging a Mixed-Integer Linear Programming (MILP) approach, the proposed system aims to minimize electricity costs. The optimization model takes into account Real-Time Pricing (RTP) tariffs, facilitating the efficient scheduling of household appliances and optimizing patterns for BESS charging and discharging, as well as EV charging and discharging. Both individual and multiple Smart Home (SH) case studies showcase noteworthy reductions in electricity costs. In the case of multiple SHs, a remarkable cost reduction of 46.38% was achieved compared to a traditional SH scenario lacking integration of a PV, BESS, and EV. Full article
(This article belongs to the Special Issue Energy Management of Smart Grids with Renewable Energy Resource)
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30 pages, 1421 KiB  
Article
Analysing the Connection between Economic Growth, Conventional Energy, and Renewable Energy: A Comparative Analysis of the Caspian Countries
by Oana Vlăduţ, George Eduard Grigore, Dumitru Alexandru Bodislav, Gabriel Ilie Staicu and Raluca Iuliana Georgescu
Energies 2024, 17(1), 253; https://doi.org/10.3390/en17010253 - 3 Jan 2024
Viewed by 1302
Abstract
The objective of this research paper is to apply a mathematical model to estimate and predict the economic growth of the Caspian countries in the period from 1995 to 2022. We use multiple regression by applying the OLS method to estimate the impact [...] Read more.
The objective of this research paper is to apply a mathematical model to estimate and predict the economic growth of the Caspian countries in the period from 1995 to 2022. We use multiple regression by applying the OLS method to estimate the impact of global oil price, energy resource production per capita, trade, and renewable energy on GDP per capita. The mathematical approach uses fixed and random effects models to assess the overall impact of the independent variables on economic growth in this region and over the period analysed. This study also aims to investigate whether the explanatory variables are cointegrated in the long run; as such, we carry out several mathematical cointegration tests, namely the Pedroni and Johansen tests. The mathematical analysis is completed by the estimation of short- and long-run parameters using the stochastic VAR/VEC models, the impulse response function, and the causality test to assess economic growth in this region. This study’s main finding is that GDP per capita is increasingly influenced by its previous values, which is confirmed by considering lag 1 and lag 2. The results of the Granger causality tests identify several bidirectional relationships between GDP per capita and oil and gas production. These relationships are clearly positive evidence of the growth trend and progress of economic activity in the Caspian region. The practical implications of the study aim to promote and support the use of renewable energy sources. In this sense, policymakers in the Caspian countries should create favourable conditions for the transition to a green economy. An important aspect is the efforts of the government authorities to make their policies more environmentally friendly, as decarbonisation is a good practice in the current context of sustainability and related choices. As the Caspian countries are heavily dependent on conventional energy production, it is essential for them to increase their export earnings from energy resources via diversifying and strengthening new energy opportunities and partnerships. Full article
(This article belongs to the Section C: Energy Economics and Policy)
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17 pages, 5161 KiB  
Article
A Generalised Series Model for the LES of Premixed and Non-Premixed Turbulent Combustion
by Weilin Zeng, Xujiang Wang, Kai Hong Luo, Konstantina Vogiatzaki and Salvador Navarro-Martinez
Energies 2024, 17(1), 252; https://doi.org/10.3390/en17010252 - 3 Jan 2024
Viewed by 641
Abstract
In this study, the generality and prediction accuracy of a generalised series model for the large eddy simulation of premixed and non-premixed turbulent combustion is explored. The model is based on the Taylor series expansion of the chemical source term in scalar space [...] Read more.
In this study, the generality and prediction accuracy of a generalised series model for the large eddy simulation of premixed and non-premixed turbulent combustion is explored. The model is based on the Taylor series expansion of the chemical source term in scalar space and implemented into OpenFOAM. The mathematical model does not depend on combustion regimes and has the correct limiting behaviour. The numerical error sources are also outlined and analysed. The model is first applied to a piloted methane/air non-premixed jet flame (Sandia Flame D). The statistical (time-averaged and RMS) results agree well with the experimental measurements, particularly with regard to the mixture fraction, velocity, temperature, and concentrations of major species CH4, CO2, H2O, and O2. However, the concentrations of the intermediates CO and H2 are over-predicted, due to the limitations of the reduced reaction mechanism employed. Then, a Bunsen-piloted flame is simulated. Most of the statistical properties of both the reactive species and progress variables are well reproduced. The only major discrepancy evident is in the temperature, which is probably attributed to the experimental uncertainties of temperature fields in the pilot stream. These findings demonstrate the model’s generality for both a premixed and non-premixed combustion simulation, as well as the accuracy of prediction of reactive species distribution. Full article
(This article belongs to the Section I2: Energy and Combustion Science)
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18 pages, 7088 KiB  
Article
Ultra-Short-Term Wind Power Prediction Based on eEEMD-LSTM
by Jingtao Huang, Weina Zhang, Jin Qin and Shuzhong Song
Energies 2024, 17(1), 251; https://doi.org/10.3390/en17010251 - 3 Jan 2024
Viewed by 692
Abstract
The intermittent and random nature of wind brings great challenges to the accurate prediction of wind power; a single model is insufficient to meet the requirements of ultra-short-term wind power prediction. Although ensemble empirical mode decomposition (EEMD) can be used to extract the [...] Read more.
The intermittent and random nature of wind brings great challenges to the accurate prediction of wind power; a single model is insufficient to meet the requirements of ultra-short-term wind power prediction. Although ensemble empirical mode decomposition (EEMD) can be used to extract the time series features of the original wind power data, the number of its modes will increase with the complexity of the original data. Too many modes are unnecessary, making the prediction model constructed based on the sub-models too complex. An entropy ensemble empirical mode decomposition (eEEMD) method based on information entropy is proposed in this work. Fewer components with significant feature differences are obtained using information entropy to reconstruct sub-sequences. The long short-term memory (LSTM) model is suitable for prediction after the decomposition of time series. All the modes are trained with the same deep learning framework LSTM. In view of the different features of each mode, models should be trained differentially for each mode; a rule is designed to determine the training error of each mode according to its average value. In this way, the model prediction accuracy and efficiency can make better tradeoffs. The predictions of different modes are reconstructed to obtain the final prediction results. The test results from a wind power unit show that the proposed eEEMD-LSTM has higher prediction accuracy compared with single LSTM and EEMD-LSTM, and the results based on Bayesian ridge regression (BR) and support vector regression (SVR) are the same; eEEMD-LSTM exhibits better performance. Full article
(This article belongs to the Topic Solar and Wind Power and Energy Forecasting)
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14 pages, 3881 KiB  
Article
Design and Analysis of a Three-Phase Interleaved DC-DC Boost Converter with an Energy Storage System for a PV System
by L. Pirashanthiyah, H. N. Edirisinghe, W. M. P. De Silva, S. R. A. Bolonne, V. Logeeshan and C. Wanigasekara
Energies 2024, 17(1), 250; https://doi.org/10.3390/en17010250 - 3 Jan 2024
Cited by 2 | Viewed by 1251
Abstract
This paper describes a groundbreaking design of a three-phase interleaved boost converter for PV systems, leveraging parallel-connected conventional boost converters to reduce input current and output voltage ripple while improving the dynamic performance. A distinctive feature of this study is the direct connection [...] Read more.
This paper describes a groundbreaking design of a three-phase interleaved boost converter for PV systems, leveraging parallel-connected conventional boost converters to reduce input current and output voltage ripple while improving the dynamic performance. A distinctive feature of this study is the direct connection of a Li-Ion battery to the DC link, which eliminates the need for an additional charging circuit, which is a departure from conventional approaches. Furthermore, the combination of an MPPT controller and a closed-loop fuzzy controller with a current control mode ensures accurate switching signal generation for all three phases. The meticulously tuned system exhibits a remarkably low ripple content in the output voltage, surpassing calculated values, and demonstrates a superior dynamic performance. The investigation extends to a comprehensive analysis of losses, encompassing inductor copper loss and semiconductor conduction loss. In all scenarios, the converter exhibits an efficiency exceeding 93%, highlighting its robust performance as an effective solution for PV systems. Full article
(This article belongs to the Section D: Energy Storage and Application)
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25 pages, 2193 KiB  
Review
Electric Vehicles—An Overview of Current Issues—Part 1—Environmental Impact, Source of Energy, Recycling, and Second Life of Battery
by Marek Guzek, Jerzy Jackowski, Rafał S. Jurecki, Emilia M. Szumska, Piotr Zdanowicz and Marcin Żmuda
Energies 2024, 17(1), 249; https://doi.org/10.3390/en17010249 - 3 Jan 2024
Cited by 1 | Viewed by 3169
Abstract
The rapid transition to electric-drive vehicles is taking place globally. Most automakers are adding electric models to their lineups to prepare for the new electric future. From the analysis of the automotive market, it is evident that there is a growing interest in [...] Read more.
The rapid transition to electric-drive vehicles is taking place globally. Most automakers are adding electric models to their lineups to prepare for the new electric future. From the analysis of the automotive market, it is evident that there is a growing interest in such vehicles. They are expected to account for half the models released after 2030. Electric-drive vehicles include battery-electric vehicles. As indicated in the research literature and emphasized by experts, electric vehicles (EVs) are supposed to be an environmentally friendly alternative to conventional vehicles. The rising number and variety of EVs contribute to a better understanding of their performance. With more EVs on the market, there are problems to be solved and challenges to overcome. This article is the first part of a two-article series reviewing the strengths and weaknesses of EVs. The article analyzes the environmental effects of EVs at each stage of their life cycle, compares large- and small-scale recycling methods, and explores the potential applications of second-life batteries. This article is an attempt to find out how environmentally friendly EVs are. Full article
(This article belongs to the Special Issue Motor Vehicles Energy Management)
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17 pages, 8606 KiB  
Article
Numerical Simulation Study of Hydrogen Blending Combustion in Swirl Pulverized Coal Burner
by Xiang Lin, Xin Lei, Chen Wang, Xuehui Jing, Wei Liu, Lijiang Dong, Qiaozhen Wang and Hao Lu
Energies 2024, 17(1), 248; https://doi.org/10.3390/en17010248 - 3 Jan 2024
Viewed by 890
Abstract
Hydrogen blending of pulverized coal in boilers is a promising technology. However, there are few studies on hydrogen blending in coal-fired boilers. In order to reduce CO2 emissions from coal-fired boilers, this study investigates the co-combustion of pulverized coal and hydrogen in [...] Read more.
Hydrogen blending of pulverized coal in boilers is a promising technology. However, there are few studies on hydrogen blending in coal-fired boilers. In order to reduce CO2 emissions from coal-fired boilers, this study investigates the co-combustion of pulverized coal and hydrogen in a swirl pulverized coal burner by numerical simulation. Itis shown that the burnout rate of fuel is 5.08% higher than that of non-hydrogen blended coal when the percentage of hydrogen blended is 5%. The water vapor generated by hydrogen blending not only leads to the formation of a low-temperature zone near the burner outlet; it also results in a prolonged burnout time of moist pulverized coal and a high-temperature zone near the furnace outlet. The greater the amount of hydrogen for blending, the higher the water produced. When 1–3% hydrogen is blended, the water vapor in the furnace reacts with the carbon to produce a large amount of CO. When the amount of hydrogen added to the furnace is more than 3%, the water content in the furnace rises, resulting in a lower temperature at the burner outlet and a decrease in the amount of CO produced. When 1–3% hydrogen is blended, the CO2 emission rises. The CO2 emission decreased by 1.49% for 5% hydrogen blending compared to non-hydrogen blending and by 3.22% compared to 1% hydrogen blending. Full article
(This article belongs to the Section A5: Hydrogen Energy)
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22 pages, 5705 KiB  
Article
Crystal Violet (CV) Biodegradation Study in a Dual-Chamber Fungal Microbial Fuel Cell with Trichoderma harzianum
by Sébastien Votat, Maxime Pontié, Emmanuel Jaspard and Laurent Lebrun
Energies 2024, 17(1), 247; https://doi.org/10.3390/en17010247 - 3 Jan 2024
Viewed by 922
Abstract
In the present study, CV dye, known as a recalcitrant dye, was tested for bioremediation via Trichoderma harzianum in a dual-chambered MFC for the first time. Two types of carbon clothes, KIP and CSV from the Dacarb company (France), were tested as electrodes [...] Read more.
In the present study, CV dye, known as a recalcitrant dye, was tested for bioremediation via Trichoderma harzianum in a dual-chambered MFC for the first time. Two types of carbon clothes, KIP and CSV from the Dacarb company (France), were tested as electrodes and supported for fungi growth. We first observed that 52% and 55% of the CV were removed by the MFC using KIP and CSV anodes, respectively. The incomplete removal of VC was explained by the relative toxicity of VC to T. harzianum and correlated with IC50 determined as 0.97 ± 0.28 mg L−1 at 25 °C. Furthermore, the MFC working with the KIP electrode was more efficient with a higher maximum power density of 1096 mW m−3 and was only 14.1 mW m−3 for CSV. The MFC experiments conducted on KIP without the T. harzianum biofilm exhibited significantly lower potential and power density values, which proves the electrocatalytic effect of this fungus. These results provide new insight into the development of an effective MFC system capable of direct energy generation and, at the same time, promoting the bioremediation of the persistent CV pollutant. Full article
(This article belongs to the Section A4: Bio-Energy)
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12 pages, 5116 KiB  
Communication
A Study of a Gain-Scheduled Individual Pitch Controller for an NREL 5 MW Wind Turbine
by Chae-Wook Lim
Energies 2024, 17(1), 246; https://doi.org/10.3390/en17010246 - 3 Jan 2024
Cited by 1 | Viewed by 617
Abstract
In order to reduce the asymmetric load acting on the blades of MW-class wind turbines, it is necessary to apply an individual pitch controller that independently adjusts the pitch angles of the three blades. This paper takes a new look at the relationship [...] Read more.
In order to reduce the asymmetric load acting on the blades of MW-class wind turbines, it is necessary to apply an individual pitch controller that independently adjusts the pitch angles of the three blades. This paper takes a new look at the relationship between the individual pitch controller applied to MW-class wind turbines and the vibration mode of the blades. The purpose of this study is to propose a method in which the individual pitch controller further reduces the 1P component of the bending moment in the out-of-plane direction acting on the blade, without exciting the in-plane vibration mode of the blade within the entire wind speed range, from the rated wind speed to the cut-out wind speed. To this end, a problem related to the excitation of the blade’s vibration mode that may occur when applying the individual pitch controller to an NREL 5 MW wind turbine is examined, and a method that uses gain scheduling to overcome this problem is presented. It is confirmed that it is possible to solve the problem of exciting the first-order vibration mode in the in-plane direction of the blade that can occur in the high wind speed range by applying the proposed gain scheduling method to the individual pitch controller aimed at reducing the 1P component of the out-of-plane bending moment of the blade. Full article
(This article belongs to the Special Issue Advances in Wind Energy Control)
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20 pages, 2769 KiB  
Article
Low-Carbon Optimal Scheduling of Integrated Energy System Considering Multiple Uncertainties and Electricity–Heat Integrated Demand Response
by Hongwei Li, Xingmin Li, Siyu Chen, Shuaibing Li, Yongqiang Kang and Xiping Ma
Energies 2024, 17(1), 245; https://doi.org/10.3390/en17010245 - 3 Jan 2024
Viewed by 792
Abstract
To realize the low-carbon operation of integrated energy systems (IESs), this paper proposes a low-carbon optimal scheduling method. First of all, considering the integrated demand response of price-based electricity and heating, an economic scheduling model of the IES integrated demand response based on [...] Read more.
To realize the low-carbon operation of integrated energy systems (IESs), this paper proposes a low-carbon optimal scheduling method. First of all, considering the integrated demand response of price-based electricity and heating, an economic scheduling model of the IES integrated demand response based on chance-constrained programming is proposed to minimize the integrated operating cost in an uncertain environment. Through the comprehensive demand response model, the impact of the demand response ratio on the operating economy of the IES is explored. Afterward, the carbon emission index is introduced, and gas turbines and energy storage devices are used as the actuators of multi-energy coupling to further explore the potential interactions between the coupling capacities of various heterogeneous energy sources and carbon emissions. Finally, the original uncertainty model is transformed into a mixed-integer linear-programming model and solved using sequence operation theory and the linearization method. The results show that the operating economy of the IES is improved by coordinating the uncertainty of the integrated demand response and renewable energy. In addition, the tradeoff between the working economy and reliability of the EIS can be balanced via the setting of an appropriate confidence level for the opportunity constraints. Full article
(This article belongs to the Section F: Electrical Engineering)
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