There are several methods for estimating the SoC of lithium-ion batteries that use electrochemical battery models or artificial intelligence and intelligent algorithms. These methods have numerous advantages but are complex and computationally intensive. This paper presents a new method for estimating the SoC of lithium-ion batteries based on identifying the transfer function of the measured battery voltage response to the charging current pulse. It is assumed that the transfer function of the battery changes with the state of charge. In the learning phase, a reference table of known SoCs and associated transfer functions is created. The parameters of these transfer functions form the reference points in hyperspace. In the phase of determining the unknown SoC of the battery, the parameters of the measured transfer function form a point in hyperspace that is compared with the reference points of the transfer functions for known SoCs. The unknown SoC of the battery at the particular meas... [more]

Hydropower is a key source of electricity production for allowing the integration of intermittent renewable energy resources. Among the various hydraulic power plants around the world, the ones equipped with Pelton turbines already provide large flexibility that is still enhanced with the development, for instance, of the hydraulic short circuit operating mode. However, the knowledge of the flow inside Pelton turbines is still a challenging task, both numerically and experimentally, despite progress in the last two decades. One key feature of the Pelton efficiency is the jet quality, i.e., the jet velocity needs to be uniform, not perturbed by secondary flows and compact. The compactness of the jet is mainly dependent o nthe location of the jet detachment at the nozzle outlet, which is challenging for computational fluid dynamics simulations mainly due to numerical diffusion. Even if this point has already been mentioned in previous papers, the present paper focuses on all the paramete... [more]

A new magnetic pole is designed and proposed for the transverse flux induction heating (TFIH) device, since the TFIH device with the original magnetic pole has the deficiencies of uneven temperature distribution on the strip surface at the outlet of the heater and large magnetic resistance of the alternating magnetic field through the magnetic circuit. Using the magnetic−thermal coupling calculation method proposed in this paper, the eddy current field and temperature field of the TFIH device with the original and new magnetic poles are calculated and analyzed under the same excitation. At the same time, the temperature distribution on the strip surface of the TFIH device with the new magnetic pole is calculated under different excitation parameters, and the magnitude and frequency are obtained when the uniformity of the temperature distribution is best.

Gas injection is a frequently used method for artificial lift and flow regime rectification in offshore production and transportation flowlines. The flow behaviour in such flowlines is complex and a better understanding of flow characteristics, such as flow patterns, void fraction/hold up distributions and pressure gradient is always required for efficient and optimal design of downstream handling facilities. Injection method and location have been shown to strongly affect downstream fluid behaviour that can have important implications for pumping and downstream facility design, especially if the development length between pipeline and downstream facility is less than L/D = 50 as reported by many investigators. In this article, we provide the results of an experimental investigation into the effects of the gas injection position on the characteristics of the downstream upwards vertical gas flow using a vertical riser with an internal diameter of 52 mm and a length of 10.5 m. A horizont... [more]

Traditional three-phase rectifier DC-link inverters have been used in industry for more than 40 years. However, electrolytic capacitors, which are widely used in traditional inverters, have very large volumes and can only be used for five years. To solve this problem, a three-phase small-film DC-link capacitor interior permanent-magnet synchronous motor drive system is investigated in this paper. This small-film capacitor not only has a longer life and smaller size than an electrolytic capacitor, but it can also improve the input harmonic currents and power factor on the grid side. A high-order band-pass filter active damping control is proposed here. In addition, a constrained predictive speed controller is designed to enhance the transient, load disturbance, and tracking speed performance. Furthermore, a constrained predictive current controller is implemented to reduce the three-phase harmonic currents of the motor. A digital signal processor, type TMS-320F-28035, manufactured by Te... [more]

Energy harvesting from piezoelectric materials is quite common and has been studied for the past few decades, but, recently, there have been a lot of new advancements in harnessing electrical energy via piezoelectric materials. In this regard, several studies were carried out in electrochemistry and fluid flow. Furthermore, consideration of productive and valuable resources is important to meet the needs of power generation. For this purpose, energy harvesting from fluids such as wind and water is significant and must be implemented on a large scale. So, developing self-powering devices can resolve the problem like that, and piezoelectric materials are gaining interest day by day because these materials help in energy generation. This review paper discusses different techniques for harnessing energy from fluid flows using piezoelectric materials. In addition, various vibration-based energy-harvesting mechanisms for improving the efficiency of piezoelectric energy harvesters have also b... [more]

By conserving natural resources and reducing the consumption of fossil fuels, sustainable energy development plays a crucial role in energy planning. Specifically, demand-side planning must be researched and anticipated based on electricity consumption at the grounded level. Due to the global warming crisis, atmospheric conditions are among the most influential components that have altered electricity consumption patterns. In this study, 66 climate variables from the ERA5 reanalysis and the observed power demand at four grid substations (GSs) in Cambodia were examined using recurrent neural networks (RNNs). Using the cross-correlation function between power demand and each climate variable, statistically significant climate variables were sorted out. In addition, a wide range of feedback delays (FDs) was generated from the data on power demand and defined using 95% confidence intervals. The combination of the improved complete ensemble empirical mode decomposition with adaptive noise (... [more]

For a bottom-liquid-cooled battery thermal management system (BTMS), the small contact area between the battery bottom and the cold plate leads to a large temperature difference in the battery height direction. In addition, the increase in coolant temperature from the inlet to the outlet results in an excessive temperature difference in the battery module in the coolant flow direction. In order to solve the above issues, a wavy channel was first designed to strengthen the heat exchange between the battery bottom and the cold plate. The maximum battery module temperature for the wavy-channel design is 29.61 °C, which is a reduction of 1.75 °C compared to the straight-channel design. Then, the transverse temperature difference in the battery module was reduced by introducing a composite-channel design. Finally, on the basis of the composite channel, phase change material (PCM) was added to the battery’s top surface to reduce the temperature difference in the battery height direction. The... [more]

Numerical simulations were conducted to research the pre-cooling effects of water injection on the turbine inlet of a turbine-based combined cycle (TBCC) engine under different flight conditions. Then, the performance of the water injection pre-compressor cooling (WIPCC) engine was calculated by mathematical modelling with different water to air ratios (WAR). It was the first time that the mass injection field of the turbine inlet of a TBCC engine was simulated, and it was also the first time that the performance of a subcomponent turbine engine of a TBCC was assessed. The calculation results showed the relationship of the inlet temperature with respect to WAR, inlet length and flight Mach number. The strategy for inlet length and water mass flow was proposed in order to meet the requirements of pre-cooling. When the length of the turbine inlet was 10 times the diameter of the inlet exit, the air could be cooled by 167.5 K with WAR = 0.09. The highest evaporation ratio reached at 93%.... [more]

When the wind power system is working in the maximum wind energy tracking area, or when its mechanical drivetrain system vibrates and the vibration frequency is relatively high, the system cannot suppress the speed vibration of the generator in the drivetrain system by adjusting the pitch angle. In this paper, a generator speed control system based on the three degrees of freedom internal model control (3-DOF-IMC) is established to control the generator speed. Thus, a scheme of using the feedback filter in the 3-DOF-IMC to suppress generator speed vibration caused by drivetrain shaft elasticity and gear clearance in the drivetrain system is proposed. Firstly, the vibration problem and waveform of the two-mass wind power drivetrain systems are discussed, and the generator’s vector control and speed control systems are analyzed. Secondly, the principle of the 3-DOF-IMC is described, and the influence of the three controllers on the speed tracking performance and anti-interference perform... [more]

In order to mitigate the negative effects of global climate change, the Chinese government has committed to achieving peak carbon emissions by 2030 and carbon neutrality by 2060. Since municipal cities are the bottom administrative level for drawing up development plans, it is necessary and important to conduct decarbonization pathway research on municipal energy systems (MESs). However, there is little research on decarbonization at the municipal level, and the impact of development paths in each forecast scenario is mostly based on expert evaluation and qualitative assessment. Therefore, this study established a complete decarbonization framework for MESs, including general research procedures, models, and a sustainable evaluation method. The models of energy consumption and carbon emission were adapted and improved for MESs. In order to quantitatively evaluate the energy system development for each scenario, we proposed an energy−economy−environment−security (3E−S) evaluation method... [more]

Turbine-induced velocity deficit is the main reason to reduce wind farm power generation and increase the fatigue loadings. It is meaningful to investigate turbine-induced wake structures by a simple and accurate method. In this study, a series of single turbine wake models are proposed by combining different spanwise distributions and wake boundary expansion models. It is found that several combined wake models with high hit rates are more accurate and universal. Subsequently, the wake models for multiple wind turbines are also investigated by considering the combined wake models for single turbine and proper superposition approaches. Several excellent plans are provided where the velocity, turbulence intensity, and wind power generation for multiple wind turbines can be accurately evaluated. Finally, effects of thrust coefficient and ambient turbulence intensity are studied. In summary, the combined wake models for both single and multiple wind turbines are proposed and validated, en... [more]

Adsorption chillers produce cold energy, using heat instead of electricity, thus reducing electrical energy consumption. A major industrial waste, fly ash, can be converted to zeolite and used in adsorption chillers as an adsorbent. In this research, three different types of zeolites were synthesised from fly ash via a hydrothermal reaction in an alkaline solution (NaOH). The obtained samples (Na-A zeolites) were modified with K2CO3 to increase the water adsorption capacity of these samples. Phase and morphology analyses shows that desired zeolites formed properly but other crystalline phases also exist along with nonporous amorphous phases. The determined specific surface areas for Na-A zeolite (12 h) and Na-A zeolite (24 h) are 45 m2/g and 185 m2/g respectively, while the specific surface area for synthesized 13X zeolite is almost negligible. Water-isotherm for each of these samples was measured. Considering the application of adsorption chillers, average adsorption capacity was very... [more]

The terminal equipment interconnection and the network communication environment are complex in power cyber−physical systems (CPS), and the frequent interaction between the information and energy flows aggravates the risk of false data injection attacks (FDIAs) in the power grid. This paper proposes an active defense framework against FDIAs of power CPS based on data-driven algorithms in order to ensure that FDIAs can be efficiently detected and processed in real-time during power grid operation. First, the data transmission scenario and false data injection forms of power CPS were analyzed, and the FDIA mathematical model was expounded. Then, from a data-driven perspective, the algorithm improvement and process design were carried out for the three key links of data enhancement, attack detection, and data reconstruction. Finally, an active defense framework against FDIAs was proposed. The example analysis verified that the method proposed in this paper could effectively detect FDIAs a... [more]

Provision of an efficient water supply system (WSS) is one of the top priorities of all municipals to ascertain adequate water supply to the city. Intake is the lifeline of the water supply system and largely effects the overall plant efficiency. The required power supply is generally fed from the main grid, and a diesel generator is commonly used as a power backup source. This results in high pumping cost as well as high operational cost. Moreover, due to operation of motor pumps and other auxiliary loads, frequent maintenance is required. Therefore, to avoid various challenges and to efficiently operate the intake system, microgrid concept has been introduced in this paper. Various distributed generations (DGs) such as solar photovoltaic (PV), interior permanent magnet machine (IPM) wind turbine generator and Battery energy storage system (BESS) are incorporated in the microgrid system. Additionally, a new approach based on adaptive neuro-fuzzy inference system (ANFIS) is proposed, w... [more]

Active Buildings can contribute to efforts to address decarbonisation and climate change targets, and have the potential to support social aspirations for technical and infrastructural change. Yet achieving such goals is challenging. Active Homes as a type of Active Building represent a particularly interesting prospect; altering how energy is produced, distributed, and consumed, but also how homes are designed, constructed, and lived in are studied. Active Homes are designed with expectations of how residents will engage with them, but residents do not always live in the homes in ways envisaged by developers. Hence, there is a risk that the homes will not be experienced as comfortable living environments, or otherwise perform as anticipated. Thus, understanding resident perspectives is crucial to the successful wider rollout of Active Homes. We draw on social science research with designers, developers, and residents to explore expectations of life in an Active Home. Our longitudinal... [more]

Italy’s first renewable energy community, located in the municipality of Magliano Alpi, was established under Italian Law 8/2020 on Energy Communities in December 2020. The community is composed of eight stakeholders and involves, in addition to public buildings in the municipality of Magliano Alpi, some residential users and small and medium-sized enterprises, realizing public−private cooperation aimed at reducing energy dependence on the public grid and, at the same time, contributing to the decarbonization of the energy sector. This article provides an analysis of the economic and energy performance during the first year of renewable community piloting. The study analyzes data collected with the community energy management system and introduces a number of key performance indices useful for evaluating further development and optimization options.

The importance of energy supply and demand has been emphasized over the past few years. Renewable energy without regional bias continues to attract attention. The improvement of the economic feasibility of renewable energy leads to the expansion of the supply, and the global supply of solar modules is also rapidly increasing. Recently, the price of polysilicon for solar modules is also rising significantly. Interest in recycling waste modules is also increasing. However, the development of cost-effective treatment technology for solar modules that have reached the end of their commercial useful life is still insufficient. We are going to propose the standards necessary to restore and reuse so-called waste solar modules in a more eco-friendly and economical way. A crystalline solar module is an aggregate of individual solar cells. The technology is stable and has good durability. The efficiency of crystalline solar cells has dramatically improved in recent decades. The grade of cell tha... [more]

With worldwide activities of carbon neutrality, clean energy is playing an important role these days. Natural gas (NG) is one of the most efficient clean energies with less harmful emissions and abundant reservoirs. This work aims at developing a swarm intelligence-based tool for NG forecasting to make more convincing projections of future energy consumption, combining Extreme Gradient Boosting (XGBoost) and the Salp Swarm Algorithm (SSA). The XGBoost is used as the core model in a nonlinear auto-regression procedure to make multi-step ahead forecasting. A cross-validation scheme is adopted to build a nonlinear programming problem for optimizing the most sensitive hyperparameters of the XGBoost, and then the nonlinear optimization is solved by the SSA. Case studies of forecasting the Natural gas consumption (NGC) in the United Kingdom (UK) and Netherlands are presented to illustrate the performance of the proposed hybrid model in comparison with five other intelligence optimization alg... [more]

In the context of the ‘carbon peaking and carbon neutrality goals’, renewable energy, with its clean and low-carbon characteristics, has become one of the key driving forces for sustainable development in China. However, the inherent disadvantages of the renewable energy industry, such as high initial investment costs, technical difficulties, and slow returns on investment, make it difficult to compete with traditional fossil energy sources in the market economy at the initial stage of its establishment. Therefore, after considering the environmental and ecological value, economic value, and industrial growth dilemma brought by the development of renewable energy industry, subsidies as a governmental incentive measure were created to support the development and growth of the renewable energy industry. At present, there are many problems with China’s renewable energy subsidy policy in practice, such as fragmented institutional policies, lack of procedural regulations, and lagging subsid... [more]

This paper presents the design, modeling, and control of a hybrid multi-degree-of-freedom motor (HMDOF motor) that can be applied to unmanned aerial vehicles, such as drones. The HMDOF motor has a rotating motor and tilting motors separately and enables multi-DOF movement by driving each motor. In addition, owing to its structural characteristics, it is designed to allow a 3- or 6-DOF movement in only one motor. In this study, the control performance of an HMDOF motor was verified using simulated and experimental results. The position control performance for the rotation speed of the rotating motor was verified, and the control performance of the motor under the speed of the rotating motor and disturbance on tilting motors were analyzed.

Indonesia is currently undergoing the energy transition from heavily fossil fuel-dependent energy to cleaner sources of energy in order to achieve its net-zero emissions by 2060. In addition to reducing fossil fuel dependency, as one of the countries with the most geothermal reserves, the optimization of geothermal energy in Indonesia could be key to facilitating the energy transition. The objective of this paper is to elaborate on the transition process, which incorporates the destabilization of fossil fuel and the growth of geothermal energy, by analyzing the impact of both exogenous and endogenous factors on the supply chain structures of both sectors. This study employs workshop involving geothermal stakeholders in Indonesia, combined with the application of the Multi-Level Perspective (MLP) framework as the theoretical lens. The study found that energy demand, environmental awareness, energy regulations, energy supply chain, and geothermal potential breakthroughs are important asp... [more]

The study presents the results of research on using fixed-bed, activated carbon (AC) adsorbers in the cleaning of heavily tar-laden producer gas from the gasification of biomass. The efficiency of removal of organic compounds as well as the remaining adsorption capacity of the bed were determined using a spectrum of commonly applied diagnostic methods, including qualitative and quantitative analyses of the adsorbed compounds and changes in the pore volume of the bed material (IN, MN). The authors compare these lab quantifications with a simple technique which is based on the analysis of the changes in the position of temperature front in the bed. The main benefit of the latter is the possibility of performing the diagnostics of the bed “online” and using low-cost temperature measurements. The test was performed using a commercially available AC Desotec AIRPEL 10-3 and real producer gas obtained through the gasification of alder chips. For tar, VOC and C2−C5 compounds, the removal effic... [more]

The energy crisis is affecting a number of countries, but particularly those that are heavily dependent on the traditional energy generation formula (e.g., Poland), as well as those neighbouring the territory of the ongoing war in Ukraine, i.e., Poland, Lithuania, Latvia and Estonia. With this in mind, the authors of this study decided to explore the issue of water energy as a source of green (cheap and environmentally safe) energy in these countries. The main objective of the paper is to review the available literature, which is needed to identify the role hydropower plays in energy security and energy transition in these energy markets. This paper is based on a review and critical appraisal of the available literature and studies together with an inference. The structure of the paper consists of an introduction, the main part of the review and conclusions. The geopolitical location and socio-economic conditions of the adopted set of countries, form the basis of the review of the exis... [more]

Nowadays, there is a growing demand for information security and security rules all across the world. Intrusion detection (ID) is a critical technique for detecting dangers in a network during data transmission. Artificial Intelligence (AI) methods support the Internet of Things (IoT) and smart cities by creating gadgets replicating intelligent behavior and enabling decision making with little or no human intervention. This research proposes novel technique for secure data transmission and detecting an intruder in a biometric authentication system by feature extraction with classification. Here, an intruder is detected by collecting the biometric database of the smart building based on the IoT. These biometric data are processed for noise removal, smoothening, and normalization. The processed data features are extracted using the kernel-based principal component analysis (KPCA). Then, the processed features are classified using the convolutional VGG−16 Net architecture. Then, the entir... [more]