According to the last census of 2019, about two million Italian buildings are more than 100 years old. Building energy retrofitting involves a diverse mix of influencing factors, depending on history, intended use, and construction techniques. This paper aims to assess the energy needs of a historic building by evaluating the variability of climatic conditions and internal loads, as well as the thermal capacity of the building envelope. The energy analysis was conducted using dynamic simulation systems (TRNSYS). The purpose of the study is to provide an analysis of the current energy conditions of the building to identify the main critical issues and suggest the most suitable interventions to be implemented. All the transformations were conducted to meet the nZEB requirements and evaluate technical and economic feasibility, compatibility with architectural and landscape constraints, and large-scale replicability. Specifically, to reach the proposed targets, a 36 kWp PV system was imple... [more]

Multi-energy systems (MES) allow various energy forms, such as electricity, gas, and heat, to interact and achieve energy transfer and mutually benefit, reducing the probability of load cutting in the event of a failure, increasing the energy utilization efficiency, and improving the reliability and robustness of the overall energy supply system. Since energy storage systems can help to restore power in the case of failure and store the surplus energy to enhance the flexibility of MES, this work provides a methodology for reliability optimization, considering different energy storage configuration schemes under weather uncertainties. First of all, a reliability evaluation model of a multi-energy system under weather uncertainties based on a sequential Monte Carlo simulation is established. Then, the reliability optimization problem is formulated as a multi-objective optimization problem to minimize the reliability index, SAIDI (system average interruption duration index), and the relia... [more]

The battery-pulse capacitor-based hybrid energy storage system has the advantage of high-energy density and high-power density. However, to achieve a higher firing rate of the electromagnetic launch, a shorter charging time of the pulse capacitor from the battery is needed. A new optimization model by formulating the charging time problem as a constrained optimization problem is presented. Unlike existing algorithms, the proposed model can find the globally optimal solution. The circuit parameters are optimized through the Enumeration algorithm to minimize the total charging time of the pulse capacitors from batteries. The simulation results show that the charging time of the proposed algorithm is shorter than the compared methods. Furthermore, a better solution could be obtained by canceling the constraint on the first peak of the charging current of the compared methods, which makes the circuit design more flexible for the hybrid energy storage system in the electromagnetic launch.

In this paper, the implementation of a switched reluctance motor (SRM) and drive system for the propulsion system of a two-seat electric motorcycle is described. The overall design focuses on the required vehicle speed, acceleration, driving distance, and overall system cost, as well as reliability. The performance of the three-phase 6/4 pole (six-stator pole and four-rotor pole) and four-phase 8/6 pole (eight-stator pole and six-rotor pole) are investigated and compared by static performance analysis and dynamic performance analysis. Their performance is further investigated by finite element analysis. The indirect torque controller in a drive system for optimal torque and efficiency operation is also mentioned. A methodology for rotor position detection and its hardware implementation are also proposed. The designed 3.5 kW three-phase 6/4 pole SRM and its drive system were constructed and tested on the test bench. A maximum efficiency of about 82% could be achieved for the SRM and dr... [more]

Supercapacitors are energy storage devices with high electrical power densities and long spanlife. Therefore, supercapacitor-based energy storage systems have been employed for a variety of applications. The modelling and simulation of SCs have been of great interest to this objective. This paper presents an electrical schema and mathematical modelling of three models of supercapacitors. The first is the RC model, the second is the two-branch model and the third is the multi-branch model. The objective of this modelling is to choose the best model that can respect the same behaviour of the experimental model. These models are compared with an experimental model. This comparison prove that the response voltage of the multi-branch model correctly describes the behaviour of the experimental model of Belhachemi. The disadvantage of this model is the slow simulation duration in MATLAB/Simulink. The RC model represented the faster model in terms of simulation. The choice of 15 branches in pa... [more]

Vehicular ad hoc networks allow vehicles to share their information for the safety and efficiency of traffic purposes. However, information sharing can threaten the driver’s privacy as it includes spatiotemporal information, and the messages are unencrypted and broadcasted periodically. Therefore, they cannot estimate their privacy level because it also depends on their surroundings. This article proposes a centralized adaptive pseudonym change scheme that permits the certificate’s authority to adjust the pseudonyms assignment for each requesting vehicle. This scheme adapts dynamically depending on the density of the traffic environment and the user’s privacy level, and it aims to solve the trade-off problem between wasting pseudonyms and Sybil attack. We employ a Knapsack problem-based algorithm for target tracking and an entropy-based method to measure each vehicle’s privacy. In order to demonstrate the applicability of our framework, we use real-life data captured during the interop... [more]

The building sector is responsible for 50% of worldwide energy consumption and 40% of CO2 emissions. Consequently, a lot of research on Building Energy Efficiency has been carried out over recent years, covering the most varied topics. While many of these themes are no longer of interest to the scientific community, others flourish. Thus, reading trends within a field of knowledge is wise since it allows resources to be directed towards the most promising topics. However, there is a paucity of research on trend analysis in this field. Therefore, this article aims to analyse the evolution of the Building Energy Efficiency field of knowledge, identifying the recurrent themes and pointing out their trends, supported by statistical methods. Such an analysis relied on more than 9000 authors’ keywords collected from 2000 articles from the Scopus database and classified into 30 topics/themes. A frequency distribution of these themes enabled us to distinguish those most published as well as th... [more]

The interdependency of electric and natural gas systems is becoming stronger. The challenge of how to meet various energy demands in an integrated energy system (IES) with minimal cost has drawn considerable attention. The optimal scheduling of IESs is an ideal method to solve this problem. In this study, a day-ahead optimal scheduling model for IES that included an electrical system, a natural gas system, and an energy hub (EH), was established. The proposed EH contained detailed models of the fuel cell (FC) and power to gas (P2G) system. Considering that the optimal scheduling of an IES is a non-convex complex optimal problem, a piecewise self-adaptive particle swarm optimization (PCAPSO) algorithm based on multistage chaotic mapping was proposed to solve it. The objective was to minimize the operating cost of the IES. Three operation scenarios were designed to analyze the operation characteristics of the system under different coupling conditions. The simulation results showed that... [more]

This paper aims to explore the dynamic relationships between the crude oil price (shocks) and investor sentiment. Specifically, this paper utilizes web crawler to construct Chinese investor sentiment index. The structural vector autoregression (SVAR) model is then used to decompose the crude oil price shocks into three types of oil price shocks. Finally, the wavelet coherence analysis (WTC) is employed to study the dynamic correlation between crude oil price (shocks) and investor sentiment in the time and frequency domain, and their asymmetric dynamic correlation under different trends of crude oil price. Using data from February 2013 to June 2021, our empirical results suggest the heterogeneous dynamic correlations and lead-lag relationships exist between crude oil price (shocks) and investor sentiment over different time and frequency domains. In addition, there are asymmetric dynamic correlations and lead−lag relationships between crude oil price (shocks) and investor sentiment unde... [more]

In the case of road cars, road safety is the primary factor. The geometry of high-speed road cars has no regulatory restrictions. In addition to the high engine power and effective shape, they can use various types of additional movable aerodynamic elements to adjust their aerodynamic characteristics to the road conditions. Based on the geometry of a two-seater prototype of such a vehicle, a numerical analysis of the influence of a number of additional movable aerodynamic elements on its aerodynamic characteristics was performed. Several of them were installed on the prototype. An electronic system recording a number of motion parameters of the entire car body and some of its movable elements installed on the body was designed and built. The system has been adapted to program the motion of additional aerodynamic elements according to the set algorithms of their activation, temporarily changing the aerodynamic characteristics of the car. An experimental study of the effect of changes in... [more]

The paper presents unique research results on the effect of coking of diesel engine injector nozzles powered by mixtures of 10%, 20% and 30% biomethanol and diesel fuel compared to the engine being supplied with pure diesel fuel. The test results, obtained from an experiment conducted in accordance with the ISO 15550-1 standard, show the legitimacy of using biomethanol as an additive to diesel fuel due to the lower coking effect of the injector nozzles, which has a positive impact on the reduction of pollutant emissions during engine operation. Regarding the CEC PF-023 test, the tendency to reduce the coking tendency increases the percentage of biomethanol additive to diesel fuel. With a 10% share of biomethnol, the average coking effect of the injectors is over 1% lower, but with a share of 30% of bio-methanol, the coking effect is nearly 2% lower.

In this study, we examined the impacts of peer-to-peer (P2P) electricity trading on the power losses in the network, which is one of the objectives optimized in the centralized approach. For this purpose, we reviewed the conventional loss management schemes and suggested the requirements to be considered in the design of P2P electricity trading. Then, we described a new loss management framework for P2P transactions and introduced the concept of the transaction guide. Based on the proposed framework, we simulated the P2P transactions with and without the transaction guide and examined the variation in the network losses. Three noteworthy remarks are derived from the simulation in this paper. First, the random characteristics of P2P trading itself do not guarantee favorable transaction ordering in terms of network losses, but when the new loss management framework is applied, the network losses can be effectively decreased. Second, through the new loss management framework, loss costs c... [more]

We examine a different approach to complete the decarbonization of the Russian economy in a world where climate policy increasingly requires the radical reduction of emissions wherever possible. We propose an energy system that can supply solar and wind-generated electricity to fulfill demand and which accounts for intermittency problems. This is instead of the common approach of planning for expensive carbon capture and storage, and a massive increase in energy efficiency and, therefore, a drastic reduction in energy use per unit of Gross Domestic Product (GDP). Coupled with this massive increase in alternative energy, we also propose using excess electricity to generate green hydrogen. Hydrogen technology can function as storage for future electricity needs or for potential fuel use. Importantly, green hydrogen can potentially be used as a replacement export for Russia’s current fossil fuel exports. The analysis was carried out using the highly detailed modeling framework, the High-R... [more]

For the past few years, research in the field of flow boiling heat transfer has gained immense popularity for unravelling the dominant mechanism responsible for controlling heat transfer and identifying a parametric trend for understanding the characteristics of flow boiling heat transfer. This has led to several assumptions and models for predicting heat transfer during flow boiling without any known generalized mechanism. This study therefore seeks to experimentally study the characteristics of heat transfer during flow boiling over a wide range but small increase in vapor quality from a single-phase subcooled region through to a two-phase superheated vapor region. The study was performed with an R134a refrigerant in a single horizontal circular stainless-steel smooth tube that had an internal diameter of 5 mm. In this experimental study, local heat transfer coefficients and frictional pressure drop were measured for low heat fluxes of 4.6−8.5 kW/m2, mass fluxes of 200−300 kg/(m2s),... [more]

The Association of the Coal Industry of Santa Catarina (SATC), together with the State Electric Energy Company (CEEE/Equatorial) of the Brazilian state of Rio Grande do Sul (RS), seeks solutions to reduce conflicts between vegetation and electrical networks. This study was carried out having as an area for pilot the city of Porto Alegre, RS, where the distributor is responsible for the supply of electricity. The objective of this proposal was to define locations for carrying out a vegetation inventory through a predictive model. From satellite images, the existing vegetation in the distribution network was digitally extracted and, from this, five prioritization factors were associated via Hierarchical Process Analysis (HPA), resulting in an equation with consistency ratio where each factor is given a specific weight, resulting in a priority map. The final model is explained by 36% by the number of power outages, 21.5% by vegetation close to the grid, 21% by the affected population, 16.... [more]

This paper presents a partial Y-bus factorization algorithm to reduce the size of a power system model for transient stability analysis. In the proposed approach, steady-state operating conditions for dynamic equivalents are maintained using the traditional Ward admittance method. Fictitious generators are attached at boundary buses to preserve transient behavior following a disturbance. The equivalent dynamic effects from eliminated generators can be maintained by choosing appropriate dynamic parameters of fictitious generators, including machine inertia, transient reactance, and the damping coefficient. Parameters are determined using the idea that the contributions from external generators mostly depend on the network configuration and impedance characterized by the Y-bus matrix. The fictitious generators’ dynamic parameters are determined by conducting partial Y-bus factorization on dynamic parameter matrices. The proposed method’s performance is validated by conducting case studie... [more]

A mechanical support in a longwall complex requires proper supervision and control of operating parameters because it is responsible for the safety of machines and workers. Its main functions are to protect the excavation against the adverse effects of rock mass and to move it along with the operational progress of the shearer and the scraper conveyor. In the era of Industry 4.0 as well as green economy and sustainable development, the development of machines and devices included in the longwall complex is an important area of invention. When it comes to the mechanical support included in the longwall complex, the authors propose changes to the hydraulic control system. The main purpose of the work was to develop a system that can automatically expand the legs of the powered support. Tests were carried out under real conditions while equipping the support section with a prototypical hydraulic system and with a system monitoring the correct operation of the prototype. This article prese... [more]

The presented work explores the structural properties, gasification reactivity, and syngas production of Greek lignite fuel (LG) and ex-situ produced chars during CO2 gasification. Three different slow pyrolysis protocols were employed for char production involving torrefaction at 300 °C (LG300), mild-carbonization at 500 °C (LG500), and carbonization at 800 °C (LG800). Physicochemical characterization studies, including proximate and ultimate analysis, X-ray Diffraction (XRD), and Raman spectroscopy, revealed that the thermal treatment under inert atmospheres leads to chars with increased fixed carbon content and less ordered surface structures. The CO2 gasification reactivity of pristine LG and as-produced chars was examined by thermogravimetric (TG) analysis and in batch mode gasification tests under both isothermal and non-isothermal conditions. The key parameters affecting the devolatilization and gasification steps in the overall process toward CO-rich gas mixtures were thoroughl... [more]

In this study, genetic programming (GP) is used for optimizing bus and line separation methods to reduce the short-circuit current. Expanding power systems led to intensive electric power and more transmission lines, reducing the grid impedance. This increases the short-circuit currents that occur during failure, and it is impossible to continue developing higher-capacity breakers to accommodate such short-circuit currents. Therefore, the short-circuit currents must be managed systematically through busbar separation and line separation. However, there are countless possible bus and line separation schemes for power systems. Furthermore, to comply with power-system reliability standards, no lines or transformers should be overloaded after such controls are applied. This paper proposes the use of GP to optimize the bus and line separation methods for obtaining a solution. The solutions are limited to methods that can be implemented in real power systems, reducing the convergence probabi... [more]

In flood control scheduling of reservoirs, the usual conventional scheduling fails to obtain the optimal solution to the problem. The dynamic programming method is applied to the field. However, the problem of ‘dimensional disaster’ restricts its application. To solve these problems, the improved DP is constructed according to the principle of period inflow and water balance, which includes a variable dispersion mechanism of the retraction space and a calculation method for the smallest discrete points of each discrete range. Taking Dongjiang Reservoir as the research object, based on the maximum peak clipping criterion and the maximum flood control safety guarantee criterion, the improved DP is used for optimization. The results find that when the former criterion is used for scheduling, the discharge flow processes of the two floods are more uniform than conventional scheduling. When the latter criterion is used for scheduling, the minimum water levels of the two floods are lower tha... [more]

On the energy markets, conscious customers may exist who are not only interested in minimising the cost of energy purchase, but, simultaneously, in optimising some other quality criteria (arising from ecological concerns, or social responsibility of the energy producers). In this paper, we develop both a mathematical optimisation problem and a market framework for balancing a power system in a peer-to-peer market setup, where product differentiation can be considered directly on the market. Thus, origins of energy may be clearly identified, and product quality characteristics can be understood by various actors (including households). We derive a multi-objective (mixed-integer) linear programming optimisation problem for balancing the energy system in a peer-to-peer energy trading environment, where not only the cost but also other additional quality criteria are considered. We have identified many possible actors to be present within the proposed market setup. They include consumers,... [more]

The storage of enormous energies is a significant challenge for electrical generation. Researchers have studied energy storage methods and increased efficiency for many years. In recent years, researchers have been exploring new materials and techniques to store more significant amounts of energy more efficiently. In particular, renewable energy sources and electric vehicle technologies are triggering these scientific studies. Scientists and manufacturers recently proposed the supercapacitor (SC) as an alternating or hybrid storage device. This paper aims to provide a comprehensive review of SC applications and their developments. Accordingly, a detailed literature review was first carried out. The historical results of SCs are revealed in this paper. The structure, working principle, and materials of SC are given in detail to be analysed more effectively. The advantages and disadvantages, market profile, and new technologies with manufacturer corporations are investigated to produce a... [more]

The Government of Canada has embraced circular economy and is supporting an increasing number of initiatives in the field. However, implementation examples remain scattered and certain stakeholders are eager to see a greater level of commitment from policy makers. The purpose of this study is to provide a Canadian perspective on how, and to what extent, forest products are compatible with circular economy strategies. This topic was investigated through interviews with 16 Canadian experts in eco-design, circular economy, forest products and/or waste management, with a focus on construction and packaging. Efforts made by forest industries at the manufacturing stage to reduce resource consumption were acknowledged, but the implementation of other circular economy strategies, such as reuse, recycling and energy recovery, is uneven. While there is low-hanging fruit for incremental improvements, such as the processing of recovered lumber in wood panels and not mixing cardboard fibres with ot... [more]

Energy communities (ECs), intended as collective action initiatives in the energy field involving citizens’ participation, have been gaining relevance for the past decades as an alternative way to organize the energy chain to challenge the incumbent system. With Europe’s recently adopted Clean Energy Package, ECs found a formal recognition by the European Union as potential actors of the transition of the energy system towards a wider and more decentralized use of renewable sources. Although the potential role of ECs in the transition is therefore hardly questionable, a thorough comprehension of the enabling factors that might foster their diffusion and scaling up is still lacking. Through a comparative analysis of the evolutionary trajectories in six EU countries regarding their energy systems, their regulatory frameworks and their historical evolution of ECs, namely through the example of cooperative models, this paper aims at providing some preliminary evidence about the factors and... [more]

A regional integrated energy system is an important carrier of the energy Internet. It is a major challenge for the operation of a regional integrated energy system to deal with the uncertainty of distributed energy and multiple loads by using the coupling characteristics of equipment in a regional integrated energy system. In this paper, a two-stage robust economic dispatch model of a regional integrated energy system is proposed considering the source-load uncertainty. Firstly, the basic architecture of the regional integrated energy system is introduced. Based on the extreme scenario of uncertain power supply and load, the uncertainty set was established, the two-stage robust optimization model of regional integrated energy system was constructed and the column-and-constraint generation algorithm was used to solve the model. The effectiveness of the two-stage robust optimization model in improving the economy and robustness of the system was analyzed.