International Journal of Energy Research最新文献

This study evaluates alternatives using the analytic hierarchy process (AHP) and Fuzzy AHP (FAHP) methodologies across five scenarios (SC1 to SC5), aiming to compare the effectiveness of both approaches in integrating environmental and technical criteria. The results indicate that, in SC1, AHP assigns weights of 14.35% to A1 and 16.22% to A2, while FAHP demonstrates greater dispersion, highlighting A6 with 35.22%. In SC2, AHP prioritizes A1 with 14.16%, whereas FAHP increases the weight of the environmental criterion to 21.18%. In SC3, A1 remains the preferred option in both methodologies, with close weights of 34.00% for AHP and 32.98% for FAHP. In SC4, both methods show similar trends, with A1 standing out at 11.12% and A4 at 34.87%. Finally, in SC5, AHP allocates 8.52% to A1, while FAHP evaluates it at 10.73%. The findings suggest that FAHP allows greater sensitivity to variations in sub-criteria, enabling a more precise evaluation aligned with sustainability objectives. The significance of environmental and social criteria across the scenarios underscores the necessity of incorporating more sustainable approaches into decision-making processes. It is concluded that, while AHP delivers consistent results, FAHP may be better suited for contexts characterized by complexity and uncertainty. Furthermore, sensitivity analysis is recommended to examine how variations in criterion weights impact final decisions.

The thermal energy storage (TES) technology has gained so much popularity in recent years as a practical way to close the energy supply–demand gap. Due to its higher energy storage density and long-term storage, thermochemical energy storage (TCES), one of the TES methods currently in use, seems to be a promising one. These potential advantages have triggered to undertake a decent amount of research investigations in the past few years. The present review paper summarizes the recent outcomes of TCES systems for building water and space heating applications and demonstrates the different kinds of systems and their configuration arrangements. The recently developed experimental as well as theoretical prototypes are looked over with respect to their arrangement (closed and open loop) and role of relevant operating conditions. Various kinds of reactor shapes are also summarized and presented. Critical issues like materials’ achievable heat storage density/capacity, stability/cyclability, charging temperature, and systems’ mass and heat transfer properties are discussed. This work also presents the current challenges and the possible suggestions to address them. This review suggests that additional research is necessary to determine the role of influencing parameters in the design and establishment of TCES prototypes for building’s water and space heating applications.

This study presents a technoeconomic analysis of a hybrid wind-PV (photovoltaic) power plant (HPP) compared to onshore wind power plants (WPPs) and photovoltaic power plants (PVPPs) in the Nordic electricity market, focusing on locations in Finland and Sweden. Wind power capacity has recently increased significantly in the Nordics, increasing the profit cannibalization of wind power. Renewable energy subsidies have been phased out in Finland and Sweden, thus new wind and PV power value creation is formed from the power market. The PV power capacity has also encountered significant growth in the Nordics. However, the capacity is still relatively low, allowing more revenue for produced PV power compared to wind power. The lower PV power profit cannibalization has increased interest in HPPs instead of WPPs. This contribution studies the economic feasibility of wind and PV power in changing market conditions in the Nordic electricity market. The market operation is modeled with three different configurations including selling all the power into the day ahead spot market and baseload or pay-as-produced power purchase agreement (PPA). In addition, a battery energy storage system (BESS) investment is analyzed using the operating strategy of shifting production to more profitable spot price hours. This study shows that due to the profit cannibalization and high cost of capital, the power plants are currently not profitable in the Nordic electricity market except when the bidding area has high average spot prices. The worst profitability was with WPPs when exposed to the market shape risk and with PVPPs when pay-as-produced PPA was agreed upon due to the higher levelized cost of electricity. However, the PV power profit cannibalization is expected to increase in the future as more PVPPs operate in the Nordic power market. Thus, the PVPP shape risk may increase in the future as well.

Integrated energy systems (IESs) can realize the conversion and complementarity of various energy sources, which provides opportunities and challenges for the energy market. Considering that the user’s energy consumption is affected by the energy price difference, there is a problem that the new energy output in the comprehensive energy system does not fully match the user’s energy demand period. In order to solve the above problems, this paper proposes a two-stage optimization model of “open source and reducing expenditure” to give full play to the potential of multiple energy sources on the load side to participate in demand response (DR) and combine low-carbon technology and market mechanisms to realize the low-carbon economic operation of the comprehensive energy system. In the first stage, a collaborative optimization strategy for electric and thermal DR is constructed from the aspect of “reducing expenditure,” a comprehensive load fuzzy DR mechanism based on the logistic function is constructed for electric load, and the load curve and time-of-use (TOU) energy price are optimized considering the coupling characteristics of user energy consumption, and nondominated sorting genetic algorithm (NSGA-II) solution to achieve peak shaving and valley filling. In the second stage, a joint operation model of carbon capture power plant (CCPP) and power-to-gas (P2G) equipment is built from the aspect of “open source,” and the ladder-type carbon trading mechanism is considered to rationalize the unit output and achieve low-carbon emission reduction. The calculation results obtained through examples show that the total cost of the model is slightly reduced by 5.44%, but the actual total carbon emission of the system is greatly increased by 50.73%. It proves that the high-carbon power plant transformation and TOU energy price optimization strategy are effective for the low-carbon economic operation of the system and realize both economic benefits and benefits of the system.

Owing to the depletion of fossil fuels, rising energy costs, and environmental pollution, there has been a growing focus on exploring and exploiting renewable energy sources. This study aims to demonstrate the modeling of a grid-connected double-chamber microbial fuel cell (DCMFC) biomass energy system via MATLAB Simulink software. The experimental measurements obtained from DCMFC outputs served as the basis for developing the inverter-grid connection model and simulation output in MATLAB Simulink software. Briefly, the DCMFC DC boost voltage was connected to the positive and negative buses of the three-phase DC‒AC inverter circuit, with switching patterns controlled by gate pulses in each transistor. Full square wave single-stage PWM pulses are generated by the gate for control. The power generated by the inverter was measured via a three-phase VI block for analysis, with voltages and currents displayed via a scope. To address potential noise during switching, an LC filter is employed to suppress noise output and stabilize power generation. Another power meter measures power from the grid, with waveforms displayed via scope blocks. Before synchronization between power from the DCMFC and the grid occurs, four requirements must be met: the grid voltage must match the inverter output voltage, the inverter frequency must match the grid frequency, the phase sequence must be the same, and the phase angle of the inverter must match that of the grid. Additionally, Institute of Electrical and Electronics Engineers (IEEE)-specific requirements were evaluated during the simulation for this study. In addition, this study critically examined whether the DCMFC inverter model conforms to conventional requirements, International Electrotechnical Commission (IEC) standards, and IEEE standards for the integration of inverters into the grid. Compared with previous studies on inverter modeling for grid connections, past studies have emphasized the efficacy of biomass power plants and different inverter topologies for photovoltaic (PV) systems. The current study focuses on optimizing a multilevel inverter-based model, achieving low total harmonic distortion (THD) below IEEE standards. In this study, the use of a multilevel inverter configuration proved highly effective in reducing the harmonic content, leading to synchronized phase sequences and enhanced coherence between the grid and inverter voltages. With a THD of 4.75% at 50 Hz, supported by a harmonic distortion value of 422.5, the chosen configuration significantly minimized the harmonic distortion. This success underpins the system’s reliability and efficiency, offering promising implications for practical applications.

With the increasing demand for gangue disposal in China, gangue slurry filling technology, as a necessary technical means for harmless disposal of gangue under low interference conditions, has been widely promoted in Western China, Mongolia, and Shaanxi regions. In order to optimize the upper limit particle size of gangue slurry under interference settlement conditions to ensure the safety of pipeline transportation, the article systematically carried out the gangue slurry characteristics and static settlement test, studied the interference settlement conditions of gangue slurry in the suspension of coarse particles characteristics, and analysis of the gangue particles obtained by the settling speed of engineering verification. The results show that gangue slurry has coarser particles, complex components, and high solid content characteristics, and its static settlement characteristics cannot truly restore the flow state in the pipeline. The particle settling velocity is affected by the concentration of slurry, rheological parameters, gangue particle size, and gangue fine particles of the density of the suspension medium through the mechanical derivation method to obtain the gangue particle settling velocity calculation formula. Moreover, take indoor large-scale tests and field applications for double verification, the upper limit of particle size of 3.00 mm under the condition of the maximum sinking speed of 1.092 × 10⁻⁶ m/s can realize the start with the material did not happen to plug the pipe accident, the field test of the neighboring grouting filling effect is good.

Electric vehicle (EV) batteries may now be conveniently charged with wireless chargers. These systems are prized for their dependability and security in a range of weather scenarios. Generally speaking, there are two kinds of EV wireless charging systems: static (for parked cars) and dynamic (for moving cars). Traditionally, EV chargers have parts like a high-frequency direct current (DC)–alternating current (AC) converter that usually requires intricate cabling and an AC–DC converter that aids in power quality management. In these systems, a process called as “transformation” occurs when energy moves from a main component—the power source—to a secondary component—the vehicle’s receiver. Eliminating physical connections, such wires and charging outlets on the car, improves convenience and lessens wear and tear on the charger. This is another advantage of wireless chargers over plug-in varieties. In this study, we investigate a novel design that substitutes a single integrated AC–AC converter on the input side for the conventional AC–DC and DC–AC converters. This creative solution lowers the demand on power switches while raising voltage levels, which not only makes the system simpler but also more efficient. To further reduce the voltage stress on these switches, we additionally employ a multilevel diode clamp inverter, which not only helps to reduce the size of the switches but also greatly increases the efficiency of the system. To validate the performance of this new converter, we provide data from the laboratory as well as simulation results.

Electric vehicle (EV) thermal management systems (TMSs) face a critical challenge in adopting environmentally friendly refrigerants, essential for adaptability, thermal safety, driving range optimization, and passenger comfort across wide temperature ranges. This study investigates the use of R290, a low-cost and environmentally friendly refrigerant, in a secondary-loop-based TMS. A system test bench was established to validate the system performance experimentally, and a comparison was made with the system using R134a. The experimental results show that the R290 charge amount is approximately 50% of that of R134a. Under low-temperature heating condition (0°C), R290 demonstrates significant performance advantages, with heating capacity and coefficient of performance (COP) increasing by up to 67.6% and 36%, respectively, compared to R134a. At extremely low temperatures (−20°C), R290 achieves a COP of 1.24, further showcasing its superior heating performance. Under high-temperature cooling conditions (35 and 43°C), R290 exhibits slightly lower cooling capacity compared to R134a; however, its performance remains sufficient to meet the operational requirements of a TMS. In summary, the proposed TMS using R290 as the refrigerant demonstrates excellent performance and promising potential for application in EVs across a wide range of operating conditions.

This study proposes a deep neural network (DNN)–based regression model for predicting the excess air ratio, which is a critical indicator for optimizing combustion efficiency and minimizing harmful emissions in industrial combustion systems. The chemiluminescence signals of the OH^∗ radicals and fuel pressure were used as the input features for the prediction model. To evaluate the effect of the multidimensional input, Case 1, with only the OH^∗ radical signal as a single input, was compared with Case 2, with the OH^∗ radical signal and fuel pressure as the inputs. The results showed that the Case 2 model reduced the mean absolute error (MAE), mean relative error (MRE), and root mean squared error (RMSE) by approximately 40.71%, 41.85%, and 19.69%, respectively, compared to Case 1, and the average relative prediction error rate was also 2.25% lower. These results demonstrate the potential for improving the accuracy and generalization ability of the model by incorporating multidimensional input features. Therefore, DNN models using multidimensional inputs can contribute to the design and implementation of combustion control systems to optimize the combustion efficiency and reduce harmful emissions in industrial combustion systems by predicting the excess air ratio.

This paper proposes a robust DC-link voltage controller designed for a multilevel-based static synchronous compensator (STATCOM), addressing both DC-link capacitance degradation and load variations. The uncertainty in DC-link capacitance is modeled as an external perturbation, leading to the development of a second-order sliding mode controller (SOSMC) based on a twisting algorithm. This controller effectively manages these uncertainties, providing high stability and robustness against parameter variations and external disturbances. Furthermore, it reduces unwanted chattering and enhances overall system performance. The impact of DC-link capacitance uncertainty on the reliability of multilevel converters is analyzed, comparing the proposed SOSMC with traditional proportional–integral (PI) controllers in the Simulink MATLAB environment. The results demonstrate that the SOSMC method outperforms the PI controller under 33% uncertainty in DC-link capacitance over 5 years. The proposed control scheme not only meets reactive power demands but also effectively manages uncertainties in DC-link capacitors. Additionally, the twisting algorithm maintains an acceptable total harmonic distortion (THD) index on the AC side, thereby improving overall reliability while reducing maintenance costs.