Energy Storage最新文献

The goal of the current study is to determine how the SST $��k�-�\omega �$ and the standard $��k�-�\varepsilon �$ turbulence models prediction on PCM with cylindrical configuration affect AC performance and PCM discharging when coupled with an AC unit. For simulation, 308.15 K and 318.15 K, the inflow air temperature has been considered with a fixed 33.6 L/s intake air flow rate. The low outside temperature charges the PCMs during the night. During the daytime, heated ambient air is cooled by the PCM heat exchanger before passing over the unit condenser. The present outcomes show that using the standard $��k�-�\epsilon �$ model, the cylindrical PCM has the lowest time of complete melting. The temperature contours demonstrate that turbulence occurs, particularly at higher temperatures, in the PCM melting zone within the solid region. This implies that there is increased convection in this area. The maximum improved percentage in COP increases as the rising input air temperature for both turbulence models increases. The average power saving of AC at 308.15 K of an input air temperature for 83.33 min is predicted by both the standard $��k�-�\varepsilon �$ and the SST $��k�-�\omega �$ to be 14.0905 W and 14.1089 W, respectively.

This review explores the utilization of lignocellulosic biomass (LCB) waste in the fabrication of graphene and its applications in hydrogen storage. Several LCB wastes, such as rice straws, coconut shells, wheat straws, and sugarcane bagasse, along with the methodology used and the characteristics of the final graphene, have been discussed in detail. It was found that the coconut shells produced crumpled multilayered graphene, rice husks (RHs) provided a mix of graphene layers and amorphous carbon, wheat straw yielded few-layered graphene, and sugarcane bagasse contributed to different graphene-like materials. This review has also focused on the various synthesis processes, such as carbonization, hydrothermal carbonization (HTC), chemical activation, pyrolysis, chemical vapor deposition (CVD), and Hummers' method for graphene fabrication from LCB waste, along with their advantages and disadvantages, for a better understanding. Various results have been discussed exploring the use of lignocellulosic biomass-derived graphene (LCB-G) and its various modified forms for hydrogen storage applications. Various challenges in graphene fabrication from LCB, such as low yield, product quality, scalability, use of expensive synthesis methods, and toxic chemicals, along with some potential solutions, have been mentioned. Finally, the review concludes with insights into the future of LCB-G and its role in hydrogen storage while identifying some gaps, such as scalability and product quality, for further research and development.

In the current work, carbon materials were used in the hydrogen adsorption process, specifically as carbons doped with platinum dispersed on ceria. The textural characterization results of the prepared samples and the starting carbon showed the presence of both micro- and mesopores. On the other hand, it has been observed that the specific areas were inversely proportional to the CeO₂ loading. In addition, the amount of adsorbed hydrogen increased after doping the carbon with platinum and, even more, when the carbon was doped with Pt dispersed on ceria (2.2 mg/g at 25°C and 30 bar). However, there was a ceria optimum from which the adsorption capacity decreased (10% wt). The results of temperature-programmed desorption (TPD) of hydrogen indicated a high affinity between Pt and H₂ that enhanced H₂ adsorption process by establishing chemical bonds between the metal particles and H₂. Precisely, the presence of metallic Pt particles dispersed on ceria considerably promotes the spillover process of hydrogen on carbon. This can be confirmed by hydrogen adsorption–desorption isotherms, that showed that complete desorption of chemisorbed hydrogen required an increase of temperature.

Despite being a cutting-edge technology, the proton exchange membrane fuel cell (PEMFC) generates a lot of heat as it works, which makes it wasteful with energy. In order to enhance energy efficiency via waste heat recovery, we provide and analyze a novel integrated energy system that utilizes PEMFC and ORC technology. There are a lot of ways to put the waste heat from fuel cells (FCs) to good use, but the most efficient one is the organic Rankine cycle (ORC) with the right working fluid. This research aims to find the optimal way to use the waste heat of the FC by testing several working fluids. The optimal solution is derived using a genetic algorithm by monitoring the objective functions that characterize the system's overall performance as they vary across different system parameters. The results show that the proposed efficient integration achieves high energy and exergy efficiency levels and achieves rates of total cost and environmental impact that are within acceptable limits. Since the fuel usage element's content significantly affects the system indicators in several ways, the results also demonstrate that it is quite relevant. Since the exergo-environmental metric and the exergy efficiency meter are always moving in different directions, choosing a design condition that meets several requirements is crucial. According to the results, fuel cells had the highest irreversibility rate at 12.2, making them the most energy-conserving piece of machinery.

The design and development of a 550 W non-isolated single-phase two-stage level-1 bidirectional on-board battery charger (OBC) for electric vehicles (EVs) have been discussed in this article, which is also capable of supplying the utility grid's reactive power needs. There are two stages in this topology. The first stage consists of a full bridge bidirectional AC to DC converter, and the second stage consists of a half-bridge bidirectional DC to DC converter with enhanced vehicle-to-vehicle (V2V) capabilities for emergency roadside charging assistance scenarios. In an emergency, if there is not a charging station nearby and the battery is dead, EVs can use this feature to charge from other EVs. It can also work like a regular vehicle-to-grid (V2G) or grid-to-vehicle (G2V) system. The suggested charging topology has a maximum efficiency of 99.09%, a power factor of 0.99, and a total harmonic distortion (THD) of 6.31%. MATLAB/Simulink is used to develop and simulate the suggested EV charger, and simulation results are compared with the other on-board chargers in the literature.

The integration of electric vehicles (EVs) into the power grid could pose challenges to power quality (PQ) depending on quantity of EVs and when they are connected. To mitigate these impacts without using drastic measures, such as disconnecting EVs, this study investigates centralized control strategies within parking facilities that prioritize EV charging based on individual State of Charge (SoC) levels. The study utilizes the IEEE 34 Bus system and conducts 3888 simulations for different scenarios to assess the impact of the quantity and placement of EVs in parking lots. The study applies the Monte Carlo method to compare the performance of different proposed controls: (i) limiting the charging current to a fixed level and (ii) varying the current based on the voltage droop step. Furthermore, Power Hardware-in-the-Loop (PHIL) simulations were carried out to validate the hierarchical control using the droop step control, demonstrating the best average performance in the previous scenarios. The findings indicated that the control responded within the expected timeframe and successfully addressed voltage sag issues, maintaining PQ in the distribution system in most cases, with its performance being influenced by the placement of parking lots in the network. Additionally, it was confirmed through quartiles that the classification based on SoC leads to a more balanced charging time for different SoC levels.

Scientists and researchers are investigating new energy conversion and storage devices continuously because of the current global hike in energy crisis. In this study, we utilized graphene oxide (GO) and composites of transition metallic oxides (CeO₂@WO₃) to fabricate electrodes intended for use in supercapacitor electrodes. These electrodes' morphology demonstrates a uniform distribution of sphere and platelet nanoparticles. The XRD measurements for these manufactured electrodes showed a noticeable crystalline character. These electrodes have outstanding electrochemical performance due to their relatively low bandgap energies. The electrochemical tests demonstrated the exceptional charge storage capabilities of the different electrodes, suggesting that CeO₂/GO, WO₃/GO, and CeO₂@WO₃/GO electrodes could be useful electrodes for supercapacitor applications. Numerous electrochemical findings made it abundantly evident that the creation of bimetallic CeO₂@WO₃/GO composites enhanced the supercapacitive performance and cycle stability of the electrodes.

A high-performance aluminum-ion supercapacitor is fabricated using 2D few-layered Nb₂CT_x MXene, as an active electrode material and Al₂(SO₄)₃ electrolyte for efficient energy storage. Nb₂CT_x MXene has been synthesized from Nb₂AlC MAX phase using HF. Nb₂CT_x MXene coated on carbon cloth (Nb@CC) displays a capacitance of 307 F g⁻¹ with 90% coulombic efficiency. The specific capacitance of Nb@CC in Al₂(SO₄)₃ electrolyte is exceptionally high compared to those (≤32.2 F g⁻¹) in H₂SO₄, Na₂SO₄, and MgSO₄ electrolytes. Both symmetric and asymmetric aluminum ion supercapacitors are fabricated with Nb@CC electrode. The Nb@CC//Nb@CC symmetric device exhibits a capacitance of 122 F g⁻¹ with a high energy density (E_d) of 33.2 Wh kg⁻¹ at 1.41 kW kg⁻¹ power density (P_d). An asymmetric supercapacitor device (ASC), Nb@CC//CNT@CC, with carbon nanotube (CNT@CC) cathode delivers a maximum E_d of 24.7 Wh kg⁻¹ at 3.41 kW kg⁻¹ P_d and excellent stability with 90% capacitance retention after 4000 cycles. A remarkably high P_d of 34 kW kg⁻¹ is maintained with 13.2 Wh kg⁻¹ E_d, and the rate capability is 53% for a 10-fold increase in current density. These results offer the feasibility of efficient aqueous supercapacitors with Al-ion as guest species, presenting new possibilities for supercapacitors.