Energy Storage最新文献

This study proposes a system to store waste heat as liquid hydrogen using a proton exchange membrane electrolyzer (PEME) and a mixed refrigerant hydrogen liquefaction cycle. The novelty of this study lies in proposing a waste heat recovery system that stores electricity as liquid hydrogen, consuming less power due to the improved exergy efficiency of the components. The proposed system is analyzed to achieve better efficiency in terms of thermal and exergy efficiencies. Waste heat is used to generate power by an organic Rankin cycle (ORC), produced electricity is utilized in the PEME unit and compressors of liquefaction cycle to produce and liquefy hydrogen, respectively. Codes are written in EES software to simulate the system. Thermodynamic analysis is done in order to achieve better thermal efficiency for the proposed model. Membrane potential at different values of current density is calculated and compared with validate the simulated model. The exergy efficiency of the liquid hydrogen production process is 57%. The exergy efficiency, rate of power produced in ORC, and rate of hydrogen production by the electrolyzer increase significantly by increasing the isentropic efficiency of the turbine. At a temperature of 340 K for the evaporator, the thermal efficiency of ORC is obtained at 8.5%, which is approximately 3% higher compared with that of the previous similar process.

Syngas rich in hydrogen, generated through renewable-powered co-electrolysis of water (H₂O) and carbon dioxide (CO₂) using solid oxide electrolysis cells (SOEC), have gained significant attention due to its high efficiency and conversion rates. This method offers a promising solution for mitigating global warming and reducing CO₂ emissions by enabling the storage of intermittent renewable energy. This study investigates solar-integrated co-electrolysis of H₂O and CO₂ via SOEC to produce hydrogen-rich syngas, which is then utilized for methanol synthesis through a series of heat exchangers and compressors. Parabolic dish solar collectors supply thermal energy, while photovoltaic modules provide electricity for SOEC operation. CO₂ from industrial processes is captured and combined with steam at the SOEC inlet for co-electrolysis. The proposed system is modeled using engineering equation solver software, incorporating mass, energy, and exergy balance equations. The system's performance is analyzed by varying key parameters such as direct normal irradiance, heat exchanger effectiveness, current density, cell temperature, and pressure. The proposed system achieves a solar-to-fuel efficiency of 29.1%, with a methanol production rate of 41.5 kg per hour. Furthermore, an economic analysis was conducted to determine the levelized cost of fuel.

In the rapidly evolving landscape of energy storage technologies, sodium-ion batteries (SIBs) have emerged as promising alternatives to conventional lithium-ion batteries. SIBs exhibit moderate to high specific energy ranging from approximately 70 to 170 Wh/kg, ensuring suitability for diverse applications. Furthermore, with their abundance of raw materials and potential for lower costs, sodium-ion batteries are attracting significant interest from researchers, manufacturers, and investors. This heightened interest is evidenced by the exponential growth in the number of patents filed for SIBs, totalling 142 648 patents. This surge in patent filings underscores the growth pattern of SIBs as promising alternatives in the energy storage landscape. In this dynamic environment, securing and maintaining a robust patent portfolio is imperative for companies and innovators to establish a competitive edge, enabling them to capitalize on the increasing market demand. This perspective examines the strategies involved in building, protecting, and managing a robust patent portfolio as well as provides intellectual property challenges and patent filing opportunities in SIB technologies.

A hybrid energy system, comprising a diesel engine as the prime mover, electrical and absorption chillers, a backup boiler, and a multi-effect distillation through thermal vapor compression (MED-TVC) unit, has been utilized to meet the requirements of a residential complex. This study focuses on redesigning and optimizing the system to enhance environmental conditions, reduce pollutants, and minimize the use of fossil energy. The feasibility and design of renewable energy systems, including wind turbines (WTs), photovoltaic panels (PVs), and flat plate collectors (FPCs), have been examined. Genetic algorithm (GA) has been employed for optimization. The hybrid system employs 21 design variables, with 24 design variables chosen for optimization alongside renewable energies. The total annual cost (TAC), encompassing investment, operation, and pollution emission fines, has been chosen as the objective function for minimization. The results indicate that the use of WTs has not been cost-effective, and solar energy can enhance the system's performance in Bandar Abbas, Hormozgan province in Iran. In the case of using a combined system, the objective function value was 2.0472 × 10⁶ $/year, and when using renewable energies, the objective function became 1.6795 × 10⁶ $/year. Thus, the proposed combined-renewable system has reduced the objective function by 17.96%.

Solar thermal energy is crucial in our transition to renewable energy sources. Recent studies have focused on enhancing the efficiency of solar collectors by minimizing thermal energy loss during absorption. A promising approach involves an innovative design that integrates phase change materials (PCMs) and rotating tubes to capture thermal energy more effectively. Advanced nitride-based salt hydrates, with boron-arsenide additives, enhance thermal performance of the collector. In a flat plate collector using composite PCMs, radiative heat loss decreases from 250 to 210 W (a 6% reduction) with tube rotation, while convective heat loss drops from 225 to 195 W (a 4% decrease). The decomposition rate of the novel PCMs is low, measuring only 0.5% at a maximum temperature of 850°C, with a specific heat capacity of up to 4.50 W/m K. This unique blend, including the Sn₃N₄-LiNO₃-KNO₃/boron arsenide mixture, enhances thermal conductivity by 30%, significantly improving thermal absorption rates. The exergy efficiency achieved with the Nano-enhanced phase change materials (NEPCM) and tube rotation reaches an impressive 90%. With tube rotation at 3 rad/min, the flat plate collector's efficiency improves by 22%, reaching an overall efficiency of 90% at a fluid flow rate of 25 kg/h. Simulations using Anaconda Jupyter Notebook and Python validate the effectiveness of both tube rotation and NEPCM in enhancing collector efficiency.

Poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP)-sodium thiocyanate (NaSCN) solid polymer electrolytes containing different weight ratios of ionic liquid (IL)—tributylmethylphosphonium iodide (TBMPI) were prepared using solution-cast approach. Electrochemical impedance data indicates that increasing ionic liquid into polymer electrolyte matrix increases ionic conductivity and the maximum value of ionic conductivity was obtained at 150 wt% TBMPI, having conductivity value of 8.3 × 10⁻⁵ S cm⁻¹. The dielectric measurement supports our conductivity data. Ionic transference number measurement affirms this system to be predominantly ionic in nature, while electrochemical stability window (ESW) was found to be 3.4 V. Polarized optical microscopy (POM) along with differential scanning calorimetry (DSC) suggest suitability of TBMPI as plasticizer, while infrared spectroscopy (FTIR) confirms ion interaction, complexation, and composite nature. The thermogravimetric analysis (TGA) shows thermal stability of these ionic liquid-doped polymer electrolytes (ILDPEs). Using maximum conducting ILDPE, a sandwiched supercapacitor has been fabricated which shows stable performance as high as 228 Fg⁻¹ using cyclic voltammetry (CV).

We utilized density functional theory (DFT) to ascertain the storage of hydrogen in Rh-decorated pristine (PG) and defective graphenes, primarily graphitic-N (GNG) and pyridinic-N (PNG). The binding energy of a single Rh atom on PG, GNG, and PNG was found to be −1.87, −2.18, and −4.01 eV, respectively. PG exhibits a weak adsorption energy of hydrogen molecules (−0.06 eV/H₂). On the other hand, Rh-decorated pristine and defective graphenes show incredibly higher hydrogen adsorption energy. As per the latest guidelines of the U.S. Department of Energy (DOE), the Rh-decorated GNG (Rh@GNG) is found to be the best hydrogen storage material out of the three systems investigated here. The single Rh atom-decorated GNG adsorbs up to 4H₂. Uniform decoration of graphene surfaces with Rh atoms is necessary to improve hydrogen storage performance. Both sides of GNG surfaces are decorated with 8Rh atoms, which can adsorb up to 24H₂ molecules, with an average adsorption energy of −0.33 eV/H₂. The mechanism of H₂ adsorption on the host system has been explored based on DFT-evaluated deformation of charge density, partial density of states (PDOS), and non-covalent interaction (NCI) plots. For a better understanding of the adsorption process, the diffusion energy barrier of Rh metal is computed using the climbing image nudged elastic band (CI-NEB) method, and the thermal stability has been evaluated through ab initio molecular dynamics (AIMD) simulations.

This study discusses the hydrogen storage and delivery capacity of Sc-decorated [6]cycloparaphenylene ([6]CPP) using dispersion-corrected density functional theory calculations (DFT + D3). The scandium atoms are decorated over [6]CPP via Dewar coordination with an average binding energy of 1.33 eV. Each Sc atom stores up to 5H₂ molecules in quasi-molecular form at an average adsorption energy ranging from 0.23 to 0.36 eV/H₂. The system's stability before and after H₂ adsorption is checked using reactivity parameters. The maximum hydrogen gravimetric capacity of the system is found to be 7.68 wt% at low temperatures at 1–60 bar pressure. With an increase in temperature (300–420 K), the gravimetric density is more than 5.5 wt% (US-DOE target) below 60 bar. Atom-Centered Density Matrix Propagation (ADMP)-molecular dynamics (MD) simulations reveal that the desorption of H₂ molecules from [6]CPP starts at around 300 K/1 bar, and complete desorption occurs above 480 K. The minimum Van't Hoff desorption temperature for [6]CPP-Sc is 296.9 K at 1 atm pressure. Insignificant change in the structure of [6]CPP-Sc during adsorption and desorption processes promises stability and reversibility of the system. Hence, we believe that Sc-decorated [6]CPP can be a promising candidate for hydrogen storage applications.

Adding thermal energy storage to nuclear power plants has been proposed as a way to allow nuclear plants to operate more flexibly and potentially be more competitive in deregulated electricity markets. The economics of these systems in deregulated markets are subject to uncertainties in capital costs, operating costs, and revenue. This study quantifies the uncertainty in the net present value of a nuclear power plant with integrated thermal energy storage in three U.S. deregulated electricity markets considering these sources of uncertainty and quantifies, for the first time, the relative contributions each source makes to the overall uncertainty. To accomplish this, a computationally efficient block bootstrap method is introduced to quantify uncertainty contributions from the stochastic time series of electricity prices, achieving a two order of magnitude decrease computational time compared to the model-based methods used in previous works while also relaxing several strict assumptions made by the model-based approach. Up to 18.5% of the overall variance in net present value is attributable to variance in the electricity price stochastic process, with this sensitivity varying significantly across markets.

The primary purpose of this research is to analyze and evaluate the effects of various discharge rates and cell configurations on the electrochemical and thermal behavior of a Li-ion battery pack that is exposed to ambient air throughout the discharge process. The three-dimensional numerical model is designed to accomplish this purpose and discusses two different cases. While the discharge rate is changed from 0.5 C to 2 C (stepping by 0.5 C) for each cell configuration considered in the first case, the numerical solutions are obtained for the various cell configurations (6S4P and 8S3P) by keeping the discharge rate constant at 1 C. The results obtained from these solutions show that the discharge rate affects a considerable amount of the battery performances and discharge times of the battery packs, activation, and ohmic losses occurring inside each battery cell. Moreover, 6S4P discharges over a longer period (about 25%) than 8S3P. While both activation and ohmic losses decrease with the increase of discharge rate, these losses remain almost constant at 0.5 C discharge rate in all analyzed conditions. As a result, having a battery pack with a long discharge time while maintaining low temperatures is useful and desired. With this in mind, while evaluating battery packs, the 6S4P battery pack looks to have the best arrangement.