Energy Storage Characteristics Research Articles

Single-step, in-situ fabrication of flower-like NiCuMn hybrid oxyhydroxide electrodes for enhanced supercapacitor performance

The rational design of highly active and low-cost electrode material is very promising for energy storage applications. The development of supercapacitors with high energy/power density is an imperative and challenging research objective. Herein, we report a highly facile synthesis approach for developing unique nano-porous hybrid NiCuMn oxyhydroxide architecture with remarkable electrochemical energy storage characteristics. The process involves dealloying of Ni15Cu15Mn70 alloy in an oxygen rich environment, resulting in a uniform 3-dimensional flower like morphology. The dealloyed electrode demonstrates ultra-high specific capacitance of 4110 F cm−3 at a high current density of 20 mA cm−2. A symmetric device exhibits a high volumetric capacitance of 365 F cm−3 at a current density of 10 mA cm−2 with a large potential window of 1.7 V. Even at very high-power density of 850 W l−1, the device exhibits a high energy density of 146 Wh l−1 along with remarkable cyclic stability of 95.4% after 10 000 cycles. The superior performance of nano-porous hybrid NiCuMn oxyhydroxide architecture was attributed to its unique microstructure that provides high surface area, and marginal internal resistance ensuring rapid charge transport.

Comparative Study of Chemical Activation and Physical Activation Approach to Optimize Biomass-Based Doped Carbons for Energy Applications

Two approaches have been utilized to optimize the energy storage characteristics of doped carbon materials derived from Lignosol, a biomass product, to address the rising energy demand issues. Herein, phosphorus and nitrogen co-doped carbon (PNDC) materials with varying doping agent volumes were synthesized by utilizing microwave irradiation. Chemical activation and physical activation were employed to enhance these materials’ characteristics. Chemical activation was performed in a one-pot, single-step process, rather than a traditional multi-step protocol, using small amounts of potassium hydroxide. Furthermore, the physical activation method required multiple steps: doped carbon was prepared via microwave, exposed to water, filtered, frozen and then dried. With this, the expansion properties of water at freezing temperatures were exploited to alter the materials’ surface characteristics. All materials were characterized and compared for their physicochemical properties. All defect ratios supported the presence of doping. Additional results revealed that both chemical and physical activation approaches effectively modify the topographical features as well as the electrochemical activity (charge storage) of the doped carbon materials. The chemically activated doped carbon exhibited the highest resulting surface area of 1352 m2 g−1 and a specific capacitance value of 347 F g−1 with excellent cycling stability as compared to other similarly synthesized materials.

Maximizing self-sufficiency and minimizing grid interaction: Combining electric and molecular energy storage for decentralized balancing of variable renewable energy in local energy systems

The increase of renewable electricity from variable sources, such as solar PV and wind turbines, leads to increasing need for energy storage to maintain balance between demand and supply, and decrease peak load on electricity grids. Energy storage options to achieve this include electric energy storage such as batteries, and molecular energy storage such as hydrogen. In this research, we use a model to simulate the behavior of a local residential grid in the Netherlands supplied exclusively by decentralized solar PV and wind energy. Our model includes combinations of batteries and hydrogen as energy storage options to investigate synergies between them. The simulation results indicate that combining the characteristics of battery and hydrogen energy storage in a single grid leads to a more resilient and flexible system compared to one in which only one of the two technologies is deployed. In our simulations of combined storage options, local demand can be met with less installed capacity, and less energy exchange with external grid takes place. However, we also conclude that diversity of storage options alone is insufficient to reduce the highest peak load on external grids, and additional measures are required to ensure net residual load remains within specific bandwidths.

Confined Space Dual-Type Quantum Dots for High-Rate Electrochemical Energy Storage.

Owing to the quantum size effect and high redox activity, quantum dots (QDs) play very essential roles toward electrochemical energy storage. However, it is very difficult to obtain different types and uniformly dispersed high-active QDs in a stable conductive microenvironment, because QDs prepared by traditional methods are mostly dissolved in solution or loaded on the surface of other semiconductors. Herein, dual-type semiconductor QDs (Co9S8 and CdS) are skillfully constructed within the interlayer of ultrathin-layered double hydroxides. Inparticular, the expandable interlayer provides a very suitable confined space for the growth and uniform dispersion of QDs, where Co9S8 originates from in situ transformation of cobalt atoms in laminate and CdS is generated from interlayer pre-embedding Cd2+. Meanwhile, XAFS and GGA+U calculations are employed to explore and prove the mechanism of QDs formation and energy storage characteristics as compared to surface loading QDs. Significantly, the hybrid supercapacitors achieve a high energy density of 329.2µWhcm-2, capacitance retention of 99.1%, and coulomb efficiency of 96.9% after 22000 cycles, which is superior to the reported QDs-based supercapacitors. These findings provide unique insights for designing and developing stable, ordered, and highly active QDs.

Peak-shaving cost of power system in the key scenarios of renewable energy development in China: Ningxia case study

Renewable energy has developed rapidly in Ningxia, and it has become the first provincial power system in China whose renewable energy power generation output exceeds the power load of the whole region. The access of a high proportion of renewable energy puts forward higher requirements for the peak-shaving capacity of the Ningxia power system. In order to solve the problem of calculating the peak-shaving cost in the key scenarios of renewable energy development in Ningxia, a quantitative model of the peak-shaving cost of the power system considering time-of-use price is proposed. We take Ningxia power system as an example to study. First, the key scenarios of the Ningxia power system peak-shaving are obtained, and the technical cost characteristic boundaries of various peak-shaving resources are determined. Second, according to the characteristics of typical daily renewable energy and load in Ningxia, the quantification model of the power system peak-shaving cost is established. The model takes the minimum total cost of the power system as the objective function and considers the constraints such as technical output of thermal power units, charge-discharge characteristics of energy storage and time-of-use price mechanism. Finally, the model is solved and the peak-shaving cost and unit output under the optimal scheme are obtained. This example shows that the model can effectively evaluate the peak-shaving cost and unit output of the Ningxia power system under the key scenarios of peak-shaving.

Research on the participation model of energy storage in electricity spot markets considering energy constraints and cost characteristics

In the context of power systems with a high proportion of renewable energy, energy storage plays a significant role in facilitating the consumption of renewable energy and ensuring the operational safety of power systems. However, the current power spot market's predominant power bidding model does not fully consider the physical and cost-operational characteristics of energy storage, which is not conducive to further incentivizing investment and construction of energy storage, and may indirectly affect the flexibility of energy storage in peak shaving and valley filling. This paper summarizes the key issues that need to be addressed for energy storage to participate in the spot market from two aspects: the power bidding model does not meet the requirements of the physical and cost-operational characteristics of energy storage, and the real-time market under this model cannot achieve optimal allocation of energy storage. Considering the energy constraints and cost characteristics of energy storage, a charge and discharge bidding model is proposed, which is based on the stored energy value of energy storage and is in line with the physical and cost-operational characteristics and real-time optimization needs of energy storage. Subsequently, a market clearing model for energy storage participation in the spot market under the state of energy bidding method is constructed, and based on the IEEE 39-bus test case, a comparative analysis of the nodal electricity prices, energy storage revenue, and total system costs under the proposed market participation model and the traditional power bidding model is conducted. Simulation results show that the proposed energy storage participation model in the spot market can better utilize the value of energy storage in peak shaving and valley filling compared to the conventional power bidding model, reducing the extreme electricity prices by up to 10%, increasing single cycle revenue of energy storage by 46%, and reducing the total operating costs of the system in scenarios with significant deviations in system load in the day-ahead and real-time markets.

Highly Exothermic and Fast Mechanochemical Redox and Intercalation Reactions of V2O5 with Sodium Hydride.

Vanadium oxides exhibit promising characteristics for electrochemical energy storage, owing to their capability to switch between different oxidation states, in combination with the incorporation of alkali metals. Here, we report on a systematic investigation of the mechanochemical reduction of V2O5 with NaH. In contrast to conventional high-temperature synthesis methods, the mechanochemical reaction occurs already after a few minutes. We observed a mixture of different (sodium) vanadium oxides with vanadium oxidation states ranging from +III to +V. Remarkably, these highly exothermic self-propagating reactions occur even within a rudimentary pistil-mortar setup. Hereby, the hydride concentration has a greater effect on the final sample composition than the milling time. In general, higher percentages of sodium vanadates are formed instead of vanadium oxides, and the lower oxidation states of vanadium are accessible with increasing amounts of NaH. Theoretical calculations confirm these experimental observations and emphasize the central role of sodium vanadates, especially with vanadium in the +V oxidation state, in carrying out the observed exothermic reactions. This comprehensive study sheds light on the mechanochemical reduction of vanadium oxides and underlines their potential for further development of electrochemical energy storage systems.

Influence of sintering temperature on electrocaloric and energy storage properties of sol-gel derived lead-free BaHf0.20Ti0.80O3 ferroelectric ceramics for sustainable energy solutions

Ferroelectric materials have emerged as intriguing contenders for a variety of applications in the ongoing effort to look for sustainable energy solutions, including energy storage and solid-state cooling systems. In this work, a systematic investigation has been conducted on the microstructural, dielectric, electrocaloric, and energy storage characteristics of sol-gel elaborated BaHf0.20Ti0.80O3 (BHT) ferroelectric ceramics. The structural investigation by Raman and X-ray diffraction indicated that when the sintering temperature increases, the tetragonality of BHT ceramics reduces, and the evolution of the cubic phase increases. The evolution of the microstructure in BHT ceramics is found to be significantly reliant on the sintering temperature. With increasing temperature of sintering, the bulk density of BHT ceramics increases. The improved dielectric and ferroelectric properties were attained in BHT ceramics at higher sintering temperatures. The BHT ceramic sintered at 1350 °C exhibited a maximum electrocaloric temperature change of ΔT ∼0.6 °C with a corresponding efficiency ΔT/ΔE of 0.3 K mm/kV near ambient temperature under a low electric field of 20 kV/cm. The BHT ceramic sintered at 1450 °C exhibited excellent room temperature recoverable energy density of JRec ∼67.84 10−3J/cm3 and high energy storage efficiency of η ∼75.13 % under a low electric field of 20 kV/cm. The highest JRec ∼73.22 10−3J/cm3 with corresponding η of 64.60 % were obtained in BHT ceramic sintered at temperature 1350 °C. These findings broaden the possibility of exploring BHT-based systems as efficient lead-free ferroelectrics for both solid-state refrigeration and energy storage applications.

High-temperature energy storage with a new tri-layers polymer composites via hybrid assembly engineering

Dielectric film capacitors are fundamental components in advanced electrical fields such as smart grids and hybrid electric vehicle. The commercial film capacitors made by biaxially oriented polypropylene (BOPP) have high energy efficiency, but low energy density of only 2.0-3.0 J/cm3, while the inferior thermal stability restricts their high temperature applications. In this work, hybrid assembly engineering is proposed to design composite films with a new polymer of poly(acrylonitrile butadiene styrene) (ABS) as the matrix, boron nitride nanosheets (BNNS) and Na0.5Bi0.5TiO3-Sr0.7Bi0.2TiO3 (NBT-SBT) as two different fillers to improve high-temperature performance. The optimized composites SBS (NBT-SBT/ABS composites layer in the outside and BNNS/ABS composites layer in the middle) exhibit excellent high temperature energy storage characteristics, and its underlying mechanism is also understood by phase-field simulations. In particular, the maximum energy density at 120 °C can reach 15.0 J/cm3 at 575 MV/m, which is 8 times that of BOPP, while the efficiency is maintained at 89 %, far exceeding the performance of BOPP (<70 % at 120 °C). Together with their excellent cycling reliability (106 cycles) and thermal stability, this strategy shows a great potential for high-temperature and high-power energy storage capacitors.

Energy storage properties influenced by relaxor ferroelectric properties dependent on the growth direction of epitaxial Bi2SiO5 thin films

Ferroelectric Bi2SiO5 (BSO) thin films were deposited by pulsed laser deposition on Nb-doped (100), (110) and (111) SrTiO3 (Nb:STO) substrates, resulting in (001)-, (113)- and (204)-oriented epitaxial films. Due to the crystallinity of BSO, in which the Bi2O2 layers are formed perpendicular to the c-axis direction, the (001)-oriented epitaxial BSO thin film showed the lowest remanent polarization and the best leakage current characteristics. On the other hand, the (113)- and (204)-oriented films showed an increase in remanent polarization due to the improvement of a-oriented crystallinity. Through experiments using vertical and lateral piezoresponse force microscopy, it has been confirmed that the distribution of in-plane-oriented domains reducing remanent polarization decreases in the order of (001)-, (113)- and (204)-oriented epitaxial BSO thin films. The epitaxial BSO thin films that exhibit ferroelectric hysteresis loops similar to the relaxor ferroelectric thin films tended to have improved energy storage characteristics as a result of improved remanent polarization and saturation polarization. In particular, the (113)-oriented epitaxial BSO thin film showed a high recoverable energy density of about 41.6 J cm−3 and an energy storage efficiency of about 85.6%.

Energy storage, thermal-hydraulic, and thermodynamic characteristics of a latent thermal energy storage system with 180-degree bifurcated fractal fins

The low thermal conductivity of organic phase change materials limits the performance of latent thermal energy storage (TES) systems. Inspired by fractal theory, this study proposes an innovative 180° fractal fin for enhancing the thermal performance of latent TES systems. The effects of length ratios (l) and fractal levels (N) are numerically investigated employing the enthalpy-porosity method. Compared with traditional rectangular fins, the results indicate that the 180° fractal fins reduce the integral average value of the maximum velocity by 2.24%–48.51%, which indicates the suppression of natural convection by the latter. Increasing l and N result in a general increase in melting time. Compared to the TES systems without fins and with rectangular fins, the 180° fractal fins can respectively reduce melting time by up to 88.79% and 28.00%, increase integral average Nusselt number by up to 7.30 times and 34.21%, and enhance energy storage power by a maximum of 8.55 times and 38.71%. Moreover, flow viscous entropy generation can be neglected compared to thermal entropy generation. In contrast to rectangular fins, the employment of fractal fins leads to a maximum reduction of 90.06% and 99.10% in total frictional entropy generation and thermal entropy generation, respectively.

Evaluation of IoT-Enabled Energy Management Systems: Uncovering Sustainable Energy Storage Parameters and Their Significance

This research begins an in-depth examination of IoT-enabled energy management systems at a time when IoT (Internet of Things) technology has a profoundly revolutionary impact. Finding the fundamental sustainable energy storage characteristics that support their operational effectiveness and environmental sustainability is its main goal. By taking a comprehensive approach, the paper carefully analyzes the existing IoT-based systems, exploring their complex architectural features, real-world uses, and related difficulties. Parallel to that, a thorough literature study is conducted, highlighting the crucial aspects of sustainable energy storage and their inherent significance in energy management systems. The results of this in-depth analysis unequivocally demonstrate how crucial these factors are for improving the effectiveness, performance, and ecological soundness of energy management systems. While highlighting the current environment and key variables, it is important to recognize the research's constraints, which are confined to an analysis of existing IoT-based energy management systems and a literature study. The design and implementation of IoT-driven energy management systems infused with the indicated sustainable energy storage characteristics are anticipated to be included in further research projects. The investigation of practical application, scalability, and a dedication to keeping up with the rapidly changing technology and practices that characterize this dynamic sector would be some of these objectives.

Investigation on the operating characteristics of a three-phase crystalline energy storage and heating system based on lithium bromide

In the current global energy landscape, energy storage has the potential to become a key technical support for global carbon neutrality. Drawing insights from a comprehensive overview of existing energy storage systems, this paper proposes a three-phase crystalline energy storage and heating system characterized by intermittent operation. The unique thermodynamic property of lithium bromide gifts the system with remarkable energy storage density and heating capacity. To further investigate its operating characteristics, this study employs the Newton iteration method, with energy storage density as a pivotal technical indicator for evaluation. The results reveal that the existence of crystals mainly benefits nighttime heating supply. By adjusting input factors, it becomes evident that increasing the temperature of high-temperature heat source can enhance the heating supply by 16.92 %, which also leads to an increase in energy storage density to 2986.85 MJ/m3. Furthermore, the raising temperature of low-temperature heat source results in a substantial 61.78 % escalation in heating supply. Additionally, the dynamic investment payback period of the system is estimated to be 2.4 years, signifying its economic viability. The findings of this paper can provide valuable theoretical support for the application of crystalline energy storage systems.

Enhanced magnetoelectric and energy storage performance of strain-modified PVDF-Ba0.7Ca0.3TiO3-Co0.6Zn0.4Fe2O4 nanocomposites

The experimental development of thin films that exhibit higher room-temperature low-field magnetoelectric (ME) sensing without compromising reliable electrical energy storage capabilities is rare. Here, an improved ferroelectric polarization, ME coupling and energy storage performance of polymer-based nanocomposites, which find applications in portable high-power dielectric capacitors, are studied. Multiferroic nanofiller-based three-phase flexible nanocomposites, polyvinylidene fluoride (PVDF)-(Ba0.7Ca0.3)TiO3-(Co0.6Zn0.4)Fe2O4, were fabricated using compression molding to enhance polarization which is pivotal for applications. PVDF with a high β-phase content (92.4 %), switchable ferroelectric behavior and higher breakdown strength (510 kV/mm) was obtained under optimized process conditions (500 MPa at 165 °C). The fabrication assisted alteration of intermolecular chain distance results in a tensile strain (1.42 %) of β-crystallites corresponding to an internal stress of ~21 MPa. The progressive increase of nanofiller content has led to enhanced polarization (11 μC/cm2), soft ferromagnetic properties, and enhanced ME coupling of 59 mV/cm-Oe due to switchable magnetostriction (λ11 = −18 ppm and dλ11/d = −22 × 10−9 Oe−1) at lower saturation field of 1.2 kOe. The ME sensitivity was found to be more than two-folds enhanced compared to solution-cast films making them prospective self-biased flexible devices for wearable electronics. Simultaneously, enhanced change of magnetization (19.6 %) under electric field was obtained. Detailed energy storage characteristics confirm that the nanofiller inclusion up to 7.12 vol% effectively improved the recoverable energy storage density (21.2 J/cm3) with an efficiency of 67 %. The experimental and simulation results corroborate a significantly improved breakdown strength of 617 kV/mm with reliable performance. Thus, careful processing provides viable polymer dielectrics with beneficial storage characteristics.

Flexible Supercapacitor with Wide Electrochemical Stable Window Based on Hydrogel Electrolyte.

Hydrogel electrolyte can endow supercapacitors with excellent flexibility, which has developed rapidly in recent years. However, the water-rich structures of hydrogel electrolyte are easy to freeze at subfreezing and dry at high temperatures, which will affect its energy storage characteristics. The low energy density of micro supercapacitors also hinders their development. Herein, a strategy is proposed to reduce the free water activity in the hydrogel to improve the operating voltage and the energy density of the device, which is achieved through the synergistic effect of the hydrogel skeleton, N, N'-dimethylformamide (DMF), NaClO4 and water. High concentrations of DMF and NaClO4 are introduced into sodium alginate/polyacrylamide (SA/PAAM) hydrogel through solvent exchange to obtain SA/PAAM/DMF/NaClO4 hydrogel electrolyte, which exhibited a high ionic conductivity of 82.1 mS cm-1, a high breaking strength of 563.2kPa, and a wide voltage stability window of 3.5V. The supercapacitor devices are assembled by the process of direct adhesion of the hydrogel electrolyte and laser induced graphene (LIG). The micro-supercapacitor exhibited an operating voltage of 2.0V, with a specific capacitance of 2.41 mF cm-2 and a high energy density of 1.34 µWh cm-2, and it also exhibit a high cycle stability, good flexibility, and integration performance.

Structural phase coexistence enhances the energy storage density of (Bi0.5Na0.5)0.8Ba0.2Ti1-ySnyO3 lead-free ceramics

In the present study, BaSnO3 was introduced into polycrystalline NBT-BT ferroelectric ceramics and conducted a comprehensive investigation into the structural, dielectric, ferroelectric, and energy storage characteristics of the (Bi0.5Na0.5)0.8Ba0.2Ti1-ySnyO3 (BNBTS) ceramics. The coexistence of structural phases P4mm and Amm2 was observed through Rietveld refinement and also confirmed by Raman analysis. The formation energy decreases with an increase in substitution concentration favouring the formation of the orthorhombic phase. The SEM analysis revealed a denser microstructure characterised by smaller grain sizes, which favourably enhances energy storage density. Furthermore, Raman spectroscopic analysis unveiled a softening of Ti–O bonds, indicating the emergence of macroscopic relaxor behaviour. Dielectric studies provided evidence of a transition from ferroelectric to relaxor behaviour, an observation further confirmed by P-E loop measurements. This transition can be linked to the partial substitution of Sn4+ ions for Ti4+ ions, disrupting the ferroelectric long-range order within the matrix phase. Notably, the polarization-electric field (P-E) loop of BNBTS2 ceramics exhibited a substantial value of polarization (Ps) 30 μC/cm2 with a reduced value of remnant polarization (Pr) 2.29 μC/cm2. These characteristics contributed to the achievement of higher energy recovery (Wrec) and lower energy loss (Wloss) values, measuring 1.184 J/cm3 and 0.142 J/cm3, respectively, with a notable efficiency of 88.8%. Consequently, the system of ternary ceramics demonstrates promise as a potential option for energy storage ceramics among NBT-BT-based materials.

Influence of sintering temperature on the electrical properties of SrTiO3–BaZrTiO3 ceramics for energy storage applications

The impact of the sintering temperature on the phase composition and electrical properties of 5%SrTiO3–95%BaZr0.15Ti0.85O3 (ST-BZT) ceramics fabricated by solid-state method and consolidated by two-step sintering is presented. A systematic analysis of the phase composition, microstructures, dielectric, ferroelectric, and energy storage characteristics. A di-phase SrTiO3–BaZrTiO3 composite is obtained at low sintering temperatures below 1400 °C. Increasing the sintering temperature causes a shift of the Curie temperature from 62 °C to 55 °C together with changes of permittivity values and of the ferroelectric loops, thus indicating a progressive interdiffusion process at the interfaces, together with a better densification. Remarkably, the ST-BZT composition sintered at 1500 °C exhibits characteristics of a single phase (Ba,Sr) (Zr,Ti)O3 solid solution, with high room temperature permittivity around 2950 and good ferroelectric response (saturation polarization Pmax = 12.6 μC/cm2 and remnant polarization Pr = 2.16 μC/cm2). Consequently, this composition displays a much greater recoverable energy density (Wrec = 54.5 mJ/cm3) in comparison to the ones of the di-phase ST-BZT composites and the parent phases. However, the (Sr0.05Ba0.95) (Zr0.14Ti0.86)O3 solid solution, demonstrates a lower energy efficiency (72%) in comparison to the ST-BZT di-phase composites sintered at lower temperatures, which exhibit higher energy efficiency values around 86%. In addition, the charge-discharge experiments were performed under different electric fields to disclose the difference in energy storage properties in 5%SrTiO3–95%BaZr0.15Ti0.85O3 ceramics. This suggests that the sintering strategy plays a crucial role in determining the energy efficiency of the obtained ceramics. Additionally, all the investigated ST-BZT ceramics present high energy efficiency at low-applied electric fields, suggesting their potential as candidates for energy storage capacitors operating at moderate fields.

Boosting specific capacitance: Harnessing redox-additive electrolytes for enhanced performance in activated porous carbon derived from palmyra palm leaves

Carbon materials derived from palmyra palm leaves and chemically activated with ZnCl2 exhibit remarkable energy storage characteristics. Carbon derived from leaves has a specific surface area of 1300 m2/g and provides extensive electrochemical interfaces. The leaf-derived carbon initially displays a specific capacitance of 75.60F/g at 5 mV/s in 0.1 M Na2SO4 electrolyte. Specific capacitance is significantly improved by introducing a redox additive into the parent electrolyte. In a potential window of 1 V, the combination of 0.1 M Na2SO4 and 0.03 M KI yields a specific capacitance of 173.04F/g at 5 mV/s. The findings highlight the exceptional performance and higher stability of leaf-derived activated carbon.

Evaluating the reliability of microgrids consisting of renewable energy sources using stochastic scheduling based on the data-driven uncertainty set

The paper addresses challenges arising from the unpredictable and probabilistic nature of wind speed and solar irradiance, leading to variable power production in renewable sources. Power imbalance issues in grids result from the difficulty in accurately estimating these variables. The study introduces an improved data-driven uncertainty set, utilizing a neural network trained with extensive historical data from a multi-microgrid system. This set efficiently identifies strong coupling and extracts characteristic scenarios, ensuring high reliability with a minimal number of scenes. The proposed probabilistic model, implemented in the coordination of pumped storage, wind, and solar power plants, incorporates energy limits and storage characteristics. A four-mode IEEE model for storage units allows quick response to system needs. Simulating storage unit states every hour, considering system load, output power, and energy limitations, optimizes power dispatch based on battery capacity. Additionally, the paper addresses the uncertainty in electric power demand in microgrids, proposing an improved data-driven uncertainty set obtained from a neural network. By eliminating unrealistic worst-case scenarios, the approach accurately captures system characteristics, maintaining high reliability while significantly reducing convergence time. The proposed uncertainty set is applied in a novel two-stage robust optimization dispatch model, transforming the optimization problem into a mixed-integer linear programming problem, and solving it using a column and constraint generation algorithm. Numerical case studies verify the feasibility and superiority of the proposed approach in terms of economy and convergence performance compared to existing robust optimization methods.

Temperature-Energy Relationships and Spatial Distribution Analysis for Nano-Enhanced Phase Change Materials Via Thermal Energy Storage

Despite the abundance and affordability of solar energy, its adoption in industrial and domestic sectors, especially in developing countries, still needs to be improved. This study addresses the gap by proposing integrated storage systems to align energy supply and demand, essential for various industrial processes. Investigating Nano-enhanced Phase Change Material (PCM), the research formulates governing equations for the phase change process, explores numerical simulations using MATLAB's Finite Volume Method, and validates models. The PCM comprises a solid salt mixture with Sodium Chloride Nanoparticles. The analysis of nano-enhanced PCMs for thermal energy storage focuses on understanding the interrelationship between temperature, energy, and nanoparticle distribution within the PCM. Visuals based on 3D surface plots and scatter plots illustrate how energy storage characteristics vary with temperature and spatial variables, identifying phase change temperatures and energy absorption/release points. These visualizations guide PCM optimization for improved thermal conductivity and heat capacity, which is crucial for diverse applications like solar energy systems and thermal management in electronics. Nano-enhanced PCM performance can be further enhanced by employing advanced numerical methods and simulation tools for accurate prediction and optimization before experimental validation.