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Structure, dielectric behaviours, enhanced polarization responses and energy storage properties in (1???x)SrTiO3–xBi(Mg1/2Ti1/2)O3 ceramics
摘要： In this work, ceramics of (1 ? x)SrTiO3–xBi(Mg1/2Ti1/2)O3 (ST–BMT, x = 0.05–0.5) were successfully prepared. A single-phase perovskite structure is formed for all the compositions. The average structure is cubic at room temperature. The Raman analysis suggests that the 5 mol% BMT addition might cause the existence of the local tetragonal distortions at room temperature. All the compositions display a frequency-dependent and highly diffused dielectric anomaly. The BMT addition can effectively shift the freezing temperature (Tf), from ~ 32 K for x = 0.1 up to ~ 240 K for x = 0.5. The compositions with x = 0.4 and 0.5 show a small change in the relative permittivity (Δε′/??′373 K < ± 15% at 1 kHz) and keep low values of the dielectric loss (tanδ < 0.01 for x = 0.01 at 1 kHz) in the temperature range of 373–523 K. The BMT addition induces an enhancement of the polarization maxima. Among the compositions, 0.7ST–0.3BMT shows the optimum energy storage performance (Wrec, 0.78 J/cm3).
关键词： ceramics,energy storage,dielectric behaviour,SrTiO3,Bi(Mg1/2Ti1/2)O3
更新于2025-09-10 09:29:36
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A review on modeling and simulation of solar energy storage systems based on phase change materials
摘要： Phase Change Materials (PCM) have been widely used in different applications. PCM is recognized as one of the most promising materials to store solar thermal energy in the form of latent heat. Utilization of PCMs for solar energy storage compensates for the intermittent characteristic of this energy source. Mathematical modeling and numerical simulation of solar energy storage systems provide useful information for researchers to design and perform experiments with a considerable saving in time and investment. This paper is focused on modeling and simulation of PCM based systems that are used in different solar energy storage applications. A thorough literature review is performed to investigate and compare the results and accuracy of different mathematical models, numerical methods and thermodynamic analysis of using different PCMs in different solar systems. Moreover, the potential research areas in numerical simulations and thermodynamic analysis of solar systems based on PCMs are determined considering the existing gaps in the literature.
关键词： Phase change materials,Solar energy storage systems,Numerical modeling,Simulation
更新于2025-09-10 09:29:36
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Crystallization kinetics and the dielectric properties of SrO-BaO-Nb2O5-B2O3 glass-ceramics
摘要： Glass-ceramics materials of SrO-BaO-Nb2O5-B2O3 system have been prepared by conventional melt-casting followed by controlled crystallization. The crystallization kinetics, phase evolution, microstructure, breakdown strength and dielectric properties have been explored by differential scanning calorimetry (DSC), X-ray diffractometer (XRD), scanning electron microscope (SEM), and multifunction LCR meter. The results reveal that crystallization mechanism of this glass is believed to be three-dimensional interfacial growth. It was observed that predominant crystalline phase is Ba0.39Sr0.61Nb2O6 in these glass-ceramics crystallized at 750 °C, and the grain size increases with increase in crystallization time. The uniform microstructure can be seen clearly in glass-ceramics crystallized at 750 °C for 3 h, and the obtained glass-ceramics was found to possess optimal properties. Moreover, glass-ceramic with a dielectric constant of 58, the dielectric loss of 0.007 and breakdown strength of 1010 kV/cm could be achieved. In addition, energy storage density of glass-ceramics reached a maximal value of 2.62 J/cm3. To our knowledge, studies on SrO-BaO-Nb2O5-B2O3 glass-ceramics without SiO2 as a glass network former are few, and the melting temperature of the B2O3-based glass is lower than that of SiO2-based glass, which is conducive to the purpose of energy saving. These findings indicate that this glass may be a candidate for high energy-storage capacitors.
关键词： Energy storage density,Glass-ceramics,Crystallization,Dielectric properties
更新于2025-09-10 09:29:36
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Enhanced energy storage properties of BaTiO3-Bi0.5Na0.5TiO3 lead-free ceramics modified by SrY0.5Nb0.5O3
摘要： In this work, a novel lead-free relaxor-ferroelectric ceramics of (1-x)(0.65BaTiO3-0.35Bi0.5Na0.5TiO3)-xSrY0.5Nb0.5O3 ((1-x)BTBNT-xSYN x ? 0.02e0.12), was designed and prepared by the conventional solid state reaction method. The results show that all of the sintered samples have a perovskite structure. The Curie Temperature (Tc) moves to the low temperature side which causes the high dielectric constant at room temperature, and the ferroelectric hysteresis loop becomes slimmer and slimmer with increasing the content of SYN. Meanwhile, the optimal energy storage properties can be obtained in 0.92BTBNT-0.08SYN ceramic with an impressive discharged energy density (Wrec) of 1.36 J/cm3 under 152 kV/cm, and the charge-discharge ef?ciency reaches 74.3%. Therefore, all these results indicate that (1-x)BTBNT-xSYN lead-free ceramics can be applied for pulsed power capacitors.
关键词： SrY0.5Nb0.5O3,Energy storage,Dielectric properties,Lead-free ceramics
更新于2025-09-10 09:29:36
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AIP Conference Proceedings [Author(s) SolarPACES 2017: International Conference on Concentrating Solar Power and Chemical Energy Systems - Santiago, Chile (26–29 September 2017)] - Numerical study of a two pass shell and tube latent heat energy storage system
摘要： The thermal behaviour of PCM in different configuration of heat exchangers is analysed for the purpose of design and optimisation of a latent heat thermal energy storage unit. Numerical modelling in conjunction with scale analyses provides a cost effective means to examine the performance of different configurations of latent heat storage systems. The main objective of this work is to scale down an experimental set up to a numerical model which can represent the thermal behaviour of the system with reasonable computational time. A U-tube element from a shell and tube thermal storage experimental set up was used as the model for a numerical study, using FLUENT. The predicted results of the temperature profiles in the PCM domain are in agreement with the measured data. Moreover, the heat transfer fluid outlet temperature and duration of the phase change processes are consistent with experimental results. Using the experimental initial temperature at each point in comparison to using an average initial temperature from all points can improve the predicted temperature profiles. Furthermore, three different mushy zone constants; namely 105, 107, 108 were used to examine the impact on the rate of melting. It was found that the constant 107 provides a closer solution to the experimental results. Results of this study show that the small scale model can represent the lab scale set up, providing more detail about the thermal behaviour of the PCM which is difficult to capture by measurement. The model can also be used for further examination of a high temperature PCM within the same set up for a CSP application.
关键词： FLUENT,shell and tube,numerical modelling,PCM,latent heat thermal energy storage
更新于2025-09-10 09:29:36
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Effects of grain size and temperature on the energy storage and dielectric tunability of non-reducible BaTiO3-based ceramics
摘要： BaTiO3-based ceramics with various grain sizes (136-529 nm) are prepared through a chemical coating method followed by sintering in a reducing atmosphere. Effects of grain size and temperature on electric properties, energy-storage properties, and dielectric tunability are studied via Current-Field (J-E) curves, ferroelectric hysteresis loops, Capacitance-Voltage (C-V) curves and Thermally stimulated depolarization currents (TSDC). At all temperatures, fine-grain ceramics yield a lower energy density but a higher energy efficiency under the same electric field, owing to a lower ferroelectric contribution. Meanwhile, fine-grain ceramics exhibit a higher maximum energy density due to their higher breakdown strength. Fine-grain ceramics with the grain size of 136 nm have the maximum energy density of 0.41 J/cm3 under the breakdown strength of 75 kV/cm, the corresponding efficiency is 81%. C-V curves show that fine-grain ceramics have better bias-field stability. According to TSDC results, fine-grain ceramics exhibit fewer oxygen vacancies and a higher relaxation activation energy.
关键词： non-reducible,grain size,dielectric tunability,energy storage,Barium titanate
更新于2025-09-10 09:29:36
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[Energy, Environment, and Sustainability] Advances in Solar Energy Research || Shell-and-Tube Latent Heat Thermal Energy Storage (ST-LHTES)
摘要： Thermal energy storage (TES) unit has become an integral part of thermal energy conservation. As the name implies, the device simply stores heat when energy from the source is available in excess, and releases the same when energy from the source falls short of the requirement. By doing so, such devices deliver heat energy across the temporal barrier, making thermal energy available for extended working hours of solar thermal power plants (STPP). High energy density and stable operation for long duration are desirable qualities which may be found in latent heat thermal energy storage (LHTES) system. To exploit the advantage of LHTES, the most common design reported in the literature is shell-and-tube type latent heat thermal energy storage (ST-LHTES) systems with phase change material ?lled in shell side, while (heat transfer ?uid) HTF ?ows in the tubes (or vice versa). The present chapter gives a detailed classi?cation of ST-LHTES systems based on geometry, orientation and relative position of PCM and HTF in heat exchanger along with the classi?cation of phase-change materials. Numerical modelling of heat transfer phenomenon is presented along with some simulated results for enhanced PCM, clearly describing the coupling between PCM and HTF domain. Various heat transfer enhancement techniques and parametric analysis have been discussed with challenges and future scope.
关键词： Latent heat,Thermal energy storage,Coupling,Shell and Tube Heat Exchanger,Heat transfer ?uid,Phase change material
更新于2025-09-10 09:29:36
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The doping effects of ZnNb <sub/>2</sub> O <sub/>6</sub> on the phase, microstructure and energy storage properties of (Sr <sub/>0.98</sub> Ca <sub/>0.02</sub> )TiO <sub/>3</sub> paraelectric ceramics
摘要： Zn(NbO3)2 doped Sr0.98Ca0.02TiO3 (SCT-xZN) paraelectric ceramics have been obtained by the traditional electroceramic processing. Phase structures and doping effects were investigated by using XRD and Raman. Surface morphology was observed by SEM to evaluate grain growth. The P-E curves were measured and employed to calculate the energy storage density and efficiency. The doping effects on dielectric properties such as permittivity, dielectric loss and breakdown strength were also measured and discussed.
关键词： phases and microstructures,ZnNb2O6 doped,Paraelectric ceramics,energy storage
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE Innovative Smart Grid Technologies - Asia (ISGT Asia) - Singapore (2018.5.22-2018.5.25)] 2018 IEEE Innovative Smart Grid Technologies - Asia (ISGT Asia) - Optimal Real-Time Scheduling of Energy Storage Systems to Accommodate PV Generation in Distribution Networks
摘要： The increasing penetration of renewables in the distribution networks (DN) can cause severe operation constraint violations, such as voltage violation and branch line overload. To deal with like photovoltaic (PV), a novel real-time scheduling (RTS) approach for energy storage systems (ESSs) in distribution networks is proposed in this paper. The distribution network operators (DNO) dispatch the PV, ESS and the substation together to minimized the weighted cost and ensure the security of system operation. The AC OPF in DN is formulated as a second-order cone programming (SOCP) problem where we can obain the global optimal solution using some off-the-shelf solvers. Case studies on 37-bus system demonstrate the effectiveness of the proposed approach as well as the exactness of the relaxation.
关键词： Active distribution network,photovoltaic,second-order cone programming,energy storage system
更新于2025-09-10 09:29:36
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[IEEE 2018 International conference on computation of power, energy, Information and Communication (ICCPEIC) - Chennai, India (2018.3.28-2018.3.29)] 2018 Internat2018 International Conference on Computation of Power, Energy, Information and Communication (ICCPEIC)ional conference on computation of power, energy, Information and Communication (ICCPEIC) - Modelling and Control of BESS for Solar Integration for PV Ramp Rate Control
摘要： PV power varies with the passing of clouds; these variations can affect power quality and system uniformity. PV system is combining with a storage device to mitigate the variations in power. During the fast movement of clouds causes sudden changes in power. Sudden changes can limit through ramp rate control. In this work employing a ramp rate control with energy storage system is capable of maintaining the system stability. This work is aimed to design a battery-based storage system integration with considered 500 kW solar photovoltaic power plant using ramp rate control method. The control scheme is tested and validated using MATLAB/Simulink environment.
关键词： solar PV,Power fluctuations smoothing,energy storage,battery,grid-connected PV plants,ramp rate control
更新于2025-09-10 09:29:36