Energy Generation Devices Research Articles

Testing and Evaluation Development of China’s Marine Energy Generation Devices

Testing and Evaluation Development of China’s Marine Energy Generation Devices

Electrodeposited Nanostructured CoFe2O4 for Overall Water Splitting and Supercapacitor Applications

To contribute to solving global energy problems, a multifunctional CoFe2O4 spinel was synthesized and used as a catalyst for overall water splitting and as an electrode material for supercapacitors. The ultra-fast one-step electrodeposition of CoFe2O4 over conducting substrates provides an economic pathway to high-performance energy devices. Electrodeposited CoFe2O4 on Ni-foam showed a low overpotential of 270 mV and a Tafel slope of 31 mV/dec. The results indicated a higher conductivity for electrodeposited compared with dip-coated CoFe2O4 with enhanced device performance. Moreover, bending and chronoamperometry studies suggest excellent durability of the catalytic electrode for long-term use. The energy storage behavior of CoFe2O4 showed high specific capacitance of 768 F/g at a current density of 0.5 A/g and maintained about 80% retention after 10,000 cycles. These results demonstrate the competitiveness and multifunctional applicability of the CoFe2O4 spinel to be used for energy generation and storage devices.

The Energy System and the Sharing Economy: Interfaces and Overlaps and What to Learn from Them

The dissemination of decentralized renewable energy generation, storage and smart metering devices has led to the need for new business models and coordination mechanisms in the energy sector. At the same time, the emerging sharing economy focuses on using digital platforms to coordinate value creation on a decentralized level. While sharing concepts have already been applied to specific energy technologies and microgrids, a more general understanding of what the sharing economy means in the context of the energy sector is still missing. This paper aims to bring these two topics together and to analyze their interfaces and overlaps. For this purpose, this paper draws from existent scientific publications, reports, blog posts, and websites as well as company workshops to discuss which activities and characteristics of the sharing economy might be applicable to the energy sector. Results show that there are significant overlaps in characteristics of the sharing economy and of the transitioning energy system. Furthermore, a broad range of business models within the energy system were found to be based on sharing resources. The findings of this study open up a range of new research and business opportunities at the interface of the sharing economy and the transitioning energy system.

Effect of solvent for tailoring the nanomorphology of multinary CuCo2S4 for overall water splitting and energy storage

Tailoring the nanomorphology of electrochemically active materials could significantly affect their resultant catalytic and charge storage performance. In this study, the nanostructured morphology of multinary CuCo2O4 and CuCo2S4 was tuned using a different volume concentration of water and ethanol resulting in different nano-shapes maintaining similar crystal structure. The electrocatalytic performance was analyzed for all the synthesized samples as the hydrogen (HER) and oxygen evolution catalyst (OER). The HER and OER study for CuCo2S4 sample synthesized using ethanol required a low overpotential of 158 mV to reach 10 mA/cm2 and 290 mV to achieve 20 mA/cm2, respectively. Furthermore, the electrolyzer cell using symmetrical electrodes required a low overall cell potential of 1.66 V to achieve a current density of 10 mA/cm2 and maintained stable performance for over 24 h, suggesting a promising bifunctional catalytic behavior. Furthermore, the synthesized samples were studied as electrodes for high-performance energy storage systems. The CuCo2S4 electrode showed an areal capacitance of 6.3 F/cm2 (3190.8 F/g) at a current density of 2 mA/cm2. The Ragone plot for the areal energy versus power density resulted to be 265 mWh/cm2 (132 Wh/kg) and 11.9 W/cm2 (5973 W/kg), respectively. Thus, from the overall study, it can be confirmed that tailoring morphology of nanostructured material such as CuCo2S4 could be a promising way for the advancement of energy generation and storage devices.

A design tool for the performances comparison of innovative energy systems for naval applications

This paper aims to develop a tool for the performances comparison of innovative energy systems on board ships, both for concentrated and distributed generation applications. In the first part of the study, the tool database has been developed throughout a wide analysis of the available market solutions in terms of energy generation devices (i.e. fuel cells, internal combustion engines, micro gas turbines), fuels (hydrogen, natural gas, diesel) and related storage technologies. Many of these data have been collected also thanks to the laboratory experience of the authors’ research group on different innovative energy systems. From the database, a wide range of maps has been created, correlating costs, volumes, weights and emissions with the installed power and the operational hours required, given by the user as input. The tool highlights the best solution according to the different relevance chosen by the user for each key parameter (i.e. costs, volumes, emissions). In the second part, two different case studies are presented in order to underline how the installed power, the different ship typology and the user requirements affect the choice of the best solution. It is worth noting that the methodology has a general value, as the tool can be applied to both the design of new ships, and to the retrofit of already existing ships in order to respect new requirements (e.g. more and more stringent normative in terms of pollutant emissions in ports and restricted areas). Furthermore, the database can be easily extended to other generation and storage technologies.

Design of Blade for Horizontal-Shaft Ocean Current Generation Device

Ocean current energy has become an important development direction of renewable energy and has broad application prospects. At present, most of the research on the energy of the current is on the improvement of the generator structure and the design of the blade, but the design of the blade is mostly the design of the wind turbine, which fails to meet the optimal condition of ocean currents. This paper aims at the development and utilization of ocean current energy, compares the application environment of wind turbines and ocean currents, and designs a blade suitable for ocean current energy generation devices. Through CFD simulation and PROFILI selection of blade airfoiled, the curve of the Lift-to-drag ratio with the angle of attack is obtained, and other parameters of the blade are obtained by solving the Wilson method through MATLAB. Finally, the 3D modeming is carried out by SolidWorks.

Photon‐Induced Spintronic Polaron Channel Modulator of CeO2‐x NP Thin Films Hydrogen Evolution Cells

AbstractWater splitting cells are the green energy generation and storage devices for saving the energy risk. Hydrogen and oxygen gases are the most important source in fuel cells. Here, a photogalvanic spin battery is observed by generating spin‐polarized charge currents without spin orbital coupling under the irradiation of the coherent circularly h−/−h− circular polarization light as the photogalvanic spin battery in water splitting cells. The polaron generated by the O vacancy and Ce ions at the CeO2 nanoparticle surface corresponding to coherent h−/–h− angular momentum circular polarization light injection is utilized in spintronic electrons generation and a modulator. Polaron channel raises the charge mobility to 2.19 × 1015 m2 (V s)−1. The energy conversion efficiency of the polaron modulated spintronic electrons hydrogen evolution water splitting cell with optical spin injection is as high as 161% and the spin polarization is up to 75%. The polaron modulated spintronic electrons are successfully applied in water splitting and hydrogen evolution devices, serving as a photogalvanic spin small‐polaron cell. The energy conversion efficiency and spintronics controlling systems of the water splitting are well controlled and can provide actual benefits in near future.

Research of electrical distribution connections for the electrical energy generation device

Research of electrical distribution connections for the electrical energy generation device

Integrated Thermoelectric Energy Generator and Organic Storage Device

Abstract We evaluate the storage performance of an integrated energy harvesting and storage system using a thermoelectric generator (TEG) and an organic energy storage device. The power generated by the TEG is obtained by varying the temperature of the heat source on the bottom surface of the TEG while keeping the opposite surface at a constant cooling temperature. The difference in temperature gradient (Δ T) increases the power generated by the TEG. Capacitance-voltage measurements were performed on the organic storage device to evaluate the storage capabilities of the embedded storage elements, CdS nanoparticles. The objective is to assess the possibility of the integrated system and evaluate the effectiveness of the storage device. Voltage, current and power density values are determined and compared for different load resistance. The results revealed that for the 100 Ω load resistor, the voltage across the capacitor was the maximum at a lower temperature gradient with a charge density of 5.14 × 10 − 3 C m 2 $5.14 \times 10^{-3} \frac{C}{m^2}$ .

Integration of solar cells with hierarchical CoSx nanonets hybrid supercapacitors for self-powered photodetection systems

We have developed a self-powered integration system consisting of a-Si:H solar cells as the energy generation device, CoSx hybrid supercapacitors (HSCs) as the energy storage device and ZnO photodetectors as the energy consumption device. The CoSx HSC plays a crucial role in determining the system performances. By elaborately designing hierachical 3D CoSx nanonets as the faradic electrode, the specific capacity reaches 225 mAh g−1 at a current density of 0.6 A g−1. The HSCs assembled with the CoSx faradic electrode and active carbon capacitive electrode have a high energy density of 32 Wh kg−1, high power density of 6.61 kW kg−1 and long-term cycling lifetime. The CoSx HSC can be charged to 0.85 V by the a-Si:H solar cell under AM 1.5 G illumination and serves as a stable power supply for driving ZnO photodetector. The CoSx HSC not only acts as a buffer to diminish the solar energy fluctuations, but also provides a strategy for designing self-powered detector systems. The integration system exhibits a stable photoelectric conversion, excellent storage characteristic and sensitive photoelectric response, verifying the feasibility and potential applications. This study is expected to offer a basic guideline for designing self-powered and environment-friendly systems.

Solar Redox Flow Batteries with Organic Redox Couples in Aqueous Electrolytes: A Minireview

In recent years, research in solar energy storage with photoelectrochemical cells (i.e., solar redox flow batteries: SRFBs) has resurged. This development is emerging in parallel with the growing field of research into organic redox couples intended for aqueous redox flow batteries (RFBs) in a range of different pH environments. In a solar flow battery, the dissolved electroactive molecules are charged directly from solar radiation by semiconductor photoelectrodes. The charged solution can then at a later stage be converted into electricity, and solar flow batteries are as such an approach to build integrated solar energy generation and storage devices. Research in RFBs and SRFBs has from their beginning been mutually linked by use of the same organic redox molecules in the electrolyte, such as quinones. Despite the long research history (since 1976), metallic-based, acidic SRFBs have shown only incremental development, while research in the use of organic redox pairs appears more promising. This review f...

Dry particle coating preparation of highly conductive LaMnO3@C composite for the oxygen reduction reaction and hydrogen peroxide sensing

Abstract Hydrogen peroxide (H2O2) sensing and oxygen reduction reaction (ORR) has considered to be a highly desirable in the areas of sensing and energy production. In recent years, researchers focus on the replacement of noble metal-based electrocatalyst used for the ORR and H2O2 sensing by low-cost materials. In this current work, we have synthesized carbon black supported LaMnO3 (LMO@C) via dry particle coating method and studied its electrocatalytic activity towards ORR and H2O2 sensing. The characterization of synthesized LMO@C was performed by using field emission scanning electron microscopy (FESEM), energy dispersive X-ray (EDX) spectroscopy, transmission electron microscopy (TEM), X-ray diffraction (XRD) spectroscopy, X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy techniques. Furthermore, the synergistic effect between LMO and carbon was established through electrochemical measurements. In case of ORR, our prepared LMO@C composite possess longer life-time (89.8%) than 20 wt% Pt/C (77.6%). In another case, this electrocatalyst (LMO@C) owns wide working range, low limits of detection and high sensitivity for the determination of H2O2. The experimental data of LMO@C towards the electrochemical sensing of H2O2 and ORR demonstrates its potential applications in the construction of sensors and energy generation devices.

Development of an Ion Exchange Membrane Characterization Protocol

The development of electrochemical devices for electric energy generation has been in constant growth in recent years because environmental challenges provide a driving force for many of today’s studies of electrochemical materials [1], among these are destacable: fuel cells, reverse electrodialysis cells, redox flow batteries, bio electrochemical systems (microbial fuel cells), etc. A key component in the behavior of all of them is the ion exchange membranes, which have high commercial value, so in the development of these technologies the need for local production is presented to make their application cheaper, so its complete characterization is required to determine if they are applicable in these technologies. This paper presents the experimental protocol developed and the results of its application to the membrane characterization of Nafion® 117, material of extended use and which its properties are widely known, in order to validate the methodology proposed with the existing literature . The characterization consists in a series of laboratory tests that deliver the most important properties of the membrane. Initially a pre-treatment of the membrane is carried out to bring it to a reproducible condition and then its properties are measured as conductivity both by a voltammetric method with controlled current and by electrochemical impedance; electroosmotic drag coefficient from measurement of potentials [2], [3], permeability to substances such as ethanol; and thermal stability. It is expected that the proposed protocol and the results obtained will be useful in the characterization of membranes, both protonic and anionic, that are currently being developed in multiple universities and educational centers around the world, as well as at the Universidad Nacional de Colombia - Sede Medellín, to make competitive these energy production technologies that use this type of solid electrolyte [4], [5].

Design of Water Deflection Mechanism for Ocean Current Energy Generation Device

Ocean current energy, as a large reserve and clean energy, has become an important direction for the development of renewable energy. Nowadays, many researches on ocean current energy have focused on the design of different kinds of generators and blades to make efficient use of currents, and there is a lack of research on how to use currents in a wider range. This paper has designed a water guiding mechanism through theoretical analysis and experimental verification, using a wider range of sea currents, increasing the kinetic energy of the impact blade and the blade energy efficiency, and improving the total power generation efficiency of the device. The water guiding mechanism is divided into a cylindrical current collecting and accelerating device, and a gradient tube based on a coupled electromagnetic field. In the current collecting and accelerating part, the cylindrical capacitor is designed, and the inductor coil is wound on it. The alternating current of the two is used to construct a composite electromagnetic field, so that the seawater undergoes deflection acceleration under the action of the electric field force, and the directional movement generates a current. The current is received in the magnetic field, making the water to accelerate the injection, so as to achieve the current acceleration effect. In the gradient tube part, the gradient tube parameters are calculated by the equal-area criterion and the law of energy loss according to the targeted increasing magnification of the flow rate. Large-scale currents flow through the current collecting and accelerating device to produce a convergent and accelerating effect, and then flow into the gradation tube. On the one hand, the velocity increases once more. On the other hand, the gradation tube can reduce the turbulence coefficient that increases due to deflection. A wider range of currents is used.

On a carbon-negative energy production scheme via a quadruple fluidized bed gasifier

To restrain the CO2 concentration in atmosphere, deployment of the carbon-negative energy generation devices is indispensable on account of the vast net carbon discharge every year. In this work, a novel and promising quadruple fluidized bed (QFB) reactor for the biomass/coal co-gasification is proposed to generate the high-quality syngas whilst separate CO2 for further sequestration or utilization. To reveal the fundamental rules governing the reactor, a one dimensional model coupling the gas-solid flow hydrodynamics and the chemical reaction kinetics is built to simulate the physicochemical processes in the QFB, and the effects of several pivotal operation parameters on the reactor performance are comprehensively analyzed. It is found that the QFB runs stably under the given condition. The H2 mole fraction in the dry syngas is higher than 70%, the CO2 mole fraction in the dry flue gas is around 97%, and the net carbon discharge can be negative when the biomass blending ratio is over 0.5. The methodology and findings in this work are of reference value for the lab, pilot or industrial scale QFB designation and operation, and can be extended to develop similar novel reactors for the carbon-negative energy generation.

Nonlinear model predictive control of a vortex-induced vibrations bladeless wind turbine

In this paper, a nonlinear model predictive controller (NMPC) is proposed for a vortex-induced vibrations bladeless wind turbine (BWT). The BWT consists of a long rigid cylinder mounted on a flexible beam. The nonlinear dynamic model of the transverse vibrations of the BWT is obtained under the fluctuating lift force due to periodically shedding vortices. The NMPC method is used to design a controller that achieves maximum energy production rate. It is observed that the power generation of the NMPC drops in high wind speeds due to a mismatch between the vortex shedding frequency and the structural natural frequency. Therefore, a secondary gain-scheduling (GS) controller is proposed to virtually increase the natural frequency of the structure to match the vortex shedding frequency for high winds. Although previous studies predicted the output power of the studied BWT to be less than 100 W, with the proposed GS-NMPC scheme the output power reaches the value of 1 kW. Therefore, the capability of the BWT as a renewable energy generation device was highly underestimated in the literature. The computed values of the aero-mechanical efficiency suggest the BWT as a major competitor to the conventional wind turbines.

ZnO/CuO/M (M = Ag, Au) Hierarchical Nanostructure by Successive Photoreduction Process for Solar Hydrogen Generation.

To date, solar energy generation devices have been widely studied to meet a clean and sustainable energy source. Among them, water splitting photoelectrochemical cell is regarded as a promising energy generation way for splitting water molecules and generating hydrogen by sunlight. While many nanostructured metal oxides are considered as a candidate, most of them have an improper bandgap structure lowering energy transition efficiency. Herein, we introduce a novel wet-based, successive photoreduction process that can improve charge transfer efficiency by surface plasmon effect for a solar-driven water splitting device. The proposed process enables to fabricate ZnO/CuO/Ag or ZnO/CuO/Au hierarchical nanostructure, having an enhanced electrical, optical, photoelectrochemical property. The fabricated hierarchical nanostructures are demonstrated as a photocathode in the photoelectrochemical cell and characterized by using various analytic tools.

(Invited) Surface Engineering of Metal Oxide Photoanodes for Photoelectrochemical Solar Water Splitting

The development of new types of energy generation devices is promoted by increasing public awareness that the Earth's oil reserves could run out during this century. As the energy needs of the planet are likely to double within the next 50 years, the stage is set for a major energy shortage, unless renewable energy can cover the substantial deficit left by fossil fuels. Photoelectrochemical (PEC) solar water splitting has become a central research theme for more than four decades, still, their efficiencies remain low. Despite extensive efforts devoted to modifying photoelectrodes through various bandgap and catalysis engineering, the efficient methodologies for charge transfer at electrode/electrolyte interface remain underdeveloped. In this seminar, I will introduce various unique methods to increase light harvesting efficiency to generate hydrogen from solar light by applying disordered engineering to metal oxide materials. Especially, high efficiency TiO2, WO3, and BiVO4 photoanodes with the modification and charge transfer across the electrode/electrolyte interface will be presented.

Incorporation of Multinuclear Copper Active Sites into Nitrogen-Doped Graphene for Electrochemical Oxygen Reduction

Multinuclear metal active sites are widely used as catalytic reaction centers in metalloenzymes and generally show high catalytic activity. For example, laccases are known to catalyze the oxygen reduction reaction (ORR) to water at a multinuclear copper site with almost no energy loss. The ORR is an important reaction not only in oxygenic respiration but also in future energy generation devices such as polymer electrolyte fuel cells and metal–air batteries. For large-scale commercialization of these devices, there is a need to develop highly active ORR electrocatalysts based on nonprecious metals. Incorporation of multinuclear metal active sites in conductive materials such as carbon will allow us to develop highly active electrocatalysts like metalloenzymes. However, such methods had not been established yet. Herein, we report a copper-based ORR electrocatalyst with multinuclear copper active sites in nitrogen-doped graphene. The electrocatalyst was synthesized from the mixture of graphene oxide and a mu...

Nanoscale mapping of dielectric properties based on surface adhesion force measurements

The detection of local dielectric properties is of great importance in a wide variety of scientific studies and applications. Here, we report a novel method for the characterization of local dielectric distributions based on surface adhesion mapping by atomic force microscopy (AFM). The two-dimensional (2D) materials graphene oxide (GO), and partially reduced graphene oxide (RGO), which have similar thicknesses but large differences in their dielectric properties, were studied as model systems. Through direct imaging of the samples with a biased AFM tip in PeakForce Quantitative Nano-Mechanics (PF-QNM) mode, the local dielectric properties of GO and RGO were revealed by mapping their surface adhesion forces. Thus, GO and RGO could be conveniently differentiated. This method provides a simple and general approach for the fast characterization of the local dielectric properties of graphene-based materials and will further facilitate their applications in energy generation and storage devices.